Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

In this study, silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4, 6, 8, 10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM), the fib-roin scaffolds prepared without methanol had porous microstructures composed of thin sheets, and the sizes of the pores decreased with the increase of the fibroin solution concentrations, while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).     

园艺学教改实践与学生素质提升的研究

为了提升学生的综合素质能力,对园艺学实验教学现状进行了分析。根据存在设计性实验教学内容的不足、部分学生参与实验的积极性不够、内容体系的优化与实验进程的合理规划尚有欠缺等问题,进行了实验教学改革。改革实验教学内容,优化课程体系,完善实验教学内容,培养了学生综合能力,同时优化实验教学方法。充分发挥了学生的主观能动性,提高了学生的科学品质,使实验教学与科研紧密结合,拓宽了学生知识面,提高了学生综合实验技能。     

一种新型城市信息化发展评价方法的建立

论述了城市信息网络评价在城市信息化评价中的重要性，并用一种较简单的新方法，将分形理论引入到对城市信息网络系统的评价之中，分析并建立了描述城市信息网络系统的评价方法和步骤，为更深入地研究城市信息网络的规划和发展打下基础。     

电力测功电机影响因素分析

讨论了变频电源输入电压的非正弦对测功电机的性能影响，提出了改善不利影响的措施。     

三氟乙烷的气相音速测量与热力学性质研究

采用球型腔体声学共振法测量了新型制冷剂三氟乙烷(HFC143a)的气相音速,得到了压力在200～800kPa范围内,温度分别为293.61、302.96、313.19和323.18K时的4条等温线共28个音速数据.根据实验数据,由热力学关系式得到了HFC143a的理想气体比定压热容和第二音速维里系数等热力学性质,同时根据现有的高精度实验数据拟合了HFC143a的理想气体比热方程.温度、压力和气体音速测量的不确定度分别为±14mK、2.0kPa和±0.0037%.     

关于气体输运系数推导详析

阐述了一种新的方法，指出了诸多文献中推导气体输运系数时常采用的两个“假设”中存在的弊病。扩展了n不等于常量时的粘滞系数和导热系数公式。     

高压脉冲电场的抑菌特性

:高压脉冲电场技术是近年来发展起来的一项很有前景的技术 ,它具有传递均匀、处理时间短、产热少、对食品风味和营养特性影响小等特点 ,能克服食品加热处理或化学单元操作带来的不良影响。综述了高压脉冲电场 (HPEF)产生机理及对微生物的作用特性     

楼宇门禁系统基于petri网的分析和设计

Petri网具有优势,比如同步、并发、冲突等特点,因此可用来对复杂系统进行建模。但是在复杂的系统建模过程中,设计者会常遇到子系统的合成问题,本文介绍了一种共享P-型子网的合成。本文以楼宇门禁系统为例,分析了门禁系统的各种情况及该情景下的Petri-网模型,最后根据各个Petri子网的特点,采用了共享P-型合成方法,合成为一个系统的整体建模图。     

Identification of sex pheromones of four economically important species in genusDendrolimus

The female-produced sex pheromone of Dendrolimus superans was identified by gas chromatography (GC), coupled GC-mass spectrometry (GC-MS), electroantennographic (EAG) studies and field tests as a blend of (Z,E)-5,7-dodecadienal (Z5,E7-12:Ald) and (Z,E)-5,7-dodeca- dien-1-ol (Z5,E7-12:OH). In D. kikuchii, (Z,E)-5,7-dodeca- dien-1-yl acetate (Z5,E7-12:OAc) and Z5,E7-12:OH were found by GC and GC-MS analyses. However, in EAG studies male antennae were more sensitive to Z5,E7-12:OAc and (Z,E)-5,7-dodecadien-1-yl propionate (Z5,E7-12:OPr) than Z5,E7-12:OH. For D. spectabilis, Z5,E7-12:OH had been previously reported as the sex pheromone. However, in our studies, traps baited with Z5,E7-12:OH, Z5,E7-12:OAc and Z5,E7-12:OPr in a ratio of 1:1:1 caught three times more males than those baited with Z5,E7-12:OH alone. Relatively strong EAG responses were elicited from male antennae by Z5,E7-12:OH, Z5,E7-12:OAc and Z5,E7-12:OPr, but in addition to Z5,E7-12:OH, only very small amounts of Z5,E7- 12:OAc was found in the pheromone gland. These facts suggest that Z5,E7-12:OAc is a pheromone minor components and Z5,E7-12:OPr is a sex attractant in D. spectabilis. For D. tabulaeformis, Z5,E7-12:OH, Z5,E7-12:OAc and Z5,E7-12: OPr were found in extracts of pheromone glands of female moths, and the three compounds elicited strong EAG responses from antennae of male moths. These three compounds have been reported as a sex attractant of D. tabulaeformis, and our data confirm their roles as components of the sex pheromone of this species. The role of blend components in antagonizing cross attraction between congeners is discussed.     

浅议快乐早操

广播操是一项极具观赏性的集体竞赛及表演项目,它具有同时参与人数多、锻炼价值高、可操作性强、实效性好等特点,还具有很高的表演及观赏价值.因此广播操常被学校选作于早操,但由于诸多原因造成学生做早操质量不高,甚至流于形式.我校一直以来都非常重视广播操,通过规范教学、合理组织、严格管理等一系列的措施.使广播操不但成为全校师生强身健体的一种好方式,而且还成为展示师生精神面貌的一个重要窗口,成为校园文化一道亮丽的风景.使全体师生都能充分享受快乐早操!