Tunable mixed-mode OTA-C universal filter

A novel electronically tunable mixed-mode universal biquad by using four single-output and one dual-output-operational transconductance amplifiers, two grounded capacitors is proposed. The proposed circuit has ability to realize voltage, current, transconductance, and transresistance mode, and can the following advantageous features: (i) realization of low-pass, band-pass, high-pass, notch, and all-pass filter responses from the same configuration, (ii) employment of only grounded capacitors ideal for integrated circuit implementation, (iii) orthogonal controlling of ω _o and Q for easily electronic tunability, and (iv) low active and passive sensitivity performance. Finally, to verify our architecture, we have designed this analog filter chip with TSMC 0.35-μm 2P4M CMOS technology. This chip operates to 1 MHz and consumes 30.95 mW. The chip area of the analog filter is about 0.823 mm².     

The Potential of Hydrogen Sulfide Donors in Treating Cardiovascular Diseases

Hydrogen sulfide (H₂S) has long been considered as a toxic gas, but as research progressed, the idea has been updated and it has now been shown to have potent protective effects at reasonable concentrations. H₂S is an endogenous gas signaling molecule in mammals and is produced by specific enzymes in different cell types. An increasing number of studies indicate that H₂S plays an important role in cardiovascular homeostasis, and in most cases, H₂S has been reported to be downregulated in cardiovascular diseases (CVDs). Similarly, in preclinical studies, H₂S has been shown to prevent CVDs and improve heart function after heart failure. Recently, many H₂S donors have been synthesized and tested in cellular and animal models. Moreover, numerous molecular mechanisms have been proposed to demonstrate the effects of these donors. In this review, we will provide an update on the role of H₂S in cardiovascular activities and its involvement in pathological states, with a special focus on the roles of exogenous H₂S in cardiac protection.     

直线要素方向公差数学模型的建立

公差信息是CAD/CAM集成中必需的信息之一。在现行的国家标准中,采用图例及文字说明的形式来定义公差,适合于手工设计环境,不适合于计算机的表达、处理以及在各阶段的数据传递。建立直线要素方向公差数学模型,以自由度变动作为直线要素方向公差模型变量,用数学的方式来描述和解释公差信息中成员的含义,表示直线要素公差域及实际直线要素的变动情况,在计算机中合理且有效地表示公差信息,有利于CAD/CAM有效集成、自动检测与评定技术的发展。     

分光光度法测定蛋白饮料中蛋白质含量的不确定度评定

目的对分光光度法测定蛋白饮料中蛋白质含量的不确定度进行评定。方法根据JJF1059.1-2012标准要求,以测定蛋白饮料中蛋白质含量为例,分析不确定度的主要来源并定量,计算相对合成标准不确定度,从而评定扩展不确定度。结果蛋白饮料中蛋白质含量为5.66 g/100 g,扩展不确定度为0.20 g/100 g (95%,k=2)。测量结果的不确定度主要来源于分光光度法标准曲线的拟合,测量重复性与氨氮标准溶液的影响次之,而样品的称量和样品的定容带来的影响可忽略不计。结论该评价方法及结果能提高实际工作中蛋白质检测的准确性。     

镶拼法技术在丁基胶塞模具模芯加工中的应用

胶塞模具是胶塞生产过程中必备的专用装备.是一件精度要求高、加工难度大的产品.一般加工方法很难保证其气密性要求.容易产生漏胶现象,采用镶拼法技术和液压密封原理,利用普通数控设备,从结构和工艺两个方面进行改进,很好地解决了漏胶与成品表面粗糙度的问题,保证了产品质量.降低了生产成本.     

基于脚本语言的转子动态特性可视化

转子是工厂中常见机器的重要组成部分。转子问题关系复杂,大量数据难以计算、理解。本文采用3DSMAX的内置脚本语言MAXScript,设计了转子运动仿真界面,对转子的运动实现了仿真。结果表明,该系统能动态可视化转子动力学特性。     

Theoretical study of the interaction energy of benzodifuranone dye molecule rings

The aim of this paper was to reveal the relationship between the interaction energy of benzodifuranone dyes and dyeing performance indices such as dyeing temperature and colour fastness. Dimer models of benzene–benzene, benzodifuranone–benzene, and benzodifuranone–benzodifuranone configuration were set up, and geometry optimisation and interaction energy were calculated using a density functional theory ωB97XD, 6-311G++ (d, p) basis set. The calculation results showed that the benzodifuranone molecule had better coplanarity. The molecular interaction energy of benzene–benzene, benzodifuranone–benzene, and benzodifuranone–benzodifuranone rings decreased at first, and then increased with growth in the distance between the rings, the lowest energy occurring at a distance of about 3.25–3.75 Å. The dispersion force affected the interaction energy of benzodifuranone–benzene rings most, while both dispersion force and electrostatic force influenced the interaction energy of benzodifuranone–benzodifuranone rings. These calculation and experimental results revealed that a greater energy was needed to destroy the dye–fibre and dye–dye interaction energy of benzodifuranone-based disperse dyes.     

基于锌扩散的InGaAs/InP平面型红外探测器快速热退火研究

系统研究了快速热退火对锌扩散的In_0.53Ga_0.47As/InP PIN探测器的影响。利用电化学电容电压和二次离子质谱技术分析了退火前后Zn和净受主的浓度分布,结果表明退火过程会影响杂质浓度,但不影响扩散深度。制备了不同退火条件的In_0.53Ga_0.47As/InP PIN探测器。器件测试反映,未退火的探测器在260~300K具有更低的器件电容和更高的激活能。通过暗电流成分拟合对器件暗电流机制进行分析,未退火器件表现出更低的肖克利-里德-霍尔产生复合电流和扩散电流,因而室温下未退火器件具有更高的峰值探测率。为了制备高性能低掺杂吸收层结构的平面型InGaAs探测器,快速热退火是不必要的工艺。     

基于Repast平台的SARS传播仿真建模研究

通过引入基于主体的建模思路和方法,根据易于描述的微观个体行为,利用Repast仿真建模平台对SARS的传播过程进行模拟,从而研究SARS传播宏观层面的规律,并根据謇验结果提出了疫情防控的策略和措施.本文初步构造了SARS传播的主体模型,定义了主体的状态转换方式以及主体之间的行为规则,并实现了一个可用于模拟SARS传播过程的简单的仿真建模框架,通过可动态扩展的规则设定、模型参数调节,为研究SARS传播提供了方便的模拟环境.