利用SCADA系统实现电网载波设备的监测

０引言随着电力系统规模的不断扩大,电力专用通信网的迅速发展,通信业务也越来越多。通信网监测系统已成为通信网建设中不可缺少的组成部分。沧州电业局根据实际情况,从１９９０年开始对所属变电站载波设备进行监测。经验表明,载波监测系统的建立应符合以下２个原则：一是监测系统的成本造价必须低于被监测设备;二是监测设备的运行可靠性必须远大于被监测系统的可靠性。在建立监测系统时,对于载波设备相对较集中的２２０ｋＶ站一般容易解决,但对于分散在各地的载波设备进行全方位地监测,则有一定难度。而利用现有成熟的ＳＣＡＤＡ系…     

单位反馈系统解耦控制器的设计

本文使用了双互质因子分解法，研究了单位反馈系统解耦时，对邓是设定的闭环对角传函矩阵，到底有那些限制文件。     

Rectal mucosal proliferation, dietary factors, and the risk of colorectal adenomas

OBJECTIVE: To evaluate a commercial microtiter enzyme immunoassay for antinuclear antibodies (ANA) by comparing the results of tests performed with this assay to an established indirect immunofluorescence method performed on human epitheliod cell substrate slides. DESIGN: Both analytical methods were used to test for the presence and levels of ANA in stored sera from 313 patients previously shown to have detectable ANA and from 102 healthy control subjects. Follow-up tests for specific autoantibodies (anti-dsDNA antibodies and antibodies to extractable nuclear antigens [ENA]) were performed on all sera from patients. The medical histories of all patients were reviewed to determine the presence of systemic rheumatic diseases (SRDs). Different cut-off levels of positivity were examined to determine the sensitivity and predictive values of positive results on the enzyme immunoassay for detecting patients with SRDs or sera with positive tests for specific autoantibodies. RESULTS: Among patients with clinically diagnosed SRDs (n = 197), the enzyme immunoassay was positive for ANA (> or =1 U) in 100% and the indirect immunofluorescence method was positive (titer > or =40) in 95.4% of cases. Among ANA-positive patients with no SRDs (n = 116), testing by enzyme immunoassay and indirect immunofluorescence yielded positive results in 97.6% and 75.6% of cases, respectively. Among healthy control subjects, each of the two methods was positive in 15% of cases. As expected, most patients with SRDs had higher levels of ANA than did ANA-positive patients with other clinical diagnoses. A cut-off level of > or =3 U on the enzyme immunoassay correctly classified 77% of patients with a SRD as "positive" and 88% of patients with other clinical diagnoses as "negative." The probability of detecting a positive result for specific autoantibodies on second-order testing increased directly with the level of ANA. A cut-off level of > or =3 U had a sensitivity of 92% for identifying sera with positive specific autoantibodies, and results > or =3 U had a predictive value of 52% for a positive second-order test result. CONCLUSION: Enzyme immunoassay is substantially equivalent to indirect immunofluorescence for detecting clinically important ANA. Cut-off levels for positive results on the enzyme immunoassay can be established that optimize the usefulness of this method in diagnostic algorithms for specific autoantibodies.     

娱乐场所的噪声——香港酒吧的情况

许多城市居民喜欢在酒吧等娱乐场所享受快乐时光。但是,他们暴露在可能造成健康危害的娱乐场所环境中。这是因为人们逗留在酒吧时,会受到昏暗的灯光、二手烟和高噪声的影响。回顾了有关酒吧噪声的文献,并在香港的六家酒吧进行了噪声测量。分析结果显示,在欢乐时间即在5：00 pm和9：00 pm之间,酒吧声音水平（L_eq,10-min）介于66.5~79.9 dB （A）之间,酒吧声音水平在繁忙时间即10：00 pm至11：30 pm介于69.5~97.0 dB （A）之间。在欢乐时间,最高噪音水平（L_max）介于78.5~96.5 dB （A）之间,在繁忙时间介于80.9~107.8 dB （A）之间。分析发现,酒吧内的声音水平可以通过L_eq,10-min测量,酒吧内的背景噪音则可以通过L₉₀测量。     

自由曲面光学元件的设计、加工及面形测量的集成制造技术

针对自由曲面光学组件的超精密制造这门崭新技术,开发出从自由曲面光学设计、CAD连续数据转化、自由曲面模型重构、多轴加工仿真与切削优化、加工误差补偿到自由曲面面形测量的集成制造信息平台。所开发的集成技术,能有效减少在同类多轴机床编写复杂数控程序的时间,优化加工条件与切削策略,针对不同类型的自由曲面光学零件的主工艺,进行数字化仿真,避免昂贵的反复试切试验,以及提高产品的面形精度。并通过一系列的试验来验证该集成平台的稳定性和有效性。     

HLA-D and T lymphocyte reactivity to specific periodontal pathogens in type 1 diabetic periodontitis

Bacterial antigen fragments complexed with class II major histocompatibility molecules (HLA-D) on antigen presenting cells (APCs) stimulate CD4+ T lymphocyte proliferation, presumably to protect the host. This study examined these responses to antigens of two periodontal pathogens in four groups (n = 15) of age- (young adult) and sex-matched Caucasian subjects with or without type 1 diabetes and moderate to severe periodontitis: Group DP = diabetics with periodontitis; Group DnP = diabetics without periodontitis; Group nDP = nondiabetics with periodontitis; and Group nDnP = nondiabetics without periodontitis. HLA-D phenotypes for each subject were determined by lymphocytotoxicity assays. T lymphocytes purified from peripheral blood were stimulated in cell culture with APC pulsed with various concentrations of tetanus toxoid, Porphyromonas gingivalis, and Capnocytophaga sputigena antigens. T lymphocyte reactivity (3H thymidine incorporation) was numerically lower in cultures from diabetics stimulated with unpulsed APC (not significant), and antigen-pulsed cultures showed low proliferation and no significant differences among groups. Stimulation indices in cultures from diabetic patients stimulated with P. gingivalis or C. sputigena, however, were significantly elevated at all antigen concentrations compared to nondiabetic cultures. The occurrence of HLA-DR4 was moderately associated with diabetes (P < 0.05) and highly associated with periodontitis (P < 0.001, log-linear model for categorical variables); and HLA-DR53 and HLA-DQ3 were significantly associated with periodontitis (P < or = 0.02). HLA-DR was crucial to lymphocyte stimulation (anti-HLA-DR blocking experiments), but the low peripheral blood T cell reactivity to antigens of periodontal pathogens could not be linked with HLA-D type or periodontitis susceptibility.(ABSTRACT TRUNCATED AT 250 WORDS)     

Survival of Anaplasma marginale in Aedes albopictus cells

Bovine red blood cells infected with Anaplasma marginale were introduced into cell line cultures from the mosquito Aedes albopictus. The cultured mosquito cells phagocytized both infected and uninfected red blood cells. The parasite remained viable, as determined by calf inoculations, for 21 days.