开放式天然气泄漏甲烷气体检测技术研究

天然气集输站场是天然气输送和储存过程中的枢纽,也是天然气泄漏检测的重点对象。传统的天然气泄漏检测技术响应慢、效率低,难以满足实际所需。可调谐半导体激光吸收光谱技术(TDLAS)以其响应速度快、灵敏度高、无需维护等优点得到广泛应用。使用可调谐半导体激光吸收光谱技术实现了同时对天然气的主要成分甲烷、乙烯、乙炔三种气体实时测量的开放式检测和报警系统。实验结果表明,该系统响应时间小于2s,其甲烷、乙烯、乙炔的测量精度分别小于100ppm-m,40ppm-m,50ppm-m,为石油化工行业中天然气泄漏检测技术提供了新的技术方法。     

在体酶生物燃料电池的研究进展

酶生物燃料电池(Enzymatic biofuel cells,EBFCs)具有高专一性和催化性能,可催化与氧化还原反应有关的燃料并获得电能.可用的生物燃料,如葡萄糖、乳酸和丙酮酸盐,可以从汗液、泪液和血液中提取,因而以体液为燃料的EBFCs在可植入式或可穿戴式设备中具有良好的应用前景.采用生物电催化机理对酶生物燃料电池在体液发电中的应用进行了研究,以及对可植入式或可穿戴式生物燃料电池的主要挑战和未来的前景进行了展望.     

基于ADS的射频前端预选器的设计与仿真

预选器作为射频接收前端的主要组成部分,对整个射频信号的接收有着重要的作用。针对实际无线通信环境下的应用,使用ADS软件设计了一种20MHz~3.6GHz的射频前端预选器。在该设计中采用了亚倍频程滤波器组进行分段滤波和抑制镜像信号,并利用低噪声放大器（LNA）对信号进行放大并减小噪声,并对设计的预选器关键部分的插入损耗、增益、噪声系数等指标进行了仿真。仿真结果显示,所设计的预选器各项性能指标均已达到了预期的要求,对接收机前端系统的研究和完善具有重要的参考价值。     

操控非线性损耗实现稳定的高功率单频激光及可调谐激光的输出

通过操控线性和非线性损耗,使激光器满足单频运转的物理条件,获得了稳定高功率单频激光输出.利用非线性损耗取代了现有的标准具锁定技术,实现无调制锁定的宽带连续可调谐激光输出.     

氧化程度对微细鳞片可膨胀石墨结构及膨胀性的影响

以平均粒径为19.71μm的天然微细鳞片石墨为原料,通过化学氧化法制备了具有不同氧化程度的可膨胀石墨,采用XRD、FTIR、Raman、SEM等对可膨胀石墨的结构与膨胀性进行了表征。结果表明:当氧化程度较低时制得的微细鳞片可膨胀石墨由石墨、石墨层间化合物和氧化石墨三相组成;随着氧化程度的增加,氧化石墨相含量与可膨胀石墨结构无序程度逐渐增高,石墨层间化合物相含量先增加后减少,石墨相含量则逐渐降低;氧化促使HSO4-或SO42-插入石墨层间,插入层间的HSO4-或SO42-量是决定可膨胀石墨膨胀容积的关键因素,制备的微细鳞片膨胀石墨的膨胀容积可达65.9mL·g-1。     

N-Protection of amines using pyridinium 2, 2, 2-trifluoroacetate ionic liquid as an efficient and reusable catalyst

A simple, green, and efficient method for the N-tert-butoxycarbonylation of amines by pyridinium 2,2,2- trifluoroacetate （[Py][OTf]） as an efficient and reusable catalyst is reported. In general, electron donating groups on aryl group give rise to the higher yields than electron withdrawing groups. Clean reaction, short reaction times, high yields, reusability of catalyst, and easy preparation of it are some advantages of this work.     

One-pot synthesis of various xanthene derivatives using ionic liquid 1, 3-disulfonic acid imidazolium hydrogen sulfate as an efficient and reusable catalyst under solvent-free conditions

In this study, 1,3-disulfonic acid imidazolium hydrogen sulfate （DSIMHS） is used as an efficient and reusable ionic liquid for the green, mild, and efficient synthesis of xanthenes under solvent-free conditions. Simple and easy work-up, low cost, green process, short reaction times and excellent yields of the products are the advantages of this procedure. Further, the catalyst can be recycled and reused at least for four times without a noticeably decrease in its catalytic activity.     

Synthesis of N-substituted-2-aminobenzothiazoles using nano copper oxide as a recyclable catalyst under ligand-free conditions in reusable PEG-400 medium

A simple and practical method for the synthesis of N-substituted-2-aminobenzothiazoles via a crosscoupling reaction of 2-iodo anilines with isothiocyanates is envisaged using nano copper oxide as a recyclable catalyst and Cs2CO3as a base in PEG-400,as a bio-degradable,reusable,inexpensive and nontoxic reaction medium,under ligand-free conditions.The present tandem process underlines environmental acceptability to access a wide range of N-substituted-2-aminobenzothiazoles in good to excellent yields.     

可循环疏水性铜酞菁催化咪唑的N-芳基化反应

研究了二价铜酞菁(CuPc)催化咪唑与芳基碘或溴的N-芳基化反应.结果表明,CuPc表现出高的催化活性,并且能够重复使用3次活性无明显降低.采用傅里叶变换红外光谱、X射线光电子能谱和紫外-可见光谱对催化剂样品进行了表征.     

Biodegradable thermogel as culture matrix of bone marrow mesenchymal stem cells for potential cartilage tissue engineering

Poly（lactide-co-glycolide）-poly（ethylene glycol）-poly（lactide-co-glycolide）（PLGA-PEG-PLGA） triblock copolymer was synthesized through the ring-opening polymerization of LA and GA with PEG as macroinitiator and stannous octoate as catalyst. The amphiphilic copolymer self-assembled into micelles in aqueous solutions, and formed hydrogels as the increase of temperature at relatively high concentrations（〉 15 wt%）. The favorable degradability of the hydrogel was confirmed by in vitro and in vivo degradation experiments. The good cellular and tissular compatibilities of the thermogel were demonstrated. The excellent adhesion and proliferation of bone marrow mesenchymal stem cells endowed PLGA-PEGPLGA thermogelling hydrogel with fascinating prospect for cartilage tissue engineering.