摘要：以聚乙二醇(PEG)为软段,六亚甲基二异氰酸酯为硬段,三聚氰胺为交联剂,制备出交联聚氨酯(CLPU),研究了不同PEG分子量对其相变性能的影响.结果表明,CLPU的焓值和相变温度随PEG分子量的改变而发生规律性变化,其中以PEG2000为原料制备的聚氨酯固固相变材料(PU-SSPCM),相变温度(T_(m)=39.9℃,T_(c)=8.7℃)在人体舒适温度区间,焓值在56.6 J/g以上,100次热循环后其性能基本保持不变.此外,还探讨了三聚氰胺含量对CLPU2000性能的影响,结果表明,随着三聚氰胺含量的增加,所得聚氨酯的焓值会降低,而相变温度则略有上升.所得聚氨酯体系具有良好的相变调温功能,将其置于手心100 s后与体温仍有3.8℃的温差.该材料体系在人体热管理领域具有广阔的应用前景,有望在智能调温服装、红外隐身等领域发挥重要作用.

摘要：基于组件的软件开发技术成为当前软件业的热点之一。COM/DCOM为分布式系统提供了一种基于组件模型的标准。本文介绍了用COM/DCOM技术实现MIS开发平台中自定义用户数据库子系统的功能设计。

摘要：目的了解北京社区人群血浆叶酸水平,探究影响叶酸水平的相关因素。方法采用横断面研究设计,对北京石景山社区居民进行问卷调查及血浆叶酸水平测定。研究共纳入5 227名研究对象。结果研究人群血浆叶酸的中位数（P25,P75）为6.18（4.98-8.18）ng/ml,其中男性为5.29（4.49-6.75）ng/ml,明显低于女性[6.79（5.45-9.02）ng/ml]。血浆叶酸水平（自然对数）的多因素线性回归分析显示：肥胖（β=-0.037,P=0.008 6）、吸烟（β=-0.118,P〈0.000 1）的个体叶酸水平（自然对数）较低;较高年龄（β=0.003,P〈0.000 1）、女性（β=0.186,P〈0.000 1）、更高的受教育程度（β=0.039,P=0.000 5）、近3个月来每周不少于5 d的运动（β=0.037,P=0.008 6）及每周不少于3 d补充B族维生素（β=0.299,P〈0.000 1）的个体血浆叶酸水平（自然对数）较高。按性别分层分析,肥胖及运动仅与女性的叶酸水平（自然对数）有关联（P〈0.05）,而其他因素对叶酸的影响趋势无性别差异。结论北京社区人群血浆叶酸处于较低水平;个体差异、生活方式及维生素的补充对叶酸水平产生影响。

摘要：　高斯计是测量空间磁场强度的计量仪表,广泛应用于以电磁场理论为基础的电气、通讯等行业.由于工科院校相继开设通讯信息专业,实验室用高斯计具有极大的需求量.本文首先介绍数字高斯计的特点,工作原理,然后从软、硬件两方面介绍数字高斯计的研制方法.

摘要：Strong shock waves and flow separation often occur during the integration of nacelle and airframe for blended-wing-bodies with podded engines. To address this problem, this paper presents an integration method with numerical simulations. The philosophy of channeling flow and avoiding the throat effect on the nacelle and airframe is established based on the analysis of flow interference in the initial configuration. A parametric integration design method is proposed from twodimensional plane to three-dimensional space with control mechanisms and selection principles of the key parameters determined by their influences. Results show that strong shock waves and flow separation can be successfully eliminated under the influence of both the reshaped channel and decelerated inflow below the nacelle. Supersonic regions around the nacelle are effectively reduced, concentrating mainly on the lip position. Thus, a significant cruise drag reduction(8.7%) is achieved though the pressure drag of the nacelle increases.

摘要：Tin monosulfide(Sn S), which is composed of earth-abundant elements, holds promise as useful high-performance solar absorber and thermoelectric material. In addition to the ground-state Pnma phase, a series of metastable phases in different crystalline structures have been reported experimentally or theoretically, yet the phase stability diagrams remain elusive. In this article, we provide a comprehensive materials design study of new phases of Sn S using first-principles global optimization structure search calculations. We find that the two-dimensional layered phases are generally more energetically favored than the three-dimensional connected phases. In addition, we discover several new phases with comparable energetics. Four lower-energy phases show clear phonon stabilities evidenced by an absence of imaginary modes. The electronic band structures, carrier transport properties, and absorption spectra of the newly discovered phases are investigated and discussed toward potential applications for solar cells and thermoelectric devices.

摘要：针对新能源特性与油气连续生产制度不匹配、常规装备及工艺与油田智能生产不适应、当前生产管控制度与协同生产管控及能源综合利用不完备的问题,开展了低碳零碳智能采油气井场新型建设模式探讨。文章分析了采油气井场生产用能特征,设计了新型的绿色智能采油气井场生产用能供配能模式。研究了油气生产多能微网协同管控关键技术,即实时感知、预测新能源供电功率和生产用能侧需求,协同优化源—网—荷—储配置及运行调度,通过微网优化控制器进行多能源耦合互补、多元负荷协同调控,提升油气生产能源使用的计划性和效率,减少弃风、弃光、弃热,解决了清洁替代中能源转换高成本、现有采油气工艺不适应新能源特点、消纳能力低的难题。实例分析了低碳零碳智能油气井场实践案例,指出了“光风能+直流母线+智能间开+电机柔性驱动”组合模式是解决低产低效抽油机井群生产提质增效的技术创新,助力了采油气生产实现从“安全高效”到“低碳智能”的跨越。

摘要：A concept of hierarchical stiffened shell is proposed in this study, aiming at reducing the imperfection sen- sitivity without adding additional weight. Hierarchical stiffened shell is composed of major stiffeners and minor stiff- eners, and the minor stiffeners are generally distributed between adjacent major stiffeners. For various types of geo- metric imperfections, e.g., eigenmode-shape imperfections, hierarchical stiffened shell shows significantly low imper- fection sensitivity compared to traditional stiffened shell. Furthermore, a surrogate-based optimization framework is proposed to search for the hierarchical optimum design. Then, two optimum designs based on two different opti- mization objectives （including the critical buckling load and the weighted sum of collapse loads of geometrically imperfect shells with small- and large-amplitude imperfections） are compared and discussed in detail. The illustrative example demonstrates the inherent superiority of hierarchical stiffened shells in resisting imperfections and the effectiveness of the proposed framework. Moreover, the decrease of imperfection sensitivity can finally be converted into a decrease of structural weight, which is particularly important in the development of large-diameter launch vehicles.

摘要：为了实现单次扫描条纹相机扫描控制模块中斜坡信号的高电压阈值、高线性斜坡、电路简单且易调试的目标,提出了利用开关放电产生大电流高压脉冲和恒流充电斜坡线性好的优点,设计出一款单次扫描线性高压斜坡信号产生电路,该电路可通过调节电阻的大小,实现线性斜坡信号斜率和线性率的调节和优化。实验表明,该电路所产生的线性高压斜坡信号可提供幅值高达1700 V的电压,产生的斜坡非线性精度小于3%,扫描时间可实现200 ns至50μs可调。与传统高压斜坡信号电路相比,电路结构简单,调试方便,斜坡时间可实现纳秒到微秒的无级调整,这可有效提高条纹相机扫描时间精度,有效减小电路串扰等问题。

摘要：本文设计合成了一系列杜仲活性成分香豆素类与苯丁酸氮芥衍生物(B-1~B-4),所有化合物均通过1HNMR、13C-NMR、HRMS进行结构确认。通过CCK-8法筛选出新型衍生物B-2对A-253细胞具有较高的抗增殖作用,IC_(50)值为18.490±1.398μM,且对人正常细胞的毒性最低,IC_(50)值为80.9±10.432μM。采用流式细胞术、蛋白免疫印迹技术、吖啶橙AO染色等方法,研究了B-2对A-253细胞细胞凋亡、细胞周期及线粒体膜电位的影响。研究发现,随着B-2浓度的升高,A-253细胞处于G2/M期的比例升高,凋亡细胞逐渐增多,线粒体功能受损逐渐加重。B-2以浓度依赖的方式下调了细胞周期相关蛋白CDK2和Cyclin A2的表达,使A-253细胞周期停滞;上调细胞凋亡关键蛋白Cleaved caspase-3和Cleaved PARP而诱导A-253细胞发生凋亡;激活自噬相关标记物Beclin 1和LC3的表达,诱导A-253细胞发生自噬,进一步抑制细胞生长。