紧凑环注入系统高压脉冲电源设计

以放电回路理论模型计算和仿真分析为指导,设计了紧凑环注入装置(CTI)高压脉冲电源,并在CTI上进行放电实验。实验结果证明所设计的CTI高压脉冲电源可产生特定频率下100kA的目标电流,保证了CTI成型场及加速场电极的供电需求。     

剖宫产术前补钙预防宫缩乏力性产后出血的效果评价

目的分析探讨产妇在进行剖宫产术前补钙以预防宫缩乏力性产后出血的临床效果,总结应用体会。方法选择深圳市盐田区盐田街道计生服务所于2014年12月—2015年12月期间收治的70例进行剖宫产的产妇作为观察对象,随机分为观察组35例与对照组35例,观察组患者于手术实施前静脉滴注葡萄糖酸钙注射液,对照组患者手术实施前不使用药物,观察两组患者的术中出血量、术后出血量、手术时间及住院时间等指标。结果观察组患者的术中出血量(178.79±23.44)m L、术后出血量(216.33±32.08)m L及术后2 h累积出血量(578.04±87.39)m L均显著少于对照组,两组间比较差异有统计学意义(P0.05);观察组患者的手术时间(34.36±5.15)min及住院时间(4.02±1.46)d均显著短于对照组,两组间比较差异有统计学意义(P0.05);观察组患者对护理质量的总体满意度为97.14%,对照组对护理质量的总体满意度为80.00%,观察组显著高于对照组,两组比较差异有统计学意义(P0.05)。结论剖宫术前补钙,可以有效预防产妇产后出血,效果确切,安全可靠,值得临床推广应用。     

B对人造金刚石表面结构及性能的影响

研究了B对人造金刚石表面结构及性能的影响。结果表明,采用渗B石墨或渗B触媒合成的金刚石,表面存在有螺旋状和阶梯状生长台阶,树枝状和河流状结晶等。但对金刚石性能影响不大。含B金刚石的性能明显优于不含B金刚石。且渗B石墨对金刚石性能的影响比渗B触媒大。     

Dynamic interaction between a moving vehicle and an infinite structure excited by irregularities – Fourier transforms solution

Summary  A new approach to calculate the dynamic interaction between a moving vehicle and an infinite structure is presented. Its main characteristics are: use of Fourier transformed domains (leading to a very general formulation of the problem), correct consideration of the motion of all components of the model; consideration of all kinds of mutual dynamic interactions between the vehicle and the track, and the possibility to include a layered half-space for the subgrade, instead of the elastic Winkler foundation used here. Examples of a single axle and a bogie model passing an irregular track illustrate characteristic effects. Received 13 December 1999; accepted for publication 21 September 2001 RID=" ID=" The research reported here was done at the Lehrstuhl für Baumechanik, (TUM). The authors are greatly indebted to Harry Grundmann for his interest and advice.     

Dipolar and electronic effects on charge transport through single transition metal complexes

Charge transport through single molecular neutral monoand di-cobalt(II) complexes with π-conjugated macromolecular wire was investigated.Scanning tunnelling spectroscopy (STS) studies revealed that the mono-cobalt(II) complex showed a pronounced rectifying effect with a large rectification ratio and finely featured NDR peaks,while the di-cobalt(II) complex showed a relatively symmetric electron transport without clear NDR peaks.Th     

新型CuCl／Hβ沸石羰基化催化剂的制备与原位红外光谱表征

采用固态离子交换法在沸石中直接引进Ｃｕ（Ⅰ）活性中心,ＣｕＣｌ分子在Ｈβ沸石中与Ｈ＾＋交换和在沸石内表面单层分散两个过程同时发生,负载阈值为２１．２％（ＣｕＣｌ％）,调节ＣｕＣｌ和Ｈβ的配比,可得到从桥羟基被部分交换到所有羟基被完全交换的ＣｕＣｌ／Ｈβ从化剂。     

面向新世纪的人工晶体

人工晶体是重要的电子、光子材料。本文结合信息技术的进步来考察电子材料、光电子材料和光子材料中人工晶体的发展。在新世纪(太元世纪)的全球信息科技的构架材料中人工晶体仍起着中心作用。     

A comparison of molecular orbital methods for the analysis of the He(I) photoelectron spectra of n-alkenes

The two highest vertical ionization potentials are calculated by the Fenske-Hall, MINDO/1, and MINDO/3 molecular orbital methods for an extensive series of n-alkenes. It is found that the Fenske-Hall method gives a better correlation with the corresponding experimental photoelectron spectral data and is the most useful for the interpretation and understanding of these results. When MINDO/3 was used for calculations by the ΔSCF method, it was not possible to obtain satisfactory agreement with the photoelectron spectroscopic measurements. Finally, the relevant findings of other calculational procedures such as ab initio and SPINDO are given.     

Mass transfer from copper melts by top-blowing of an argon-hydrogen plasma jet

The volatilization of lead, copper, tin, and zinc from copper melts using the technique of top-blowing with an argon-hydrogen plasma jet was experimentally investigated and theoretically evaluated. A plasma burner with 16 kW power was used in the experiments. The mole flow of the plasma gases was 0.017 mol/s (25 liters/min when T = 25°C and P_G = 1 bar). The temperature was 1830°C on the surface of the melt and between 1200 and 1500°C in the molten solution. When the zinc concentration is above 2 mole%, supersaturation of zinc occurs on the surface. In this range of concentrations the ratio of dilution of the concentration in relation to time is linear (zeroth-order reaction). When the concentration of zinc is below 2 mole%, the time dependence of volatilization can be described by an exponential law corresponding to a first-order reaction, because in this case the rate-determining step is the mass transport of zinc in the molten copper phase. From the change from zeroth-order to first-order reaction during the volatilization of zinc, the temperature on the surface of the melt can be estimated with a high degree of accuracy. On the other hand, the volatilization of tin and lead is determined by mass transfer in the gas phase, which leads to an exponential law for the whole range of concentrations. Reaction models were set up on the basis of the experimental data. The relationships thereby obtained permit one to evaluate in advance the yield of future industrial volatilization processes with top-blown plasma jets.Nomenclature A activity - A _e , m² effective mass-transport or mass-transfer area - k, mol/m² s^–1 mass-transfer coefficient - k _g , mol/m² s^–1 mass-transfer coefficient in the gas phase - k _s , mol/m² s^–1 mass-transfer coefficient in the melt phase - k, mol/m² s^–1 overall mass-transfer coefficient - K =P _i /x _i equilibrium coefficient (distribution coefficient) - K _T =P _i /a _i equilibrium coefficient - n _s , mol number of moles of the melt phase - n _G , mol number of moles of the gas phase - n _g , mol/s mole flow of the top-blown gas - n _i , mol/s mole flow of the extract i into the gas phase - P _i , N/ M² partial pressure of extract substance i in the gas phase - t, s time - T, °C or K temperature: T_s, in the melt; T , at the phase interface - x _i , mol/mol concentration in the melt - X _f ¹ , mol/mol concentration in the melt at the phase interface - w, s^–1 rate constant - y _i , mol/mol concentration in the gas phase - y _f ⁱ , mol/mol concentration in the gas phase at interface - z, m coordinate in the direction of mass transfer - activity coefficient - ^O Henry coefficient     

Emission phenomena in electrochemical systems: Investigation of solvated and delocalized electrons in polar media

The principles of using the results of studies of emission phenomena in electrochemical systems for determination of the energy levels of excess (solvated and delocalized) electrons in electrolyte solutions are formulated. The energy characteristics of excess electrons in hexamethylphosphoric triamide have been estimated on the basis of data obtained by the author and literature data (results of photo- and thermoelectron emission measurements and equilibria studies in solutions of solvated electrons). The energy levels of solvated electron and bi-electron, their photoionization energies and solvent reorganization energies have been found. The nature of the absorption spectra is discussed.