Evolution of aggregation structure of polyacrylonitrile fibers in the cyclization reaction

The aggregation structure of polyacrylonitrile precursor evolves gradually with progress of cyclization. In this work, the variety of cyclization degrees were determined by Fourier transform infrared spectroscopy and the evolution of aggregation structure of PAN fibers were characterized by wide‐angle X‐ray diffraction. Experimental results showed that the cyclization occurred first in the amorphous parts when the heating temperature was below 200°C. After heated at 200°C for 30 min, molecular chains in the pseudo‐crystalline regions started to pack into crystalline regions due to the increasing stress which was produced by cyclization occurred in the amorphous phase, and the crystallinity and crystallite size increased slowly. When the temperature reached to 220°C, pseudo‐crystalline regions rearranged obviously under stress, while molecular chains in the crystalline region started to participate in cyclization, and the original crystalline structures were destructed. The two competitive processes induced that the crystallinity and crystallite size grew to the maximum values at 30 min. When the temperature up to 240°C, the cyclization occurred in the crystalline region became more intensely, while the crystallinity and crystallite size decreased out of synchronize. A scheme of evolution of aggregation structure in cyclization was modified based on the above results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

坑中坑施工技术在万达工程中的使用

本文结合佛山南海万达广场工程实例，通过介绍工程坑中坑施工支护方式、降水措施、土方开挖顺序及现场整体道路规划实施，缩短了施工工期确保施工进度节点，产生了良好的经济效益。     

DVB-S2中BCH译码器的硬件设计

DVB-S2是新一代数字卫星广播标准,标准采用了新的调制与编码技术,在一定的复杂程度下取得最大的信道容量与较好的系统可扩展性。其中编码方式采用了由BCH与LDPC级联的前向纠错系统,使系统性能接近香农限,但长二进制BCH码,也极大地增加了译码器硬件实现难度。针对标准中BCH码的特殊性,通过对长BCH码优化方法的研究与讨论,提出实现该译码器简单有效的FPGA硬件结构,在满足速度要求的前提下尽量减小面积。     

基于LabVIEW的虚拟信号发生器的研究与实现

在电子测量和自动化控制领域,虚拟仪器技术取得了巨大的发展。同时传统的信号发生器的设计大多采用嵌入式处理器直接来实现。从探索研究的角度出发,介绍了LabVIEW技术以及用该技术实现虚拟信号发生的硬件与软件设计。该系统通过单片机作为主控芯片,基于LabVIEW来实现虚拟信号发生,完成了正余弦和方波信号发生器的信号系统,然后对该虚拟信号发生器的输出信号进行了实测和分析,并与实际信号比较,进行了理论分析和实验验证。     

统计工作在企业中的地位和作用

统计工作在企业管理中有着至关重要的地位,发挥着服务和监督的作用。欲保持这种地位和作用,一要靠各级领导的重视,二要靠统计人员自身的勤奋和努力。大冶有色金属公司所属井巷公司其所以能在掘进中屡破进尺新记录,与常年坚持不懈地做好统计工作有着密不可分的关系     

基于代理服务器的校园网计费系统

计费是校园网网络管理中一个重要方面,针对面向ＩＰ计费存在面向机器与可能被盗用的缺陷,介绍了基于代理服务器面向用户的校园网计费方案,对计费原理和系统模型作了较详细的阐述,并结合校园网流量计费系统的开发,介绍了数据采集、计费处理、收费规则维护及数据查询等主要模块的设计。     

价值工程在水利水电工程施工项目管理中的应用

本文结合水利水电施工项目管理现状,指出价值工程在水利水电施工项目管理中应用的重要作用和现实意义,为我国水利水电施工企业施工项目管理提供了理论借鉴和启示。     

Puerarin-V Improve Mitochondrial Respiration and Cardiac Function in a Rat Model of Diabetic Cardiomyopathy via Inhibiting Pyroptosis Pathway through P2X7 Receptors

There is a new form of puerarin, puerarin-V, that has recently been developed, and it is unclear whether puerarin-V has a cardioprotective effect on diabetic cardiomyopathy (DCM). Here, we determined whether puerarin-V had any beneficial influence on the pathophysiology of DCM and explored its possible mechanisms. By injecting 30 mg/kg of STZ intraperitoneally, diabetes was induced in rats. After a week of stability, the rats were injected subcutaneously with ISO (5 mg/kg). We randomly assigned the rats to eight groups: (1) control; (2) model; (3) metformin; (4–6) puerarin-V at different doses; (7) puerarin (API); (8) puerarin injection. DCM rats were found to have severe cardiac insufficiency (arrythmia, decreased LVdP/dt, and increased E/A ratio). In addition, cardiac injury biomarkers (cTn-T, NT-proBNP, AST, LDH, and CK-MB), inflammatory cytokines (IL-1β, IL-18, IL-6, and TNF-α), and oxidative damage markers (MDA, SOD and GSH) were markedly increased. Treatment with puerarin-V positively adjusts these parameters mentioned above by improving cardiac function and mitochondrial respiration, suppressing myocardial inflammation, and maintaining the structural integrity of the cardiac muscle. Moreover, treatment with puerarin-V inhibits the P2X7 receptor-mediated pyroptosis pathway that was upregulated in diabetic hearts. Given these results, the current study lends credence to the idea that puerarin-V can reduce myocardial damage in DCM rats. Furthermore, it was found that the effect of puerarin-V in diabetic cardiomyopathy is better than the API, the puerarin injection, and metformin. Collectively, our research provides a new therapeutic option for the treatment of DCM in clinic.     

一种新型多通道远程监控数据采集系统

介绍了一种基于SOC新型高速单片机的新型多通道数据采集与远程监控系统;针对实际应用中数据采集和传输很难保证实时性和可靠性的现状,通过详细的电路分析,文章在多通道设计、远程通讯、数据采集的实时性和可靠性方面,做了较为详细的论述;给出了整个系统的具体实现方案;独特的设计方法很好地保证了系统的实时性和可靠性;通过一定的频谱分析和数据计算,远程监控软件可以清晰地再现现场设备的工作信号,并给与一定的控制措施;经现场应用检验,该监测系统运行稳定可靠,测量精度高,具有一定的实用性和推广价值。     

热泵精馏隔壁塔分离宽沸程物系的模拟

将中间换热和热泵精馏两种精馏节能技术应用到隔壁塔中,提出了带中间换热器的热泵精馏隔壁塔流程,以解决隔壁塔在分离宽沸程物系时出现的塔顶与塔底温差过高而不宜应用热泵精馏的问题。利用精馏塔总复合曲线图,可确定中间产品塔板采出流股的相态,从而得到不同类型的热泵精馏隔壁塔流程。宽沸程物系分离实例的模拟计算结果表明,该类流程在主塔气液相流量较大的情况下具有较高的节能效率。