可循环泡沫钻井液在宝302井欠平衡井段的应用

介绍了可循环泡沫钻井液的配方，性能及在宝302井欠平衡井段中的应用情况，结果表明该体系悬浮和携岩能力强，抗高温，抗污染效果好，能够满足宝南区块深井欠平衡压力钻井的需要，且保护油气层效果好，同时，这也是国内首次将可循环泡沫钻井液成功应用于井泥岩及煤层井，拓宽了泡沫钻井液的应用范围。     

SMAR公司现场总线控制系统System302的设计

通过对SMAR公司现场总线控制系统System302各设计环节的介绍和性能、特点分析，从经济投入和技术水平两方面说明现场总线控制系统是DCS系统的升级换代产品。     

Transport Phenomena in Zonal Centrifuge Rotors. III. Particle Sedimentation in Gradient Solutions

Abstract

An analysis is presented for the prediction of (a) a particle position as a function of rotation time, (b) an instantaneous particle sedimentation velocity, and (c) an instantaneous observed particle sedimentation coefficient in a gradient solution characterized by viscosity and density profiles which are expressed in polynomials as functions of radial distance of the zonal rotor. Effect on variation of those predicted quantities with (a) particle size and rotor speed, (b) the density ratio between a particle and the light end of the gradient solution, and (c) the profiles of a gradient solution are also discussed from the computed numerical results.     

采用LinkSwitch-TN系列离线转换器的非隔离恒流LED驱动器电路

LinkSwitch-TN系列离线转换器IC专门设计去取代所有线性和电容降压非隔离电源,仅需用非常少量的元件,即可组成恒流LED驱动器电路。文中在介绍LinkSwitch-TN结构与特点的基础上,给出了由其构筑的LED驱动电路。     

A longitudinal observational study of the dynamics of Mycoplasma bovis antibodies in naturally exposed and diseased dairy cows

Mycoplasma bovis is an important pathogen causing disease and substantial economic losses in cattle. However, knowledge of the dynamics of antibody responses in individual cows in the face of an outbreak is currently extremely limited. The use of commercial antibody tests to support clinical decision-making and for surveillance purposes is therefore challenging. Our objective was to describe the dynamics of M. bovis antibody responses in 4 Danish dairy herds experiencing an acute outbreak of M. bovis-associated disease, and to compare the antibody dynamics between dairy cows with different disease manifestations. A total of 120 cows were examined using a standardized clinical protocol and categorized into 4 disease groups: “mastitis,” “systemic,” “nonspecific,” and “none.” Paired blood and milk samples were collected and tested using a commercial M. bovis antibody–detecting ELISA. Plots of raw data and generalized additive mixed models with cow and herd as random effects were used to describe serum and milk antibody dynamics relative to the estimated time of onset of clinical disease. Cows with mastitis had high optical density measurement (ODC%) of antibodies in both milk and serum at disease onset. The estimated mean ODC% in milk was below the manufacturer's cut-off for the other groups for the entire study period. The estimated mean serum ODC% in the “systemic” group was high at onset of disease and stayed above the cut-off until 65 d after disease onset. However, the lower 95% confidence interval (CI) for the mean ODC% was only above the manufacturer's cut-off between 7 and 17 d after onset of disease. The CI of the “systemic” and “none” groups did not overlap at any time between the day of disease onset and 65 d after disease onset, and the estimated mean ODC% for both the “nonspecific” and “none” groups were generally below the cut-off for the majority of the study period. In conclusion, the serum antibody responses were highly dynamic and showed a high level of variation between individual cows. This strongly suggests that serology is unlikely to be useful for individual diagnosis of M. bovis-associated disease in dairy cows. However, it might still be useful for herd- or group-level diagnosis. Antibodies in milk were only increased in cows with M. bovis mastitis, indicating that milk antibody measurements only have diagnostic utility for cows with mastitis.     

单片机两片系统的应用研究

传统的单片机硬件电路设计中，使用的外围芯片较多，这往往使得印制电路板的面积过大，布线复杂，使可靠性降低，为克服这一缺陷，本文讨论了用PSD302芯片与16位微处理器80C196KC组成的单片机两片系统，并详细论述了该系统的实现思路，并以调速系统电机中转速的采集为例说明其在控制系统中的应用。     

采用LinkSwitch-TN系列寓线转换器的非隔离恒流LED驱动器电路

LinkSwitch-TN系列离线转换器IC专门设计去取代所有线性和电容降压非隔离电源。仅需用非常少量的元件，即可组成恒流LED驱动器电路。文中在介绍LinkSwitch-TN结构与特点的基础上。给出了由其构筑的LED驱动电路。     

MS302多媒体软件功能记忆法

本文介绍了ＭＳ３０２多媒体软件（生理学专用）基于功能的记忆法，为例于学生快速而准确地记忆，普及现代化的多媒体教学手段，提高实验课堂教学效果，提高教学质量，深化实验教学改革提供资料。     

Extraction Mechanism of La^3 ＋ from Hydrochloric Acid Solution Using Cyanex 302

The solvent extraction of La3 from hydrochloric acid solutions was investigated using bis (2, 4, 4-trimethylpentyl) monothiophosphinic acid (Cyanex 302, HL) as an extractant. The effect of .equilibrium of aqueous acidity on extraction of La^3 using Cyanex 302 in different diluents was discussed. The effects of extractant concentration and chloride ion on the extraction reaction were also studied. Stoichiometry of the extraction reactions and the nature of metal complexes formed were determined using slope analysis technique and IR measurement.     

基于DSP的多路数据采集系统的设计

DSP是一种适用于进行实时数字信号处理的微处理器。基于DSP的多路数据采集系统相对于基于单片机的数据采集系统更能满足数据采集系统在精确度和实时性方面的要求。它解决了数据采集系统中数据采集速度慢、不能多路数据同时采集的问题。文中首先对芯片CD4060和TMS302LF2407A的特点做了介绍,重点介绍了多路数据采集系统的系统组成、硬件设计和软件设计。该系统以TMS302LF2407A为控制核心,主要完成对外部多路模拟信号的快速、精确采集,实现对多路数据的采集与转换。