钴原子插层增强磷烯纳米片析氢反应活性

本文基于第一性原理计算,证明了钴插层磷烯的析氢催化活性可以显著增强.钴插层磷烯具有金属特性,电荷从钴原子向磷烯转移,增强了磷烯的催化活性.钴插层磷烯表面的氢吸附吉布斯自由能与铂(111)表面相当,与氢覆盖度无关.研究结果表明钴原子插层提供了一种有效的方法来增强磷烯的析氢反应催化活性.     

C/Fe-Bi_2WO_6光催化氧化诺氟沙星废水的效能及其机理

采用树脂碳化和水热两步法制备C/Fe-Bi_2WO_6光催化剂,对不同光催化剂光催化降解诺氟沙星溶液的去除效果进行对比研究。考察了条件因素对诺氟沙星(NOR)溶液在模拟太阳光下光催化氧化降解的影响规律。结果表明,在实验条件下,NOR光催化氧化降解符合L-H拟一级反应动力学模型,在NOR溶液初始浓度10 mg/L、溶液p H=7.0、催化剂用量0.75 g/L、H_2O_2浓度为200 mg/L、500 W氙灯照射60 min条件下,NOR完全分解,表观速率常数K_(app)为0.0751 min-1。采用分子荧光光谱法,对C/Fe-Bi_2WO_6光催化氧化去除NOR体系中羟基自由基生成规律进行研究,并推测了反应机理。结合LC-MS的分析结果,推测了NOR可能的降解路径和中间产物。     

Characterization of ZnO nanowire field-effect transistors and exposed to ultraviolet radiation

A ZnO nanowire (NW) field-effect transistor (FET) is fabricated and characterized, and its characterization of ultraviolet radiation is also investigated. On the one hand, when the radiation time is 5~min, the radiation intensity increases to 5.1~μ W/cm², while the saturation drain current (I_\rm dss) of the nanowire FET decreases sharply from 560 to 320~nA. The field effect mobility (μ ) of the ZnO nanowire FET drops from 50.17 to 23.82~cm²/(V.s) at V_\rm DS=2.5~V, and the channel resistivity of the FET increases by a factor of 2. On the other hand, when the radiation intensity is 2.5~μ W/cm^2 , the DC performance of the FET does not change significantly with irradiation time (its performances at irradiation times of 5 and 20~min are almost the same); in particular, the I_\rm dss of NW FET only reduces by about 50~nA. Research is underway to reveal the intrinsic properties of suspended ZnO nanowires and to explore their device applications.     

Ni与Co掺杂Fe2O3（0001）表面增强析氧反应活性

Fe based oxides are considered as a promising catalyst for the oxygen evolution reaction (OER) due to their low cost and high stability. Here, based on density functional theory calculations, the electrocatalytic behaviors of pure and metal (Ni, Co) doped Fe-terminated Fe₂O₃(0001) are investigated. The potential-limiting step for OER is determined as the formation of O^* by dehydrogenating surface hydroxyl and it is suggested that the doping enhances the catalytic activity of Fe₂O₃(0001) by reducing the free energy change of rate limiting step on doped Ni or Co atom. Especially, the calculated over-potential of Co-doped Fe₂O₃ (0001) surface is about 0.63 eV on Co site, which is comparable with the theoretical over-potential of 0.56 eV for RuO₂.     

利用2DCOS进行多组分混合气体傅里叶变换红外光谱分析中同分异构体谱峰的辨别

在利用傅里叶变换红外光谱进行混合气体定量分析中,针对烃类尤其是同分异构体等构成的混合气体其谱图特征相似、吸收峰严重交叠,不易进行特征吸收成分的判别和特征变量选择的问题,为增强谱峰分辨力,采用广义二维相关光谱和傅里叶变化红外光谱对烃类混合气体分析中同分异构体进行辨别,以异丁烷和正丁烷的红外光谱及受浓度扰动组成的光谱组为例进行二维相关红外光谱分析。通过观察全波段和主吸收峰波段单组分气体的傅里叶变换红外光谱,可知其谱图相似,吸收峰严重交叠,如果混合在一起,将基本无法辨别何种分子结构及成分。通过广义二维相关光谱的变换,其二维相关光谱的同步谱和异步谱可以清晰地辨别出异丁烷和正丁烷的特征吸收峰及其各自强度,实验结果可知,异丁烷在2 893,2 954和2 977 cm-1,正丁烷在2 895和2 965 cm-1具有强的吸收特征谱线。分析结果初步验证了二维红外相关光谱在多组分混合气体傅里叶变换红外光谱定量分析中谱分辨率增强方面的应用。     

气体光谱分析应用中傅里叶变换红外光谱基线漂移分段比校正方法

针对气体光谱分析应用中傅里叶变换红外光谱仪长时间连续工作时易出现光谱基线漂移、畸变问题,对红外光源温度波动及漂移、动镜倾斜、分束器性能变化以及检测器横向偏移对光谱基线的影响进行了仿真研究,结果表明光谱基线的漂移近似线性。基于此,本文提出分段比光谱基线漂移修正法SBCPD校正光谱基线。通过比较基线校正前后仿真光谱峰高变化、偏最小二乘(PLS)定量分析模型预测不确定度、油气探井气测录井在线基线校正性能,发现SBCPD性能优越,要优于传统的多项式拟合法及airPLS法。经检验,该方法性能稳定,计算量小,便于工程应用。     

变压器油溶解气体的FTIR定量分析

针对色谱进行变压器溶解气体在线监测需要载气、定期标定、安全性低等缺陷,试图建立一种傅里叶变换红外光谱法的油溶解气体在线分析系统。考虑特征气体量小、成分多、检测限及安全要求高,根据特征气体的吸收光谱特征与分析要求,利用分段比基线校正、改进TR正则化特征变量提取算法,建立稀疏偏最小二乘的定量分析模型。以CH₄,C₂H₆,C₃H₆和CO₂等特征气体为例,给出了分析的测试结果。结果表明,在光谱波数分辨率为1 cm-1,光程为10 cm情况下,可以满足变压器绝缘油溶解气体分析要求。     

A novel P-channel SOI LDMOS structure with non-depletion potential-clamped layer

A novel structure is proposed for doubling the vertical breakdown voltage of silicon-on-insulator(SOI) devices. In this new structure, the conventional buried oxide(BOX) in an SOI device is split into two sections: the source-section BOX and the drain-section BOX. A highly-doped Si layer, referred to as a non-depletion potential-clamped layer(NPCL), is positioned under and close to the two BOX sections. In the split BOXes and the Si region above the BOXes, the blocking voltage(BV) is divided into two parts by the NPCL. The voltage in the NPCL is clamped to be nearly half of the drain voltage. When the drain voltage approaches a breakdown value, the voltage sustained by the source-section BOX and the Si region under the source are nearly the same as the voltage sustained by the drain-section BOX and the Si region under the drain. The vertical BV is therefore almost doubled. The effectiveness of this new structure was verified for a P-channel SOI lateral double-diffused metal-oxide semiconductor(LDMOS) and can be applied to other high-voltage SOI devices. The simulation results show that the BV in an NPCL P-channel SOI LDMOS is improved by 55% and the specific on-resistance(Ron,sp) is reduced by 69% in comparison to the conventional structure.     

衍生物气相色谱法测定蔗糖发酵液中的寡果糖

 将蔗糖发酵液中的混合糖浆进行三甲基硅烷化衍 生后,利用大口径毛细管柱进行气相色谱分析。实验结果表明,利用改装的国产气相色谱仪 SP2308,采用大口径毛细管柱OV-101,在选定的色谱条件下,混合糖浆各组分可得到较好的分离。利用该法对寡果糖进行测定,重现性好,具有理想的回收率。     

MoVOx催化甘油选择性氧化性能研究

通过添加亮氨酸/谷氨酸制备了MoVOx复合金属氧化物,考察了亮氨酸/谷氨酸添加浓度对MoVOx晶相组成及含量的影响。将制备的MoVOx用于催化甘油选择性氧化性能研究。研究表明,添加亮氨酸/谷氨酸能够抑制产物中V2O5的生成。与谷氨酸相比,添加亮氨酸可以进一步减少产物中MoO3的含量。此外,当添加谷氨酸摩尔比为Mo:V:Glu=1:1:0.5时制备的MoVOx呈现出特殊的多层片状结构,该样品(Mo/V/Glu-0.5)在催化甘油选择性氧化反应中表现出优异的性能,当催化反应温度为340 ℃时,甘油的转化率为98.17%,丙烯醛和丙酮选择性分别为45.96%和34.84%。此时,体系中MoV2O8和MoO3的含量分别为65.56%和34.44%,表明MoVOx催化甘油选择性氧化反应中MoV2O8和MoO3具有明显的协同效应。