美国著名计算结构力学专家、地震工程专家Ray W Clough和Anil K Chopra分别写有在全世界范围内有很大影响的专著《DYNAMICS OF STRUCTURES》.两部著作在关于逐步积分算法的论述中都曾指出加速度由当前位移和速度代入运动方程求解将能得...美国著名计算结构力学专家、地震工程专家Ray W Clough和Anil K Chopra分别写有在全世界范围内有很大影响的专著《DYNAMICS OF STRUCTURES》.两部著作在关于逐步积分算法的论述中都曾指出加速度由当前位移和速度代入运动方程求解将能得到更好的结果.但这一点存在可商榷之处,为避免读者误用,从算法的稳定性出发,经分析指出:专著观点应用于Newmark法增量格式时确实使得算法的谱半径有所减小;然而,应用于Newmark法全量格式时,算法特性并未发生改变,结果得不到改善;此外,书中给出了增量格式Wilsonθ法的推导步骤,按此推导的算法相对于全量格式稳定界限发生了改变——只有当θ≥1.5时算法才是无条件稳定的.如果误将加速度由当前位移和速度代入运动方程求解推广到Wilsonθ法全量格式,算法的稳定性将变得非常差.展开更多
基于动量叶素理论,推导同半径对旋风力机功率与前、后级轴向速度诱导因子的关系,结果与经典模型吻合;将单级风力机Wilson设计法发展为考虑级间干扰的对旋风机设计法,实现以环形微元盘面功率系数最大为目标,前、后级轴向和环向诱导因子...基于动量叶素理论,推导同半径对旋风力机功率与前、后级轴向速度诱导因子的关系,结果与经典模型吻合;将单级风力机Wilson设计法发展为考虑级间干扰的对旋风机设计法,实现以环形微元盘面功率系数最大为目标,前、后级轴向和环向诱导因子为变量的优化设计,并完成2 k W单级和对旋风力机设计实例。最后采用CFD方法验证对旋风力机实验结果和设计结果,数值计算表明,设计工况下,对旋风机的风能利用率(46.32%)高于单级风力机(41.44%),并分析了数值预测的风能利用率与理论最佳值(64.00%)和(59.26%)的差异。展开更多
The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for diffi...The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for difficult intubation, to estimate the frequency of difficult intubation. Endotmcheal intubation is the basic reanimation procedure performed both in hospital and out-of-hospital settings. It is carded out whenever chest movements and spontaneous respiration are compromised. Respiratory arrest may occur for a variety of reasons （such as cardac arrest, coma of any origin, poisining） or direct damage to the airways, e.g. in various traumas （damages to the face, oropharynx, larynx, trachea, chest）. The basic endotracheal intubation kit contains： laryngoscope, endotracheal tubes, connectors （tube and Ambu bag connectors）, complete Ambu kit （face mask and bag）, 20 mL syringe for cuff inflating, suction apparatus, stylete, and Magill forceps. In order to assess the successfulness of endotracheal intubation, it is necessary first to identify patients who need to be intubated. With the aim of identifying such patients, numerous screening tests and scales have been created to predict difficult intubation. The best known and most commonly used are the Mallampati and Wilson classifications as well as the LEMON airway assessment method. Nevertheless, difficult intubation accounts for 1% of cases. It usually occurs when manipulation of the laryngoscope blade is not possible in obese patients and patients with short neck, in congenital restricted mouth opening, limited neck movement as well as limited temporomandibular joint mobility; in cases of edema, fibrosis and lesions of the tongue, pharynx and larynx; when there are anatomical variations and congenital malformations of the oral cavity, pharynx, larynx, head, neck and chest.展开更多
In this paper the Wilson nonconforming finite element is employed to solve Sobolev and viscoelasticity type equations. By means of post-processing technique, global superconvergence estimates are obtained for quasi-un...In this paper the Wilson nonconforming finite element is employed to solve Sobolev and viscoelasticity type equations. By means of post-processing technique, global superconvergence estimates are obtained for quasi-uniform rectangular meshes. Finally, an error correction scheme is presented.展开更多
文摘美国著名计算结构力学专家、地震工程专家Ray W Clough和Anil K Chopra分别写有在全世界范围内有很大影响的专著《DYNAMICS OF STRUCTURES》.两部著作在关于逐步积分算法的论述中都曾指出加速度由当前位移和速度代入运动方程求解将能得到更好的结果.但这一点存在可商榷之处,为避免读者误用,从算法的稳定性出发,经分析指出:专著观点应用于Newmark法增量格式时确实使得算法的谱半径有所减小;然而,应用于Newmark法全量格式时,算法特性并未发生改变,结果得不到改善;此外,书中给出了增量格式Wilsonθ法的推导步骤,按此推导的算法相对于全量格式稳定界限发生了改变——只有当θ≥1.5时算法才是无条件稳定的.如果误将加速度由当前位移和速度代入运动方程求解推广到Wilsonθ法全量格式,算法的稳定性将变得非常差.
文摘基于动量叶素理论,推导同半径对旋风力机功率与前、后级轴向速度诱导因子的关系,结果与经典模型吻合;将单级风力机Wilson设计法发展为考虑级间干扰的对旋风机设计法,实现以环形微元盘面功率系数最大为目标,前、后级轴向和环向诱导因子为变量的优化设计,并完成2 k W单级和对旋风力机设计实例。最后采用CFD方法验证对旋风力机实验结果和设计结果,数值计算表明,设计工况下,对旋风机的风能利用率(46.32%)高于单级风力机(41.44%),并分析了数值预测的风能利用率与理论最佳值(64.00%)和(59.26%)的差异。
文摘The aim of the study is to assess the possibility of intubation in each patient, the lyche to be difficult intubation, to fred all the causes of the difficult intubation, to fred and apply appropriate scales for difficult intubation, to estimate the frequency of difficult intubation. Endotmcheal intubation is the basic reanimation procedure performed both in hospital and out-of-hospital settings. It is carded out whenever chest movements and spontaneous respiration are compromised. Respiratory arrest may occur for a variety of reasons （such as cardac arrest, coma of any origin, poisining） or direct damage to the airways, e.g. in various traumas （damages to the face, oropharynx, larynx, trachea, chest）. The basic endotracheal intubation kit contains： laryngoscope, endotracheal tubes, connectors （tube and Ambu bag connectors）, complete Ambu kit （face mask and bag）, 20 mL syringe for cuff inflating, suction apparatus, stylete, and Magill forceps. In order to assess the successfulness of endotracheal intubation, it is necessary first to identify patients who need to be intubated. With the aim of identifying such patients, numerous screening tests and scales have been created to predict difficult intubation. The best known and most commonly used are the Mallampati and Wilson classifications as well as the LEMON airway assessment method. Nevertheless, difficult intubation accounts for 1% of cases. It usually occurs when manipulation of the laryngoscope blade is not possible in obese patients and patients with short neck, in congenital restricted mouth opening, limited neck movement as well as limited temporomandibular joint mobility; in cases of edema, fibrosis and lesions of the tongue, pharynx and larynx; when there are anatomical variations and congenital malformations of the oral cavity, pharynx, larynx, head, neck and chest.
文摘In this paper the Wilson nonconforming finite element is employed to solve Sobolev and viscoelasticity type equations. By means of post-processing technique, global superconvergence estimates are obtained for quasi-uniform rectangular meshes. Finally, an error correction scheme is presented.
