LDMOS 功率器件在固态雷达发射系统中应用研究与实践

介绍了LDMOS 功率器件的特性,通过与传统Si 功率器件相比较,LDMOS 器件具有低成本、高增益、高线性度、热稳定性好和高可靠性等特点,在固态雷达发射系统中有广阔的应用前景,本文对LDMOS 功率器件在固态雷达发射系统中应用进行理论分析,并利用LDMOS 功率器件设计制作了P 波段300W 功放组件,对LDMOS 功率放大组件进行性能测试,根据试验数据分析应用LDMOS 功率器件对固态雷达发射系统的影响。     

利用真空固态反应合成高质量二维过渡金属二硫化物晶体及其应用

二维过渡金属二硫化物(TMD)晶体由于其结构的多样性和独特的性质备受关注。真空固态反应法是生长高质量二维TMD晶体的一种强有力工具,此方法大大推动了基于二维TMD晶体的基础研究和应用探索。在这篇综述中,我们总结了在真空系统中生长高质量二维TMD晶体的方法,并讨论了影响二维TMD晶体尺寸、质量、形态和多型性的因素。我们还简要讨论了二维TMD晶体的物理性质及各种应用。最后,对真空固态反应法在二维TMD晶体生长中的应用进行了展望。     

基于LabVIEW的甲烷产气量自动测量系统设计

针对实验室现有的厌氧发酵装置产气测量存在费时费力、人眼读数误差较大、自动化程度低等问题,设计一种基于LabVIEW的甲烷产气量自动测量系统.提出采用排水法与称重计量法结合的测量方法,以实现产气量自动测量.称重传感器获取发酵甲烷产气排水后得到水的质量,经换算得到排水体积即甲烷产气体积.利用LabVIEW编写软件平台,采用...     

纤维素乙醇生产技术及产业化现状

在阐述我国发展纤维素乙醇必要性的基础上,综述了纤维素乙醇的水解发酵、同步糖化发酵、同步糖化共发酵、同步多菌产酶水解发酵等工艺及研究进展,分析了各工艺优缺点,并讨论了各工艺过程需要解决的关键技术问题;概述了国内外纤维素乙醇的产业化现状;展望了纤维素乙醇的产业化前景。     

黄山头大曲酒独特醇甜型风格成因初探

从黄山头酒业所处地理位置的自然生态环境、有机原料基地的建设、生产工艺特点、民俗习惯、现代生物技术的应用与传统工艺的改进、酒体微量成分与人体健康等六个方面探讨了黄山头大曲酒的＂绵、甜、爽、净、香＂风格特征的成因。决定黄山头大曲酒醇甜型风格的六大主要因素为自然生态环境、原辅料、微生物区系、糖化发酵剂、酿酒工艺、储存设备与环境。     

破乳菌B_3菌株分批发酵动力学分析

以从采油废水中筛选到的一株高效生物破乳菌株B3为试验菌株,为认识其发酵机理并指导发酵工艺设计,利用分批发酵的方法研究破乳菌株B3菌体生长和葡萄糖消耗情况.根据分批发酵实验结果,采用Logistic方程和Lu-edeking-Piret方程,建立破乳菌株B3的菌体生长和葡萄糖消耗动力学模型,利用拟线性法求得破乳菌分批发酵的动力学模型参数.模型计算值与实验值能够较好地拟合,相对误差分别小于9%和6%,表明所建立的动力学模型能够反映B3破乳菌株发酵过程的动力学特征.     

Production of ethanol from raw juice and thick juice of sugar beet by continuous ethanol fermentation with flocculating yeast strain KF-7

Sugar beet juice can serve as feedstock for ethanol product due to its high content of fermentable sugars and high energy output/input ratio. Batch ethanol fermentation of raw juice and thick juice proved that addition of mineral nutrients could not improve ethanol concentration, but could accelerate the fermentation rate. Fermentation of thick juice with an initial pH of 9.1 did not affect the fermentation process. The continuous ethanol fermentation of raw juice was performed at 35 °C with a dilution rate of 0.3 h⁻¹, resulting in ethanol concentration, ethanol yield and productivity of 70.7 g L⁻¹, 89.8% and 21.2 g L⁻¹ h⁻¹, respectively. A two-stage reactor was used in the continuous ethanol fermentation of thick juice by feeding fresh yeast cells into the second reactor. This process was stable at a total process dilution rate of 0.11 h⁻¹ with an overall sugar concentration of 190 g L⁻¹ in the influent. The ethanol concentration was kept at approximately 80 g L⁻¹, corresponding to ethanol yield of 82.5% and productivity of 8.8 g L⁻¹ h⁻¹.     

Novel repeated batch operation for flash fermentation system: Experimental data and mathematical modelling

A novel repeated batch operation mode was proposed for ethanol fermentation, where the fermenter beer was periodically exchanged between the fermenter with biomass recycle and the distillation unit, to promote the selective removal of ethanol. Using the mathematical model developed, as based on the experimental results, the optimal operation of the proposed method was shown to attain high performance, with a productivity of about 12 g dm⁻³ h⁻¹ and a product concentration of 400 g dm⁻³.     

The use of biomass and stillage recycle in conventional ethanol fermentation

Modifications of the conventional ethanol fermentation process using biomass and stillage recycle were investigated and the advantages of the technique were studied. The biomass recycle method resulted in a reduction in the use of approximately 8% raw material (molasses). The recycle of 15–70% of stillage (dealcoholised) from a previous fermentation was also tested successfully. Generally the results of these experiments revealed 13–47% less water consumption and consequently about 13–47% reduction of stillage volume, which was more economical for further treatments.     

Lignin Impact on Fibre Degradation: 1—Quinone Methide Intermediates Formedfrom Lignin DuringIn VitroFermentation ofCorn Stover*

Experiments were conducted to determine whether formation of quinone methide intermediates from lignin occurs during ruminal fermentation of corn stover, as indicated by nucleophilic addition reaction with sulphur-containing reducing agents. Corn stover leaf and stem fractions harvested at full maturity were incubated in buffered ruminal fluid without reducing agents or with (NH₄)₂SO₄ (S-control), Na₂S.9H₂O, cysteine-HCl (cysHCl), or cysHCl plus Na₂S.9H₂O; and in only buffer with or without cysHCl plus Na₂S.9H₂O. Mixed reducing agents (cysHCl plus Na₂S.9H₂O) enhanced ( P< 0.001) in vitro fibre degradation after 48 h, tended to increase solubilisation of fibre ( P =0.07) and dry matter ( P =0.06) in buffer alone, and elevated ( P< 0.001) S-content of residual fibre. In vitro incorporation of S into the undegraded fibre was determined for corn stover fractions of varying lignin compositions that were harvested at two maturities (early dent and full maturity) in 2 years. Extent of fibre degradation was correlated with extent of S-incorporation ( r =-0.54, P< 0.001), and with lignin methoxyl content ( r =-0.84, P< 0.001). The negative association of lignin methoxyl content with digestibility is explained by the relative likelihood of quinone methide intermediate formation from guaiacyl and syringyl units in lignin.