摘要：It is very important to analyze and study the motion process of droplets impacting superhydrophobic surface, which is of great significanee to understand the mechanism of superhydrophobic surface and guide the design and manufacture of superhydrophobic surface. Taking by three-dimensional volume of fluid (VOF) simulation coupling coupled level set (CLS) algorithm, on the one hand, we simulate the morphological changes in the process of droplet impingement, as well as the internal velocity and the pressure distribution;on the other hand,we focus on the effects of droplet impact velocity, surface wettability, surface tension on the dynamics of the droplets. The CLSVOF model inherits the advantages of the VOF model for accurately constructing the phase interface and inherits the advantage that the level set can accurately calculate the surface tension, which improves the accuracy of the calculation of the droplet impact on the superhydrophobic surface. The computed results distinctly demonstrated there were four stages: falling, spreading, shrinking and rebounding. The time history of each stage agreed well with the pictures captured by high-speed camera, which indicated the computational fluid dynamics scheme was effective. Moreover, the motion mechanism of the droplets impacting on the solid surface is elaborated, which was helpful to control the solid-liquid interface to achieve a variety of solid interface characteristics.

摘要：四开关升降压(four-switch Buck-Boost,FSBB)变换器凭借其出色的软开关特性、宽范围调压能力、输入输出电压极性相同等优势被应用在数据中心供电架构中。然而,FSBB变换器软开关控制方式的多控制自由度特性,使得其控制策略复杂多变、增加了效率优化的难度。针对以上问题,研究并设计一种多模式高效控制策略,以提高FSBB变换器在全负载范围内的转换效率。首先,在FSBB变换器零电压开通(zero voltage switch,ZVS)的基础上得到控制量的约束条件,并确定电感电流有效值最低时控制量的取值规则;然后,构建FSBB变换器完整的损耗模型,以总损耗最低为目标,提出一种多模式的高效控制策略,并通过数据拟合的方式进行控制量的设计;最后,在Simplis中仿真验证并制作一个300 W的实验样机。测试结果表明:所设计的实验样机能在全输入、输出电压范围和全负载范围内实现较高的转换效率。其中最高峰值效率达到98.5%、最高平均效率达到97.93%,开关频率范围为500 kHz~1 MHz。

摘要：In silico modeling and analysis of small molecules substantially accelerates the process of drug development. Representing and understanding molecules is the fundamental step for various in silico molecular analysis tasks. Traditionally, these molecular analysis tasks have been investigated individually and separately.

摘要：Purpose：The aim of the study was to examine the knowledge need toward Traditional Chinese Medicine （TCM） in nurses who worked in Community Health Centers, and to explore the related factors in the current situation of China. Subject and setting： Participants worked in five community health centres across Chaoyang Beijing, and each com- munity health centre includes 4-7 health stations. A questionnaire survey was administered to 218 registered commu- nity nurses using cluster sampling. The investigation was conducted after obtaining informed consent from each par- ticipant. Design： A descriptive cross-sectional design was used to gather data in this study. Instruments： The survey tool was a 5-point Likert-type questionnaire designed by experts in TCM and related fields, which had good face va- lidity and internal consistency. Results： The nursing technology of TCM scored highest score in our research （42.87±5.74）. Next came disease prevention in TCM （21.02±2.67）. The lowest mean score was for the usage of Chinese herbal medicine （15.03±2.77）. The significant related factors for nurses＇ knowledge need towards TCM were educa- tional background （P 〈 0.05）, working unit （P 〈 0.01）, ＂on-the-job training on TCM＂ （P 〈 0.01） and ＂have studied lit- erature on Chinese medicine＂ （P 〈 0.05）. Conclusion： This results suggest nurses working in community care would like to learn more about TCM. Improving community nurses＇ understanding and learning of TCM can promote the application and promotion of TCM nursing technology in the community. Therefore, we could adopt targeted education for community nurses, in order to meet their knowledge needs, and to promote the application of traditional Chinese medicine knowledge to the community.

摘要：为精确计算各类型截面钢筋混凝土偏心受压构件的截面应力,提出一种基于优化算法的计算方法,该方法考虑受拉区混凝土退出工作后截面的应力重分布效应。首先,将中性轴方程参数作为优化变量,以受压区混凝土和全部钢筋提供的截面抵抗力矩与外荷载差作为目标函数,采用优化算法搜索目标函数最小时的中性轴位置,实现内外力平衡;随后,根据所提出方法编制FORTRAN程序,以7个不同类型的截面为算例,验证提出方法和程序;最后,将应力计算程序编译连接进有限元程序ANSYS UPFs提供的用户命令子程序中,进行二次开发,实现梁单元模拟的钢筋混凝土构件截面应力计算功能。研究结果表明:算例的外荷载与截面抵抗力矩的差值均较小,采用提出方法计算截面应力的精度较高;编制程序可应用于任意截面的双向偏心受压构件应力重分布计算,通用性较强;二次开发后的ANSYS程序可大幅提高在荷载步较多时的截面应力分析效率;提出的优化数学模型建立思路,以及对ANSYS二次开发实现定制功能的方法可为解决同类工程问题提供参考。

摘要：针对传统圣女果品质质量分级机只能通过圣女果果实大小进行分级,不能检测圣女果表面缺陷的问题,采用迁移学习方法,对比不同的网络模型,选出更适用于进行圣女果果实表面缺陷识别的神经网络InceptionV3。以InceptionV3为基本模型进行改进。首先,通过引入并修改宽度因子α来压缩通道数量,提高模型训练速度;然后,修改全连接层神经元个数;最后,插入注意力网络结构并对比插入不同的注意力网络结构,提出一种基于改进InceptionV3神经网络的深度学习模型(N—InceptionV3_FD)。结果表明,N—InceptionV3_FD模型在圣女果表面缺陷检测识别中准确率达97.06%,比原InceptionV3模型提高7.84个百分点,且损失函数值更加平稳,稳定在0.1左右,为圣女果的表面缺陷检测提供理论基础。

摘要：In this study,the Cr2O3/C@TiO2 composite was synthesized via the calcination of yolk–shell MIL-101@*** composite presented core–shell structure,where Cr-doped TiO2 and Cr2O3/C were the shell and core,*** introduction of Cr^3+and Cr2O3/C,which were derived from the calcination of MIL-101,in the composite enhanced its visible light absorbing ability and lowered the recombination rate of the photogenerated electrons and *** large surface area of the Cr2O3/C@TiO2 composite provided numerous active sites for the photoreduction ***,the photocatalytic performance of the composite for the production of H2 was better than that of pure *** the irradiation of a 300 W Xe arc lamp,the H2 production rate of the Cr2O3/C@TiO2 composite that was calcined at 500°C was 446μmol h−1 g−1,which was approximately four times higher than that of pristine TiO2 ***,the composite exhibited the high H2 production rate of 25.5μmol h−1 g−1 under visible light irradiation(λ>420 nm).The high photocatalytic performance of Cr2O3/C@TiO2 could be attributed to its wide visible light photoresponse range and efficient separation of photogenerated electrons and *** paper offers some insights into the design of a novel efficient photocatalyst for water-splitting applications.

摘要：In order to enhance the targeted delivery of anticancer drugs by polymeric micelles, folic acid(FA), the ligand of folate receptor(FR) over-expressed in the most cancer cells, modified p H-sensitive polymeric micelles were designed and fabricated to encapsulate doxorubicin(DOX) by combination of p H-sensitive amphiphilic polymer poly(2-ethyl-2-oxazoline)-poly(D,L-lactide) with FA-conjugated poly(2-ethyl-2-oxazoline)-poly(D,L-lactide). The prepared micelles were characterized to have about 36 nm in diameter with narrow distribution, well-defined spherical shape observed under TEM and p H-responsive drug release behavior. Moreover, the tumor targeting ability of the FA-modified p H-sensitive polymeric micelles was demonstrated by the cellular uptake, in vitro cytotoxicity to FR-positive KB cells and in vivo real time near-infrared fluorescence imaging in KB tumor-bearing nude mice. The efficient drug delivery by the micelles was ascribed to the synergistic effects of FR-mediated targeting and p H-triggered drug release. In conclusion, the designed FR-targeted p H-sensitive polymeric micelles might be of great potential in tumor targeted delivery of water-insoluble anticancer drugs.

摘要：基于CRISPR/Cas9系统的基因编辑已被成功应用于多种细胞类型中。计算机辅助的向导RNA(Guide RNA)设计是使用CRISPR系统成功进行基因编辑的关键步骤之一。目前的计算工作主要致力于利用计算模型来提高sgRNA的打靶效率并降低其脱靶。文中对于目前存在的sgRNA设计工具进行综述,并且说明可以通过建立高效的计算模型,对当前的异质基因编辑数据进行整合挖掘,以获得无偏差的sgRNA设计规则,并预测影响sgRNA设计的关键特征。笔者认为,对于sgRNA打靶和脱靶效果的系统总结和评价,将有助于使用CRISPR系统进行更加精准的基因编辑和基因治疗。

摘要：针对空冷型质子交换膜燃料电池(PEMFC)电堆温度控制问题,设计一种模糊自整定串级PID(FSC-PID)温度控制器,并基于Matlab/Simulink建立空冷型PEMFC电堆热模型,对所设计的FSC-PID控制器进行仿真和性能对比分析。仿真测试结果表明,FSC-PID温度控制器在控制精度、响应速度和稳定性等方面均优于常规串级PID控制器。为验证FSC-PID控制器的实际应用效果,基于STM32平台并使用300 W电堆进行FSC-PID温度控制实验。实验结果表明,FSC-PID能有效控制电堆温度,保证电堆的性能和寿命,进一步验证所建立热模型的准确性和可靠性。