The fast growth of Tetracentron sinense is a potential valuable timber resource, but whether its anatomy and chemical components are suitable for timber is unknown. We used light microscopy and SEM to examine the anat...The fast growth of Tetracentron sinense is a potential valuable timber resource, but whether its anatomy and chemical components are suitable for timber is unknown. We used light microscopy and SEM to examine the anatomical structure and FITR to measure the chemical components of the phloem and xylem of this tree. Radial variations in growth ring width and tracheid dimensions were also evaluated. The sieve tube, phloem parenchyma cell and sclereids clusters were the main cells in phloem, and the tracheid was the fundamental cell in xylem. An unusual tracheid type, fiber-tracheids or vessel-liked elements was visible. Wood rays nonstoried, uniseriate and multiseriate, including heterogeneous II, occasionally I, and usually 3-6 cells wide. The mean growth-ring width was 2.53 +/- 0.46 mm, and the percentage of late wood was over 60%. For radial variation, growth-ring width increased at an early growth stage, and reached the largest increment during years 11-15, then decreased. The maximum growth-ring width was 5.313 mm. During late growth (60-85 years), trees also maintained a high radial growth increment. Radial variation in the percentage of late wood was uniform, about 50-70%, throughout the growth years. Growth patterns in the length and width of early and late wood were similar as the trees aged. From the FTIR results, the chemical components differed significantly between xylem and phloem, hemicellulose in particular was higher in the xylem than in the phloem, where it was apparently absent. All of these suggest that the composition of phloem in T. sinense is very similar to that of hardwood, and it has higher growth ratio and uniform wood properties.展开更多
Seed clearing is a critical stage during precision seed metering process to ensure high seed singulation.However,there is a lack of understanding of the dynamics in the seed clearing process.In this study,a model was ...Seed clearing is a critical stage during precision seed metering process to ensure high seed singulation.However,there is a lack of understanding of the dynamics in the seed clearing process.In this study,a model was developed to predict initial seed clearing angle,in the seed clearing process using vector fields.The model was applied to an existing high-speed metering device and soybean seeds,and the model was evaluated with bench testing results.Results showed that dynamic changes in forces and constraints of seeds during the seed clearing process could be abstracted as vectors,and the changes of vector directions could be described by their phase angles.The phase angles were functions of the rotational angle of the seed meter.The phase angle of the constraint boundary linearly increases with the increase of the rotational angle.The phase angle of the force fluctuates,as the rotational angle changes.Initial seed clearing angle obtained from the phase angles varies from 8°to 59°,depending on the seeder travel speed.When comparing the values of the initial seed clearing angles predicted by the model with those from the bench tests,the root mean square error(RMSE)were from 2.73 to 3.14,and the correlation(r)between predict and observer were all higher than 0.98,indicating that the model had reasonably good accuracy.展开更多
We obtain some sufficient conditions on the number of non-（sub）normai nonabelian subgroups of a finite group to be solvable, which extend a result of Shi and Zhang in 2011.
Let G be a finite group and H a subgroup of G. Recall that H is said to be aTI-subgroup ofG ifHg∩H = 1 or H for each b∈ G. In this note, we prove that if all non-nilpotent subgroups of a finite non-nilpotent group G...Let G be a finite group and H a subgroup of G. Recall that H is said to be aTI-subgroup ofG ifHg∩H = 1 or H for each b∈ G. In this note, we prove that if all non-nilpotent subgroups of a finite non-nilpotent group G are TI-subgroups, then G is soluble, and all non-nilpotent subgroups of G are normal.展开更多
We obtain a complete characterization of the structure of a finite group G in which every maximal subgroup is nilpotent or a TI-subgroup or has order p'for any fixed prime divisor p of|G|.Moreover,we show that the...We obtain a complete characterization of the structure of a finite group G in which every maximal subgroup is nilpotent or a TI-subgroup or has order p'for any fixed prime divisor p of|G|.Moreover,we show that there exists at most one prime divisor q of|G|such that G is neither q-nilpotent nor q-closed.展开更多
To generate arbitrary shape magnetic field waveforms for advanced scientific research,a reconfigurable pulsed high magnetic field facility(PHMFF)was developed at Wuhan National Pulsed High Magnetic Field Centre(WHMFC)...To generate arbitrary shape magnetic field waveforms for advanced scientific research,a reconfigurable pulsed high magnetic field facility(PHMFF)was developed at Wuhan National Pulsed High Magnetic Field Centre(WHMFC).First,the basic elements of PHMFF are introduced,and a ternary physical model composed of energy storage unit,magnet,transmission circuits and other auxiliary units is summarised to describe various magnetic field systems.Second,in order to realise the reconfiguration of magnetic field systems based on detailed elements,the control system with the ability of dynamic construction and control sequence reconfiguration is designed.On this basis,the PHMFF has been realised and various magnetic field systems are constructed to produce arbitrary shape magnetic field waveforms,such as half‐sine,ultra‐high,flat‐top and repetitive field pulses,which not only enhances the capability and efficiency of PHMFF,but also makes more scientific research possible in pulsed magnetic fields.So far,a peak magnetic field of 94.8 T,a flat‐top magnetic field of 64 T/10 ms and a repetitive magnetic field waveform of 20 T/60 Hz have been achieved,and some experiments and studies on the physical properties of materials have been carried out at WHMFC.展开更多
A finite group G is called a special local 2-nilpotent group if G is not 2-nilpotent,the Sylow 2-subgroup P of G has a section isomorphic to the quaternion group of order 8,Ω(P∩G')≤Z(P)and NG(P)is 2-nilpotent.I...A finite group G is called a special local 2-nilpotent group if G is not 2-nilpotent,the Sylow 2-subgroup P of G has a section isomorphic to the quaternion group of order 8,Ω(P∩G')≤Z(P)and NG(P)is 2-nilpotent.In this paper,it is shown that SL2(q),q>3,is a special local 2-nilpotent group if and only if q^2≡1(mod 16),and that GL2(q),q>3,is a special local 2-nilpotent group if and only if q is odd.Moreover,the solvability of finite groups is also investigated by giving two generalizations of a result from[A note on p-nilpotence and solvability of finite groups,J.Algebra 321(2009)1555-1560].展开更多
基金financially supported by the Youth Science and Technology Innovation Fund of NJFU(CXL2015018)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The fast growth of Tetracentron sinense is a potential valuable timber resource, but whether its anatomy and chemical components are suitable for timber is unknown. We used light microscopy and SEM to examine the anatomical structure and FITR to measure the chemical components of the phloem and xylem of this tree. Radial variations in growth ring width and tracheid dimensions were also evaluated. The sieve tube, phloem parenchyma cell and sclereids clusters were the main cells in phloem, and the tracheid was the fundamental cell in xylem. An unusual tracheid type, fiber-tracheids or vessel-liked elements was visible. Wood rays nonstoried, uniseriate and multiseriate, including heterogeneous II, occasionally I, and usually 3-6 cells wide. The mean growth-ring width was 2.53 +/- 0.46 mm, and the percentage of late wood was over 60%. For radial variation, growth-ring width increased at an early growth stage, and reached the largest increment during years 11-15, then decreased. The maximum growth-ring width was 5.313 mm. During late growth (60-85 years), trees also maintained a high radial growth increment. Radial variation in the percentage of late wood was uniform, about 50-70%, throughout the growth years. Growth patterns in the length and width of early and late wood were similar as the trees aged. From the FTIR results, the chemical components differed significantly between xylem and phloem, hemicellulose in particular was higher in the xylem than in the phloem, where it was apparently absent. All of these suggest that the composition of phloem in T. sinense is very similar to that of hardwood, and it has higher growth ratio and uniform wood properties.
基金supported by the National Natural Science Foundation of China(Grant No.32372009)the National Natural Science Foundation of China(Grant No.31971802).
文摘Seed clearing is a critical stage during precision seed metering process to ensure high seed singulation.However,there is a lack of understanding of the dynamics in the seed clearing process.In this study,a model was developed to predict initial seed clearing angle,in the seed clearing process using vector fields.The model was applied to an existing high-speed metering device and soybean seeds,and the model was evaluated with bench testing results.Results showed that dynamic changes in forces and constraints of seeds during the seed clearing process could be abstracted as vectors,and the changes of vector directions could be described by their phase angles.The phase angles were functions of the rotational angle of the seed meter.The phase angle of the constraint boundary linearly increases with the increase of the rotational angle.The phase angle of the force fluctuates,as the rotational angle changes.Initial seed clearing angle obtained from the phase angles varies from 8°to 59°,depending on the seeder travel speed.When comparing the values of the initial seed clearing angles predicted by the model with those from the bench tests,the root mean square error(RMSE)were from 2.73 to 3.14,and the correlation(r)between predict and observer were all higher than 0.98,indicating that the model had reasonably good accuracy.
文摘We obtain some sufficient conditions on the number of non-（sub）normai nonabelian subgroups of a finite group to be solvable, which extend a result of Shi and Zhang in 2011.
基金The first author was supported by NSFC （Grant 11201401） and the China Postdoctoral Science Foundation （Grant 201104027）. The second author was supported by H.C. Orsted Postdoctoral Fellowship at DTU （Technical University of Denmark）.
文摘Let G be a finite group and H a subgroup of G. Recall that H is said to be aTI-subgroup ofG ifHg∩H = 1 or H for each b∈ G. In this note, we prove that if all non-nilpotent subgroups of a finite non-nilpotent group G are TI-subgroups, then G is soluble, and all non-nilpotent subgroups of G are normal.
基金supported by Shandong Provincial Natural Science Foundation,Chin(ZR2017MA022 and ZR2020MA044)and NSFC(11761079).
文摘We obtain a complete characterization of the structure of a finite group G in which every maximal subgroup is nilpotent or a TI-subgroup or has order p'for any fixed prime divisor p of|G|.Moreover,we show that there exists at most one prime divisor q of|G|such that G is neither q-nilpotent nor q-closed.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFA1600301National Natural Science Foundation of China,Grant/Award Numbers:U21A20458,52107152,51821005。
文摘To generate arbitrary shape magnetic field waveforms for advanced scientific research,a reconfigurable pulsed high magnetic field facility(PHMFF)was developed at Wuhan National Pulsed High Magnetic Field Centre(WHMFC).First,the basic elements of PHMFF are introduced,and a ternary physical model composed of energy storage unit,magnet,transmission circuits and other auxiliary units is summarised to describe various magnetic field systems.Second,in order to realise the reconfiguration of magnetic field systems based on detailed elements,the control system with the ability of dynamic construction and control sequence reconfiguration is designed.On this basis,the PHMFF has been realised and various magnetic field systems are constructed to produce arbitrary shape magnetic field waveforms,such as half‐sine,ultra‐high,flat‐top and repetitive field pulses,which not only enhances the capability and efficiency of PHMFF,but also makes more scientific research possible in pulsed magnetic fields.So far,a peak magnetic field of 94.8 T,a flat‐top magnetic field of 64 T/10 ms and a repetitive magnetic field waveform of 20 T/60 Hz have been achieved,and some experiments and studies on the physical properties of materials have been carried out at WHMFC.
基金Shandong Provincial Natural Science Foundation,China(ZR2017MA022)NSFC(11561021 and 11761079)+3 种基金Slovenian Research Agency(research program P1-0285research projects N1-0038,N1-0062,J1-6720,J1-6743,J1-7051,J1-9110)in part by NSFC(11561021)NSFC(11201403 and 11561021).
文摘A finite group G is called a special local 2-nilpotent group if G is not 2-nilpotent,the Sylow 2-subgroup P of G has a section isomorphic to the quaternion group of order 8,Ω(P∩G')≤Z(P)and NG(P)is 2-nilpotent.In this paper,it is shown that SL2(q),q>3,is a special local 2-nilpotent group if and only if q^2≡1(mod 16),and that GL2(q),q>3,is a special local 2-nilpotent group if and only if q is odd.Moreover,the solvability of finite groups is also investigated by giving two generalizations of a result from[A note on p-nilpotence and solvability of finite groups,J.Algebra 321(2009)1555-1560].
