A new method for calculating loss coefficients [of power systems]

A method is proposed which avoids many limitations associated with traditional B-coefficient loss coefficient calculation. The proposed method, unlike the traditional B-coefficient method, is very fast and can handle line outages. The method utilizes network sensitivity factors which are established from DC load flow solutions, Line outage distribution factors (ODFs) are formulated using changes in network power generations to simulate the outaged line from the network. The method avoids the use of complicated reference frame transformations based upon Kron's tenser analysis. The necessity of data normalization used in least squares and the evaluation of the slope of &thetas;_j versus PG_n is not necessary with the proposed method. Using IEEE standard 14-bus and 30-bus systems, the method's results are compared against results obtained from an AC load flow program (LFED). The method's solution speed is compared to that of the LFED method, the base case database method and the conventional B-coefficient method based on A_jn-factor. The proposed method is easy to implement and, when compared to other methods, has exhibited good accuracy and rapid execution times. The method is well suited to online dispatch applications     

Conductor design with high-Tc superconducting Bi(Pb)—2223/Ag multifilamentary tapes

With high upper critical fields, high temperature superconductors (HTSC) have been recognised as candidate materials for coil and magnet applications. High field devices, at one time or another, when operated close to their rated limits are often faced with instability problems which normally are electrical, magnetic or mechanical in nature. The determination of stability parameters, therefore, is of interest to the conductor designer which very much assists in the processing aspect of long length production of wires and tapes. Due to the morphology of the superconductor most HTSC devices made with Bi(Pb)—2223 precursor exist in tape form. Here the determination of stability parameters (for flux-jump and cryogenic stability) for multifilamentary Bi(Pb)—2223/Ag tapes are presented. Processing parameters such as intermediate deformation and filling factors have been found to play a crucial role, not only on the critical current density of the tapes but on the stability aspect in conductor design as well.     

生命科学中的激光技术

本文综述了激光技术在细胞生物学和临床医学中的新发展。     

添加尖晶石对氧化锌压敏电阻性能的影响

通过添加尖晶石（Ｚｎ７Ｓｂ２Ｏ（１２））改性研制出电位梯度为１００Ｖ／ｍｍ左右，压敏电压在８２～１５０Ｖ，通流容量可达１６００Ａ／ｃｍ２，漏电流＜２μＡ系列压敏电阻器，从而满足了国内电话交换机行业对８２Ｖ、１００Ｖ、１２０Ｖ、１５０Ｖ压敏电阻器的电性能要求。从工艺的角度解释了尖晶石对氧化锌瓷晶粒的作用原理，并分析了尖晶石的微观结构及粒度对瓷片电性能的影响。     

一种8毫米波变张角,半径突变多模圆锥馈源

我们研制了一种8毫米波变张角、半径突变的多模圆锥馈源。计算出其模比并推导出其辐射方向图公式;给出其在两个主平面——E平面与H平面上的辐射方向图和波束场分布特性的测试结果以及电压驻波比VSWR的测量结果;同时给出频带和旁瓣特性。分析与测试共同表明,在34.5GHz～37GHz频带里,该多模馈源的辐射图在大于24dB范围内获得幅度等化且不出现旁瓣,因此具有一定的应用价值。     

东津水电站引水隧洞进口不良地质段施工

东津水电站引水隧洞进口段工程地质条件恶劣，施工干扰大，渡汛工期紧。采用喷锚支护洞脸边坡，洞口明挖３ｍ浇筑钢筋混凝土明拱和Ｌ形护坡墙；洞身段采用新奥法施工，先打通上导洞；进口４０ｍ分段开挖，分段衬砌；进水塔压板混凝土模板采用门字框架钢支撑；排除了施工干扰，防止了洞口滑塌，进口段塌方的恶性事故发生，保证了引水隧洞工程的顺利施工。     

HDPE的耐磨蚀性与抗冲击性的研究

用自制的旋臂式磨蚀实验仪，研究了５种高密度聚乙烯和１种顺丁橡胶改性的高密度聚乙烯，在铁尾矿和铁精矿浆体中的耐磨蚀性。耐磨蚀性最差的是ＨＤＰＥ２２００Ｊ，耐磨蚀性较差的是ＨＤＰＥ６３００Ｍ；ＨＤＰＥ５０００ｓ，６０９８和２４８０的耐磨蚀性较好；ＨＤＰＥ／ｃｉｓ－ＢＲ的耐磨蚀性最好。     

残余应力对55SiMnVB弹簧钢疲劳性能的影响

研究了５５ＳｉＭｎＶＢ弹簧钢板疲劳断口特征及裂扩展过程。结果表明，喷丸强化在表层产生的残余压应力可明显提高疲劳抗力，增强裂纹闭合效应，降低裂纹扩展速度。     

Invasive group A streptococcal disease in Taiwan is not associated with the presence of streptococcal pyrogenic exotoxin genes

We reviewed the clinical features of 44 patients with invasive group A streptococcal (GAS) disease who were treated at two teaching hospitals in southern Taiwan from 1991 to 1994. Genes encoding streptococcal pyrogenic exotoxin types A (speA), B (speB), C (speC), and F (speF) and serotypes of M1, M6, and M12 were determined by polymerase chain reaction to target specific sequences in the 44 isolates recovered from these patients and in 28 isolates recovered from upper respiratory sites in 28 additional patients during the study period. The protease activity of these isolates was tested by using the casein plate method. Of the 44 patients with invasive diseases, 25 (57%) had no obvious underlying diseases, and 14 (32%) had preexisting neoplastic diseases or had previously used steroids. Twenty-five patients (57%) presented with cellulitis or necrotizing fasciitis, 24 (55%) had bacteremia, and eight (18%) had streptococcal toxic shock syndrome (STSS). Eight patients (18%) died of invasive GAS disease; seven had STSS, and seven had underlying diseases. All eight patients died within 48 hours after hospitalization. The presence of speA, speC, or speF was not implicated in any particular clinical syndrome in patients with invasive GAS disease. High-level protease activity and the M1 serotype of the isolates were significantly associated with the clinical signs of STSS and with mortality. M1 serotype and protease activity, as well as host immune status, might play significant roles in the pathogenesis of invasive GAS disease in Taiwan.     

ST－4型节能全自动辊道双推板窑

ＳＴ－４型全自动辊道双推板窑是为永磁铁氧体规模生产而研制的一种节能型空气烧结窑。它根据永磁铁氧体烧结的工艺要求，设计了合理的温区，使规模生产烧结成品率达９５％以上；采用辊道推板相结合的窑床形式与复合保温结构，达到了永磁铁氧体能耗１．２ｋｗｈ／ｋｇ；采用优化设计，使设备性能先进，稳定可靠。