基于电流实部与虚部双向追踪的输电设备利用份额模型及应用

:针对输电设备利用份额的传统定义不能计及有功和无功潮流的耦合作用,基于电流的实部与虚部分量提出输电设备利用份额的新模型及定义。该模型将节点和支路功率转换为电流,通过对电流的实部和虚部分别进行双向追踪,可得到全网用户对输电网的利用份额。该模型不受分配模式的限制,通过恰当处理对地支路,可直接用于联营体模式下输电损耗和成本的完全分摊,文中给出了相关证明。采用“节点分裂”的等效方法和面向元件的分配模式,该方法可实现联营-双边交易共存模式下输电损耗的分摊。以5节点系统为例,对新定义和几种不同定义进行了比较,并对双边交易的增量和边际损耗及本文结果进行了分析。给出的IEEE-30节点算例验证了该方法的有效性。     

一种用于推挽式电压型逆变器的低损耗无源吸收电路

提出并实现了一种推挽式PWM电压型逆变器用无源吸收电路;设有独立的放电回路让缓冲电容器上的能量部分地回馈到直流电源中,高频放电能量不会叠加在输出电压上;缓冲电容器的电压被钳位,使得推挽电路特有的倍压不会在吸收电路上造成额外的损耗。给出吸收电路参数的设计准则和计算实例,在200VDC和30kW级的中压中功率逆变装置中发挥了推挽拓扑的优点。理论分析和实验验证了所提方法的有效性。     

Calibration of the Weibull stress scale parameter, σu, using the Master Curve

This work proposes that the Weibull stress scale parameter, σ_u, increases with temperature to reflect the increasing microscale toughness of ferritic steels caused by local events that include plastic shielding of microcracks, microcrack blunting, and microcrack arrest. The Weibull modulus, m, then characterizes the temperature invariant, random distribution of microcrack sizes in the material. Direct calibration of σ_u values at temperatures over the DBT region requires extensive sets of fracture toughness values. A more practical approach developed here utilizes the so-called Master Curve standardized in ASTM Test Method E1921-02 to provide the needed temperature vs. toughness dependence for a material using a minimum number of fracture tests conducted at one temperature. The calibration procedure then selects σ_u values that force the Weibull stress model to predict the Master Curve temperature dependence of K_Jc values for the material. At temperatures in mid-to-upper transition, the process becomes more complex as fracture test specimens undergo gradual constraint loss and the idealized conditions of high-constraint, small-scale yielding assumed in E1921-02 gradually degenerate. The paper develops the σ_u calibration process to incorporate these effects in addition to consideration of threshold toughness effects and the testing of fracture specimens with varying crack-front lengths. Initial illustrations of the calibration process for simpler conditions, i.e. 1T crack-front lengths, use the temperature dependent flow properties and a range of toughness levels for an A533B pressure vessel steel. Then using the extensive fracture toughness data sets for an A508 pressure vessel steel generated recently by Faleskog et al. [Engng. Fract. Mech., in press], the paper concludes with calibrations of both m and σ_u over the DBT region and assessments of the Master Curve calibration approach developed here.     

低压省煤器在电站锅炉中的应用

针对排烟损失大的问题，某些电厂在电除尘器出口加装低压省煤器，用来加热凝结水或热网补水，从而吸收烟气热量，实际测试结果表明，对于节能降耗和保证安全运行均起到了重要作用。     

亚麻针织产品的酶整理工艺探讨

为改善亚麻针织物的舒适性能，探讨用生物酶整理工艺来提高其柔软性。选取酶剂浓度、pH值、温度和时间4个因素作为正交实验的因子，进行了四因素四水平的正交实验。通过对实验结果的分析，确定了合理的生物酶整理工艺条件。工艺参数分别为：酶整理温度为50℃，整理液pH值为5，酶剂浓度为2%，整理时间为60min,亚麻针织坯布经过这种优化的酶整理后柔软性改善效果十分显著。     

The AC losses measurement and analysis of superconducting NbTi CICC for HT-TU superconducting Tokamak

Superconducting TF and PF coils have been measured in SULTAN test facility. Segregated copper strands are included in four NbTi CICC and this is a technical innovation. Two AC losses measurement methods, calorimetric and electromagnetic methods, have been used in the experiments, and a broad frequency range (from 0.05 Hz to 6 Hz) is covered in sample test. The purpose of this experiment was to investigate AC losses of TF and PF CICC conductor including segregated copper and to check the design of PF and TF CICC coated with different resistive barriers (Pb-30Sn-2Sb and Ni plating on NbTi strands).     

火电厂锅炉火用损失大不等于节能潜力大

本文通过对电厂锅炉火用损失的进一步分析计算，认为现有锅炉火用损失之大部分是不可避免的，“锅炉火用效率可以大幅度提高”的观点是不切实际的。文章对火电厂节能工作具有一定的指导作用。     

计算铁心附加损耗系数的公式推导及其验证

阐述了铁心空载损耗产生的原因，分析推导了二片一叠铁心附加损耗系数的计算公式，给出了不同结构铁心附加损耗系数的计算式，并通过实例加以验证。     

预烧淬火速度对NiCuZn铁氧体性能的影响

采用传统的氧化物法制备NiCuZn铁氧体,预烧保温后采用了三种不同方式冷却,研究了冷却速度对材料微观结构和磁性能的影响。发现随着冷却速度的加快,可获得更好微观结构、更高起始磁导率、更低损耗、更高烧结密度之低温共烧材料。     

降低极薄金矿脉开采成本新途径的研究

傲汉旗撰山子金矿用人工底柱代替矿石顶底柱，铁溜井代替木溜井、《金属量》承包代替作业进尺的方法，减小了极薄金矿脉开采的损失率与贫化率，为同类矿山降低开采成本开创了一条新途径。