木质纤维素水解物生物脱毒的研究进展

利用木质纤维素通过稀酸处理生产乙醇的过程中会产生大量影响发酵的毒素物质,而筛选特异性微生物选择性地去除这些酵母发酵代谢抑制物,是一种经济环保的脱毒方法。本文综述了近年来木质纤维素水解物生物脱毒的研究进展,系统地介绍了木质纤维素稀酸水解物的构成和水解物毒素的形成及毒性作用,分析了脱毒菌株的筛选途径及微生物脱毒效应,阐述了生物脱毒微生物与发酵酵母的协同效应以及耐毒或脱毒代谢工程菌的构建,提出了木质纤维素水解物微生物脱毒发酵生产乙醇的研究方向,并对未来的发展前景进行了展望。     

冻干A群C群脑膜炎球菌多糖结合疫苗在3~8月龄健康婴幼儿人群中的免疫原性和安全性评价

目的评价冻干A群C群脑膜炎球菌多糖结合疫苗在3~8月龄健康婴幼儿人群中的免疫原性和安全性。方法采用随机、盲法、对照设计,在广西全州县选择3~8月龄健康婴幼儿300人,按照1∶1分别随机进入试验组和对照组,对照组接种已上市A群C群脑膜炎球菌多糖结合疫苗,试验组接种冻干A群C群脑膜炎球菌多糖结合疫苗。分别于免疫前和全程免疫后30 d采集静脉血,检测血清中抗A、C群流脑抗体滴度,并计算阳转率(4倍增长)。观察并记录每针次疫苗接种后30 min、6~8 h、24 h、48 h、72 h^7 d的不良反应,并随访30 d。结果 261名受试者完成免疫原性观察,对照组(132人)和试验组(129人)A群、C群抗体阳转率分别为93. 94%、96. 90%和97. 73%、98. 45%,试验组与对照组率差为2. 96%(-2. 09%,∞)和0. 72%(-2. 60%,∞);A群和C群免疫后抗体GMT分别为134. 90、163. 89和152. 22、154. 48,组间比较差异均无统计学意义(P均> 0. 05)。300名受试者均进入安全性分析集,对照组(150人)和试验组(150人)全身反应发生率分别为50. 00%和56. 67%,局部反应发生率分别为6. 00%和3. 33%,组间比较差异均无统计学意义(P均> 0. 05)。结论冻干A群C群脑膜炎球菌多糖结合疫苗在3~8月龄健康婴幼儿人群中具有良好的免疫原性和安全性。     

Facile preparation and optical properties of Te/Pb-free Y3Al5O12:Ce3+ phosphor-in-glass via a screen-printing route for high-power WLEDs

The applications in high-power fields of white light-emitting diodes (WLEDs) are restricted due to their poor thermal stability. Transparent Y₃Al₅O₁₂:Ce³⁺ phosphor-in-glass (YAG-PiG) provides an efficient way to resolve this problem. In this work, novel transparent Te/Pb-free YAG-PiGs are successfully prepared via a facile screen-printing route. It is revealed that 5 mol% Eu₂O₃ optimizes the concentration in substrate glass. Slight erosion of YAG particles occurs in the as-prepared samples. With increasing YAG concentration and film thickness, the intensities of photoluminescence spectra of YAG-PiGs increase. The energy transfer from Eu³⁺ to Ce³⁺ is greatly suppressed. Superior thermal stability and high quantum efficiency are obtained. The optimal optical performance values in terms of a luminous efficiency of 117.2 lm/W, a correlated color temperature of 5859 K and a color rendering index of 77.2 are achieved in YAG-PiGs. All of the results reveal that the as-prepared YAG-PiGs are promising candidates for high-power WLEDs.     

Photocatalytic oxidation of methylene blue dye under visible light by Ni doped Ag2S nanoparticles

Ag₂S nanoparticles were prepared using a hydrothermal method, and Ni was doped via a photo-assisted deposition method. The samples produced were characterized using different tools. Furthermore, the catalytic performance of the Ag₂S and Ni/Ag₂S samples was examined in the degradation of methylene blue dye under visible light. The UV–vis spectral analysis detected a red shift after loading of Ni. The maximum degradation efficiency achieved was 100% with 3 wt% Ni/Ag₂S as the photocatalyst after a 40-min reaction time. The catalyst could be reused without any loss in activity for the first five cycles.     

两种不同提取方法所得莪术油的成分对比分析

利用气相色谱、气相色谱-质谱联用分析技术,对水蒸气蒸馏和超临界CO2萃取两种不同方法提取得到的莪术油化学成分进行分析鉴定,分别从中分离出60余和90余个组分,并确认了其中50多种化学成分,得到鉴定的组分峰面积占总馏出峰面积的90%以上。根据成分鉴定结果,对不同提取方法所得莪术油的主要化学成分进行比较分析。两种不同提取方法获得的莪术油组分不完全相同,含量也不尽相同,但主要化学成分基本一致,超临界CO2萃取的莪术油所含化学成分较多且相对分子质量较大的重组分较多。同时,对不同方法提取的莪术油中莪术醇等主要特征成分,采用薄层色谱、气相色谱、质谱进行分析测定。研究结果可为莪术油的开发与质量控制提供科学依据。     

Solvothermal synthesis and electrochemical performance of rod-like V6O13 as cathode material for lithium ion battery

Belt-like V₆O₁₃ precursor was successfully synthesized via a simple solvothermal method for the first time. The heat-treatment changed its chemical composition, morphology, structure and electrochemical performance. When heat-treated at 350 °C, the product is rod-like particles, which are 0.3 μm wide and 0.4 μm–2 μm long, exhibits the best electrochemical performance. At a rate of 0.1C and in the voltage range of 1.5–4.0 V, it delivered an initial discharge capacity of 323.5 mAhg^?1. After 50 cycles, it can still sustain a discharge capacity of 267 mAhg^?1. The enhanced electrochemical performance originates from its higher total conductivity, higher lithium diffusion coefficient and better structural reversibility.     

考虑风电的电压稳定概率评估的随机响应面法

为了准确描述电力系统中不确定因素对静态电压稳定分析的影响,掌握负荷裕度或临界功率的概率分布信息,确定某一负荷水平下电压失稳的概率,提出了基于随机响应面方法的电压稳定概率评估方法。用随机响应面法将概率分析问题转化为确定性的非线性规划问题,然后采用内点法求解。电压稳定概率评估模型中考虑了并网风电场输出功率的随机性和负荷的不确定性,并利用正交变换技术处理风电场间风速相关性,分析了风速相关性对临界功率概率分布的影响。IEEE 118和IEEE 300节点系统计算结果表明,与蒙特卡罗方法相比,该方法在保持较高计算精度的同时,需要较少量的采样。     

四桥臂微网逆变器高性能并网H-∞控制研究

微网三相逆变器输出电压波形受电网畸变电压、负载谐波电流和直流侧电压中点平衡的共同作用,为使直流侧电压中点维持稳定,并使输出电压波形跟踪参考电压,针对一种四桥臂逆变器结构进行建模,采用H-∞控制策略构造高带宽鲁棒控制器对中线桥臂和三相桥臂进行统一控制。仿真和实验表明,在较大中线电流和电网电压畸变情况下,中线桥臂能够控制中点输入和输出电流近似相等,三相桥臂能够使输出电压维持较低的谐波畸变率,提升微网供电质量。     

基于差分策略的多目标电力系统无功优化

针对计及有功网损、电压偏差和电压稳定裕度的多目标无功优化问题,提出一种基于差分策略的粒子群算法对多目标电力系统无功优化进行求解。在粒子的速度更新操作中引入差分策略,防止算法陷入局部最优;应用目标序列排序矩阵评价个体适应度,根据适应度大小选择最优引导粒子;该算法在寻优机制中嵌入非劣排序和拥挤距离排序以对种群实施精英选择操作,使算法快速收敛到Pareto前沿;引入自适应参数调整策略,提高了算法的鲁棒性。对IEEE14节点系统和IEEE 30节点系统进行测试仿真,结果验证了所提方法的有效性和可行性。     

水轮机尼科尔斯比例–积分–微分调速器设计

根据闭环系统谐振峰值 Mr 与系统响应最大峰值 Mp之间的关系,构建一个与系统参数及控制器参数都相关的优化问题,通过该问题的求解获得控制器参数与系统参数之间的数学关系.针对线性水轮机模型,设计了基于尼科尔斯曲线的 PID 控制器.系统负荷干扰及参数摄动的仿真结果表明:所设计的 PID 控制器对系统参数摄动及外部有界干扰信号具有很好的鲁棒性能,系统过渡过程性能明显优于传统PID 调节器结果.