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基于STD法的光岳楼木结构自振频率计算 被引量:7
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作者 孟昭博 胡博森 +2 位作者 赵庆双 金杰 徐栋 《聊城大学学报(自然科学版)》 2015年第4期37-41,共5页
自振频率是古建筑木结构振动特性的重要模态参数指标,准确计算其自振频率对采用数值方法分析结构的动力反应及对结构进行安全评估至关重要.本文基于实测振动数据,采用STD方法计算得到了光岳楼木结构的自振频率,并与东华振动测试系统的... 自振频率是古建筑木结构振动特性的重要模态参数指标,准确计算其自振频率对采用数值方法分析结构的动力反应及对结构进行安全评估至关重要.本文基于实测振动数据,采用STD方法计算得到了光岳楼木结构的自振频率,并与东华振动测试系统的模态分析软件中OP.Polylscf算法计算得到的光岳楼木结构的自振频率进行了对比分析.表明:采用上述两种方法计算得到的反映木结构振动特性的1阶频率差别甚小;采用OP.Polylscf法计算光岳楼木结构的其他各阶频率均大于采用STD法计算结果,但误差均在5.7%以内,说明采用STD法计算木结构的自振频率具有较好的精度. 展开更多
关键词 std方法 木结构 自振频率
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Evaluation of Diagnostic Algorithms and Risk Assessment Among Women Attending STD Clinics with Vaginal Discharge in China
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作者 王千秋 杨凭 +1 位作者 钟铭英 王广聚 《Chinese Journal of Sexually Transmitted Infections》 2001年第1期17-22,共6页
Objectives: To determine the aetiologies of vaginal discharge syndromes, to calculate the performance of different management algorithms, and validate these algorithms in STD clinics in China. These algorithms were ad... Objectives: To determine the aetiologies of vaginal discharge syndromes, to calculate the performance of different management algorithms, and validate these algorithms in STD clinics in China. These algorithms were adopted from those proposed by the World Health Organization. Methods: A total of 315 consecutive patients with vaginal discharge were enrolled at three STD clinics. Cervical infection was defined as presence of Neisseria gonorrhoeae on culture and/or Chlamydia trachomatis by polymerase chain reaction.Other laboratory tests included wet mount microscopy and pH testing of vaginal fluid. Sensitivity, specificity, and positive predictive value of different algorithms were determined using standard methods. Results: Cervical infection was identified in 37.8% of patients (20.6% gonorrhea, 12.7% chlamydial infection, 4.4%gonorrhea in combination with chlamydial infection). The sensitivity, specificity, and positive predictive value of algorithms A and B for the identification of Neisseria gonorrhoeae and/or Chlamydia trachomatis were respectively 71.4% and90.8%, 65.3% and 46.9%, 55.6% and 50.9%. Conclusions: The vaginal discharge algorithms could be applied for clinical management. Their sensitivities are acceptable. However, there is a need to further improve their specificity and positive predictive value. The two algorithms could be used in clinical settings with different facilities. These algorithms should also be validated in populations with lower disease prevalence. 展开更多
关键词 Neisseria gonorrhoeae Chlamydia trachomatis vaginal discharge ALGORITHM China
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