The recently published study by Duan et al introduces a promising method that combines genomic instability and long non-coding RNAs to improve the prognostic evaluation of hepatocellular carcinoma(HCC),a deadly cancer...The recently published study by Duan et al introduces a promising method that combines genomic instability and long non-coding RNAs to improve the prognostic evaluation of hepatocellular carcinoma(HCC),a deadly cancer associated with considerable morbidity and mortality.This editorial aims to analyze the methodology,key findings,and broader implications of the study within the fields of gastroenterology and oncological surgery,highlighting the shift towards precision medicine in the management of HCC.展开更多
A geomagnetic storm is a global disturbance of Earth?s magnetosphere,occurring as a result of the interaction with magnetic plasma ejected from the Sun.Despite considerable research,a comprehensive classification of s...A geomagnetic storm is a global disturbance of Earth?s magnetosphere,occurring as a result of the interaction with magnetic plasma ejected from the Sun.Despite considerable research,a comprehensive classification of storms for a complete solar cycle has not yet been fully developed,as most previous studies have been limited to specific storm types.This study,therefore,attempted to present complete statistics for solar cycle 24,detailing the occurrence of geomagnetic storm events and classifying them by type of intensity(moderate,intense,and severe),type of complete interval(normal or complex),duration of the recovery phase(rapid or long),and the number of steps in the storm?s development.The analysis was applied to data from ground-based magnetometers,which measured the Dst index as provided by the World Data Center for Geomagnetism,Kyoto,Japan.This study identified 211 storm events,comprising moderate(177 events),intense(33 events),and severe(1 event)types.About 36%of ICMEs and 23%of CIRs are found to be geoeffective,which caused geomagnetic storms.Up to four-step development of geomagnetic storms was exhibited during the main phase for this solar cycle.Analysis showed the geomagnetic storms developed one or more steps in the main phase,which were probably related to the driver that triggered the geomagnetic storms.A case study was additionally conducted to observe the variations of the ionospheric disturbance dynamo(Ddyn)phenomenon that resulted from the geomagnetic storm event of 2015July 13.The attenuation of the Ddyn in the equatorial region was analyzed using the H component of geomagnetic field data from stations in the Asian sector(Malaysia and India).The variations in the Ddyn signatures were observed at both stations,with the TIR station(India)showing higher intensity than the LKW station(Malaysia).展开更多
What is sustainability? Does it only concern the environment or even socio-economic policies? It is only a question of ethics or a redefinition of industrial policy oriented towards the use of renewable energy, it can...What is sustainability? Does it only concern the environment or even socio-economic policies? It is only a question of ethics or a redefinition of industrial policy oriented towards the use of renewable energy, it can bring benefits both atmospheric and social employment. The need for the development of renewable sources can be in tune with the correct management of the territory in consideration of the fact that these sources involve the widespread implementation of small and medium-sized plants. A model of economic development based on renewable sources should respect the peculiarities and characteristics of the territories involved. It should also think of the territory as a “value” to be strengthened and used in a sustainable and integrated way and no longer as a passive platform on which to install plants. Solar thermal and photovoltaic, biomass, geothermal, hydrological, wind power are some of the sources the various countries must constantly invest. This publication is based on these concepts starting from an analysis of the employment data of the OECD “Organisation for Economic Co-operation and Development countries”, comparing them successively with the results of renewable energy productivity. The analysis was performed by analyzing a sample of 22 countries over a period of 20 years, after which the regression curve for the variables with the OLS method was created. This econometric method has allowed us to analyze the impact that renewable technologies have on the parameters of social welfare and in particular on unemployment.展开更多
In the banking system, a context characterized by growing instability and by the speed of evolution of business dynamics, the system of corporate governance plays a key role, both for large banks and for banks with a ...In the banking system, a context characterized by growing instability and by the speed of evolution of business dynamics, the system of corporate governance plays a key role, both for large banks and for banks with a smaller size. The paper aims to investigate the influence of corporate governance of the banks that operate in the cooperative credit system on performance and quality of loans, over the years 2010-2011-2012. In order to achieve this aim, the following research hypotheses have been formulated： There is a statistically significant relationship between the size and the structure of the board and banks Performance operating in the cooperative credit system; there is a statistically significant relationship between the size and structure of the board and the credit quality of banks operating in the cooperative credit system. The analysis is conducted on a sample composed of 48 Italian banks, divided into 24 cooperative banks and 24 popular banks. The sample is made up of banks from all over Italy and very different in terms of dimension. For the sample construction, data relative to governance of banks were collected from the balance sheets in the period from June to August 2014. Financial-economic data were collected from the Financial Statements and from Bankscope database. The methodology of analysis is based on multivariate OLS （ordinary least squares） regression models. The main results refer to the presence of significant relationships between board dimension and the quality of loans and among the number of committees and performance and the quality of loans. The presence of a significant and negative relationship between the board dimension and the ratio of impaired loans to gross loans indicates the possibility that enlargement of board dimension allows a better quality of loans. The presence of a positive relationship between the number of committees and the ratio of impaired loans to gross loans signals the possibility that a greater number of committees can produce a worse quality of loans. The presence of a negative relationship between the number of committees and bank performance suggests to limit and manage the complexity of governance in banks operating in the cooperative credit system.展开更多
The work investigates the use of trade credit in Italy for reasons of a financial nature. The analysis considers Italian small and medium-sized enterprises （SMEs） and investigates, over the years of 2009-2011： the ...The work investigates the use of trade credit in Italy for reasons of a financial nature. The analysis considers Italian small and medium-sized enterprises （SMEs） and investigates, over the years of 2009-2011： the existence of functional relationships between the incidence of trade receivables and payables and corporate profitability; the existence of interdependencies between trade credit policy and trade debt policy; and the coexistence of interchangeable and complementary conditions between trade debts and bank loans and other sources of funding. To verify the research hypotheses, linear regression models on a yearly basis are used and these models are put under observation over the years of 2009-2011. We can conclude that there are interdependencies between trade credit policy and trade debt policy and that trade credit is a source of flexible way of financing, also available in periods of crisis, which has a positive effect on the profitability of SMEs and can be utilized as a complementary and substitute source of financing to bank loans.展开更多
In the following article, the “Satisfaction with the Environmental Condition” in the 20 Italian regions between 2004 and 2020 was estimated using ISTAT-BES data. The data were analyzed using the following econometri...In the following article, the “Satisfaction with the Environmental Condition” in the 20 Italian regions between 2004 and 2020 was estimated using ISTAT-BES data. The data were analyzed using the following econometric techniques, namely: Panel Data with Random Effects, Panel Data with Fixed Effects, Dynamic Panel, Pooled OLS, WLS. The results show that satisfaction with the environmental situation is positively associated with the following variables “People with at least high school diploma”, “Satisfaction with leisure time”, “Concern for the deterioration of the landscape” and negatively associated with “Gross disposable income per capita”, “Dissatisfaction with the landscape of the place of life”, “Perception of the risk of crime”. A cluster analysis was then carried out using the unsupervised k-Means algorithm optimized through the Silhouette coefficient and 3 clusters were found. A comparative analysis was then carried out between eight different machine learning algorithms to predict the trend of satisfaction by environmental situation. The analysis showed that the Tree Ensemble Regression algorithm is the best predictor and estimates a reduction of the variable of 0.05%. Subsequently, using augmented data, a further prediction was made with an estimated result equal to -1.93%.展开更多
Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort...Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort after surgery. Aim: The aim of this study was to explore patient reported discomfort, pain and functional decrease two hours, 24 hours and four weeks after laparoscopic resection of the colon in the prone lithotomy position, as well as factors potentially associated with reported pain. Methods: A longitudinal self-report questionnaire study was conducted at three time-points. Results: A total of 37 patients responded. Findings show that patients mostly reported pain in relation to the surgical area, but also related to other areas that may be linked to positioning. Conclusion: Even though patients reported mild pain, several of the patients still reported this, four weeks postoperatively, as well as some functional decrease. Our findings support the need to focus on preventing positioning injuries.展开更多
We fabricate Fe3O4 thin films on Si（100） substrates at different temperatures using pulsed laser deposition, and study the effect of annealing and deposition temperature on the structural and magnetic properties of ...We fabricate Fe3O4 thin films on Si（100） substrates at different temperatures using pulsed laser deposition, and study the effect of annealing and deposition temperature on the structural and magnetic properties of Fe3O4 thin films. Subsequently, the films are characterized by x-ray diffraction （XRD）, scanning electron microscopy （SEM） and vibrating sample magnetometery （VSM）. The XRD results of these films confirm the presence of the Fe3O4 phase and show room-temperature ferromagnetism, as observed with VSM. We demonstrate the optimized deposition and annealing conditions for an enhanced magnetization of 854 emu/cm3 that is very high when compared to the bulk sample.展开更多
Single-phase Zn_(0.95)Co_(0.05)O and Zn_(0.90)Co_(0.05)Al_(0.05)O samples were prepared by a novel combustion method.Xray diffraction studies exhibit the pure phase wurtzite structure of doped ZnO.Energy dispersive x-...Single-phase Zn_(0.95)Co_(0.05)O and Zn_(0.90)Co_(0.05)Al_(0.05)O samples were prepared by a novel combustion method.Xray diffraction studies exhibit the pure phase wurtzite structure of doped ZnO.Energy dispersive x-ray analysis confirms the incorporation of dopants into the host material.Scanning electron microscopy shows the ordered morphology in both of the samples.Temperature-dependent resistivity analysis describes the expected semiconducting behavior that is similar to the parent ZnO materials.Room-temperature magnetic measurements reveal the absence of ferromagnetism in Co-doped ZnO,while the Co and Al co-doped sample displays apparent room-temperature ferromagnetic behavior.The decrease of resistivity and presence of ferromagnetic behavior in Al-doped ZnCoO system corroborate the significant role of free carriers.展开更多
Ultra-wide band-gap nitrides have huge potential in micro-and optoelectronics due to their tunable wide band-gap,high breakdown field and energy density,excellent chemical and thermal stability.However,their applicati...Ultra-wide band-gap nitrides have huge potential in micro-and optoelectronics due to their tunable wide band-gap,high breakdown field and energy density,excellent chemical and thermal stability.However,their application has been severely hindered by the low p-doping efficiency,which is ascribed to the ultrahigh acceptor activation energy originated from the low valance band maximum.Here,a valance band modulation mode is proposed and a quantum engineering doping method is conducted to achieve high-efficient p-type ultra-wide band-gap nitrides,in which GaN quantum-dots are buried in nitride matrix to produce a new band edge and thus to tune the dopant activation energy.By non-equilibrium doping techniques,quantum engineering doped AIGaN:Mg with Al content of 60%is successfully fabricated.The Mg activation energy has been reduced to about 21 meV,and the hole concentration reaches higher than 10^(18)cm^(-3)at room temperature.Also,similar activation energies are obtained in AIGaN with other Al contents such as 50%and 70%;indicating the universality of the quantum engineering doping method.Moreover,deep-ultraviolet light-emission diodes are fabricated and the improved performance further demonstrates the validity and merit of the method.With the quantum material growth techniques developing,this method would be prevalently available and tremendously stimulate the promotion of ultra-wide band-gap semiconductor-based devices.展开更多
Helicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address suc...Helicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.展开更多
Rapid development of solid-state lighting technology requires new materials with highly efficient and stable luminescence,and especially relies on blue light pumped red phosphors for improved light quality.Herein,we d...Rapid development of solid-state lighting technology requires new materials with highly efficient and stable luminescence,and especially relies on blue light pumped red phosphors for improved light quality.Herein,we discovered an unprecedented red-emitting Mg_(2)AI_(4)Si_(5)0_(18):Eu^(2+)composite phosphor(λex=450 nm,λem=620 nm)via the crystallization of MgO-AI_(2)O_(3)-Sio_(2) aluminosilicate glass.Combined experimental measurement and first-principles calculations verify that Eu^(2+)dopants insert at the vacant channel of Mg_(2)AI_(4)Si_(5)0_(18)crystal with six-fold coordination responsible for the peculiar red emission.Importantly,the resulting phosphor exhibits high internal/external quantum efficiency of 94.5/70.6%,and stable emission against thermal quenching,which reaches industry production.The maximum luminous flux and luminous efficiency of the constructed laser driven red emitting device reaches as high as 274 Im and 54lm W^(-1),respectively.The combinations of extraordinary optical properties coupled with economically favorable and innovative preparation method indicate,that the Mg_(2)AI_(4)Si_(5)0_(18):Eu^(2+)composite phosphor will provide a significant step towards the development of high-power solid-state lighting.展开更多
Dy2O3 is a rare earth oxide having a number of advanced applications in various fields including protective or antireflective coatings,Main objective of this novel research work is to check the effect of Cr and Cu add...Dy2O3 is a rare earth oxide having a number of advanced applications in various fields including protective or antireflective coatings,Main objective of this novel research work is to check the effect of Cr and Cu addition on different properties of Dy2O3 and achievement of antireflective thin films with enhanced abso rption.Thin films of these materials we re deposited using DC magnetron with reactive cosputtering.XRD studies reveals the crystalline nature of thin films having Dy2O3(222)reflection in all samples with Cr2O3(116)and CuO(111)reflections in Cr and Cu containing compositions.Field emission scanning electron microscopy demonstrates the homogeneous deposition of thin films with uniform shape,size and distribution of grains.Refractive index,extinction coefficient and absorption coefficient significantly increase while optical reflectance decreases with Cr and Cu mediation corroborating an improved antireflective mechanism.The imaginary part of dielectric constant is found to increase slightly with low tangent loss for Cr containing composition co nsidered favorable for energy storage applications.展开更多
For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility paramet...For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (SiiE, Sobisch, Peukert, Lerche,& Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below lOnm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.展开更多
Despite the initial skepticism and challenges,minimally invasive liver surgery especially laparoscopic liver resections(LLR),has become a first-choice surgical treatment for various liver tumors in many specialized ce...Despite the initial skepticism and challenges,minimally invasive liver surgery especially laparoscopic liver resections(LLR),has become a first-choice surgical treatment for various liver tumors in many specialized centers worldwide(1-3).It is a safe alternative to open surgery thanks to advantages such as reduced blood loss and complication rates,shorter hospital stay,and better quality of life(4-7).However,laparoscopy requires relatively long learning,and complex procedures are limited to high-volume expert centers(8).展开更多
文摘The recently published study by Duan et al introduces a promising method that combines genomic instability and long non-coding RNAs to improve the prognostic evaluation of hepatocellular carcinoma(HCC),a deadly cancer associated with considerable morbidity and mortality.This editorial aims to analyze the methodology,key findings,and broader implications of the study within the fields of gastroenterology and oncological surgery,highlighting the shift towards precision medicine in the management of HCC.
基金funding by Fundamental Research Grant Scheme(FRGS)under Ministry of Higher Education(KPT)Malaysia with the grant No.FRGS/1/2023/STG07/UKM/02/1supported by Universiti Sains Malaysia through Short-Term Grant with project No.304/PFIZIK/6315730supported by JSPS KAKENHI grant Nos.JP20H01961,JP22K03707,JP21H04518,JP22K21345。
文摘A geomagnetic storm is a global disturbance of Earth?s magnetosphere,occurring as a result of the interaction with magnetic plasma ejected from the Sun.Despite considerable research,a comprehensive classification of storms for a complete solar cycle has not yet been fully developed,as most previous studies have been limited to specific storm types.This study,therefore,attempted to present complete statistics for solar cycle 24,detailing the occurrence of geomagnetic storm events and classifying them by type of intensity(moderate,intense,and severe),type of complete interval(normal or complex),duration of the recovery phase(rapid or long),and the number of steps in the storm?s development.The analysis was applied to data from ground-based magnetometers,which measured the Dst index as provided by the World Data Center for Geomagnetism,Kyoto,Japan.This study identified 211 storm events,comprising moderate(177 events),intense(33 events),and severe(1 event)types.About 36%of ICMEs and 23%of CIRs are found to be geoeffective,which caused geomagnetic storms.Up to four-step development of geomagnetic storms was exhibited during the main phase for this solar cycle.Analysis showed the geomagnetic storms developed one or more steps in the main phase,which were probably related to the driver that triggered the geomagnetic storms.A case study was additionally conducted to observe the variations of the ionospheric disturbance dynamo(Ddyn)phenomenon that resulted from the geomagnetic storm event of 2015July 13.The attenuation of the Ddyn in the equatorial region was analyzed using the H component of geomagnetic field data from stations in the Asian sector(Malaysia and India).The variations in the Ddyn signatures were observed at both stations,with the TIR station(India)showing higher intensity than the LKW station(Malaysia).
文摘What is sustainability? Does it only concern the environment or even socio-economic policies? It is only a question of ethics or a redefinition of industrial policy oriented towards the use of renewable energy, it can bring benefits both atmospheric and social employment. The need for the development of renewable sources can be in tune with the correct management of the territory in consideration of the fact that these sources involve the widespread implementation of small and medium-sized plants. A model of economic development based on renewable sources should respect the peculiarities and characteristics of the territories involved. It should also think of the territory as a “value” to be strengthened and used in a sustainable and integrated way and no longer as a passive platform on which to install plants. Solar thermal and photovoltaic, biomass, geothermal, hydrological, wind power are some of the sources the various countries must constantly invest. This publication is based on these concepts starting from an analysis of the employment data of the OECD “Organisation for Economic Co-operation and Development countries”, comparing them successively with the results of renewable energy productivity. The analysis was performed by analyzing a sample of 22 countries over a period of 20 years, after which the regression curve for the variables with the OLS method was created. This econometric method has allowed us to analyze the impact that renewable technologies have on the parameters of social welfare and in particular on unemployment.
文摘In the banking system, a context characterized by growing instability and by the speed of evolution of business dynamics, the system of corporate governance plays a key role, both for large banks and for banks with a smaller size. The paper aims to investigate the influence of corporate governance of the banks that operate in the cooperative credit system on performance and quality of loans, over the years 2010-2011-2012. In order to achieve this aim, the following research hypotheses have been formulated： There is a statistically significant relationship between the size and the structure of the board and banks Performance operating in the cooperative credit system; there is a statistically significant relationship between the size and structure of the board and the credit quality of banks operating in the cooperative credit system. The analysis is conducted on a sample composed of 48 Italian banks, divided into 24 cooperative banks and 24 popular banks. The sample is made up of banks from all over Italy and very different in terms of dimension. For the sample construction, data relative to governance of banks were collected from the balance sheets in the period from June to August 2014. Financial-economic data were collected from the Financial Statements and from Bankscope database. The methodology of analysis is based on multivariate OLS （ordinary least squares） regression models. The main results refer to the presence of significant relationships between board dimension and the quality of loans and among the number of committees and performance and the quality of loans. The presence of a significant and negative relationship between the board dimension and the ratio of impaired loans to gross loans indicates the possibility that enlargement of board dimension allows a better quality of loans. The presence of a positive relationship between the number of committees and the ratio of impaired loans to gross loans signals the possibility that a greater number of committees can produce a worse quality of loans. The presence of a negative relationship between the number of committees and bank performance suggests to limit and manage the complexity of governance in banks operating in the cooperative credit system.
文摘The work investigates the use of trade credit in Italy for reasons of a financial nature. The analysis considers Italian small and medium-sized enterprises （SMEs） and investigates, over the years of 2009-2011： the existence of functional relationships between the incidence of trade receivables and payables and corporate profitability; the existence of interdependencies between trade credit policy and trade debt policy; and the coexistence of interchangeable and complementary conditions between trade debts and bank loans and other sources of funding. To verify the research hypotheses, linear regression models on a yearly basis are used and these models are put under observation over the years of 2009-2011. We can conclude that there are interdependencies between trade credit policy and trade debt policy and that trade credit is a source of flexible way of financing, also available in periods of crisis, which has a positive effect on the profitability of SMEs and can be utilized as a complementary and substitute source of financing to bank loans.
文摘In the following article, the “Satisfaction with the Environmental Condition” in the 20 Italian regions between 2004 and 2020 was estimated using ISTAT-BES data. The data were analyzed using the following econometric techniques, namely: Panel Data with Random Effects, Panel Data with Fixed Effects, Dynamic Panel, Pooled OLS, WLS. The results show that satisfaction with the environmental situation is positively associated with the following variables “People with at least high school diploma”, “Satisfaction with leisure time”, “Concern for the deterioration of the landscape” and negatively associated with “Gross disposable income per capita”, “Dissatisfaction with the landscape of the place of life”, “Perception of the risk of crime”. A cluster analysis was then carried out using the unsupervised k-Means algorithm optimized through the Silhouette coefficient and 3 clusters were found. A comparative analysis was then carried out between eight different machine learning algorithms to predict the trend of satisfaction by environmental situation. The analysis showed that the Tree Ensemble Regression algorithm is the best predictor and estimates a reduction of the variable of 0.05%. Subsequently, using augmented data, a further prediction was made with an estimated result equal to -1.93%.
文摘Background: Our hypothesis was that only established and persistent injuries and complications after positioning in the Trendelenburg position are reported and detected, despite that patients may have great discomfort after surgery. Aim: The aim of this study was to explore patient reported discomfort, pain and functional decrease two hours, 24 hours and four weeks after laparoscopic resection of the colon in the prone lithotomy position, as well as factors potentially associated with reported pain. Methods: A longitudinal self-report questionnaire study was conducted at three time-points. Results: A total of 37 patients responded. Findings show that patients mostly reported pain in relation to the surgical area, but also related to other areas that may be linked to positioning. Conclusion: Even though patients reported mild pain, several of the patients still reported this, four weeks postoperatively, as well as some functional decrease. Our findings support the need to focus on preventing positioning injuries.
文摘We fabricate Fe3O4 thin films on Si（100） substrates at different temperatures using pulsed laser deposition, and study the effect of annealing and deposition temperature on the structural and magnetic properties of Fe3O4 thin films. Subsequently, the films are characterized by x-ray diffraction （XRD）, scanning electron microscopy （SEM） and vibrating sample magnetometery （VSM）. The XRD results of these films confirm the presence of the Fe3O4 phase and show room-temperature ferromagnetism, as observed with VSM. We demonstrate the optimized deposition and annealing conditions for an enhanced magnetization of 854 emu/cm3 that is very high when compared to the bulk sample.
基金by the Higher Education Commission(HEC)of Pakistan under the indigenous Ph.D.fellowship 5000 Scheme.
文摘Single-phase Zn_(0.95)Co_(0.05)O and Zn_(0.90)Co_(0.05)Al_(0.05)O samples were prepared by a novel combustion method.Xray diffraction studies exhibit the pure phase wurtzite structure of doped ZnO.Energy dispersive x-ray analysis confirms the incorporation of dopants into the host material.Scanning electron microscopy shows the ordered morphology in both of the samples.Temperature-dependent resistivity analysis describes the expected semiconducting behavior that is similar to the parent ZnO materials.Room-temperature magnetic measurements reveal the absence of ferromagnetism in Co-doped ZnO,while the Co and Al co-doped sample displays apparent room-temperature ferromagnetic behavior.The decrease of resistivity and presence of ferromagnetic behavior in Al-doped ZnCoO system corroborate the significant role of free carriers.
基金the National Natural Science Foundation for Distinguished Young Scholars of China[61725403]National Natural Science Foundation of China[62004196,61922078,61827813,61834008,61922077]+1 种基金Youth Innovation Promotion Association of CAS[Y201945,2017154]Open Project of Suzhou Institute of Nano-Tech and Nano-Bionics,CAS[20YZ10].
文摘Ultra-wide band-gap nitrides have huge potential in micro-and optoelectronics due to their tunable wide band-gap,high breakdown field and energy density,excellent chemical and thermal stability.However,their application has been severely hindered by the low p-doping efficiency,which is ascribed to the ultrahigh acceptor activation energy originated from the low valance band maximum.Here,a valance band modulation mode is proposed and a quantum engineering doping method is conducted to achieve high-efficient p-type ultra-wide band-gap nitrides,in which GaN quantum-dots are buried in nitride matrix to produce a new band edge and thus to tune the dopant activation energy.By non-equilibrium doping techniques,quantum engineering doped AIGaN:Mg with Al content of 60%is successfully fabricated.The Mg activation energy has been reduced to about 21 meV,and the hole concentration reaches higher than 10^(18)cm^(-3)at room temperature.Also,similar activation energies are obtained in AIGaN with other Al contents such as 50%and 70%;indicating the universality of the quantum engineering doping method.Moreover,deep-ultraviolet light-emission diodes are fabricated and the improved performance further demonstrates the validity and merit of the method.With the quantum material growth techniques developing,this method would be prevalently available and tremendously stimulate the promotion of ultra-wide band-gap semiconductor-based devices.
基金This work was financially supported by the LGD-SNU incubation program funded by LG Display and the National Research Foundation of Korea(NRF)grants(NRF-2019R1A2C3003129,CAMM-2019M3A6B3030637,NRF-2019R1A5A8080290)funded by the Ministry of Science and ICT(MSIT)of the Korean government.M.Q.M acknowledges a research grant by Higher Education Commission(HEC)of Pakistan through National Research Program for Universities(NRPU)[Project No.10177/Punjab/NRPU/R&D/HEC/2017]to support this work.M.Q.M.,T.T.,K.R.,U.Y.,and M.Z.acknowledge their internal research grants from ITU.M.A.A.acknowledges the Pre-Doctoral Fellowship from ITU.I.K.acknowledges the NRF Sejong Science fellowship(NRF-2021R1C1C2004291)funded by the MSIT of the Korean government.
文摘Helicity-multiplexed metasurfaces based on symmetric spin–orbit interactions (SOIs) have practical limits because they cannot provide central-symmetric holographic imaging. Asymmetric SOIs can effectively address such limitations, with several exciting applications in various fields ranging from asymmetric data inscription in communications to dual side displays in smart mobile devices. Low-loss dielectric materials provide an excellent platform for realizing such exotic phenomena efficiently. In this paper, we demonstrate an asymmetric SOI-dependent transmission-type metasurface in the visible domain using hydrogenated amorphous silicon (a-Si:H) nanoresonators. The proposed design approach is equipped with an additional degree of freedom in designing bi-directional helicity-multiplexed metasurfaces by breaking the conventional limit imposed by the symmetric SOI in half employment of metasurfaces for one circular handedness. Two on-axis, distinct wavefronts are produced with high transmission efficiencies, demonstrating the concept of asymmetric wavefront generation in two antiparallel directions. Additionally, the CMOS compatibility of a-Si:H makes it a cost-effective alternative to gallium nitride (GaN) and titanium dioxide (TiO2) for visible light. The cost-effective fabrication and simplicity of the proposed design technique provide an excellent candidate for high-efficiency, multifunctional, and chip-integrated demonstration of various phenomena.
基金the National Natural Science Foundations of China(Grant Nos.51972118,51961145101,51722202 and 11974022)the Guangzhou Science&Technology Project(202007020005)+1 种基金the Fundamental Research Funds for the Central Universities(D2190980)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137).
文摘Rapid development of solid-state lighting technology requires new materials with highly efficient and stable luminescence,and especially relies on blue light pumped red phosphors for improved light quality.Herein,we discovered an unprecedented red-emitting Mg_(2)AI_(4)Si_(5)0_(18):Eu^(2+)composite phosphor(λex=450 nm,λem=620 nm)via the crystallization of MgO-AI_(2)O_(3)-Sio_(2) aluminosilicate glass.Combined experimental measurement and first-principles calculations verify that Eu^(2+)dopants insert at the vacant channel of Mg_(2)AI_(4)Si_(5)0_(18)crystal with six-fold coordination responsible for the peculiar red emission.Importantly,the resulting phosphor exhibits high internal/external quantum efficiency of 94.5/70.6%,and stable emission against thermal quenching,which reaches industry production.The maximum luminous flux and luminous efficiency of the constructed laser driven red emitting device reaches as high as 274 Im and 54lm W^(-1),respectively.The combinations of extraordinary optical properties coupled with economically favorable and innovative preparation method indicate,that the Mg_(2)AI_(4)Si_(5)0_(18):Eu^(2+)composite phosphor will provide a significant step towards the development of high-power solid-state lighting.
基金the Deanship of Scientific Research at King Saud University for funding under Research Group(No.RG 1435-004)
文摘Dy2O3 is a rare earth oxide having a number of advanced applications in various fields including protective or antireflective coatings,Main objective of this novel research work is to check the effect of Cr and Cu addition on different properties of Dy2O3 and achievement of antireflective thin films with enhanced abso rption.Thin films of these materials we re deposited using DC magnetron with reactive cosputtering.XRD studies reveals the crystalline nature of thin films having Dy2O3(222)reflection in all samples with Cr2O3(116)and CuO(111)reflections in Cr and Cu containing compositions.Field emission scanning electron microscopy demonstrates the homogeneous deposition of thin films with uniform shape,size and distribution of grains.Refractive index,extinction coefficient and absorption coefficient significantly increase while optical reflectance decreases with Cr and Cu mediation corroborating an improved antireflective mechanism.The imaginary part of dielectric constant is found to increase slightly with low tangent loss for Cr containing composition co nsidered favorable for energy storage applications.
文摘For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (SiiE, Sobisch, Peukert, Lerche,& Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below lOnm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.
文摘Despite the initial skepticism and challenges,minimally invasive liver surgery especially laparoscopic liver resections(LLR),has become a first-choice surgical treatment for various liver tumors in many specialized centers worldwide(1-3).It is a safe alternative to open surgery thanks to advantages such as reduced blood loss and complication rates,shorter hospital stay,and better quality of life(4-7).However,laparoscopy requires relatively long learning,and complex procedures are limited to high-volume expert centers(8).
