低压差线性稳压器电磁抗扰度测试与建模

采用直接功率注入法,在1 MHz~2 GHz频率范围的传导电磁干扰下,测试获得了低压差线性稳压器的传导电磁抗扰度。针对抗扰度仿真预测,提出了一种以Taylor级数表示的非线性系统和以线性滤波器表示的线性系统的级联模型,同时对于测试系统中分立器件采用传统集总参数方法建模,最终实现低压差线性稳压器的传导电磁干扰仿真。仿真结果表明,模型在1 MHz~2 GHz范围内预测的抗扰度和测试数据具有很好的一致性。     

WO3/ZnO复合光催化剂的制备及其光催化性能

采用沉淀-研磨法制备了一系列不同WO3含量的WO3/ZnO复合光催化剂,应用N2物理吸附、X射线衍射、扫描电镜、傅里叶变换红外光谱、紫外-可见光谱和光致发光谱等手段对催化剂进行了表征,并以λ=365nm的紫外光为光源,评价了该催化剂光催化降解酸性橙Ⅱ的活性,考察了WO3的复合对WO3/ZnO样品光催化性能的影响.结果表...     

负载锑的水滑石催化环己酮Baeyer-Villiger氧化制ε-己内酯

 通过浸渍法制备了负载Sb的镁铝水滑石类化合物Sb/HT, 用X射线衍射(XRD)和热重(TG)等技术对催化剂的结构进行了表征,研究了其对环己酮Baeyer-Villiger(BV)氧化制ε-己内酯的催化性能,考察了催化剂制备条件和反应条件对催化活性的影响以及催化剂的再生性能. 结果表明,在乙腈作为溶剂的体系中,负载Sb的镁铝水滑石对环己酮氧化制ε-己内酯具有较高的催化活性. 在水滑石前驱体中镁/铝摩尔比为3, Sb含量为1.5%和焙烧温度为450 ℃时制备的Sb/HT催化剂的催化活性最高,在10 ml乙腈和140 mmol 30%H2O2中于70 ℃反应4 h后,环己酮的转化率达42%,ε-己内酯选择性达94%. 催化剂可多次再生重复使用,催化活性稳定.     

Analysis of RF heating and sample stability in aligned static solid-state NMR spectroscopy

Sample instability during solid-state NMR experiments frequently arises due to RF heating in aligned samples of hydrated lipid bilayers. A new, simple approach for estimating sample temperature is used to show that, at 9.4 T, sample heating depends mostly on (1)H decoupling power rather than on (15)N irradiation in PISEMA experiments. Such heating for different sample preparations, including lipid composition, salt concentration and hydration level was assessed and the hydration level was found to be the primary parameter correlated with sample heating. The contribution to RF heating from the dielectric loss appears to be dominant under our experimental conditions. The heat generated by a single scan was approximately calculated from the Q values of the probe, to be a 1.7 degrees C elevation per single pulse sequence iteration under typical sample conditions. The steady-state sample temperature during PISEMA experiments can be estimated based on the method presented here, which correlates the loss factor with the temperature rise induced by the RF heating of the sample.     

SOD1抑制与活性氧信号转导的调控

铜锌超氧化物歧化酶（Copper-zinc Superoxide Dismutase,SOD1）是胞内广泛存在的抗氧化酶,催化O₂^·-歧化为H₂O₂和O₂,维持胞内活性氧物种（ROS）内稳态。癌细胞的生长、增殖都依赖于适度高浓度的H₂O₂,高表达的SOD1维持癌细胞内较高水平的H₂O₂和ROS内稳态。抑制癌细胞内SOD1的活性,可以有效调节ROS信号通路,抑制癌细胞的生长、增殖,阻滞癌细胞周期,促进癌细胞凋亡。因此,通过抑制其活性调控癌细胞内ROS信号网络并选择性杀死癌细胞已经成为抗癌药物设计的一个重要方向。本文主要总结了各类SOD1抑制剂,以及SOD1抑制对ROS信号转导的调控,分析了SOD1特异抑制选择性杀死癌细胞的机制。     

Examination of functional zwitterionic polymer hydrogels based on polypyridinium salt by a convenient cross-linker

In this work, two novel zwitterionic polymer hydrogels (Gel-P4VP-psl (d), Gel-P4VP-bpa (d)) and cationic polymer hydrogels (Gel-P4VP-eb (f)) were prepared for the first time. The differences of functionality between cationic polymer hydrogels and zwitterionic polymer hydrogels were studied fully. The results showed that when the molar quantity ratio of cross-linker/pyridinium unit in Gel-P4VP-psl (d) and Gel-P4VP-bpa (d) was about 0.25:1, they would have proper mechanical property, excellent antibacterial ability and antifouling ability. Correspondingly, the charge quantity ratios of negative charges/positive charges in Gel-P4VP-psl (d) and Gel-P4VP-bpa (d) could be calculated to be 1:2 theoretically. Although Gel-P4VP-eb (f) with only positive charges had strongly antibacterial ability, being lack of negative charges in cationic polymer hydrogels made its antifouling ability disappear completely. Gel-P4VP-psl (d) and Gel-P4VP-bpa (d) have potential in the application of antibacterial and antifouling materials.     

强震作用下RC延性框架的简化计算

提出了一种RC延性框架抗震设计方法,选取合理的倒塌机构并用虚功原理将其转化为等效的单自由度系统,针对选取的倒塌机构、设防烈度及场地条件计算刚塑性反应谱并据此计算结构的动力需求。以五层和九层RC框架为算例并与弹塑性时程分析比较,研究表明该方法计算简单,精度可靠,可以满足强烈地震作用下RC延性框架抗震设计要求。     

润滑脂数据库的数据模型与功能模块设计

在“百科全书”和“坑口电站”的设计思想指导下，规划设计了润滑脂数据库．这种数据库设计有９条查询途径，查询得到有关润滑脂的各种数据、资料和知识；设计有８个功能模块，使数据库具有查询、选用、代用、故障诊断与失效分析、学习、设计计算和维护等功能，因而数据库具有广泛的应用价值     

A test for a parametric form of the volatility in second-order diffusion models

Second-order diffusion models have been found to be promising in analyzing financial market data. Based on nonparametric fitting, Nicolau (Stat Probabil Lett 78(16):2700–2704, 2008) suggested that the quadratic function may be an appropriate specification of the volatility when a second-order diffusion model is used to analyze some European and American financial market data sets, which motivates us to develop a formal statistical test for this finding. To achieve the task, a generalized likelihood ratio test is proposed in this paper and a residual-based bootstrap is suggested to compute the p value of the test. The analysis of many real-world financial market data sets demonstrates that the quadratic specification of the volatility function is in general reasonable.     

Improved chemical synthesis of o-nirtrobenzyl-tyrosine for concise site-specific 15N-tyrosine NMR analysis demonstrated by plant ABA receptor PYL10

The yield of unnatural amino acid o-nitrobenzyl-tyrosine (oNBTyr), which was able to recover to natural tyrosine after UV-photocleavage was greatly improved from 20% to 81% by using 2-nitrobenzyl bromide as the nucleophilic reagent. Through genetically introducing ¹⁵N-oNBY and consequent photo-cleavage, the site-specific ¹⁵N-Tyr NMR analysis of plant ABA (abscisic acid) receptor PYL10 was implemented without any residue variation. This isotope labelling of tyrosine onto protein backbone provides a convenient strategy for NMR analysis.