Synthesis of amphoteric nanocomposite hydrogels with ultrahigh tensibility

Amphoteric nanocomposite hydrogels (NC gels) were synthesized by in situ copolymerization of acrylic acid (AA) and N[‐3(dimethylamino)propyl] methacrylamide (DMAPMA) in an aqueous dispersion of laponite XLG. Mechanical analyses demonstrated that this type of hydrogels had a combination of high tensile strength and excellent stretchability. The tensile strength was increased by 5 times up to 316 kPa when the laponite content was increased from 0.1 wt% to 20 wt%, and a maximum fracture strain of 2,317% was achieved for hydrogels containing 3 wt% laponite. Additionally, the marked improvements in strength were achieved with minimal sacrifice of the tensibility. This work provided a continuation to previous efforts of the preparation and properties of ionic NC gels. POLYM. COMPOS. 36:538–544, 2015. © 2014 Society of Plastics Engineers     

High performance modification of hyperbranched polyborate on diglycidyl ether of bisphenol‐a resin

High performance epoxy resin was obtained by introducing hyperbranched polyborate (HBPB) into diglycidyl ether of bisphenol A (DGEBA) resin to overcome the defects such as low char yield and poor toughness of DGEBA resin. By virtue of the massive functional end groups, hyperbranched and rigid boron‐containing structures of HBPB, the thermal resistance of DGEBA resin cured with diamino diphenyl sulfone (DDS) can be greatly improved. Moreover, with the toughening effect of hyperbranched structures of HBPB, the mechanical properties such as flexural strength and interlaminar shear strength of the carbon fiber reinforced DGEBA‐DDS composite could be greatly increased by HBPB without a decrease on modulus and glass transition temperature of DGEBA‐DDS resin. POLYM. COMPOS. 36:424–432, 2015. © 2014 Society of Plastics Engineers     

Performance enhancement of multicrystalline silicon solar cells and modules using double‐layered SiNx:H antireflection coatings

Silicon nitride coating deposited by the plasma‐enhanced chemical vapor deposition method is the most widely used antireflection coating for crystalline silicon solar cells. In this work, we employed double‐layered silicon nitride coating consisting of a top layer with a lower refractive index and a bottom layer (contacting the silicon wafer) with a higher refractive index for multicrystalline silicon solar cells. An optimization procedure was presented for maximizing the photovoltaic performance of the encapsulated solar cells or modules. The dependence of their photovoltaic properties on the thickness of silicon nitride coatings was carefully analyzed. Desirable thicknesses of the individual silicon nitride layers for the double‐layered coatings were calculated. In order to get statistical conclusions, we fabricated a large number of multicrystalline silicon solar cells using the standard production line for both the double‐layered and single‐layered antireflection coating types. On the cell level, the double‐layered silicon nitride antireflection coating resulted in an increase of 0.21%, absolute for the average conversion efficiency, and 1.8 mV and 0.11 mA/cm² for the average open‐circuit voltage and short‐circuit current density, respectively. On the module level, the cell to module power transfer factor was analyzed, and it was demonstrated that the double‐layered silicon nitride antireflection coating provided a consistent enhancement in the photovoltaic performance for multicrystalline silicon solar cell modules than the single‐layered silicon nitride coating. Copyright © 2015 John Wiley & Sons, Ltd.     

一种高精度数字可调RC振荡器设计

在对常见的RC振荡器进行分析比较的基础上,提出了一种高精度的RC振荡器。对其进行温度补偿的改进,并采用数字修调方式实现频率微调以消除电源及工艺带来的误差,双比较器对称性结构设计有效的消除了比较器迟滞带来的频率误差。利用CSMC的0.5μm工艺Bsim3模型和Hspice仿真器对该电路进行了模拟和仿真,结果表明该电路与传统的振荡器相比具有精度高、误差可调的优点。最后对该电路进行版图设计。     

酶法快速测定植物油中游离甾醇

目的 基于甾醇在胆固醇氧化酶的作用下与显色剂产生显色反应,建立了固相萃取结合酶法测定植物油中游离甾醇含量的快速检测方法。方法 采用固相萃取（Solid Phase Extraction, SPE）结合酶法40 min内实现对植物油中的游离甾醇含量测定,并应用于植物油中游离甾醇含量的测定。结果 方法学验证的结果显示,植物甾醇含量在浓度范围0.3~7.5 mg/mL之间线性良好,检出限为0.018 mg/g,日内精密度为7.94%,日间精密度为6.88%,回收率在84.75%~99.50% 之间,实际样品的检测结果显示,酶法与气相色谱-串联质谱法（gas chromatography-tandem mass spectrometry, GC-MS）的相对误差在±20%以内,且酶法的检测效率比GC-MS法提高3倍。常见的几种植物油中,游离甾醇含量较高的是玉米油和菜籽油,分别为1.53~3.66 mg/g和1.98~3.02mg/g。结论 本研究建立的SPE结合酶法检测植物油中游离甾醇的快速检测方法稳定性、重现性好、灵敏可靠,可满足植物油中游离甾醇的现场批量快速检测。     

基于滤波与图优化的定位与建图系统

针对室外大场景环境建图精度不高,地图出现重影和漂移等问题,提出一种融合滤波与图优化理论实时定位与建图系统。该系统由点云数据预处理、基于滤波紧耦合惯性里程计和后端位姿图优化等三部分构成。首先,点云数据预处理采用随机采样一致性算法分割地面,并提取地面模型参数构建后端优化中的地面约束因子。然后,前端紧耦合惯性里程计采用迭代误差状态卡尔曼滤波,以激光里程计作为观测值,IMU预积分结果作为预测值,通过构建联合函数,滤波融合得到较为精准的激光惯导里程计。最后,后端结合图优化理论引入闭环因子、地面约束因子以及帧与图匹配的里程计因子作为约束条件,构建因子图并优化地图位姿。其中闭环因子采用改进的扫描文本的闭环检测算法进行位置识别,可以降低环境误识别率。本文提出的算法在室外厂区楼栋,停车场以及室内车间等多个场景完成场景建图,在距离,水平和高程三个方向的累积偏差均控制10厘米左右,能够有效解决地图的重影和漂移问题,具有高鲁棒性和高精度。     

一种分布式自治物流信息系统构架

针对物流企业及零售商分散的特点和客户的多样化个性化需求,为了整合分散的物流信息,建立具有弹性的物流对象协同运作模式,解决RFID与该构架的信息集成,提出了一种基于Internet的分布式协调自治物流信息系统构架。详细描述了系统的各关键环节。     

Identification and Functional Analysis of a Defensin CcDef2 from Coridius chinensis

Coridius chinensis belongs to Dinidoridae, Hemiptera. Previous studies have indicated that C. chinensis contains abundant polypeptides with antibacterial and anticancer activities. Antimicrobial peptides (AMPs), as endogenous peptides with immune function, play an indispensable role in the process of biological development and immunity. AMPs have become one of the most potential substitutes for antibiotics due to their small molecular weight and broad-spectrum antimicrobial activity. In this study, a defensin CcDef2 from C. chinensis was characterized based on bioinformatics and functional analyses. The mature peptide of CcDef2 is a typical cationic peptide composed of 43 amino acid residues with five cations, and contains three intramolecular disulfide bonds and a typical cysteine-stabilized αβ motif in defensins. Phylogenetic analysis showed that CcDef2 belongs to the insect defensin family. Analysis of gene expression patterns showed that CcDef2 was expressed throughout developmental stages of C. chinensis with high levels at the nymphal stage and in adult tissues tested with the highest level in the fat body. In addition, the CcDef2 expression was significantly upregulated in adults infected by bacteria. After expressed in Escherichia coli BL21(DE3) and renatured, the recombinant CcDef2 showed a significant antibacterial effect on three kinds of Gram-positive bacteria. These results indicate that CcDef2 is an excellent antibacterial peptide and a highly effective immune effector in the innate immunity of C. chinensis. This study provides a foundation for further understanding the function of CcDef2 and developing new antimicrobial drugs.     

城市道路照明工程设计施工中存在的问题和对策

城市建设中,道路照明是关系到城市形象的工程,反映一个城市公共设施和市政建设的总体水平。城市道路照明工程设计和施工中存在一些常见的缺陷,在设计和施工中应认真研究,防止事故的发生,保证工程的质量。