掺铁InP肖特基势垒增强InGaAs MSM光电探测器

采用ＬＰ－ＭＯＶＰＥ方法及常规器件工艺制成了ＩｎＰ：Ｆｅ肖特基势垒增强ＩｎＧａＡｓＭＳＭ光电探测器。用自建测试系统对其直流和瞬态特性进行了测试，测试结果表明，器件的击穿电压大于１０Ｖ，２Ｖ偏压下暗电流为１７０ｎＡ，对应的暗电流密度约为３ｍＡ／ｃｍ２；瞬态响应中上升时间ｔｒ为２１ｐｓ，半高宽ＦＷＨＭ为７５ｐｓ。     

基于随机轨迹模型的汉语连续语音识别方法研究

本文在指出隐马尔可夫模型（HMM）不合理假设的基础上,介绍了随机轨迹模型（STM）的理论机制及优越性。随机轨迹模型将语音基元的声学观察表示为参数空间中轨迹的聚类,并将轨迹建模为状态随机序列概率密度函数的混合,该模型可以克服HMM的不合理假设,在理论上更合理。根据STM的特点及汉语语音特色,本文对汉语连续语音识别基元的选取进行了讨论,提出了音素类单元作为识别系统的识别基元。基于STM的汉语连续语音识别的实验结果证明了STM的有效性和音素类单元的一致性。     

Dynamic Behaviour of Self-Diffraction in Bacteriorhodopsin Film

We investigate the dependences of the diffraction efficiency of the first order self-diffracted beam in bacteriorhodopsin (bR) films on the illumination time, the intensity and wavelength of the incident light. When the blue light (λ = 488 nm) and low intensity red light (λ = 632.8 nm) are incident on the bR film respectively,the diffraction efficiencies increase from zero to a stable value with the illumination time. When the green light (λ = 533 nm) and high-intensity red light illuminate the bR film respectively, the diffraction efficiencies increase from zero to the maximum and then decrease to a stable value with the illumination time. Rise and decay times are dependent on the intensity and wavelength of the incident light. The maximal diffraction efficiency of the red light is twice as high as that of the green light. The highest diffraction efficiency of 5.4% is obtained at 633nm.The diffraction efficiency change with the time for the green light is larger than that for the blue and red light.     

表面解吸常压化学电离源的研制及应用

根据表面解吸常压化学电离源(SDAPCI)对表面痕量待测物进行常压解吸化学电离的原理,自行研制了SDAPCI电离源及其与线性离子阱(LTQ)质谱仪的接口,成功地在LTQ上实现了表面解吸常压化学电离。此方法无需样品预处理,直接利用电晕放电产生的H3O 在常压下对待测样品进行表面解吸化学电离,避免了甲醇等有毒试剂的使用。在优化的仪器参数条件下,分别用正/负离子模式成功地检测了片剂药品中的氯雷他定、乙酰氨基酚等活性成分和其它不同表面上TNT、氨基酸和多肽等物质,对这些常见物质的检出限不高于10pg/cm2。采用氩气作为电离试剂,观测到乙酰氨基酚、多肽等物质形成的自由基阳离子,提出了在氩气氛围中获得自由基阳离子的可能机理。实验表明SDAPCI具有灵敏度较高,选择性好,适用范围宽等特点,适合用于药品、食品等非破坏、无污染检测以及对复杂基体物质进行快速现场分析。     

小型微波谐振腔用于蛋白质微波辅助酶解

采用微波谐振腔对细胞色素c以及牛血清白蛋白进行微波辅助酶解, 通过电喷雾三级四极杆质谱对得到的肽段进行分析, 证明该方法可用很低的微波功率将蛋白质彻底酶解为多肽. 通过调整微波条件可以使蛋白质的酶解效率基本达到100％, 细胞色素c和牛血清白蛋白的序列覆盖率分别为45％和26％. 该方法不但可将蛋白酶解时间由传统方法的16 h缩短为20 min, 还将功率由使用微波炉时的数百瓦降至20 W.     

树脂吸附法处理异丙隆生产过程中含异丙隆废水的研究

本文用CHA—101树脂处理异丙隆生产过程中的含异丙隆废水,控制泄漏点在异丙隆浓度为140mg/l时,树脂可处理废水36BV,树脂工作吸附量约70mg/ml,树脂的吸附率达95％,吸附后废水经试验可完全套用到生产异丙隆工段中去,实现了闭路循环。树脂吸附饱和后,用工业酒精能基本脱附异丙隆。     

无滤共沉淀富集-等离子体原子发射光谱法测定痕量稀土元素

以编结反应器 (KR)作为反应场所,用NH3～NH4NO3缓冲溶液在线沉淀、富集,电感耦合等离子体原子发射光谱法(ICP-AES)检测稀土元素,系统地研究了稀土元素在线沉淀及溶解的最佳条件.实验结果表明:在80 ℃时,稀土离子与pH 9.0的NH3～NH4NO3缓冲溶液在线混合后经2 m KR富集120 s,用1 mol/L HNO3以1.0 mL/min流速洗脱时富集效果最好,富集倍数可达52～76倍,进样频率为10/h.同时考察了共存离子的干扰及其消除方法.方法的稀土元素的检出限为0.07～1.23 μg/L,精密度RSD在1.7%～4.3%之间(n=6),线性范围2～10 μg/L.应用于标准样品中痕量稀土元素的测定,其测定值与标准值吻合.     

亚临界水-火焰离子化检测-柱后分流色谱分离某些醇、酚和羧酸类化合物

采用柱前预热和柱后分流技术,构建了亚临界水-氢火焰离子化检测器色谱系统(SubWC-FID)。采用Polymerx RP-1聚合物色谱柱和纯水流动相,在亚临界状态下(柱温160~210℃),分离了某些醇、酚和羧酸类化合物,优化了FID稳定工作条件,考察了柱温、流动相流速和分流比对样品分离的影响。结果表明:在不高于1.48mL/min的流动相流速下,柱后分流模式的FID系统能稳定工作,方法的线性动力学范围在2~3个数量级之间,在分流比为1∶20时,乙醇、苯酚和乙酸的检出限分别为17、54和68ng。     

桥联β-环糊精液相色谱键合固定相研究

合成了两种桥联β-环糊精固定相,将其用于芳香烃位置异构体、氨基酸的对映异构体的拆分,同时比较了其与β-CD固定相的手性拆分效果。研究结果表明,桥联环糊精固定相对一些对映异构体具有较好的选择性;其对普通的环糊精固定相的选择性具有一定的补充或者改进作用。     

Depression of Calcium Transients After Exposure to High K~+ Solution in Li~+-loaded Frog Twitch Muscle Fibres and Its Reversal by Exogenous Myo-inositol

Using Arsenazo Ⅲ as a myoplasmic calcium indicator, we have studied the calcium transients evoked by voltage-clamp depolarizing pulses in frog twitch muscle fibres which had been temporarily depolarized by 80 mmol/LK~+ in the absence or presence of myoplasmic Li~+. After the high K~+ exposure, for either a short (15 rain) or long(1 h) time, the post-K~+ calcium transients could gradually be restored to the level of the pre-K~+ ones, if the fibres were not loaded with Li~+.In contrast, the post-K~+ calcium transients of Li~+-loaded fibres could not fully recover,and were depressed in a Li~+ concentration-dependent manner.The mean amplitude of the post-K~+ responses recorded more than 3.5 h after 15 min high K~+ exposure was reduced to 56% of pre-K~+ control in the fibres which had been loaded with Li~+ in 20 mmol/L Li~+ Ringer's solution.This depression could be prevented or partially reversed by exogenous myo-inositol.More depression could be induced by 1 h high K~+ exposure, but the presence of exogen