美国MEDICA公司Easylyte电解质分析仪常见故障的排除

目前美国MEDICA公司生产的Easylyte电解质分析仪在很多医院的门诊化验室使用 ,这里对它的一些常见故障的排除作一介绍     

美国小学教师教育体系的基本特点与思考

美国小学教师的培养在几十年的发展过程中形成了一个具有特色的教师教育体系,在招生和专业选择上,能够录取那些乐意当教师的学生;在课程体系方面,前两年的通识教育课程具有较大的选择性,后两年的专业教育课程重视结合小学的教学实际,很少有选修课程,同时教学实习长达四个学期;在教学方法上,呈现多样化特征,以小组讨论为主。这些特点对于我国当下小学教育专业的建设与发展具有参考价值。     

美国汽车车体装配与焊接研究现状

介绍美国近年来在车体装配、焊接等领域的研究现状，并介绍一些相关技术的发展趋势。     

A rapid and simple technique for correlating light microscopy,transmission and scanning electron microscopy of fixed tissues in Epon blocks

A simplified and standardized technique for close correlation between light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) is described. Perfusion and immersion fixed tissue specimens were embedded in Epon 812 and cut for conventional LM and TEM. The Epon blocks with remaining tissue were thereafter treated with epoxy solvent (ethanol-NaOH solution) for partial epoxy resin removal only (dissolving rate approx 33μm/h). The blocks with partially blotted tissue specimens were then critically point dried and gold coated for SEM. This method, in an easy way, allows repeated observations with LM, TEM and SEM with preserved fine structure and exact correlation. Since the technique is so simple and there is no need for special equipment the method can easily be adopted in all laboratories with basic SEM standards.     

A study of control strategy for the bin system with tube mill in the coal fired power station

The pulverized coal systems with tube mills are widely used in coal fired power plants. As there are many controlled variables and disturbances in this system, and startup and shutdown of the system is frequent and the dynamic characteristic of the controlled plant is also extraordinary, the automatic control system for this kind of pulverized coal system is not ideally implemented for long. The authors of this paper investigated and tested a pulverized coal system with tube mill in Nanjing Thermal Power Station, and based on various different controlled plants and control objectives, proposed rather independent control subsystems. These subsystems can organize a whole automatic control system of pulverized coal system that can be used in different conditions. The control system presented in this paper has worked well since it was put into operation in May 1998, and good economic benefits have been acquired.     

美国教育博士与教育哲学博士之争的缘起和发展

美国教育博士（Ed．D．）学位与教育哲学博士（Ph．D．）学位之争由来已久。这既有复杂的历史原因,也与美国高等教育多样性、不同利益诉求、对学位教育质量关切等因素有关。从历史角度分析两种学位之争的缘起、演变及成因,并探讨其对发展我国教育博士专业学位教育的启示,具有积极的现实意义。     

Normarski differential interference microscopy study of the ferroelastic domains in NaCN,RbCN and KCN

Photomicrographs of the ferroelastic domains present in the low temperature, intermediate phase of NaCN, RbCN and KCN are presented with their linear dimensions and angular orientations. The Normarski optical technique used to display the domain surfaces in colour and used to determine the small out-of-plane angular orientations is discussed in detail. Figures and the construction details are presented of the cold stage that allowed microscopic examination of the crystal surfaces by either reflected or transmitted light down to liquid nitrogen temperatures.     

A quantitative evaluation of the glomerular capillary endothelium in rat and human kidneys: Utilization of vascular perfusion,freeze-cracking of tissue,and scanning electron microscopy

Modern morphological investigation requires the use of a variety of technological approaches and the employment of rigorous morphometric analysis for an adequate evaluation of the structural and ultrastructural features of a tissue or organ. The introduction of the technique of freeze-cracking of tissue to expose new surfaces has made it possible to quantitate the normal surface characteristics of the glomerular capillaries of the mammalian kidney. This report describes the techniques used for the preparation and quantitative assessment of normal glomerular endothelial morphology. The techniques of in vivo and in vitro vascular perfusion of kidneys as a method of fixation and the freeze-cracking of tissue are outlined in detail. In addition, a morphometric analysis of the endothelial surface characteristics are described and values are reported for the control rat and human kidneys from transplant donors.     

A study on the deposit formation in the cylinder and intake valve of a S. I. Engine

A spark ignition engine with port fuel injection (P.F.I.) system was used to accumulate cylinder head deposit (C.H.D.), intake valve deposit (I.V.D.), and piston top deposit (P.T.D.) on an engine dynamometer. In this study, the effect of base gasoline on I.V.D. was examined. The deposit forming tendency and the influence of the fuel component for decreasing deposits have been experimentally examined. The amount of I.V.D. has been observed to increase linearly with the engine operating time. It is also observed that the amount of valve deposit with newly blended gasoline is less than that with base gasoline.