汽轮机驱动往复式压缩机的技术探讨

阐述中小氮肥企业采用汽轮机替代电机驱动往复式压缩机来降低成本的迫切性对汽轮机设计的特殊要求,分析汽轮机转子的强度,系统的正常开停机和紧急停机对汽轮机的影响,以及汽轮机替代电机驱动往复式压缩机的投资和收益。图2     

安森美半导体应用于LED区域照明的电源、保护及联网方案

本文介绍了安森美半导体LED区域照明应用中的电流可调节恒流功率因数校正及超高能效大功率等驱动电源方案,LED串保护方案以及联网型LED街灯控制方案。     

超声波电机的数学模型及其实验研究

首先对行波型超声波电机的工作原理、基本方程式、等效电路进行了讨论。在此基础上,对超声波电机在调频和调压下的机械特性进行了研究。针对超声波电机容性负载的特点,作者在对超声波电机的功率因数特性进行充分分析的基础上,从功率因数的角度提出了并联电感的补偿原则。仿真和实验结果表明：所提方案是切实可行的。     

高温超导磁悬浮模型车驱动性能的分析

本文简要地介绍了一辆高温超导磁悬浮模型车的结构,利用解析法,分析了直线电机的磁场分布,推导出驱动系统的驱动力,功率因素和效率的一般表达式。     

φ4.0m×10.7m PS炼铜转炉的加长改造

原设计年产10万t电解铜的金隆公司,通过生产挖潜和局部设备改造,电解铜产量提高到15万t,电铜加工成本每吨降低400元。此项改造后,其炼铜PS转炉的冰铜装入量由每炉160t增加到230t,满足了公司扩产后对转炉的能力要求。本文介绍了转炉改造的加长方法、内容及特点,重点阐述了改造中转炉驱动系统方案的设计选择及采用伞齿 圆柱齿减速机的实际使用效果,为相关转炉扩容改造提供了实践经验。     

基于PLC和直流驱动的龙门刨控制系统

本文运用PLC控制技术和直流调速技术改造大型龙门刨B2025的电气控制系统和直流驱动系统,讨论了机床的控制及驱动要求,完成了整个系统的硬件设计和软件设计,并给出了详细的速度控制电路和横梁升降、刀架进给控制程序。通过改造,提高了机床的可靠性、稳定性,对同类机床的改造具有实际意义。     

Are biomarkers of chronic alcohol misuse useful in the assessment of DWI recidivism status?

A first driving while impaired by alcohol (DWI) conviction is a key opportunity to identify offenders who are at high risk for recidivism. Detection of alcohol use disorder (AUD) is a major target of current DWI assessments. However, offenders frequently underreport their alcohol consumption, and use of biomarkers has been proposed as a more objective indicator. Among the best established are aspartate aminotranferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), mean corpuscular red blood cell volume (MCV), carbohydrate-deficient transferrin (CDT), and thiamine. To our knowledge, no research has directly verified whether AUD biomarkers predict DWI recidivism status. Using a cross-sectional design, this study tested three hypotheses related to the utility of biomarkers in DWI assessment.

Hypotheses

(1) DWI recidivists possess biomarkers indicative of greater prevalence of AUD compared to first-time offenders; (2) multiple biomarkers better differentiate first-time offenders from recidivists compared to individual biomarkers; and (3) biomarkers add significantly to the prediction of recidivism over and above psychosocial questionnaires.

Methods

First-time offenders (n = 49) and recidivists (n = 95) participated in the study. In addition to self-reported information on sociodemographic and driving characteristics, data from several AUD questionnaires were gathered: Michigan Alcoholism Screening Test, Alcohol Use Disorders Identification Test, Composite International Diagnostic Interview, and Timeline Follow-Back. Blood samples were collected to measure AST, ALT, GGT, MCV, CDT, and thiamine.

Results

AUD biomarkers, taken individually or in combination, did not indicate that recidivists had more frequent AUD compared to first-time offenders. Also, they failed to significantly differentiate first-time offenders from recidivists or predict recidivism status. Finally, the superiority of biomarkers over psychosocial AUD questionnaires was not supported in the laboratory setting.

Conclusion

The present findings suggest that biomarkers of chronic patterns of heavy drinking may not be adequate to capture the multiple processes that appear to promote recidivism (e.g., binge drinking, other risky behavioural and personality features). Despite their objectivity, caution is warranted in the interpretation of a positive score on these biomarkers in DWI assessment. Longitudinal research is needed to more comprehensively explore the relationship between positive biomarkers in first-time offenders and their risk of becoming recidivists.