基于水光电力系统时序生产模拟模型的水光优化配比研究

基于考虑系统负荷、新能源发电出力等时序变化特性的时序生产模拟法,建立了水光电力系统时序生产模拟模型;从系统结构性、经济性、灵活性与可靠性方面综合确定最佳水光容量配比,并通过金沙江上游川藏段水光系统验证了模型的合理性。金沙江上游川藏段光伏电站与水电站出力具有较好的年内、日内互补特性;对于2030年水平年,考虑枯期水电留存,913.6万kW水电配套400万kW光伏的方案综合性能更优,其新增非水可再生电量约60亿kW·h。     

Positivity of entropy production in nonequilibrium statistical mechanics

We analyze different mechanisms of entropy production in statistical mechanics, and propose formulas for the entropy production ratee() in a state . When is steady state describing the long term behavior of a system we show thate()0, and sometimes we can provee()>0.     

批量制造业模糊交货期准时化生产计划方法

通过建立批量制造业模糊交货期下的准时化生产计划模型,将隶属度函数引入到生产计划问题中,从而拓宽了准时化生产计划问题的研究范围,并为实际生产计划的编制提供了一种有效途径。     

基于分散网络化生产系统的车间生产管理模式及系统设计研究

基于分散网络化生产系统,针对我国中小型机械制造企业技术现状,提出了在基本上不改变现有车间基础设施的前提下,通过信息集成建立产品数据,财务和计算机辅助车间调度等管理子系统,以增强企业适应产品市场多变的能力;采用多品种,小批量生产方式,以满足产品生命周期缩短和２１世纪国际化大市场竞争的需求。     

我国东南低山丘陵区土地粮食生产潜力研究──以桂林市为例

我国东南低山丘陵区资源丰富,历来为重要的粮食生产基地．但其粮食生产近年发展缓慢．根据采用趋势潜力与资源潜力相结合的方法,所进行的桂林市土地粮食生产潜力及其发挥和实现影响因素的研究结果,该区粮食生产潜力较大,但目前发挥和实现程度低．为促进粮食生产潜力的发挥．并保证其持续发展．今后应大力改造中产田．提高土地质量和耕地灌溉保证率．加强粮食生产的物化投入,保证活劳动投入的需要,并同时注意协调化肥的投入结构．     

可见光化的半导体光催化剂

光解水制氢能否实用化取决于太阳光的有效利用率, 研究开发可见光化的光催化剂成为当前光催化剂研究中的重要课题.本文介绍了利用 光解水制氢的反应机理,综述了近年来半导体光催化剂在利用可见光方面的研究进展,重点描述了这些光催化剂的结构,并对该领域今后的研究方向进行了展望.     

废弃生物质在超临界水中转化制氢过程的研究

以废弃生物质转化为富氢气体为目的，使用间歇式超临界水反应器，在反应温度773 K～923 K、压力15.5 MPa～34.5 MPa停留时间1 min～30 min和Ca/C摩尔比0～0.56范围内，对木屑在超临界水条件下生成的气体组成及产率进行了考察。实验表明，Ca/C摩尔比和温度对木屑转化的影响较大。当Ca/C摩尔比为0.48时，碳的气体转化率和氢气产率提高了近一倍。温度从773 K提高到923 K，碳的气体转化率由47％提高到76％，氢气产率由4.5 mmol/g上升到6.9 mmol/g。与温度相比，停留时间和压力的影响不大。     

Liquid fluidized bed starter culture ofTrichoderma reesei for cellulase production

A starter culture ofTrichoderma reesei (Rut-C30) prepared in a liquid fluidized bed reactor (LFBR) gave better growth and greater cellulase production in submerged fermentation than a conventional shake flask inoculum. The LFBR starter was prepared by first coatingT. reesei spores to 0.25 mm size corncob (1.0x10⁸g^-1) in a medium containing 1.0% corncob, 0.5 gL^-1 xylose and 0.1 gL^-1 lactose in a balanced salt solution, then fluidizing the particles in the LFBR for 36 h to allow germination of the spores, and covering the particles with an approx 30 μm thick biofilm. This biofilm that developed in constant adherence to the lignocellulosic carrier, apparently became well adapted to grow rapidly on insoluble cellulose substrates (Solca Floc), and had the enzymes of the cellulase complex induced for increased cellulase production. The LFBR starter used in a stirred tank reactor (STR) gave 15 gL^-1 biomass production and 6.5 IU mL^-1 overall cellulase activity with a volumetric productivity of 64 IU L^-1h^-1 in a 5 d fermentation, compared with a 7 d shake flask inoculum that gave 11 gL^-1 biomass and 3.2 IU mL^-1 cellulase activity, with a volumetric productivity of 31IU L^-1h^-1. The LFBR starter culture retained its viability in dry storage for 6–9 mo.     

Diminished Respirative Growth and Enhanced Assimilative Sugar Uptake Result in Higher Specific Fermentation Rates by the MutantPichia stipitis FPL-061

A mutant strain ofPichia stipitis, FPL-061, was obtained by selecting for growth on L-xylose in the presence of respiratory inhibitors. The specific fermentation rate of FPL-061, was higher than that of the parent,Pichia stipitis CBS 6054, because of its lower cell yield and growth rate and higher specific substrate uptake rate. With a mixture of glucose and xylose, the mutant strain FPL-061 produced 29.4 g ethanol/L with a yield of 0.42 g ethanol/g sugar consumed. By comparison, CBS 6054 produced 25.7 g ethanol/L with a yield of 0.35 gJg. The fermentation was most efficient at an aeration rate of 9.2 mmoles O₂ L^-1 h^-1. At high aeration rates (22 mmoles O₂ L^-1 h^-1), the mutant cell yield was less than that of the parent. At low aeration rates, (1.1 to 2.5 O₂ L^-1 h^-1), cell yields were similar, the ethanol formation rates were low, and xylitol accumulation was observed in both the strains. Both strains respired the ethanol once sugar was exhausted. We infer from the results that the mutant, P.stipitis FPL-061, diverts a larger fraction of its metabolic energy from cell growth into ethanol production.     

Carob pod: A new substrate for citric acid production by Aspergillus niger

The production of citric acid from carob pod extract byA. niger in surface fermentation was investigated. A maximum citric acid concentration (85.5 g/L), citric acid productivity (4.07 g/L/d), specific citric acid production rate (0.18 g/g/d), and specific sugar uptake rate (0.358 g/g/d) was achieved at an initial sugar concentration of 200 g/L, pH of 6.5, and a temperature of 30°C. Other kinetic parameters, namely, citric acid yield, biomass yield, specific biomass production rate, and fermentation efficiency were maximum at pH 6.5, temperature 30°C, and initial sugar concentration 100 g/L. The external addition of methanol into the carob pod extract at a concentration up to 4% (v/v) improved the production of citric acid.