The geometric structure parameters and radial density distribution of 1s2s1S excited state of the two-electron atomic system near the critical nuclear charge Z_(c)were calculated in detail under tripled Hylleraas basi...The geometric structure parameters and radial density distribution of 1s2s1S excited state of the two-electron atomic system near the critical nuclear charge Z_(c)were calculated in detail under tripled Hylleraas basis set.Contrary to the localized behavior observed in the ground and the doubly excited 2p^(23)Pe states,for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system,the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z_(c).This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.展开更多
The integrated circuit chip with high performance has a high sensitivity to the defects in manufacturing environments.When there are defects on a wafer,the defects may lead to the degradation of chip performance.It is...The integrated circuit chip with high performance has a high sensitivity to the defects in manufacturing environments.When there are defects on a wafer,the defects may lead to the degradation of chip performance.It is necessary to design effective detection approaches for the defects in order to ensure the reliability of wafer.In this paper,a new method based on image boundary extraction is presented for the detection of defects on a wafer.The method uses island model genetic algorithms to perform the segmentation of wafer images,and gets the optimal threshold values.The island model genetic algorithm uses two distinct subpopulations,it is a coarse grain parallel model.The individuals migration can occur between the two subpopulations to share genetic materials.A lot of experimental results show that the defect detection method proposed in this paper can obtain the features of defects effectively.展开更多
It is necessary to perform the test of system on chip,the test scheduling determines the test start and finishing time of every core in the system on chip such that the overall test time is minimized.A new test schedu...It is necessary to perform the test of system on chip,the test scheduling determines the test start and finishing time of every core in the system on chip such that the overall test time is minimized.A new test scheduling approach based on chaotic ant colony algorithm is presented in this paper.The optimization model of test scheduling was studied,the model uses the information such as the scale of test sets of both cores and user defined logic.An approach based on chaotic ant colony algorithm was proposed to solve the optimization model of test scheduling.The test of signal integrity faults such as crosstalk were also investigated when performing the test scheduling.Experimental results on many circuits show that the proposed approach can be used to solve test scheduling problems.展开更多
With the complexity of integrated circuits is continually increasing, a local defect in circuits may cause multiple faults. The behavior of a digital circuit with a multiple fault may significantly differ from that of...With the complexity of integrated circuits is continually increasing, a local defect in circuits may cause multiple faults. The behavior of a digital circuit with a multiple fault may significantly differ from that of a single fault. A new method for the detection of multiple faults in digital circuits is presented in this paper, the method is based on binary decision diagram （BDD）. First of all, the BDDs for the normal circuit and faulty circuit are built respectively. Secondly, a test BDD is obtained by the XOR operation of the BDDs corresponds to normal circuit and faulty circuit. In the test BDD, each input assignment that leads to the leaf node labeled 1 is a test vector of multiple faults. Therefore, the test set of multiple faults is generated by searching for the type of input assignments in the test BDD. Experimental results on some digital circuits show the feasibility of the approach presented in this paper.展开更多
The Si_3N_4 thin film is prepared by MWECR-PECVD at different deposition tem-perature and the structure of the Si_3N_4 thin film is investigated. The results indicate that thestructure of the Si_3N_4 thin film prepare...The Si_3N_4 thin film is prepared by MWECR-PECVD at different deposition tem-perature and the structure of the Si_3N_4 thin film is investigated. The results indicate that thestructure of the Si_3N_4 thin film prepared at low deposition temperature is in the amorphousphase. However, when the deposition temperature increases to 280℃, the Si_3N_4 thin film changesto crystalline α-Si_3N_4. With a further increase of the deposition temperature, the grain of theSi_3N_4 thin film becomes more fine, uniform and flat. XRD analysis shows that the structure ofthe Si_3N_4 thin film prepared at 280℃ is of a crystalline structure.展开更多
Nitrogen ion was implanted into the nano-TiO2 film surfaces by electron cyclotron resonance （ECR） plasma modification to improve the optical reactivity in visible-light region for nano-TiO2. Diagnosing the N2 plasma...Nitrogen ion was implanted into the nano-TiO2 film surfaces by electron cyclotron resonance （ECR） plasma modification to improve the optical reactivity in visible-light region for nano-TiO2. Diagnosing the N2 plasma by optical emission spectroscopy （OES） was applied to the process of plasma modification. X-ray photoelectron spectroscopy （XPS） was used for analysis of the binding of element after plasma modification. It is shown that the surface modification was caused by excitated N. The injecting of N2 and N＋ leads to the increase in the dissociative interstitial state N in the films. The doped N makes for TiO2-xNx appearing in the TiO2 films. TiO2-xNx forms the impurity energy state in the TiO2 energy band gap and reduces the energy band gap. This is the main reason leading to the red shift of absorption edge.展开更多
Complete relativistic corrections of an effective Hamiltonian for a single-particle system in an external electromagnetic field and their unitary equivalent form up to the order of mα^(8) are obtained.The derivation ...Complete relativistic corrections of an effective Hamiltonian for a single-particle system in an external electromagnetic field and their unitary equivalent form up to the order of mα^(8) are obtained.The derivation is based on two approaches applying Foldy-Wouthuysen(FW)transformation to the Dirac Hamiltonian for a particle in an external electromagnetic field.The results are consistent with the previous work at the mα^(6) and mα^(8) order correction[Phys.Rev.A 71012503(2005);Phys.Rev.A 100012513(2019)].We also further consider the effect of anomalous magnetic moments,namely,the Dirac-Pauli equation,and obtain FW-Hamiltonians at the same order.The results obtained can be used for the subsequent calculation of relativistic and radiation effects in simple atomic and molecular systems.展开更多
The main task of system reliability design is to find the best layout of components to maximize reliability or to minimize cost. A reliability optimization approach using neural networks to identify the choice of comp...The main task of system reliability design is to find the best layout of components to maximize reliability or to minimize cost. A reliability optimization approach using neural networks to identify the choice of components in series-parallel systems with multiple constraints is presented in this paper. The McCullochPittes neural network model is used in this approach. The design methods of the neural network construction and its energy function are described in detail. The optimal solutions of the reliability problem are obtained by minimizing the energy function of the neural networks. Simulation results show the reliability optimization approach using neural networks can find the optimal or near-optimal solutions for most of the problems in a relatively short time, it is a useful alternative for system reliability design of complex systems.展开更多
A general solution is obtained to a canonical problem of the reflection and refraction of an arbitrary shaped beam by using a uniaxially anisotropic chiral slab.The reflected,internal as well as refracted shaped beams...A general solution is obtained to a canonical problem of the reflection and refraction of an arbitrary shaped beam by using a uniaxially anisotropic chiral slab.The reflected,internal as well as refracted shaped beams are expanded in terms of cylindrical vector wave functions,and the expansion coefficients are determined by using the boundary conditions and method of moments procedure.As two typical examples,the normalized field intensity distributions are evaluated for a fundamental Gaussian beam and Hermite-Gaussian beam,and some propagation properties,especially the negative refraction phenomenon,are discussed briefly.展开更多
The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamb...The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.展开更多
Zr-based Zr_50Pd_40Al_10 metallic glasses has not only crystalline phases of about 5 nm in diameter but also amorphous phases. In this work, the radial distribution functions(RDFs) of amorphous structure of Zr_50Pd_40...Zr-based Zr_50Pd_40Al_10 metallic glasses has not only crystalline phases of about 5 nm in diameter but also amorphous phases. In this work, the radial distribution functions(RDFs) of amorphous structure of Zr_50Pd_40Al_10 metallic glasses were firstly measured by electron diffraction, and then Reverse Monte Carlo(RMC) optimization accompanied by density functional theory(DFT) calculations. The amorphous structure has not only short-range order but also good medium-range order. In the RDFs of its amorphous structure, the first and the second peaks are located at 2.96 ? and 4.79 ?, respectively. Partial radical distribution functions(PRDFs) show that the contributions of the first and the second nearest-neighbor distances of various atom pairs to the G(r) peak values, and the first nearest-neighbor distances of Pd–Zr and Zr–Zr atom pairs are the sources of main G(r) peak values between 2? and 6?. The competition mechanism for generating the Pd_25Zr_55 Al_20 amorphous phase and the intermetallic crystalline phase Pd_11Zr_9 is associated with the differences of atomic radius, the proportion, and the melting point of different atoms, as well as the heat of mixing between atoms, leading to an equilibrium state of the two phases. Accordingly, a composite system with intertwined nanocrystals and amorphous phases is in turn formed, and improves the stability of the material.展开更多
The interconnect temperature of very large scale integration（VLSI） circuits keeps rising due to self-heating and substrate temperature, which can increase the delay and power dissipation of interconnect wires. The t...The interconnect temperature of very large scale integration（VLSI） circuits keeps rising due to self-heating and substrate temperature, which can increase the delay and power dissipation of interconnect wires. The thermal vias are regarded as a promising method to improve the temperature performance of VLSI circuits. In this paper, the extra thermal vias were used to decrease the delay and power dissipation of interconnect wires of VLSI circuits. Two analytical models were presented for interconnect temperature, delay and power dissipation with adding extra dummy thermal vias. The influence of the number of thermal vias on the delay and power dissipation of interconnect wires was analyzed and the optimal via separation distance was investigated. The experimental results show that the adding extra dummy thermal vias can reduce the interconnect average temperature, maximum temperature, delay and power dissipation. Moreover, this method is also suitable for clock signal wires with a large root mean square current.展开更多
Chiral structures are promising in many applications,such as biological sensing and analytical chemistry,and have been extensively explored.In this paper,we theoretically investigate the chiral response of twisted bil...Chiral structures are promising in many applications,such as biological sensing and analytical chemistry,and have been extensively explored.In this paper,we theoretically investigate the chiral response of twisted bilayerα-MoO_(3).Firstly,the analytical formula for the transmissivity is derived when the structure is illuminated with circularly polarized plane waves.Furthermore,the results demonstrate that the twisted bilayerα-MoO_(3)can excite the strong chirality with the maximum circular dichroism(CD)of 0.89.In this case,the chirality is due to the simultaneous breaking the rotational symmetry and mirror symmetry,which originates from the relative rotation of twoα-MoO_(3)layers.To better understand the physical mechanism,the polarization conversion between the left-hand circular polarization(LCP)and right-hand circular polarization(RCP)waves is discussed as well.Moreover,it is found that the structure can maintain the strong chirality(CD>0.8)when the twisted angle varies from 69°to 80°,which effectively reduces the strictness in the requirement for rotation angle.In addition,the CD can be larger than 0.85 when the incidence angle of circularly polarized plane wave is less than 40°,implying that the chirality is robust against the angle of incidence.Our work not only provides an insight into chirality induced by the twisted bilayerα-MoO_(3),but also looks forward to applications in biolo gical sensing.展开更多
To meet the range requirements of electric vehicles,the lithium nickel-rich manganese cobalt oxides(nickel-rich LiNi_(x)Mn_(y)Co_(1-x-y)O_(2);x≥0.5 or NMC)material is a promising contender due to its superior energy ...To meet the range requirements of electric vehicles,the lithium nickel-rich manganese cobalt oxides(nickel-rich LiNi_(x)Mn_(y)Co_(1-x-y)O_(2);x≥0.5 or NMC)material is a promising contender due to its superior energy and power density.Commercial polycrystalline nickel-rich NMC(PC-NMC)materials typically exhibit layered structures in which primary particles aggregate to form secondary particles to increase the contact area density.Thereby increasing the cathode energy density.However,PC-NMC materials present a number of challenges in terms of cycle life and thermal stability,many of which stem from their extensive surface area,including severe surface phase transitions,intergranular microcracks,oxygen evolution,and transition metal dissolution.To address these challenges,single-crystal NMC(SCNMC)materials were introduced,which exhibited higher capacity retention and thermal robustness owing to their unique structures,characterized by lower active surface area and heightened mechanical strength.Nevertheless,SC-NMC materials also had their own problems,including sluggish Li+bulk diffusion kinetics and nonuniform distribution of lattice strain,as well as their complex high-temperature calcination process.This review concentrates on discussing the merits and demerits of SC-NMC over PC-NMC materials and introduces the current research efforts aimed at improving the electrochemical performance of SC-NMC.展开更多
With the continuous advancement of semiconductor technology, the interconnects crosstalk has had a great influence on the performances of VLSI circuits. To date, most of the research about the interconnects of VLSI ci...With the continuous advancement of semiconductor technology, the interconnects crosstalk has had a great influence on the performances of VLSI circuits. To date, most of the research about the interconnects of VLSI circuits focus on the voltage-mode signaling （VMS） scheme while the current-mode signaling （CMS） scheme is rarely analyzed. First of all, an equivalent circuit model of two-line coupled interconnects is presented in this paper, which is applicable to both the CMS and VMS schemes. The coupling capacitive and mutual inductive are taken into account in the equivalent circuit model. Secondly, the output noise of CMS and VMS schemes are investigated in the paper according to the decoupling technique and A B CD parameter matrix approach at local level, intermediate level and global level, respectively. Moreover, the experimental results show that the CMS interconnects have lesser noise peak, noise width and noise amplitude than the VMS interconnects in the same cases, and the CMS scheme is especially suitable for the global interconnects communication of VLSI circuits. It is found that the results obtained by A B CD parameter matrix approach are in good accordance with the simulation results of the advanced design system.展开更多
Zinc oxide（ZnO） microrod arrays were synthesized on Si substrate by a vapor phase transport（VPT） method in a tube furnace.The obtained ZnO microrods are characterized by scanning electron microscopy（SEM） and X-r...Zinc oxide（ZnO） microrod arrays were synthesized on Si substrate by a vapor phase transport（VPT） method in a tube furnace.The obtained ZnO microrods are characterized by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The photoluminescence（PL） measurement indicates that the ZnO microrods have a strong ultraviolet（UV） emission centered at ~391 nm and a defect-related emission centered at ~530 nm.After the microrods were coated with graphene oxide（GO）,the PL intensity of the hybrid microstructure is quenched compared with that of the bare one at the same excitation condition,and the PL intensity changes with the concentration of the GO.The fluorescence quenching mechanism is also discussed in this work.展开更多
In the framework of the left-right twin Higgs(LRTH) model, we study the Higgs boson and single top quark associated production at the LHC. We investigate the processes pp → thj, pp → thˉb and pp → th W at the 8(14...In the framework of the left-right twin Higgs(LRTH) model, we study the Higgs boson and single top quark associated production at the LHC. We investigate the processes pp → thj, pp → thˉb and pp → th W at the 8(14) Te V LHC and find that the production cross sections of the three processes can be enhanced at different levels. Among them,the production cross section of the process pp → thˉb is enhanced significantly due to the contribution of the new particles predicted by the LRTH model.展开更多
New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model,which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider(LHC).Based on a mo...New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model,which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider(LHC).Based on a model-independent framework,we propose to search for the vectorlike B-quark(VLQ-B)and focus on resonant production via b-gluon fusion through chromomagnetic interactions.We then explore the possible signals of the VLQ-B through the B→tW decay mode at the 14 TeV LHC.After a rapid simulation of signal and background events,the 2σ excluded regions and the 5σdiscovery reach in the parameter plane of k_(B)-M_(B)are obtained at the LHC with an integrated luminosity of 300(3000)fb^(-1)in the dilepton final states.展开更多
The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot o...The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot of advantages such as high speed information processing.Small perturbations in the manufacturing of GaAs materials can lead to defects.The defects in the GaAs materials can degrade the performance of materials.A new method is presented in this paper for detecting the micro-defects in GaAs materials by using time resolved emissions.In this method,the micro-defects in GaAs materials are detected by making use of the photon emission features of microdefects.The strength of the emitted photons from the micro-defects is increased by applying the electric current or the periodic pulse signals to GaAs materials.The singlephoton detector is used to detect the photon emissions of the micro-defects.The time resolved photon emissions and single-photon detection are used to record and compare the amounts of the emitted photons that come from the given regions of the normal GaAs materials and the defective GaAs materials.A lot of experimental results show that the micro-defects in the GaAs materials can be detected by using the method proposed in this paper.展开更多
Collaborative enhancements from surface plasmons （SPs） and whispering-gallery modes （WGMs） can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One ...Collaborative enhancements from surface plasmons （SPs） and whispering-gallery modes （WGMs） can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One can construct a highly efficient hybrid microcavity using semiconducting materials through resonant coupling between SPs and WGMs. Hexagonal ZnO micro-/nanostructures, which have been employed as natural WGM microcavities for ultraviolet （UV） lasing, can be used as ideal platforms to construct such hybrid microcavities. Here, we comprehensively review the recent efforts for improving lasing performance by resonant coupling between SPs and WGMs. Traditional SPs originating from various metals as well as novel SPs originating from atomic layers such as graphene are considered. Moreover, we discuss the mechanism of light-matter interactions beyond the improvements in lasing performance.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12074295,12304271,and 12104420).
文摘The geometric structure parameters and radial density distribution of 1s2s1S excited state of the two-electron atomic system near the critical nuclear charge Z_(c)were calculated in detail under tripled Hylleraas basis set.Contrary to the localized behavior observed in the ground and the doubly excited 2p^(23)Pe states,for this state our results identify that while the behavior of the inner electron increasingly resembles that of a hydrogen-like atomic system,the outer electron in the excited state exhibits diffused hydrogen-like character and becomes perpendicular to the inner electron as nuclear charge Z approaches Z_(c).This study provides insights into the electronic structure and stability of the two-electron system in the vicinity of the critical nuclear charge.
基金supported by Guangdong Provincial Natural Science Foundation of China (7005833)
文摘The integrated circuit chip with high performance has a high sensitivity to the defects in manufacturing environments.When there are defects on a wafer,the defects may lead to the degradation of chip performance.It is necessary to design effective detection approaches for the defects in order to ensure the reliability of wafer.In this paper,a new method based on image boundary extraction is presented for the detection of defects on a wafer.The method uses island model genetic algorithms to perform the segmentation of wafer images,and gets the optimal threshold values.The island model genetic algorithm uses two distinct subpopulations,it is a coarse grain parallel model.The individuals migration can occur between the two subpopulations to share genetic materials.A lot of experimental results show that the defect detection method proposed in this paper can obtain the features of defects effectively.
基金supported by Guangdong Provincial Natural Science Foundation of China (7005833)
文摘It is necessary to perform the test of system on chip,the test scheduling determines the test start and finishing time of every core in the system on chip such that the overall test time is minimized.A new test scheduling approach based on chaotic ant colony algorithm is presented in this paper.The optimization model of test scheduling was studied,the model uses the information such as the scale of test sets of both cores and user defined logic.An approach based on chaotic ant colony algorithm was proposed to solve the optimization model of test scheduling.The test of signal integrity faults such as crosstalk were also investigated when performing the test scheduling.Experimental results on many circuits show that the proposed approach can be used to solve test scheduling problems.
基金Supported by the National Natural Science Foun-dation of China (60006002) Natural Science Research Project of Education Department of Guangdong Province of China (02019)
文摘With the complexity of integrated circuits is continually increasing, a local defect in circuits may cause multiple faults. The behavior of a digital circuit with a multiple fault may significantly differ from that of a single fault. A new method for the detection of multiple faults in digital circuits is presented in this paper, the method is based on binary decision diagram （BDD）. First of all, the BDDs for the normal circuit and faulty circuit are built respectively. Secondly, a test BDD is obtained by the XOR operation of the BDDs corresponds to normal circuit and faulty circuit. In the test BDD, each input assignment that leads to the leaf node labeled 1 is a test vector of multiple faults. Therefore, the test set of multiple faults is generated by searching for the type of input assignments in the test BDD. Experimental results on some digital circuits show the feasibility of the approach presented in this paper.
基金The project supported by the Natural Science Foundation of Guangdong province (No. 000675)
文摘The Si_3N_4 thin film is prepared by MWECR-PECVD at different deposition tem-perature and the structure of the Si_3N_4 thin film is investigated. The results indicate that thestructure of the Si_3N_4 thin film prepared at low deposition temperature is in the amorphousphase. However, when the deposition temperature increases to 280℃, the Si_3N_4 thin film changesto crystalline α-Si_3N_4. With a further increase of the deposition temperature, the grain of theSi_3N_4 thin film becomes more fine, uniform and flat. XRD analysis shows that the structure ofthe Si_3N_4 thin film prepared at 280℃ is of a crystalline structure.
基金the Guangdong Provincial Natural Science Foundation under grant No. 031502.
文摘Nitrogen ion was implanted into the nano-TiO2 film surfaces by electron cyclotron resonance （ECR） plasma modification to improve the optical reactivity in visible-light region for nano-TiO2. Diagnosing the N2 plasma by optical emission spectroscopy （OES） was applied to the process of plasma modification. X-ray photoelectron spectroscopy （XPS） was used for analysis of the binding of element after plasma modification. It is shown that the surface modification was caused by excitated N. The injecting of N2 and N＋ leads to the increase in the dissociative interstitial state N in the films. The doped N makes for TiO2-xNx appearing in the TiO2 films. TiO2-xNx forms the impurity energy state in the TiO2 energy band gap and reduces the energy band gap. This is the main reason leading to the red shift of absorption edge.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074295 and 12104420)。
文摘Complete relativistic corrections of an effective Hamiltonian for a single-particle system in an external electromagnetic field and their unitary equivalent form up to the order of mα^(8) are obtained.The derivation is based on two approaches applying Foldy-Wouthuysen(FW)transformation to the Dirac Hamiltonian for a particle in an external electromagnetic field.The results are consistent with the previous work at the mα^(6) and mα^(8) order correction[Phys.Rev.A 71012503(2005);Phys.Rev.A 100012513(2019)].We also further consider the effect of anomalous magnetic moments,namely,the Dirac-Pauli equation,and obtain FW-Hamiltonians at the same order.The results obtained can be used for the subsequent calculation of relativistic and radiation effects in simple atomic and molecular systems.
基金Supported by the National Natural Science Foundation of China (60006002) and Natural Science Research Project of Education Depart-ment of Guangdong Province of China (02019)
文摘The main task of system reliability design is to find the best layout of components to maximize reliability or to minimize cost. A reliability optimization approach using neural networks to identify the choice of components in series-parallel systems with multiple constraints is presented in this paper. The McCullochPittes neural network model is used in this approach. The design methods of the neural network construction and its energy function are described in detail. The optimal solutions of the reliability problem are obtained by minimizing the energy function of the neural networks. Simulation results show the reliability optimization approach using neural networks can find the optimal or near-optimal solutions for most of the problems in a relatively short time, it is a useful alternative for system reliability design of complex systems.
基金Project supported by the National Natural Science Foundation of China(Grant No.61771385)the Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(Grant No.2020JC-42)+1 种基金the Fund from the Science and Technology on Solid-State Laser Laboratory,China(Grant No.6142404180301)the Science and Technology Research Plan of Xi’an City,China(Grant No.GXYD14.26).
文摘A general solution is obtained to a canonical problem of the reflection and refraction of an arbitrary shaped beam by using a uniaxially anisotropic chiral slab.The reflected,internal as well as refracted shaped beams are expanded in terms of cylindrical vector wave functions,and the expansion coefficients are determined by using the boundary conditions and method of moments procedure.As two typical examples,the normalized field intensity distributions are evaluated for a fundamental Gaussian beam and Hermite-Gaussian beam,and some propagation properties,especially the negative refraction phenomenon,are discussed briefly.
基金The project supported by the Natural Science Foundation of Guangdong province (No. 000675) the Key project tackled of Guangdong province (ZKM01401G)
文摘The ion density distribution in the reaction chamber was diagnosed by a Langmuir probe. The rules of the ion density distribution were obtained under the pressures of 9 Pa, 13 Pa, 27 Pa and 53 Pa in the reaction chamber, different radio-frequency powers and different positions. The result indicates that the ion density decreases as the pressure increases, and increases as the power decreases. The ion density of axial position z =0 achieves 5.8×1010 on the center of coil under the power of 200 w and pressure of 9 Pa in the reaction chamber.
基金supported by National Science Fund for Excellent Young Scholars of China (No. 51422203)the National Natural Science Foundation of China (Nos. 51572091 and 51372001)+4 种基金the Natural Science Foundation of Guangdong Province, China (No. 2018A030313395)the China Postdoctoral Science Foundation (No. 2017M610522)the Science and Technology Program of Guangzhou, China (No. 201604046027)the Fundamental Research Funds for the Central Universities (No. 2017BQ035)the fund of the State Key Laboratory of Solidification Processing in NWPU (No. SKLSP201716)
文摘Zr-based Zr_50Pd_40Al_10 metallic glasses has not only crystalline phases of about 5 nm in diameter but also amorphous phases. In this work, the radial distribution functions(RDFs) of amorphous structure of Zr_50Pd_40Al_10 metallic glasses were firstly measured by electron diffraction, and then Reverse Monte Carlo(RMC) optimization accompanied by density functional theory(DFT) calculations. The amorphous structure has not only short-range order but also good medium-range order. In the RDFs of its amorphous structure, the first and the second peaks are located at 2.96 ? and 4.79 ?, respectively. Partial radical distribution functions(PRDFs) show that the contributions of the first and the second nearest-neighbor distances of various atom pairs to the G(r) peak values, and the first nearest-neighbor distances of Pd–Zr and Zr–Zr atom pairs are the sources of main G(r) peak values between 2? and 6?. The competition mechanism for generating the Pd_25Zr_55 Al_20 amorphous phase and the intermetallic crystalline phase Pd_11Zr_9 is associated with the differences of atomic radius, the proportion, and the melting point of different atoms, as well as the heat of mixing between atoms, leading to an equilibrium state of the two phases. Accordingly, a composite system with intertwined nanocrystals and amorphous phases is in turn formed, and improves the stability of the material.
基金Supported by the Guangdong Provincial Natural Science Foundation of China(2014A030313441)the Guangzhou Science and Technology Project(201510010169)+1 种基金the Guangdong Province Science and Technology Project(2016B090918071,2014A040401076)the National Natural Science Foundation of China(61072028)
文摘The interconnect temperature of very large scale integration（VLSI） circuits keeps rising due to self-heating and substrate temperature, which can increase the delay and power dissipation of interconnect wires. The thermal vias are regarded as a promising method to improve the temperature performance of VLSI circuits. In this paper, the extra thermal vias were used to decrease the delay and power dissipation of interconnect wires of VLSI circuits. Two analytical models were presented for interconnect temperature, delay and power dissipation with adding extra dummy thermal vias. The influence of the number of thermal vias on the delay and power dissipation of interconnect wires was analyzed and the optimal via separation distance was investigated. The experimental results show that the adding extra dummy thermal vias can reduce the interconnect average temperature, maximum temperature, delay and power dissipation. Moreover, this method is also suitable for clock signal wires with a large root mean square current.
基金Project supported by the Training Program of the Major Research Plan of the National Natural Science Foundation of China(Grant No.92052106)the National Natural Science Foundation of China(Grant Nos.61771385 and 52106099)+4 种基金the Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(Grant No.2020JC-42)the Science and Technology on Solid-State Laser Laboratory,China(Grant No.6142404190301)the Science and Technology Research Plan of Xi'an City,China(Grant No.GXYD 14.26)the Shandong Provincial Natural Science Foundation,China(Grant No.ZR2020LLZ004)the Start-Up Funding of Guangdong Polytechnic Normal University,China(Gtrant No.2021SDKYA033)。
文摘Chiral structures are promising in many applications,such as biological sensing and analytical chemistry,and have been extensively explored.In this paper,we theoretically investigate the chiral response of twisted bilayerα-MoO_(3).Firstly,the analytical formula for the transmissivity is derived when the structure is illuminated with circularly polarized plane waves.Furthermore,the results demonstrate that the twisted bilayerα-MoO_(3)can excite the strong chirality with the maximum circular dichroism(CD)of 0.89.In this case,the chirality is due to the simultaneous breaking the rotational symmetry and mirror symmetry,which originates from the relative rotation of twoα-MoO_(3)layers.To better understand the physical mechanism,the polarization conversion between the left-hand circular polarization(LCP)and right-hand circular polarization(RCP)waves is discussed as well.Moreover,it is found that the structure can maintain the strong chirality(CD>0.8)when the twisted angle varies from 69°to 80°,which effectively reduces the strictness in the requirement for rotation angle.In addition,the CD can be larger than 0.85 when the incidence angle of circularly polarized plane wave is less than 40°,implying that the chirality is robust against the angle of incidence.Our work not only provides an insight into chirality induced by the twisted bilayerα-MoO_(3),but also looks forward to applications in biolo gical sensing.
基金supported financially by the following institutions:the Start-Up Research Funding of the University of Science and Technology,Beijing,China,the National Natural Science Foundation of China(grant no.52102204)the Natural Science Foundation of China(grant no.22309179)+2 种基金Natural Sciences and Engineering Research Council of Canada,University of Waterloo,Canada,and theWaterloo Institute for Nanotechnology,Canada,the Strategic Priority Research Program of the Chinese Academy of Sciences,China(grant no.XDB0600100)the Start-Up Research Funding of ZhouKou Normal University,China(grant no.ZKNUC2022016)the Scientific Research Projects of Universities in Henan Province,China(grant no.24B140017).
文摘To meet the range requirements of electric vehicles,the lithium nickel-rich manganese cobalt oxides(nickel-rich LiNi_(x)Mn_(y)Co_(1-x-y)O_(2);x≥0.5 or NMC)material is a promising contender due to its superior energy and power density.Commercial polycrystalline nickel-rich NMC(PC-NMC)materials typically exhibit layered structures in which primary particles aggregate to form secondary particles to increase the contact area density.Thereby increasing the cathode energy density.However,PC-NMC materials present a number of challenges in terms of cycle life and thermal stability,many of which stem from their extensive surface area,including severe surface phase transitions,intergranular microcracks,oxygen evolution,and transition metal dissolution.To address these challenges,single-crystal NMC(SCNMC)materials were introduced,which exhibited higher capacity retention and thermal robustness owing to their unique structures,characterized by lower active surface area and heightened mechanical strength.Nevertheless,SC-NMC materials also had their own problems,including sluggish Li+bulk diffusion kinetics and nonuniform distribution of lattice strain,as well as their complex high-temperature calcination process.This review concentrates on discussing the merits and demerits of SC-NMC over PC-NMC materials and introduces the current research efforts aimed at improving the electrochemical performance of SC-NMC.
基金supported by the Guangdong Provincial Natural Science Foundation of China(No.2014A030313441)the Guangzhou Science and Technology Project(No.201510010169)+1 种基金the Guangdong Province Science and Technology Project(No.2016B090918071)the National Natural Science Foundation of China(No.61072028)
文摘With the continuous advancement of semiconductor technology, the interconnects crosstalk has had a great influence on the performances of VLSI circuits. To date, most of the research about the interconnects of VLSI circuits focus on the voltage-mode signaling （VMS） scheme while the current-mode signaling （CMS） scheme is rarely analyzed. First of all, an equivalent circuit model of two-line coupled interconnects is presented in this paper, which is applicable to both the CMS and VMS schemes. The coupling capacitive and mutual inductive are taken into account in the equivalent circuit model. Secondly, the output noise of CMS and VMS schemes are investigated in the paper according to the decoupling technique and A B CD parameter matrix approach at local level, intermediate level and global level, respectively. Moreover, the experimental results show that the CMS interconnects have lesser noise peak, noise width and noise amplitude than the VMS interconnects in the same cases, and the CMS scheme is especially suitable for the global interconnects communication of VLSI circuits. It is found that the results obtained by A B CD parameter matrix approach are in good accordance with the simulation results of the advanced design system.
基金supported by the National Natural Science Foundation of China(Nos.1140428911404328 and 11547227)+1 种基金the Key Technologies R&D Program of Henan Province(No.142102210642)the High-level Talents Research and Startup Foundation Projects for Doctors of Zhoukou Normal University(No.ZKNU2015104)
文摘Zinc oxide（ZnO） microrod arrays were synthesized on Si substrate by a vapor phase transport（VPT） method in a tube furnace.The obtained ZnO microrods are characterized by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The photoluminescence（PL） measurement indicates that the ZnO microrods have a strong ultraviolet（UV） emission centered at ~391 nm and a defect-related emission centered at ~530 nm.After the microrods were coated with graphene oxide（GO）,the PL intensity of the hybrid microstructure is quenched compared with that of the bare one at the same excitation condition,and the PL intensity changes with the concentration of the GO.The fluorescence quenching mechanism is also discussed in this work.
基金Supported by the National Natural Science Foundation of China under Grant No.U1404113the Aid Project for the Mainstay Young Teachers in Henan Provincial Institutions of Higher Education of China under Grant Nos.2016GGJS-135,2014GGJS-283Colleges and Universities in Henan Province Key Scientific Research Project for 2016(16B140002)
文摘In the framework of the left-right twin Higgs(LRTH) model, we study the Higgs boson and single top quark associated production at the LHC. We investigate the processes pp → thj, pp → thˉb and pp → th W at the 8(14) Te V LHC and find that the production cross sections of the three processes can be enhanced at different levels. Among them,the production cross section of the process pp → thˉb is enhanced significantly due to the contribution of the new particles predicted by the LRTH model.
基金Supported by the Foundation of the Key Research Projects in Universities of Henan(22A140019)the Natural Science Foundation of Henan Province(222300420443)the Project of Innovation and Entrepreneurship Training for College Students in Henan Province(S202110478024)。
文摘New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model,which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider(LHC).Based on a model-independent framework,we propose to search for the vectorlike B-quark(VLQ-B)and focus on resonant production via b-gluon fusion through chromomagnetic interactions.We then explore the possible signals of the VLQ-B through the B→tW decay mode at the 14 TeV LHC.After a rapid simulation of signal and background events,the 2σ excluded regions and the 5σdiscovery reach in the parameter plane of k_(B)-M_(B)are obtained at the LHC with an integrated luminosity of 300(3000)fb^(-1)in the dilepton final states.
基金supported by the National Natural Science Foundation of China (61072028)the Project of Department of Education of Guangdong Province (2012KJCX0040)Guangdong Province and Chinese Ministry of Education Cooperation Project of Industry,Education and Academy (2009B090300339)
文摘The GaAs material is a major semiconductor material,and it has high electron transfer rate and direct transition energy band structure.The devices and integrated circuits fabricated on the GaAs substrates have a lot of advantages such as high speed information processing.Small perturbations in the manufacturing of GaAs materials can lead to defects.The defects in the GaAs materials can degrade the performance of materials.A new method is presented in this paper for detecting the micro-defects in GaAs materials by using time resolved emissions.In this method,the micro-defects in GaAs materials are detected by making use of the photon emission features of microdefects.The strength of the emitted photons from the micro-defects is increased by applying the electric current or the periodic pulse signals to GaAs materials.The singlephoton detector is used to detect the photon emissions of the micro-defects.The time resolved photon emissions and single-photon detection are used to record and compare the amounts of the emitted photons that come from the given regions of the normal GaAs materials and the defective GaAs materials.A lot of experimental results show that the micro-defects in the GaAs materials can be detected by using the method proposed in this paper.
文摘Collaborative enhancements from surface plasmons （SPs） and whispering-gallery modes （WGMs） can induce intense near-field effects with high spatial localization around the surface of a semiconducting material. One can construct a highly efficient hybrid microcavity using semiconducting materials through resonant coupling between SPs and WGMs. Hexagonal ZnO micro-/nanostructures, which have been employed as natural WGM microcavities for ultraviolet （UV） lasing, can be used as ideal platforms to construct such hybrid microcavities. Here, we comprehensively review the recent efforts for improving lasing performance by resonant coupling between SPs and WGMs. Traditional SPs originating from various metals as well as novel SPs originating from atomic layers such as graphene are considered. Moreover, we discuss the mechanism of light-matter interactions beyond the improvements in lasing performance.
