The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N（CN）2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electro...The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N（CN）2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electronic band structure, density of states （DOSs） and spin magnetic moments were all calculated. The calculations reveal that the compound Cr[N（CN）2]2 is a really half-metallic ferromagnet with a integral magnetic moment of 2.0000 μB per molecule in the optimized lattice constant. Based on the spin distribution and the DOS, it is found that the total magnetic moment is mainly from the Cr2＋ with relative small contribution from C and N atoms. The sensitivity of the half-metallicity to small change in lattice constant is also discussed.展开更多
In this paper, the concept of uniform π _semiprime family in po_semigroups and semigroups is introduced. We give characterizations of left π _regular po_semigroups which generalize the results given by N. Keha...In this paper, the concept of uniform π _semiprime family in po_semigroups and semigroups is introduced. We give characterizations of left π _regular po_semigroups which generalize the results given by N. Kehayopulu in [1].展开更多
Objective: Thorough, prompt enteral decompression technique without contamination was de- veloped to ensure safety for emergent colon resection and primary anastomosis. Methods: After isolating the mesentery, the “to...Objective: Thorough, prompt enteral decompression technique without contamination was de- veloped to ensure safety for emergent colon resection and primary anastomosis. Methods: After isolating the mesentery, the “to be resected colon segment” was cut at its lower end, then the proximal cut end was put into a plastic bag which was adhered to one side of the operating table. After releasing the clamp, the content could ?ow into this bag. The operator could squeeze the bowel with two hands by turns, from proximal to farness, and from small bowel to large bowel, until the entire bowel content was fully discharged. Then the upper end of this “to be resected colon segment” was cut, and was removed together with the plastic bag. Results: 31 cases of left colon cancer with acute obstruction were decompressed with this technique. They all recovered smoothly, without anastomosis ?stula. Another 6 cases of hepatic seg- mentectomy with incidental colonectomy were decompressed with this technique and had the same results. This technique was also used in di?erent kinds of acute small intestinal obstruction and gained satisfactory results. Conclusion: This technique could be considered as the preferable choice for intraoperative enteral decompression.展开更多
The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type...The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type aerodynamic balance were used to test the pressure distribution and aerodynamic force of the head car respectively from the 1.5-and 3-coach grouping city EMU models.Meanwhile,the effects of the yaw angles on the pressure distribution of the streamlined head as well as the aerodynamic forces of the train were analyzed.The experimental results showed that the pressure coefficient was the smallest at the maximum slope of the main shape-line.The side force coefficient and pressure coefficient along the head car cross-section were most affected by crosswind when the yaw angle was 55°,and replacing a 3-coach grouping with a 1.5-coach grouping had obvious advantages for wind tunnel testing when the yaw angle was within 24.2°.In addition,the relative errors of lift coefficient C_(L),roll moment coefficient C_(Mx),side force coefficient C_(S),and drag coefficient C_(D) between the 1.5-and 3-coach cases were below 5.95%,which all met the requirements of the experimental accuracy.展开更多
Under the soil and climate conditions in semi-arid area of Jilin Province, the growth and development, yield and its components of maize under one-off fertilization and traditional fertilization were compared and anal...Under the soil and climate conditions in semi-arid area of Jilin Province, the growth and development, yield and its components of maize under one-off fertilization and traditional fertilization were compared and analyzed in this study. The results showed that, under the same field management, the two fertilization methods had no effect on the time when maize plants grew into each growth stage; the one-off fertilization was slightly better than the traditional fertilization in dry weight of each part of the plant, ear traits and yield; and the values of the two methods of fertilization varied from each other and were unstable. In production, the one-off fertilization saves the top dressing process, simplifes the operation process and reduces the production input, which is of great signifcance to the development of modern agriculture.展开更多
We study the entropy of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger （GMGHS） charged black hole, originated from the effective action that emerges in the low-energy of string theory, beyond semiclassical approxi-...We study the entropy of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger （GMGHS） charged black hole, originated from the effective action that emerges in the low-energy of string theory, beyond semiclassical approxi- mations. Applying the properties of exact differentials for three variables to the first law thermodynamics we derive the quantum corrections to the entropy of the black hole. The leading （logarithmic） and non leading corrections to the area law are obtained.展开更多
Although bulk SnP3 has been fabricated by experiments in the 1970’s,its electronic and optical properties within several layers have not been reported.Here,based on first-principles calculations,we have predicted two...Although bulk SnP3 has been fabricated by experiments in the 1970’s,its electronic and optical properties within several layers have not been reported.Here,based on first-principles calculations,we have predicted two-dimensional SnP3 layers as new semiconducting materials that possess indirect band gaps of 0.71 eV(monolayer)and 1.03 eV(bilayer),which are different from the metallic character of bulk structure.Remarkably,2D SnP3 possesses high hole mobility of 9.17×10^4cm^2·V^-1s^-1 and high light absorption(~10^6 cm^-1)in the whole visible spectrum,which predicts 2D SnP3 layers as prospective candidates for nanoelectronics and photovoltaics.Interestingly,we found that 2D SnP3 bilayer shows similar electronic and optical characters of silicon.展开更多
The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order...The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order elliptic boundary value problem by using an exponential variable transformation. The techniques of a priori estimates and Leray-Schauder＇s fixed-point theorem are employed to prove the existence. Furthermore, the uniqueness of solutions and the semiclassical limit δ→0 from QDD to the classical drift-diffusion （DD） model are studied.展开更多
The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the self...The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the selfconsistent field theory, the transient probe absorption coefficient is calculated. These calculations are beyond the previous steady-state assumption. Transient probe absorption spectra are calculated under different pumping intensity and various pump probe delay.展开更多
NOx can cause severe environmental problems such as acid rain and photochemical smog,endangering human health and the living environment.Among them,NO pollution accounts for about 95%.NO can exist stably in the air fo...NOx can cause severe environmental problems such as acid rain and photochemical smog,endangering human health and the living environment.Among them,NO pollution accounts for about 95%.NO can exist stably in the air for a long time when the concentration is lower than the ppm level.Therefore,the conversion of low concentration of NO has attracted more and more attention.However,traditional physical or chemical methods are difficult to deal with low concentration of NO,having high requirements on equipment and being not cost‐effective.Semiconductor photocatalytic technology can convert low concentration of NO into non‐toxic products and reduce its harm.This work briefly surveys the commonly used materials,modification methods,and mechanisms for semiconductor photocatalytic conversion of low concentration of NO.In addition,the challenges and prospects of ppb level of NO treatment are also discussed,aiming to promote the development of semiconductor photocatalytic conversion of NO.展开更多
The pyrolysis behaviors of corn stalk(CS) and pine sawdust(PS) were investigated with thermogravimetry-mass spectroscopy(TG-MS).The peak temperature of PS was higher and the main decomposition region shifted to higher...The pyrolysis behaviors of corn stalk(CS) and pine sawdust(PS) were investigated with thermogravimetry-mass spectroscopy(TG-MS).The peak temperature of PS was higher and the main decomposition region shifted to higher temperature compared with CS,which implied that the hemicellulose and cellulose of PS were more thermally stable than those of CS.However,the hemicellulose and cellulose of PS were more easily decomposed into gaseous products than those of CS during pyrolysis.The pyrolysis process of biomass can be described by a two-step independent first-order kinetic model.This fundamental study provides a basic insight into the biomass pyrolysis,which is beneficial for understanding the pyrolysis mechanism of biomass and developing an advanced thermal process for effective utilization of biomass.展开更多
We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the ...We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the total energy of the cell and the spin magnetic moment of CoNCN and NiNCN were calculated. The calculations reveal that the compound CoNCN and NiNCN have hall-metallic properties in ferromagnetic ground state, and the spin magnetic moment per molecule is about 7.000 μB and 6.000 μB for CoNCN and NiNCN, respectively.展开更多
基金ACKNOWLEDGMENTS This work was supported by the the National Natural Science Foundation of China （No.10974048） and the Excellent Middle Age and Youth People Science and Technology Creative Team Foundation of the Educational Department of the Hubei Province （No.T200805）.
文摘The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N（CN）2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electronic band structure, density of states （DOSs） and spin magnetic moments were all calculated. The calculations reveal that the compound Cr[N（CN）2]2 is a really half-metallic ferromagnet with a integral magnetic moment of 2.0000 μB per molecule in the optimized lattice constant. Based on the spin distribution and the DOS, it is found that the total magnetic moment is mainly from the Cr2＋ with relative small contribution from C and N atoms. The sensitivity of the half-metallicity to small change in lattice constant is also discussed.
文摘In this paper, the concept of uniform π _semiprime family in po_semigroups and semigroups is introduced. We give characterizations of left π _regular po_semigroups which generalize the results given by N. Kehayopulu in [1].
文摘Objective: Thorough, prompt enteral decompression technique without contamination was de- veloped to ensure safety for emergent colon resection and primary anastomosis. Methods: After isolating the mesentery, the “to be resected colon segment” was cut at its lower end, then the proximal cut end was put into a plastic bag which was adhered to one side of the operating table. After releasing the clamp, the content could ?ow into this bag. The operator could squeeze the bowel with two hands by turns, from proximal to farness, and from small bowel to large bowel, until the entire bowel content was fully discharged. Then the upper end of this “to be resected colon segment” was cut, and was removed together with the plastic bag. Results: 31 cases of left colon cancer with acute obstruction were decompressed with this technique. They all recovered smoothly, without anastomosis ?stula. Another 6 cases of hepatic seg- mentectomy with incidental colonectomy were decompressed with this technique and had the same results. This technique was also used in di?erent kinds of acute small intestinal obstruction and gained satisfactory results. Conclusion: This technique could be considered as the preferable choice for intraoperative enteral decompression.
基金Project(2020YFA0710903) supported by the National Key R&D Program of ChinaProjects(2020zzts111, 2020zzts117)supported by the Graduate Student Independent Innovation Project of Central South University,ChinaProject(202037)supported by Transport Department of Hunan Province Technology Innovation Project,China。
文摘The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type aerodynamic balance were used to test the pressure distribution and aerodynamic force of the head car respectively from the 1.5-and 3-coach grouping city EMU models.Meanwhile,the effects of the yaw angles on the pressure distribution of the streamlined head as well as the aerodynamic forces of the train were analyzed.The experimental results showed that the pressure coefficient was the smallest at the maximum slope of the main shape-line.The side force coefficient and pressure coefficient along the head car cross-section were most affected by crosswind when the yaw angle was 55°,and replacing a 3-coach grouping with a 1.5-coach grouping had obvious advantages for wind tunnel testing when the yaw angle was within 24.2°.In addition,the relative errors of lift coefficient C_(L),roll moment coefficient C_(Mx),side force coefficient C_(S),and drag coefficient C_(D) between the 1.5-and 3-coach cases were below 5.95%,which all met the requirements of the experimental accuracy.
文摘In this paper, we introduce O-F-inverse semigroups and characterize O-F-inverse categorical semigroups by using their minimal primitive congruence β.
基金Supported by National Maize Industry Technical System Project(CARS-02-42)Scientific and Technological Innovation Project for High Yield and Efficiency of Food Grain(2017YFD0300605)Gongzhuling Scientific Observation and Experiment Station for High Efficiency Water Use in Crop,Ministry of Agriculture~~
文摘Under the soil and climate conditions in semi-arid area of Jilin Province, the growth and development, yield and its components of maize under one-off fertilization and traditional fertilization were compared and analyzed in this study. The results showed that, under the same field management, the two fertilization methods had no effect on the time when maize plants grew into each growth stage; the one-off fertilization was slightly better than the traditional fertilization in dry weight of each part of the plant, ear traits and yield; and the values of the two methods of fertilization varied from each other and were unstable. In production, the one-off fertilization saves the top dressing process, simplifes the operation process and reduces the production input, which is of great signifcance to the development of modern agriculture.
基金Supported by the Universidad Nacional de Colombia.Project Code 2010100
文摘We study the entropy of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger （GMGHS） charged black hole, originated from the effective action that emerges in the low-energy of string theory, beyond semiclassical approxi- mations. Applying the properties of exact differentials for three variables to the first law thermodynamics we derive the quantum corrections to the entropy of the black hole. The leading （logarithmic） and non leading corrections to the area law are obtained.
基金supported by the National Natural Science Foundation of China(No.11604146,No.51522206,and No.11774173)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Outstanding Youth Fund of Nanjing Forestry University(NLJQ2015-03)+1 种基金the Fundamental Research Funds for the Central Universities(No.30915011203)the support from the Shanghai Supercomputer Centre
文摘Although bulk SnP3 has been fabricated by experiments in the 1970’s,its electronic and optical properties within several layers have not been reported.Here,based on first-principles calculations,we have predicted two-dimensional SnP3 layers as new semiconducting materials that possess indirect band gaps of 0.71 eV(monolayer)and 1.03 eV(bilayer),which are different from the metallic character of bulk structure.Remarkably,2D SnP3 possesses high hole mobility of 9.17×10^4cm^2·V^-1s^-1 and high light absorption(~10^6 cm^-1)in the whole visible spectrum,which predicts 2D SnP3 layers as prospective candidates for nanoelectronics and photovoltaics.Interestingly,we found that 2D SnP3 bilayer shows similar electronic and optical characters of silicon.
文摘The weak solutions to the stationary quantum drift-diffusion equations （QDD） for semiconductor devices are investigated in one space dimension. The proofs are based on a reformulation of the system as a fourth-order elliptic boundary value problem by using an exponential variable transformation. The techniques of a priori estimates and Leray-Schauder＇s fixed-point theorem are employed to prove the existence. Furthermore, the uniqueness of solutions and the semiclassical limit δ→0 from QDD to the classical drift-diffusion （DD） model are studied.
基金the National Fund for Distinguished Young Scholars of China，国家重点基础研究发展计划(973计划)，上海市科委资助项目
文摘The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the selfconsistent field theory, the transient probe absorption coefficient is calculated. These calculations are beyond the previous steady-state assumption. Transient probe absorption spectra are calculated under different pumping intensity and various pump probe delay.
文摘NOx can cause severe environmental problems such as acid rain and photochemical smog,endangering human health and the living environment.Among them,NO pollution accounts for about 95%.NO can exist stably in the air for a long time when the concentration is lower than the ppm level.Therefore,the conversion of low concentration of NO has attracted more and more attention.However,traditional physical or chemical methods are difficult to deal with low concentration of NO,having high requirements on equipment and being not cost‐effective.Semiconductor photocatalytic technology can convert low concentration of NO into non‐toxic products and reduce its harm.This work briefly surveys the commonly used materials,modification methods,and mechanisms for semiconductor photocatalytic conversion of low concentration of NO.In addition,the challenges and prospects of ppb level of NO treatment are also discussed,aiming to promote the development of semiconductor photocatalytic conversion of NO.
基金Supported by the National Basic Research Program of China("973"Program,No.2012CB215302)National Natural Science Foundation of China(No.21206188 and No.21106177)+1 种基金China Postdoctoral Science Foundation(No.2012M511339)Fundamental Research Funds for the Central Universities(China University of Mining and Technology,No.2011QNA23)
文摘The pyrolysis behaviors of corn stalk(CS) and pine sawdust(PS) were investigated with thermogravimetry-mass spectroscopy(TG-MS).The peak temperature of PS was higher and the main decomposition region shifted to higher temperature compared with CS,which implied that the hemicellulose and cellulose of PS were more thermally stable than those of CS.However,the hemicellulose and cellulose of PS were more easily decomposed into gaseous products than those of CS during pyrolysis.The pyrolysis process of biomass can be described by a two-step independent first-order kinetic model.This fundamental study provides a basic insight into the biomass pyrolysis,which is beneficial for understanding the pyrolysis mechanism of biomass and developing an advanced thermal process for effective utilization of biomass.
文摘We studied the electronic structure of the two new transition-metal carbodiimides CoNCN and NiNCN using first-principles method, which is based on density-functional theory （DFT）. The density of states （DOS）, the total energy of the cell and the spin magnetic moment of CoNCN and NiNCN were calculated. The calculations reveal that the compound CoNCN and NiNCN have hall-metallic properties in ferromagnetic ground state, and the spin magnetic moment per molecule is about 7.000 μB and 6.000 μB for CoNCN and NiNCN, respectively.
