转子动不平衡载荷的在线识别

本文提出用复模态影响系数来解决转了大衡的在线以别和诊断问题，讨论了影响系数矩阵的力学意义．试验中可不加试重求出影响系数，并编制了相应的计算程序．     

大学生英语交际能力的培养

培养学生用英语进行交际的能力是大学英语教学的重点。要提高学生的交际能力 ,就要注意学生听说能力的培养 ,这需要我们教师从课堂教学入手。     

对三农问题的哲学思考

农业在国民经济中的重要性众所周知。本文通过对最能体现农业重要性的例子、四大文明的诞生和英国的工业革命等人类文明史的阐述,用哲学的思维对当代中国的农业、农村、农民做了初步的探讨。     

Bootstrap Estimation of Benchmark Doses and Confidence Limits with Clustered Quantal Data

The benchmark dose (BMD) is an exposure level that would induce a small risk increase (BMR level) above the background. The BMD approach to deriving a reference dose for risk assessment of noncancer effects is advantageous in that the estimate of BMD is not restricted to experimental doses and utilizes most available dose-response information. To quantify statistical uncertainty of a BMD estimate, we often calculate and report its lower confidence limit (i.e., BMDL), and may even consider it as a more conservative alternative to BMD itself. Computation of BMDL may involve normal confidence limits to BMD in conjunction with the delta method. Therefore, factors, such as small sample size and nonlinearity in model parameters, can affect the performance of the delta method BMDL, and alternative methods are useful. In this article, we propose a bootstrap method to estimate BMDL utilizing a scheme that consists of a resampling of residuals after model fitting and a one-step formula for parameter estimation. We illustrate the method with clustered binary data from developmental toxicity experiments. Our analysis shows that with moderately elevated dose-response data, the distribution of BMD estimator tends to be left-skewed and bootstrap BMDL s are smaller than the delta method BMDL s on average, hence quantifying risk more conservatively. Statistically, the bootstrap BMDL quantifies the uncertainty of the true BMD more honestly than the delta method BMDL as its coverage probability is closer to the nominal level than that of delta method BMDL. We find that BMD and BMDL estimates are generally insensitive to model choices provided that the models fit the data comparably well near the region of BMD. Our analysis also suggests that, in the presence of a significant and moderately strong dose-response relationship, the developmental toxicity experiments under the standard protocol support dose-response assessment at 5% BMR for BMD and 95% confidence level for BMDL.     

论太平天国时期的周庄枪匪集团

:以费秀元、费金绶父子为首的周庄枪匪集团 ,是清末太湖地区众多枪匪中势力较大的一支。费氏通过捐输取得官衔、功名 ,约束土匪劣性 ,获地主士绅和清政府的支持。太平军攻占苏州后 ,该集团负隅顽抗 ,继而被迫假意受抚 ,最终公开投降清军。在李鸿章率淮军攻占太平天国苏福省的战斗中 ,周庄枪匪绘呈地图、担任向导、随军作战 ,出力颇巨 ,后为李鸿章收编。     

传染性浆膜炎对鸭免疫功能的影响

本文报道鸭人工感染鸭疫里默氏杆菌后主要免疫器官的病理组织学研究结果 ,发现法氏囊、脾脏病理变化严重 ,胸腺的病变较轻微 ,血清中γ -球蛋白含量显著下降。结果表明 :鸭传染性浆膜炎对体液免疫功能有较大的影响     

建设社会主义先进文化如何面对社会科学高度政治化问题的思考

高度政治化是我国社会科学发展的一个突出特点,也是困扰社会科学健康发展的重要因素。社会科学高度政治化同自身特点和现实需要有关,同时又有深刻的历史背景和体制原因。正确处理学术和政治的关系,实现学术与政治的相对分离,既需要政治民主作为外在的制度保障,又需要学术界自身的严格自律,借鉴西方的有关经验有利于我们重新梳理两者的关系,实现学术与政治的健康互动。     

互联网对大学生的影响及对策

互联网所带来的便捷和机遇正在改变着大学生的生活。为了引导大学生正确地应用网络,学生工作者应当从多个方面实施教育工作。     

A novel kernel-free nonlinear SVM for semi-supervised classification in disease diagnosis

Journal of Combinatorial Optimization - Semi-supervised classification methods are widely-used and attractive for dealing with both labeled and unlabeled data in real-world problems. In this paper,...     

CEO差序来源对民营上市公司创新产出的影响

基于差序格局理论,将CEO来源按关系亲疏分为本人、亲人、熟人和外人CEO,以2007—2019年民营上市公司为样本,实证研究了CEO差序来源对企业创新产出的直接作用、中介作用和调节作用。结果表明：CEO差序来源对民营上市公司创新产出的影响显著为负,即CEO差序来源越疏远,民营上市公司创新产出越少;创新投入在CEO差序来源对企业创新产出的影响中起到了中介作用;企业的盈利能力和现金持有水平调节了CEO差序来源对企业创新产出的影响。据此,建议民营上市公司在聘请CEO时,优先选择亲人CEO和熟人CEO,在亲人CEO资源缺乏的情况下,可聘用熟人CEO,这样,更能提升企业的创新产出;同时,企业应提高自身盈利能力和现金持有水平,为企业创新活动奠定基础。