考虑直吹式钢球磨电耗的厂级负荷优化分配

已有的厂级负荷优化分配研究,只单一从煤耗角度,或者从煤耗与某些实际要求结合的角度,如综合考虑快速性或污染排放数量最优。但对于装备直吹式钢球磨煤机的火电厂,分配指令可能引起投运成本,也即厂用电量高并未进行研究。因此,针对此类高电耗量的磨煤机,提出一种综合考虑磨投运成本与总煤耗量的厂级负荷优化分配策略,并基于在混合策略与编码策略两方面进行改进的遗传-禁忌混合算法实现,以确保煤耗量与磨煤机厂用电量二者达到综合最小。最后通过对某厂4 300 MW机组仿真说明提出的厂级优化分配策略,以及成本计算与优化算法的有效性。     

Optimisation of block erection scheduling based on a Petri net and discrete PSO

The shipyard block erection system (SBES) is a typical discrete-event dynamic system. To model multiprocessing paths and a concurrent assembly procedure, a timed Petri net (TPN) is proposed. The definition of a Petri net is extended to accord with the real-world SBES organisation. The basic TPN modules are presented to model the corresponding variable structures in the SBES, and then the scheduling model of the whole SBES is easily constructed. A modified discrete particle swarm optimisation (PSO) based on the reachability analysis of Petri nets is developed for scheduling of the SBES. In the proposed algorithm, particles are coded by welding transitions and selecting places of the TPN model, and then the collaboration and competition of particle individuals is simulated by crossover and mutation operators in a genetic algorithm. Numerical simulation suggests that the proposed TPN–PSO scheduler can provide an improvement over the conventional scheduling method. Finally, a case study of the optimisation of a back block erection process is provided to illustrate the effectiveness of the method.     

Stimulated emission from distyrylbenzene derivative crystals grown by vapor deposition

Narrowed spectra at 452 nm from a thin platelike crystal of distyrylbenzene derivative, 2,5-diphenyl-1,4-distyrylbenzene with two trans double bonds (trans-DPDSB) grown by vapor deposition, are observed. The trans-DPDSB crystal is irradiated by the third harmonic (355 nm) of a Nd:YAG laser. The FWHM of the narrowed spectra can reach 6 nm for the crystal when the pumping energy is 400 microJ/pulse. The threshold value for an optically pumped laser is approximately 350 microJ/pulse.     

A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability

Despite advanced sterilization and aseptic techniques, infections associated with medical implants have not been eradicated. Most present coatings cannot simultaneously fulfil the requirements of antibacterial and antifungal activity as well as biocompatibility and reusability. Here, we report an antimicrobial hydrogel based on dimethyldecylammonium chitosan (with high quaternization)-graft-poly(ethylene glycol) methacrylate (DMDC-Q-g-EM) and poly(ethylene glycol) diacrylate, which has excellent antimicrobial efficacy against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Fusarium solani. The proposed mechanism of the antimicrobial activity of the polycationic hydrogel is by attraction of sections of anionic microbial membrane into the internal nanopores of the hydrogel, like an 'anion sponge', leading to microbial membrane disruption and then microbe death. We have also demonstrated a thin uniform adherent coating of the hydrogel by simple ultraviolet immobilization. An animal study shows that DMDC-Q-g-EM hydrogel coating is biocompatible with rabbit conjunctiva and has no toxicity to the epithelial cells or the underlying stroma.     

基于信任技术的最优潮流新算法

信任技术（Trust-Tech）是一种求解非线性优化问题的有效方法,文中将其应用于电力系统最优潮流计算中。该计算方法分2个求解阶段：第1个阶段建立约束条件的非线性动态系统——商梯度系统,并求解该动态系统的稳定平衡点,得到最优潮流（OPF）问题的可行解,同时采用有效集的思想处理不等式约束以降低计算量;第2个阶段对OPF问...     

Stereoselective synthesis, efficient light emission, and high bipolar charge mobility of chiasmatic luminogens

Stereoregular tetraphenylethene derivatives (Z)-o-BCaPTPE and (Z)-o-BTPATPE featured with chiasmatic conformations and aggregation-enhanced emission characteristics are synthesized using a McMurry reaction. Both luminogens exhibit high hole and electron mobilities. Organic light-emitting diodes (OLEDs) using (Z)-o-BCaPTPE and (Z)-o-BTPATPE as both the light-emitting and electron-transporting layers show high efficiencies.     

海上稠油井筒降黏及配套举升工艺

海上稠油开采面临井筒降黏技术优选及举升工艺配套的问题。围绕渤海L油田明化镇组高黏稠油开采难度大的问题,结合井筒降黏方式室内实验结果,推荐采用稠油掺稀油的井筒降黏技术及配套的射流泵举升工艺。同时,对稀油动力液的地面处理流程及注入参数进行了研究。现场应用表明,稠油掺稀油井筒降黏技术及配套的射流泵举升工艺效果明显,单井平均产量比ODP配产方案增加了80%,为该油田及类似油田稠油的开发提供了参考。     

以通道运行可用率作为直流输电系统可靠性指标的研究

随着高压直流输电系统的快速发展,传统的可靠性指标在实际的考核应用中暴露出一些问题。通过分析传统能量可用率指标评估存在的问题和缺陷,提出一种基于功率影响的通道运行可用率指标。通过算例解析通道运动可用率指标的算法,并以南方电网公司直流输电系统为例分析新指标的应用效果,从优化检修安排的角度为提高直流输电系统的运行可靠性提供一定的参考信息和决策依据。     

致密油层水平井缝间干扰因素及干扰界限

多缝压裂所造的裂缝虽起增产作用,但缝间干扰现象更明显,而且各参数的相互干扰很难全面分析确定。建立压裂裂缝数值模型模拟确定各参数的相关性,研究影响裂缝干扰的主次因素,确定不同储层条件下的干扰界限。研究认为:在其他参数一定时,缝间干扰随原油流度和压力系数的增加而增加;裂缝长度对缝间干扰很小,可以忽略不计。研究成果对水平井压裂裂缝参数优化具有重要指导意义。     

Silica Gel Chemically Modified with Ionic Liquid as Novel Sorbent for Solid-Phase Extraction and Preconcentration of Lead from Beer and Tea Drink Samples Followed by Flame Atomic Absorption Spectrometric Determination

Lead is a harmful metal element that has aroused considerable concern; therefore, it is of great importance to develop sensitive and reliable analytical techniques for the precise monitoring of lead in various foodstuffs. In the present study, an enrichment and separation procedure for lead via its solid-phase extraction as dithizone chelate on an ionic liquid 1,3-di(n-butyl) imidazolium hexafluorophosphate [DnBIM][PF₆]-chemically modified silica gel has been established prior to its flame atomic absorption spectrometric determination. The parameters that affect the extraction recovery of lead was investigated, including sample pH, dithizone concentration, eluent type and volume, and flow rate of sample and eluent. The analytical performance of the method was evaluated. Under the optimized conditions (sample pH, 8.0; dithizone concentration, 0.0005 % (w/v); eluent, 2 mL of 1.0 mol/L HNO₃; sample flow rate, 3 mL/min; eluent flow rate, 0.5 mL/min), the limit of detection was 0.36 μg/L (3σ, n?=?7), and the relative standard deviation was 3.5 % (c?=?5.0 μg/L, n?=?7). The proposed method was successfully applied to the determination of trace lead in beer and tea drink, and the recoveries for the spiked samples were in the range of 97.3–102.5 %.