The strained Si techique has been widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E-k relations of strained Si/(111)Si1-xGex, the valence band and hole effective m...The strained Si techique has been widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E-k relations of strained Si/(111)Si1-xGex, the valence band and hole effective mass along the [111] and [-110] directions were obtained in this work. In comparison with the relaxed Si, the valence band edge degeneracy was partially lifted, and the significant change was observed band structures along the [111] and [-110] directions, as well as in its corresponding hole effective masses with the increasing Ge fraction. The results obtained can provide valuable references to the investigation concerning the Si-based strained devices enhancement and the conduction channel design related to stress and orientation.展开更多
We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyze...We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyzed the relationship between the characteristic of FACs at the PSBL in magnetotail and the Kp index. The main results indicated the followings： 1） In the different geomagnetic activity levels, the relative occurrence of FACs in PSBL increased monotonically with geomagnetic activity. 2） The density of FACs in PSBL increased monotonically with Kp index. In the storm main phase, the density of FACs increased dramatically, the maximum FACs approximately equaled 19.05 nA m-2 while Kp equaled 5.3） The variation of FACs density in PSBL was consistent with the variation of the Kp index. However, when AE〈800 nT, FACs density in PSBL increased with increasing AE, and when AE〉800 nT, it decreased with increasing AE. Therefore, our results suggested that the FACs density in PSBL had a closer correlation with Kp index.展开更多
In this paper, the modified CK＇s direct method to find symmetry groups of nonlinear partial differential equation is extended to （2＋1）-dimensional variable coeffficient canonical generalized KP （VCCGKP） equation...In this paper, the modified CK＇s direct method to find symmetry groups of nonlinear partial differential equation is extended to （2＋1）-dimensional variable coeffficient canonical generalized KP （VCCGKP） equation. As a result, symmetry groups, Lie point symmetry group and Lie symmetry for the VCCGKP equation are obtained. In fact, the Lie point symmetry group coincides with that obtained by the standard Lie group approach. Applying the given Lie symmetry, we obtain five types of similarity reductions and a lot of new exact solutions, including hyperbolic function solutions, triangular periodic solutions, Jacobi elliptic function solutions and rational solutions, for the VCCGKP equation.展开更多
The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration （ETc） of...The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration （ETc） of cauliflower and red cabbage crops was calculated according to the water balance approach. Reference evapotranspiration （ETo） was calculated with FAO Penman-Monteith equation. Pan evaporation （Epan） was measured by using Class A pan. Seasonal ETc was determined as 475 mm for cauliflower and 556 nun for red cabbage. Seasonal pan coefficient （kp=ETo/Epan） was determined as 0.82, and the seasonal crop coefficient （kc=ETc/ETo） was determined as 0.84 for cauliflower and 0.83 for red cabbage. So the evapotranspiration of cauliflower and red cabbage crops was estimated as 70% Class A pan evaporation.展开更多
The determinant representation of the gauge transformation operators is establised. In this process, the generalized Wronskian determinant is introduced. As a simple application, the authors present a construction of ...The determinant representation of the gauge transformation operators is establised. In this process, the generalized Wronskian determinant is introduced. As a simple application, the authors present a construction of the special T-function obtained firstly by Chau et al. (Commun. Math. Phys., 149(1992), 263), which involves the generalized Wronskian determinant. Also, some properties of this determinant are given.展开更多
Magnetic activity indices are widely used in theoretical studies of solar-terrestrial coupling and space weather prediction. However, the indices suffer from various uncertainties, which limit their application and ev...Magnetic activity indices are widely used in theoretical studies of solar-terrestrial coupling and space weather prediction. However, the indices suffer from various uncertainties, which limit their application and even mislead to incorrect conclu-sion. In this paper we analyze three most popular indices, Kp, AE and Dst. Three categories of uncertainties in magnetic indices are discussed: "data uncertainty" originating from inadequate data processing, "station uncertainty" caused by in-complete station covering, and "physical uncertainty" stemming from unclear physical mechanism. A comparison between magnetic disturbances and related indices indicate that the residual Sq will cause an uncertainty of 1―2 in K meas-urement, the uncertainty in saturated AE is as much as 50%, and the uncertainty in Dst index caused by the partial ring currents is about a half of the partial ring cur-rent.展开更多
目的通过调查重症监护病房(intensive care unit,ICU)一起肺炎克雷伯菌(Klebsiella pneumoniae,KP)聚集性定植原因,评价防控措施的有效性。方法对2020年4月8日至6月28日入住ICU检出KP的患者进行流行病学调查及其病房周围环境监测,并进...目的通过调查重症监护病房(intensive care unit,ICU)一起肺炎克雷伯菌(Klebsiella pneumoniae,KP)聚集性定植原因,评价防控措施的有效性。方法对2020年4月8日至6月28日入住ICU检出KP的患者进行流行病学调查及其病房周围环境监测,并进行药敏试验。结果2020年第二季度KP检出例次阳性率为10.58%(20/189),高于去年同期水平(χ2=6.68,P=0.01),调查期内入住ICU患者119人次,其中10名患者痰培养KP阳性,1例为呼吸机相关性肺炎(ventilator associated pneumonia,VAP),9例为院内定植,其主要发现于4、8、9、11、13、16床,其中8、9两床共计检出5例;对ICU病房环境采样45份,石蜡油瓶表面及导丝盒中检出KP;石蜡油瓶表的KP菌株和10位患者检出的KP抗菌谱完全一致或高度相似。结论本次KP聚集事件传播途径主要考虑为床间交叉使用表面被KP污染的石蜡油瓶,采取相应的防控措施后得到有效控制。展开更多
The multiple patterns of internal solitary wave interactions(ISWI)are a complex oceanic phenomenon.Satellite remote sensing techniques indirectly detect these ISWI,but do not provide information on their detailed stru...The multiple patterns of internal solitary wave interactions(ISWI)are a complex oceanic phenomenon.Satellite remote sensing techniques indirectly detect these ISWI,but do not provide information on their detailed structure and dynamics.Recently,the authors considered a three-layer fluid with shear flow and developed a(2+1)Kadomtsev-Petviashvili(KP)model that is capable of describing five types of oceanic ISWI,including O-type,P-type,TO-type,TP-type,and Y-shaped.Deep learning models,particularly physics-informed neural networks(PINN),are widely used in the field of fluids and internal solitary waves.However,the authors find that the amplitude of internal solitary waves is much smaller than the wavelength and the ISWI occur at relatively large spatial scales,and these characteristics lead to an imbalance in the loss function of the PINN model.To solve this problem,the authors introduce two weighted loss function methods,the fixed weighing and the adaptive weighting methods,to improve the PINN model.This successfully simulated the detailed structure and dynamics of ISWI,with simulation results corresponding to the satellite images.In particular,the adaptive weighting method can automatically update the weights of different terms in the loss function and outperforms the fixed weighting method in terms of generalization ability.展开更多
Based on an analysis of symmetry, the dispersion relations near the Ai valley in strained Si1-x Gex （0≤x〈0.45）/ （001）, （111）, （101）Si are derived using the KP method with perturbation theory. These relations...Based on an analysis of symmetry, the dispersion relations near the Ai valley in strained Si1-x Gex （0≤x〈0.45）/ （001）, （111）, （101）Si are derived using the KP method with perturbation theory. These relations demonstrate that △^i levels in strained Si1-x Gex are different from the △1 level in relaxed Si1-x Gex, while the longitudinal and transverse masses （m1^＊ and mt^＊ ） are unchanged under strain. The energy shift between the △^i levels and the △1 level follows the linear deformation potential theory. Finally,a description of the conduction band （CB） edge in biaxially strained layers is given.展开更多
We explain how to construct a quantum deformation of a spectral curve associated to a tau-function of the KP hierarchy.This construction is applied to Witten-Kontsevich tau-function to give a natural explanation of so...We explain how to construct a quantum deformation of a spectral curve associated to a tau-function of the KP hierarchy.This construction is applied to Witten-Kontsevich tau-function to give a natural explanation of some earlier work.We also apply it to higher Weil-Petersson volumes and Witten’s r-spin intersection numbers.展开更多
基金supported by the National Ministries and Commissions (Grant Nos. 51308040203, 9140A08060407DZ0103, and 6139801)
文摘The strained Si techique has been widely adopted in the high-speed and high-performance devices and circuits. Based on the valence band E-k relations of strained Si/(111)Si1-xGex, the valence band and hole effective mass along the [111] and [-110] directions were obtained in this work. In comparison with the relaxed Si, the valence band edge degeneracy was partially lifted, and the significant change was observed band structures along the [111] and [-110] directions, as well as in its corresponding hole effective masses with the increasing Ge fraction. The results obtained can provide valuable references to the investigation concerning the Si-based strained devices enhancement and the conduction channel design related to stress and orientation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40804031, 41074114, 40921063)the Specialized Research Fund for State Key Laboratories
文摘We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyzed the relationship between the characteristic of FACs at the PSBL in magnetotail and the Kp index. The main results indicated the followings： 1） In the different geomagnetic activity levels, the relative occurrence of FACs in PSBL increased monotonically with geomagnetic activity. 2） The density of FACs in PSBL increased monotonically with Kp index. In the storm main phase, the density of FACs increased dramatically, the maximum FACs approximately equaled 19.05 nA m-2 while Kp equaled 5.3） The variation of FACs density in PSBL was consistent with the variation of the Kp index. However, when AE〈800 nT, FACs density in PSBL increased with increasing AE, and when AE〉800 nT, it decreased with increasing AE. Therefore, our results suggested that the FACs density in PSBL had a closer correlation with Kp index.
基金The project supported by the Natural Science Foundation of Shandong Province of China under Grant Nos. 2004zx16 and Q2005A01
文摘In this paper, the modified CK＇s direct method to find symmetry groups of nonlinear partial differential equation is extended to （2＋1）-dimensional variable coeffficient canonical generalized KP （VCCGKP） equation. As a result, symmetry groups, Lie point symmetry group and Lie symmetry for the VCCGKP equation are obtained. In fact, the Lie point symmetry group coincides with that obtained by the standard Lie group approach. Applying the given Lie symmetry, we obtain five types of similarity reductions and a lot of new exact solutions, including hyperbolic function solutions, triangular periodic solutions, Jacobi elliptic function solutions and rational solutions, for the VCCGKP equation.
文摘The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration （ETc） of cauliflower and red cabbage crops was calculated according to the water balance approach. Reference evapotranspiration （ETo） was calculated with FAO Penman-Monteith equation. Pan evaporation （Epan） was measured by using Class A pan. Seasonal ETc was determined as 475 mm for cauliflower and 556 nun for red cabbage. Seasonal pan coefficient （kp=ETo/Epan） was determined as 0.82, and the seasonal crop coefficient （kc=ETc/ETo） was determined as 0.84 for cauliflower and 0.83 for red cabbage. So the evapotranspiration of cauliflower and red cabbage crops was estimated as 70% Class A pan evaporation.
基金Project supported by the State Education Commission, the 973 Project "Nonlinear Science" the National Natural Science Foundation of China (No.9725104, No.19971084).
文摘The determinant representation of the gauge transformation operators is establised. In this process, the generalized Wronskian determinant is introduced. As a simple application, the authors present a construction of the special T-function obtained firstly by Chau et al. (Commun. Math. Phys., 149(1992), 263), which involves the generalized Wronskian determinant. Also, some properties of this determinant are given.
基金the National Natural Science Foundation of China (Grant No. 40436016)the National Basic Research Program of China ("973") (Grant No. 2006CB806305)the KIP Pilot Project of the Chinese Academy of Sciences (Grant No. kzcx3-sw-144)
文摘Magnetic activity indices are widely used in theoretical studies of solar-terrestrial coupling and space weather prediction. However, the indices suffer from various uncertainties, which limit their application and even mislead to incorrect conclu-sion. In this paper we analyze three most popular indices, Kp, AE and Dst. Three categories of uncertainties in magnetic indices are discussed: "data uncertainty" originating from inadequate data processing, "station uncertainty" caused by in-complete station covering, and "physical uncertainty" stemming from unclear physical mechanism. A comparison between magnetic disturbances and related indices indicate that the residual Sq will cause an uncertainty of 1―2 in K meas-urement, the uncertainty in saturated AE is as much as 50%, and the uncertainty in Dst index caused by the partial ring currents is about a half of the partial ring cur-rent.
基金supported by the National Natural Science Foundation of China under Grant Nos.12275085,12235007,and 12175069Science and Technology Commission of Shanghai Municipality under Grant Nos.21JC1402500 and 22DZ2229014.
文摘The multiple patterns of internal solitary wave interactions(ISWI)are a complex oceanic phenomenon.Satellite remote sensing techniques indirectly detect these ISWI,but do not provide information on their detailed structure and dynamics.Recently,the authors considered a three-layer fluid with shear flow and developed a(2+1)Kadomtsev-Petviashvili(KP)model that is capable of describing five types of oceanic ISWI,including O-type,P-type,TO-type,TP-type,and Y-shaped.Deep learning models,particularly physics-informed neural networks(PINN),are widely used in the field of fluids and internal solitary waves.However,the authors find that the amplitude of internal solitary waves is much smaller than the wavelength and the ISWI occur at relatively large spatial scales,and these characteristics lead to an imbalance in the loss function of the PINN model.To solve this problem,the authors introduce two weighted loss function methods,the fixed weighing and the adaptive weighting methods,to improve the PINN model.This successfully simulated the detailed structure and dynamics of ISWI,with simulation results corresponding to the satellite images.In particular,the adaptive weighting method can automatically update the weights of different terms in the loss function and outperforms the fixed weighting method in terms of generalization ability.
文摘Based on an analysis of symmetry, the dispersion relations near the Ai valley in strained Si1-x Gex （0≤x〈0.45）/ （001）, （111）, （101）Si are derived using the KP method with perturbation theory. These relations demonstrate that △^i levels in strained Si1-x Gex are different from the △1 level in relaxed Si1-x Gex, while the longitudinal and transverse masses （m1^＊ and mt^＊ ） are unchanged under strain. The energy shift between the △^i levels and the △1 level follows the linear deformation potential theory. Finally,a description of the conduction band （CB） edge in biaxially strained layers is given.
基金Supported by NSFC grants(Grant Nos.11171174,11661131005 and 11890662)。
文摘We explain how to construct a quantum deformation of a spectral curve associated to a tau-function of the KP hierarchy.This construction is applied to Witten-Kontsevich tau-function to give a natural explanation of some earlier work.We also apply it to higher Weil-Petersson volumes and Witten’s r-spin intersection numbers.
