Performance Evaluation of the ADS 1000 Ventilator Using a Lung Model

A laboratory evaluation was performed to evaluate the performance characteristics of a new veterinary ventilator. The ventilator studied was configured according to manufacturer's directions and attached to a test lung via a pneumotachograph and differential pressure transducer interfaced to a pulmonary mechanics analyzer system. Constant resistance (R=10 cm H₂O/L/sec) and compliance (C=3 ml/cm H₂O) factors were maintained for all trials. The ventilator operated at the manufacturer's preprogrammed parameters. In the first trial, body weight was the only variable. In the second trial, an endotracheal tube was placed in series between the ventilator's breathing circuit and the pneumotachograph. Body weights from 1–20 kgs were evaluated. Mean values for respiratory rate (RR), minute ventilation (VE), inspiratory time (Ti), peak inspiratory pressure (PIP), and peak inspiratory flow (Fpki) displayed on the ventilator control panel; tidal volume (VT), calculated from the displayed minute volume, and identical parameters measured by the pulmonary mechanics system at each body weight, were compared using a two factor analysis of variance. Significant differences (P< 0.05) were found between mean displayed and measured values for RR, PIP, and Fpki.     

Effects of storage on the physico-chemical properties of corn tortillas prepared with glycerol and salt

Corn tortillas have a short shelf life due to increased firmness and microbial spoilage. Commercial corn tortillas use carboxymethyl cellulose (CMC) to delay staling; however this gum is expensive when compared to the rest of the tortilla ingredients. Glycerol has been added to bread and wheat tortillas to increase pliability and salt has been shown to mask the flavor of glycerol in corn tortillas. The possibility to reduce staling in corn tortillas by adding glycerol/salt as an alternative to CMC was investigated by monitoring changes in physico-chemical properties during 2 weeks of storage at 25 °C. Molecular and macroscopic changes were followed using thermal and mechanical analysis. During storage an increase in amylopectin recrystallization was observed in all samples. The “freezable” water content of all tortillas decreased over the first 3–5 days of storage with an increase after 7 days, while moisture content and water activity remained constant. Glycerol/salt tortillas exhibited a sharper transition region in the DMA temperature scan suggesting a more homogenous sample. CMC tortillas were significantly stiffer than glycerol tortillas after 14 days of storage. Glycerol/salt combinations may offer at least a partial replacement for CMC since it helped control the stiffness, water homogeneity and distribution during storage.     

AutoCAD二次开发工具探讨

针对当前要械设计领域最常用的ＣＡＤ软件平台ＡｕｔｏＣＡＤ二次开发工具ＡｕｔｏＬＩＳＰ、ＡＤＳ和ＯｂｊｅｃｔＡＲＸ进行全方位比较,提出ＡｔｕｏＣＡＤ二次开发工具的使用应该建立在所开发的对象及结合企业自身情况的基础上。     

ADS程序向ARX应用程序的移植

对ＡｕｔｏＣＡＤ软件平台的ＡＤＳ和ＡＲＸ的二次开发环境的应用程序进行对比,基于ＡＤＳＲＸ应用程序,介绍了ＡＤＳ程序向ＡＲＸ程序的移植技术。     

尺寸公差标注系统设计

尺寸公差标注是绘制机械图的一项重要内容。为了使机械ＣＡＤ软件中的尺寸标注符合我国机械制图标准,作者以ＡｕｔｏＣＡＤＲ１２为操作平台,在ＤＯＳ环境下,利用ＡｕｔｏＣＡＤＲ１２的高级用户开发系统,即ＡＤＳ语言及对话框控制语言（ＤＣＬ）,研究并开发了尺寸标注系统。     

Effect of methyl parathion and chlorpyrifos on certain biomarkers in various tissues of guppy fish, Poecilia reticulata

Tests of acute toxicity were performed on the most common species of aquarium fish, Poecilia reticulata. Guppies (P. reticulata) were exposed to progressive concentrations of methyl parathion (MP) and chlorpyrifos (CPF); a semi-static method according to guidelines of OECD was used. Tests of acute toxicity were conducted using 10 fish for each separate concentration and for the control group. The results were subjected to probit analysis to determine the 96 h LC₅₀ values. The 96 h LC₅₀ values of MP and CPF to P. reticulata were 8.48 ppm/L (5.98–10.89) and 0.176 ppm/L (0.313–0.224) respectively. In addition, behavioral changes at each concentration were observed for the individual fish. Fish were exposed for 96 h to different sublethal concentrations of MP and CPF (¼ LC₅₀, 1/8 LC₅₀ and 1/10 LC₅₀) and their oxidative stress-induction potential was estimated in brain, liver and gills of fish. MDA content is induced in all tissues but maximum rise was observed in gills (161% and 153% for MP and CPF respectively). With regard to antioxidant defense system (ADS), GSH level decreased in the brain, liver and gills of tissues of MP treated fishes (22%, 6% and 13% respectively) and showed increase in brain and gills CPF treated (23% and 21% respectively). CAT, GST, GR and SOD levels fluctuated in all treatment groups relative to the control. Brain AChE showed dose-dependent inhibition in fish exposed to the higher concentrations reached 45% and 66% for MP and CPF respectively. Collective findings demonstrated that pesticide exposure of fish induced an increase in MDA and fluctuated ADS along with inhibited AChE. These findings may be used as valuable biomarkers for evaluation of water pollution.     

基于LTCC工艺的7阶L-C高通滤波器的设计与测试

基于低温共烧陶瓷(LTCC)工艺设计了集中参数高通滤波器的结构。采用了ADS软件设计滤波器的拓扑结构,然后利用电磁仿真软件HFSS仿真所需电容和电感的集中参数值。通过优化每个部分中的细节,将生成的原理图三维设计成符合LTCC加工方法的模型并进行了仿真测试,获得了符合设计指标的滤波器结构。该滤波器采用7阶L-C模型,截止频率大于2 GHz,2.5GHz-4.0GHz插入损耗小于2 dB,驻波系数小于1.5,DC-1.8GHz内插入损耗大于15 dB。     

基于AutoCAD的三维塑料注射模具结构CAD系统的开发

阐述了一个三维塑料注射模具ＣＡＤ系统的整体开发方案,并通过对ＡｕｔｏＣＡＤ的二次开发,详细说明了注射件尺寸向型芯,型腔尺寸的自动转换,建立注塑模标准零件库以及标准模架组合装配程序的开发方法。     

多传感器的高精度湿度测量仪

介绍了一种湿度测量仪的设计方案,给出了硬件设计的总体框图;详细阐述了3款湿度传感器的信号采集电路;介绍了显示电路、电源模块、通讯接口以及湿度信号采集电路的软件设计。电路设计以高性能的JN5121为核心,简化了外围接口电路的设计,提高了系统的性价比,并利用低功耗、低价格及性能稳定的ZigBee技术构成了无线传感器网络。     

基于ARM 7的农业机械故障检测系统

介绍了一种基于ARM7芯片的农业机械故障检测系统,对农业机械的机械部分和伺服系统(如螺纹连接松动、联轴器振动、熔断器温度过高、法兰和阀门泄露等)进行实时监控,以便在出现问题的时候及时处理,保证零件加工的高精度性.该系统具有实时性、体积小以及预知维修的特点,集数据的采集、分析、显示、故障诊断、数据存储和通讯于一身,完能成各种机械设备运行信息的实时分析, 并记录存储处理结果, 为机械设备建立完善的运行记录, 从而为预知维修提供服务.