超声波辐照下N,N,N’,N’-四甲基二氨基二苯 甲烷的合成研究

本文报道了Ｎ,Ｎ,Ｎ’,Ｎ’－四甲基二氨基二苯甲烷的催化合成反应研究,讨论了超声空化场对氨基苯磺酸和阴离子表面活性剂等条件对该反应的催化作用。     

Optimization of the two-stage common-emitter transistor amplifier for equalization circuit in visible light communication system

The equalization circuit in the visible light communication (VLC) system has large impacts on the frequency response and can greatly improve the 3-dB modulation bandwidth. The optimization of the two-stage common-emitter transistor amplifier for equalization circuit is presented in detail and the design rules are disclosed. At first, the frequency response of the single-stage amplifier is derived and the simulated characteristic curves illustrated the changing regularity of four main factors are given. Subsequently, the frequency response of the two-stage amplifier is investigated by simulation. It is shown that the capacitors in the resistance–capacitance (RC) network has large impacts on the low-frequency range, while the resistors in the RC network can adjust the high-frequency, and the resistors in the emitter can adjust the low-frequency. Experimental measurements of the fabricated equalization circuit demonstrated the simulation results. Then, the two-stage amplifier is induced as post-equalization circuit (post-EQC) or pre-equalization circuit (pre-EQC) and the measured frequency response curves are given. The equalization circuit with proper sets of capacitors and resistors would flatten the frequency response curve of the VLC system. It is shown that the 3-dB modulation bandwidth of the VLC system equipped with post-EQC or pre-EQC can be expanded to 292 MHz or 304 MHz, respectively. Moreover, if the photoelectric receiver and the post-EQC are combined in the optimization, the 3-dB modulation bandwidth can be expanded to 375 MHz.     

Nanocomposite of polymerized ionic liquid and graphene used as modifier for direct electrochemistry of cytochrome c and nitric oxide biosensing

In the present work, nanocomposite of polymerized ionic liquid (PIL), poly (1-vinyl-3-ethyl imidazolium) bromide, modified graphene nanosheet (PIL-Gr) was prepared. The PIL-Gr nanosheet composite was evaluated using scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Then, a robust and effective sensing strategy based on the nanocomposite for cytochrome c (Cyt c) immobilization on basal plane graphite (BPG) electrode surface was proposed. Direct electrochemistry and electrocatalysis of immobilized Cyt c were investigated in detail. The cyclic voltammogram results indicated that the PIL-Gr nanocomposite film showed an obvious promotion for the direct electron transfer between Cyt c and the underlying electrode. The immobilized Cyt c exhibited an excellent electrocatalytic activity towards the reduction of nitric oxide (NO). The fabricated biosensor exhibited a fast response and a good electrochemical activity for NO with comparable liner range and low detection limit. The low apparent Michaelis–Menten constant $ (K_{\text{m}}^{\text{app}}) $ indicated the affinity of PIL-Gr and Cyt c. Moreover, the modified electrode displayed a rapid response to NO and possessed good stability and reproducibility. Based on the nanocomposite, a third-generation reagentless biosensor could be constructed for the determination of NO. The present work broadens the applications of graphene and ionic liquid in biosensor field.     

一种海水中溶解无机碳的准确简易测定方法

海水中的溶解无机碳(DIC)可占海水中总碳的95％以上,其准确测量是研究海洋碳循环的基础。目前测量DIC所使用的仪器较为昂贵、复杂,不适于外海调查。实验设计了一套密封的气提一吸收装置,并通过大量的实验建立了一种简便、快速的DIC现场测定方法,即取大约100～150mL海水,加10％H2PO4将其中的CO2释放出来,用0．1mol／LNaOH进行二级吸收,以酚酞和溴甲酚绿．甲基红混合指示剂指示终点,用HCl标准溶液滴定所吸收的CO2,计算DIC含量。经检验该方法具有较高的精密度和准确度,相对标准偏差为0．76％。用该方法测定了2003年6月取自胶州湾的水样,结果表明：胶州湾内表层水DIC平均为2066μmol／L,底层水为2075μmol／L;湾外表层水平均为1949μmol／L,底层水为2147μmol／L。     

静高压对Mn_4Si合金液－固转变中间相形成的影响及准晶相的截获

利用静高压熔态淬火方法对Ｍｎ＿４Ｓｉ合金液－固非平衡转变过程进行了研究。发现真空熔炼的合金中常见的（Ｍｎ＿４Ｓｉ）ξ相在高压下是不稳定的。而真空熔炼合金中没有的（Ｍｎ＿６Ｓｉ）Ｒ相在高压液－固转变过程中出现了。首次在４．５ＧＰａ压力下通过熔态淬火截获到了十二次准晶相。使用透射电子衍射技术对其进行了鉴别；使用Ｘ射线衍射对各晶体相和准晶相的结构和稳定性进行了研究。     

基于LIBS技术的脐橙中铜含量联合区间偏最小二乘法定量分析

选用60个果形相当的脐橙样品进行激光诱导击穿光谱(LIBS)试验,引入联合区间偏最小二乘法(siPLS)的分析方法,实现水果脐橙中重金属铜元素的LIBS定量分析。先对脐橙在320~340nm波段内激光诱导击穿光谱进行九点平滑处理,并提取特征光谱CuI324.75nm为分析线。采用siPLS方法将光谱划分为25个子区间,当选择其中5、14、16、22 4个子区间建立的模型时效果最佳,其校正集相关系数和均方根误差分别为0.988 3和5.61,预测集相关系数和均方根误差分别为0.979 2和8.62。研究表明,与偏最小二乘法(PLS)相比,改进的siPLS模型更能有效利用光谱中的信息,减少模型计算量,提高预测能力。为进一步实现水果中痕量重金属元素的快速定量分析提供了方法。     

阵列波导光栅中心波长温度稳定性的研究

阵列波导光栅中心波长的温度不稳定性成为限制其应用的主要原因。为了设计温度不敏感阵列波导光栅,结合弹性多层板热应力理论和应力集中效应给出掩埋波导芯层应力的解析解,利用等效折射率法计算阵列波导的有效折射率及其温度系数,考虑波导材料折射率和波导长度随温度的变化得到了硅基二氧化硅阵列波导光栅中心波长的温度系数。并研究了贴有应力板的阵列波导光栅中心波长的温度特性,结果表明在芯片底部贴有0.37 mm厚的铝板时,TE模和TM模中心波长的温度系数分别是5.9 pm/℃和8.0 pm/℃,下降到传统阵列波导光栅中心波长温度系数的一半。     

CCl4喇曼光谱退偏度在超声空化作用下的变化研究

本文测量了在超声空化作用下CCl4喇曼光谱退偏度的变化，通过假设超声空化拉长了样品的分子轴，解释了超声空化使所测样品的退偏度减小这一实验现象，并指出不同振动谱线的退偏度变化不同。     

态|Ψ(3)>q中广义电场分量的偶数次N次方Y压缩

构造了由多模复共轭虚相干态、多模复共轭虚相干态的相反态和多模复共轭相干态的线性叠加所组成的一种新型的三态叠加多模叠加态光场|Ψ⁽³⁾>_q.利用多模压缩态理论,研究了态|Ψ⁽³⁾>_q中广义电场分量的偶数次等幂次N次方Y压缩特性.结果发现:态|Ψ⁽³⁾>_q是一种典型的三态叠加多模非经典光场;当压缩次数N等于2P且P为2m’+1(m’=0,1,2,…,…)时,如果各模的初始相位φ_j(j=1,2,3,…,…,q)、态间的初始相位差(θ₁-θ₂)、(θ₁-θ₃)和(θ₂-θ₃),以及各单模相干态光场的总的平均光子数等分别满足各自的取值条件,则在这种情况下态|Ψ⁽³⁾>_q的广义电场分量可呈现出偶数次的广义非线性等幂次2(2m’+1)次方Y压缩效应.     

超声空化对丙酮激光喇曼光谱的影响

本研究设计了一种可吸入超声的喇曼光谱样品池,对丙酮的激光喇光曼谱的检测表明,超声空化降低了喇曼光谱的强度,我们认为,超声空化减少了激光光路上参与散射的丙酮分子数是光谱强度降低的主要原因。