具有高活性宽光谱响应的新型光催化材料

以二氧化钛为代表的传统光催化材料只能利用短波长的紫外光,太阳光利用率和量子效率低,其广泛应用受到极大限制．针对这一问题,近年来我们开展了一系列具有高活性和（或）宽光谱响应（包括紫外及可见光）的新型纳米光催化材料的研究．本文简要总结了相应工作的进展,并对可能影响光催化材料的活性和光谱响应的相关因素进行了探讨．     

二氨基马来腈共聚合改性氮化碳光催化剂

利用二氨基马来腈(DMNA)与二聚氰胺(DCDA)的高温共聚合反应, 制备了石墨相氮化碳 (g-C₃N₄), 并通过X射线衍射(XRD)、傅里叶变换红外(FT-IR)光谱、透射电镜 (TEM)、氮气吸脱附实验 (N₂-sorption)、电子顺磁共振 (EPR)、紫外-可见漫反射光谱 (UV-Vis DRS) 和荧光 (PL) 光谱等表征手段,系统考察了共聚合改性对g-C₃N₄晶体结构、化学结构、能带结构、织构、光吸收性能和光催化性能等的影响.研究结果表明:共聚合改性后氮化碳材料仍保持石墨相晶体结构, 但其π电子的离域性增强, 并在催化剂表面产生异质结构, 进而提高了氮化碳在可见光区域的光吸收性能, 并促进了光生载流子的有效分离. 性能评价结果显示, DMNA改性的氮化碳在可见光下光催化产氢活性明显高于未改性的样品, 当DMNA用量为0.01g时, 催化剂的产氢速率最高, 达到45.0 μmol·h^-1, 为纯氮化碳样品的4.5倍.     

不确定环境下服务资源配置优化

在服务资源配置过程中,按维修状态将服务对象分成三类:完全维修、部分维修及最小维修.由于维修服务的特性,服务成本与服务时间均是一个模糊数,并且维修对象在服务时所处的维修状态也具有一定的不确定性.针对这类情况下的服务资源配置问题,提出了同时考虑模糊服务成本和模糊服务时间及不确定维修状态的最小化服务成本为优化指标的服务资源配置模型.在模型的求解过程中采用多粒子群算法,通过仿真计算表明了该方法的可行性和有效性.     

太阳能光伏热水系统的能量梯级利用

为了实现太阳能光伏发电系统中用于冷却太阳能电池的低品位热能利用,本文提出了太阳能光伏热水系统。通过对单体光伏光热系统(PV/T)的实验研究表明,在单体PV/T放置角度为30°,流量为200 L/h时,集热效率可达到最大值65.6%,系统的平均发电效率为14.3%,瞬时综合效率最大为83%,达到了能量的梯级利用。     

研究性核反应堆的现状、应用和发展

回顾了世界过去50多年研究堆的发展历程,分析了世界研究堆的现状以及未来的应用发展趋势,同时结合我国脉冲堆的实际情况,对其应用发展前景进行了初步展望。     

蚕丝丝胶蛋白的结构、性能及利用

丝绸厂排放的废水中含有大量的丝胶蛋白。丝胶蛋白是一种球状蛋白,含有多种多肽,由18种氢基酸组成,含有较多的丝氨酸,天门冬氨酸和甘氨酸,极性侧链氨基酸占74．61％,丝胶蛋白具有易溶,吸水,凝胶化,可改性和抗氧化等特性,在化妆品,食品、医药和生物材料等方面具有良好的开发潜能。     

Modeling of saccharide utilization in primary beer fermentation with yeasts immobilized in calcium alginate

Immobilized beer fermentation was studied using an industrial bottom-fermenting yeast strain Saccharomyces cerevisiae. The yeast cells were immobilized in 2.5% calcium alginate gel and used for brewing in a five-vessel cascade reactor. The fermentation was performed at 15°C at various flow rates. A nonstructured mathematical model was developed to simulate the performance of continuous primary fermentation of lager beer. The model was based on the following variables: maltose, maltotriose, glucose, fructose, ethanol, and cell concentration. Experimental values of these variables were determined in samples taken at regular intervals. For experimental data fitting a nonlinear regression was used. Substrate consumption was characterized by specific substrate consumption rate and saturation constant. The values of these two parameters were optimized for all four substrates. Inhibition effects of substrates and product were analyzed using various inhibition patterns. Only the inhibition effect of maltose on maltose consumption was clearly identified. A good-fitting relationship for maltose inhibition was found, and inhibition constants were calculated.     

炼铝工业固体废料(赤泥)的物质组成与工程特性及其防治利用研究

据保守估算 ,我国每年排放的铝工业固体废料赤泥至少在 5 0 0万 t以上。由于赤泥对生态环境的严重危害 ,赤泥坝、赤泥库的安全已成为令人关注的环境问题。各类固体废弃物 (包括生活垃圾 )储存、处理和利用的研究不仅是当代环境科学的重要任务 ,亦是当代环境工程地质学、环境岩土工程学最重要、最迫切的研究任务之一。本文利用工程岩土学的有关理论和方法 ,系统地研究了赤泥的化学、矿物成分、不良工程特性及其形成变化机理 ,并在此基础上提出了赤泥的储存、加固 (处理 )和综合利用的原理和途径。     

Bandwidth allocation for guaranteed versus best effort service categories

Modern communication networks evolve towards integration of guaranteed-performance and best-effort service types. The coexistence of these two service types offers substantial benefits, such as resource sharing between service classes, and the ability of the user to select an appropriate service class according to its individual requirements and preferences. Notwithstanding, such interaction gives rise to more complicated system behavior and related performance issues, which need to be explored and understood in order to allow efficient network operation. In this paper we examine potential congestion phenomena, which arise due to the combined effect of bandwidth sharing and user migration between service classes. We propose a simplified fluid model for session flow, consisting of two coupled queues with state-dependent flows, which captures the essential ingredients of service-class interaction. Our analysis shows that the system might exhibit bistable behavior, in the sense that transient congestion may stir the system from a stable and efficient operating point to an inefficient and congested one. We identify conditions which give rise to bistability, and propose a call admission control scheme which prevents the system from getting trapped in a congested-type equilibrium, while not interfering with normal system operation. This revised version was published online in June 2006 with corrections to the Cover Date.     

Multi-user cognitive radio network resource allocation based on the adaptive niche immune genetic algorithm

Multi-user cognitive radio network resource allocation based on the adaptive niche immune genetic algorithm is proposed, and a fitness function is provided. Simulations are conducted using the adaptive niche immune genetic algorithm, the simulated annealing algorithm, the quantum genetic algorithm and the simple genetic algorithm, respectively. The results show that the adaptive niche immune genetic algorithm performs better than the other three algorithms in terms of the multi-user cognitive radio network resource allocation, and has quick convergence speed and strong global searching capability, which effectively reduces the system power consumption and bit error rate.