Efficient polarized basis sets for evaluation of static and dynamic molecular electric properties

New medium size Gaussian‐type basis set R‐ORP for evaluation of static and dynamic electric properties in molecular systems is presented. It is obtained in a close resemblance to the original ORP basis set, from the source basis set through addition of two first‐order polarization functions whose exponent values are optimized with respect to the finite field restricted open‐shell Hartree–Fock (ROHF) atomic polarizabilities. As the source set the VTZ basis set of Ahlrichs and coworkers, augmented with additional diffuse functions and contracted to the form [6s/3s] for hydrogen and [11s7p/4s3p] for carbon through fluorine, is chosen. The resulting basis set is of the form [6s2p/3s2p] for hydrogen and [11s7p2d/4s3p2d] for other atoms. Presented basis set is next tested in the CCSD static and dynamic molecular polarizability and hyperpolarizability calculations for a set of ten and four test molecules, respectively, for which very accurate reference data exist. Additionally, the recently developed ORP basis set is employed in the calculations to examine the limits of its applicability. Results are compared to the literature data obtained in both, large and diffuse, as well as reduced‐size basis sets. In the case of polarizability calculations, the aug‐pc‐1 and R‐ORP are the optimal choices among the investigated smaller basis sets, with the overall performance of the aug‐pc‐1 set being better. Among the larger sets, the ORP performs better in the case of average polarizability, while the RMSE values for polarizability anisotropy are practically identical for d‐aug‐cc‐pVDZ and ORP sets. Finally, the R‐ORP and ORP basis sets compete other small bases in the evaluation of the first hyperpolarizability in investigated systems. © 2016 Wiley Periodicals, Inc.     

一种提高风能利用率的风力发电机控制策略

在变速恒频风力发电机组的各类并网逆变器控制策略中,零d轴电流控制和空间矢量脉宽调制(SVPWM)以能够提高风能利用系数和稳定逆变器输出电压的优势得到了广泛的应用.在理论研究阶段需要对其进行仿真,然而在Matlab/Simulink中并没有可以实现上述功能的并网仿真模型.因此推导了变速恒频风力发电机组及控制策略的数学模型,并在Matlab/Simulink中完成搭建、当风速恒定不变时,对发电系统的运行情况进行了仿真.结果表明,零d轴电流控制与SVPWM的结合,既提高了风能利用系数,又有效地提高了逆变器的输出电压,保证当电网电压升高时不影响发电系统向电网输送功率的效率.     

电动汽车充电站选址问题研究

研究了电动汽车作为通勤工具情况下的充电站选址问题.首先根据城市通勤道路长度、各条道路上的通勤人员拟使用电动汽车的数量,以及电动汽车的最大续航里程等信息,构建了包含两种边的赋权网络图,进一步将电动汽车充电站选址问题转化为赋权网络图的最大覆盖问题,并建立了以极大化满足用户需求为目标的充电站选址问题整数非线性规划模型,设计了求解模型的启发式算法.最后,通过一个具体算例对模型及算法进行了验证,结果显示,模型和算法是解决电动汽车充电站选址问题有效方法.     

Bioassay‐guided isolation of an active compound with protein tyrosine phosphatase 1B inhibitory activity from Sargassum fusiforme by high‐speed counter‐current chromatography

A rapid and efficient method using high‐speed counter‐current chromatography was established for the bioassay‐guided separation of an active compound with protein tyrosine phosphatase 1B inhibitory activity from Sargassum fusiforme. Under the bioassay guidance, the ethyl acetate extract with the best IC₅₀ value of 0.37 ± 0.07 μg/mL exhibited a potential protein tyrosine phosphatase 1B inhibitory activity, which was further separated by high‐speed counter‐current chromatography. The separation was performed with a two‐phase solvent system composed of n‐hexane/methanol/water (5:4:1, v/v). As a result, dibutyl phthalate (19.7 mg) with the purity of 95.3% was obtained from 200 mg of the ethyl acetate extract. Its IC₅₀ was 14.05 ± 0.06 μM, which was further explained by molecular docking. The result of molecular docking showed that dibutyl phthalate enfolded in the catalytic site of protein tyrosine phosphatase 1B. The main force between dibutyl phthalate and protein tyrosine phosphatase 1B was the hydrogen bond interaction with Gln266. In addition, hydrogen bond, van der Waals force and hydrophobic interaction with the amino acids (Ala217, Ile219, and Gly220) were also responsible for the stable protein‐ligand complex.     

片上制备横向结构ZnO纳米线阵列紫外探测器件

将纳米技术与传统的微电子工艺相结合, 片上制备了横向结构氧化锌(ZnO)纳米线阵列紫外探测器件, 纳米线由水热法直接自组织横向生长于叉指电极之间, 再除去斜向的多余纳米线, 其余工艺步骤与传统工艺相同. 分别尝试了铬(Cr)和金(Au)两种金属电极的器件结构: 由于Cr电极对其上纵向生长的纳米线有抑制作用, 导致横向生长纳米线长度可到达对侧电极, 光电响应方式为受表面氧离子吸附控制的光电导效应, 光电流大但增益低, 响应速度慢, 经二次电极加固, 纳米线根部与电极金属直接形成肖特基接触, 光电响应方式变为光伏效应, 增益和速度得到了极大改善; 由于Au电极对其上纵向生长的纳米线有催化作用, 导致溶质资源的竞争, 相同时间内横向生长的纳米线不能到达对侧, 而是交叉桥接, 但却形成了紫外光诱导的纳米线间势垒结高度调控机理, 得到的器件特性为最优, 在波长为365 nm的20 mW/cm²紫外光照下, 1 V电压时暗电流为10^-9 A, 光增益可达8×10⁵, 响应时间和恢复时间分别为1.1 s和1.3 s.     

四轮轮毂电动汽车横摆角速度自抗扰控制

汽车的横摆角速度对汽车稳定性和安全性有较大影响,针对汽车行驶控制时的抗干扰能力,目前还没有特别有效的汽车横摆角速度控制策略;创新性设计了基于自抗扰控制理论的用于四轮轮毂电动汽车横摆角速度的高性能控制策略;首先分析了汽车横摆角速度控制的动态模型,并通过数学变换,将其转换为二阶自抗扰控制器被控对象的标准形式;再设计双层控制结构,包括直接横摆力矩制定层和转矩分配层;在直接横摆力矩制定层,利用二阶自抗扰控制器计算出控制汽车横摆角速度所需的附加横摆力矩;在转矩分配层,设计了转矩分配算法,利用附加横摆力矩得到4个车轮的指令转矩,进而控制电动汽车横摆角速度;最后,通过Matlab/Simulink和汽车动力学仿真软件CarSim联合仿真验证了所设计控制策略的有效性。     

可接入射频半实物的试验数据转换系统设计与实现

试验环节是产品研制生命周期中的重要环节,但是一直以来都缺乏有效的管理手段,在整个测试阶段都存在大量的人为的、重复性的工作,导致试验效率低下,为改善这一现状,提高试验效率,提出了一种基于PXIe数据采集系统,借助LabVIEW和DIAdem软件的测试系统解决方案：以LabVIEW控制数据高速同步采集,DIAdem调用LabVIEW模块执行算法分析,通过软件集成,实现对测试系统的全面管理,包括数据采集、数据检索、数据分析、报表生成及整个流程的自动化控制。本文以C919飞机电源测试系统为介绍对象,对该套测试系统解决方案进行阐述,实际测试情况表明,在数据吞吐率大于200M/S的情况下,相对传统测试方法,该测试方案在保证测试精度的基础上,极大的提高了试验效率,极大的提高了系统的可扩展性和可维护性。     

场板结终端对金刚石SBD内部电场分布及击穿特性的影响

建立了场板结终端对金刚石肖特基势垒二极管(SBD)的数值模拟模型,采用Silvaco软件中的器件仿真工具ATLAS模拟了场板长度L、绝缘层厚度TOX、衬底掺杂浓度NB、场板结构形状对器件内部电场分布以及击穿电压的影响,并对结果进行了物理分析和解释。结果表明:当TOX=0.4μm、NB=1015cm-3、L在0~0.2μm范围内时,击穿电压随着L的增加而增加;L0.2μm后,击穿电压开始下降。当L=0.2μm、NB=1015cm-3、TOX在0.1~0.4μm范围内时,击穿电压随着TOX的增加而增加;TOX0.4μm后,击穿电压开始下降。当L=0.2μm、TOX=0.4μm、NB=1015cm-3时,器件的击穿电压达到最大的1 873 k V。与普通场板结构相比,采用台阶场板可以更加有效地提高器件的击穿电压。     

Control of EOF in CE by different ways of application of radial electric field

Various ways of application of radial electric field for the control of electrokinetic potential and EOF in a home-made device for CE are presented. The device comprises three high-voltage power supplies, which are used to form a radial electric field across the fused-silica capillary wall. One power supply provides the internal electric field - a driving force for electrophoretic migration of charged analytes and for the EOF. Two power supplies are connected to the ends of the outer low-conductivity polymeric coating, which is formed by the dispersion of insoluble conductive copolymer of aniline and p-phenylendiamine in polystyrene matrix (dissolved in N-methylpyrrolidone) attached to the original outer polyimide coating of the capillary. They are able to constitute the external longitudinal electric field with variable values of electric potential at both ends of the outer coating. The potential gradient between the external and internal electric field is perpendicular to the capillary wall and forms a radial electric field across the capillary wall, which affects the electrokinetic potential at the solid-liquid interface and EOF inside the capillary. The developed device and methodology has been applied for the analysis of both chiral and achiral molecules such as terbutaline enantiomers and oligopeptides (diglycine and triglycine). The effect of magnitude, orientation, and different ways of application of the radial electric field on the flow rate of the EOF and on the speed, efficiency, and resolution of CZE separations of the above analytes in the internally noncoated fused-silica capillaries have been evaluated.     

Modeling and simulation of chemo-electro-mechanical behavior of pH-electric-sensitive hydrogel

A chemo-electro-mechanical multi-field model, termed the multi-effect-coupling pH-electric-stimuli (MECpHe) model, has been developed to simulate the response behavior of smart hydrogels subject to pH and electric voltage coupled stimuli when the hydrogels are immersed in a pH buffer solution subject to an externally applied electric field. The MECpHe model developed considers multiphysics effects and formulates the fixed charge density with the coupled buffer solution pH and electric voltage effects, expressed by a set of nonlinear partial differential governing equations. The model can be used to predict the hydrogel displacement and the distributive profiles of the concentrations of diffusive ionic species and the electric potential and the fixed charge density in both the hydrogels and surrounding solution. After validation of the model by comparison of current numerical results with experiment data extracted from the literature, one-dimensional steady-state simulations were carried out for equilibrium of the smart hydrogels subject to pH and electric coupled stimuli. The effects of several important physical conditions, including the externally applied electric voltage, on the distributions of the concentrations of diffusive ionic species, the electric potential, the fixed charge density, and the displacement of the hydrogel strip were studied in detail. The effects of the ionic strength on the bending deformation of the hydrogels under the solution pH and electric voltage coupled stimuli are also discussed.