激光诱导等离子体冲击波增强水和重水晶格振动受激拉曼散射

利用532 nm的脉冲激光进行了水和重水受激拉曼散射研究,不仅实现了O—H和O—D的伸缩振动受激拉曼散射,同时还实现了晶格振动的受激拉曼散射。水在激发光能量为130 mJ时出现低频受激Stocks和Anti-Stoks 313 cm-1谱线;重水在激发光能量为160 mJ时出现低频受激Stocks和Anti-Stoks 280 cm-1谱线。利用激光诱导等离子体解释了这种拉曼散射增强模式。     

柠檬酸和乙二胺改性前后麦秸秆的红外光谱分析比较

对天然麦秸秆(NWS)、柠檬酸改性麦秸秆(CWS)、乙二胺改性麦秸秆(EWS)的红外光谱进行了比较分析.NWS的红外吸收光谱主要由碳水化合物如木质素、纤维素等吸收带组成.NWS表面的羟基吸收峰出现在3405.16cm-1、2916.81cm-1处的吸收峰来自亚甲基中C—H的伸缩振动.1736.02cm-1和1602.21cm-1处的吸收峰是由C=O的伸缩振动引起的;苯环的骨架伸缩振动峰出现在1511.33cm-1;1425.47cm-1处的吸收峰是来自羧基的C—O伸缩振动,1376.19cm-1处为CH2的弯曲振动峰.与NWS的红外光谱图相比,CWS的主要变化为1738.13cm-1和1592.06cm-1处C=O吸收峰强度显著增加;EWS的主要变化为3405.16cm-1处的吸收峰蓝移至3417.43cm-1,且强度增加,1736.02cm-1处的吸收峰消失,CH2的C—H伸缩振动峰(2903.49cm-1)和弯曲振动峰(1382.91cm-1)强度显著增加,结果说明改性后分别引入了羧基和胺基.     

酯化前后酵母菌的红外光谱比较

对啤酒酵母酯化前后的红外光谱进行了分析。啤酒酵母的红外光谱图主要由蛋白质的吸收带、碳水化合物的吸收带组成。1 652 cm-1处的吸收峰为酰胺Ⅰ带,是CO的伸缩振动,1 542 cm-1的吸收峰是酰胺Ⅱ带,振sup>振动和N—H的弯曲振动引起的。1 454 cm-1处的吸收峰为CH₃和CH₂的弯曲振动峰;1 160 cm-1处出现的峰可能为细胞壁的主要成分——碳水化合物中C—O的伸缩振动峰;1 080 cm-1处的吸收峰是由啤酒酵母中的RNA,DNA或细胞壁中存在的碳水化合物或醇中的C—O伸缩振动引起的。用甲醇酯化后在1 744和1 454 cm-1处的吸收峰强度增加,说明酵母菌细胞表面的羧基发生了酯化反应。酯化后细胞的主要成分和结构保持完整。     

Sr3TaGa3Si2O14(STGS)单晶的晶格振动

根据空间群理论,预测了Sr3TaGa3Si2O14(STGS)单晶的振动模式,并分别计算了非极性和极性振动模式的Raman散射强度。测量了STGS晶体的Raman光谱,并对其振动模式进行了指认。实验结果表明STGS晶体具有6个A1对称类特征振动模式:波数为126cm-1的振动峰可指认为SiO4团簇、Sr原子和TaO6团簇间的相对平动;245cm-1的振动峰是SiO4团簇的扭曲振动和Sr—TaO6—Sr伸缩振动耦合的结果;特征峰557和604cm-1分别来源于O—Ta—O和O—Ga—O的伸缩振动;896cm-1谱带对应着两个SiO4四面体的O—Si—O伸缩振动;991cm-1的谱带对应着两个SiO4四面体的Si—O伸缩振动。实验结果和理论计算结果均确证了STGS晶体的层状结构,其弱的各项异性和压电模量归因于十面体结构单元的微弱形变。     

生态滤池出水悬浮物的元素分析和红外光谱分析

对生态滤池出水悬浮物的碳氢氮三元素和红外光谱进行了分析比较。元素分析结果表明,生态滤池出水悬浮物的无机成分比普通滤池稍高,用中颗粒惰性填料时复合床生态滤床的出水悬浮物无机物含量高。出水悬浮物的红外吸收光谱图主要由蛋白质的吸收带、碳水化合物的吸收带组成。1 655 cm-1处的吸收峰为酰胺Ⅰ带,是CO的伸缩振动,1 542 cm-1的吸收峰是酰胺Ⅱ带,是N—H的弯曲振动和C—N的伸缩振动,1 235 cm-1附近是酰胺Ⅲ带,是C—N的伸缩振动和N—H的弯曲振动引起的。单层普通滤池和单层生态滤池出水SS(suspend substance)红外光谱图差别很小;采用中颗粒填料的生态滤池,出水SS的红外光谱图中,1 042 cm-1处的吸收峰相对强度比粗颗粒填料的高,而2 924和2 852 cm-1的甲基伸缩振动峰和1 720～1 200 cm-1区域的相应吸收峰强度,比用粗颗粒填料的低。     

胞嘧啶-水分子氢键团簇结构特性理论研究

使用密度泛函理论B3LYP方法,在6-311++G(d , p)基组水平上,研究了C4H5N3O·(H2O)n (n=1~3)分子团簇的基态结构及红外线光谱。通过对C4H5N3O·(H2O)n (n=1~3)分子团簇结构优化,获得了团簇的六种稳定结构。三种最稳定结构的分子团簇的红外光谱表明O—H…O和N—H…O氢键的形成使得O—H和N—H之间伸缩频率减小,发生了红移; O—H…N氢键使O—H之间的伸缩振动频率变大,发生了蓝移。AIM程序分析表明：电子密度的强弱反映了红移和蓝移的大小。之后使用Veda4软件对C4H5N3O·(H2O)n (n=1~3)分子团簇红外光谱的振动频率进行了分析,并对振动频率进行了比较。     

介质阻挡放电等离子体沉积多孔硅纳米颗粒膜的光发射及红外光谱

用介质阻挡放电(DBD)等离子体增强化学气相沉积(PECVD)的方法,以硅烷为源气体,在沉积区域加载脉冲负偏压进行调节,在玻璃基片上沉积得到具有荧光特征的多孔硅纳米颗粒膜。沉积过程的发射光谱结果表明,在412 nm处出现S iH*(A2Δ→X2Π0-0)特征峰,证明放电沉积过程中存在不同程度的硅烷裂解。将脉冲负偏压固定在-300 V,当占空比从0.162增大到0.864时,薄膜的红外光谱显示S i—O—S i在1 070cm-1伸缩振动吸收峰与800 cm-1的弯曲振动峰都有所增强,而930 cm-1的S i—H弯曲振动减弱。说明随着占空比的增加,S i—O—S i键的结合越来越明显。     

航天诱变育种甜椒品系的红外光谱分析

首次采用傅里叶变换红外光谱法(FTIR)对航天诱变育种甜椒品系种子和一般大田生产的甜椒品种种子进行了对比研究,比较了它们红外光谱的异同。甜椒种子的红外光谱主要由蛋白质的吸收带和碳水化合物的吸收带组成。航天育种的两个甜椒品系种子(SP11和SP18)红外光谱的主要吸收峰的峰位、峰形与普通甜椒品系种子相同,表明经航天诱变的甜椒其主要化学成分和基本结构并未发生变化。太空甜椒种子,在2 854,1 652, 1 542以及1 160～1 062 cm-1范围内的吸收都较普通甜椒种子增加。2 855 cm-1峰是CH₂—伸缩振动,1 652 cm-1处的吸收峰为酰胺Ⅰ带,是CO的伸缩振动峰,1 542 cm-1的吸收峰是酰胺Ⅱ带,是N—H的弯曲振动和C—N的伸缩振动,1 160 cm-1处的峰可能为碳水化合物的C—O的伸缩振动引起。表明航天诱变使甜椒种子的蛋白质和碳水化合物含量增加。     

乙酰丙酮-5,10,15,20-四取代苯基卟啉稀土铥络合物的吸收光谱

络合物Tm(g)Tppacac(g:H,O—NO_2,P—NO_2,O—Cl,m—Cl,P—Cl,P-CH_3O;HTpp:5,10,15,20-四苯基卟啉;Hacac:乙酰丙酮)在可见和红外区的吸收光谱被讨论。HTpp、H(P—CH_3O)Tpp、H(O—NO_2)Tpp、H(P—NO_2)Tpp、H(P—Cl)Tpp、H(O—Cl)Tpp和H(m-Cl)Tpp的核的N—H伸缩振动分别在3317、3318、3318、3320、3321和3324cm~(-1),取代物与HT_(pp)比较向长波位移1—7cm~(-1)。络合后,由于N—H上的氢被稀土离子取代,此带消失·络合物中的1516—1518cm~(-1)谱带在卟啉和过渡金属卟啉中不存在,它们与乙酰丙酮配位相关,是乙酰丙酮环上的C—C伸缩振动。但对Tm(O—NO_2)Tppacac和Tm(P—NO_2)Tppacac,产生强宽谱带1523和1519cm~(-1),这是由于邻、对位硝基苯基卟啉的反对称N—O伸缩振动1512和1524cm~(-1)与乙酰丙酮的C—C伸缩振动的迭加结果。TmTppacac的M—O伸缩振动在372cm~(-1),取代络合物此带向低波数发生明显位移,其位移次序为: Tm(m—Cl)Tppacac>Tm(O—Cl)Tppacac>Tm(P—Cl)Tppacac> Tm(P>NO_2)Tppacac>Tm(O—NO_2)Tppacac>Tm(P—CH_3O)Tppacac 按此次序,它们的带频率分别为350、355、356、357、360和366,向低波数位移6—27cm~(-1)。还有一些谱带,如吡咯的βC—H摇摆和C—H弯曲振动、吡咯和苯环的—C=C—伸缩振动等也参照文献进行了归属。可见谱带中,取代络合物与TmTppacac比较,大多数谱带都向长波或短波长方向发生位移。     

大肠杆菌基于微波法制备的纳米银胶的SERS光谱研究

在微波法制备的纳米银上获得了大肠杆菌的表面增强拉曼光谱, 大肠杆菌在650、952、1125、1242、1320、1372、1459 cm-1有明显的拉曼振动峰。其中650 cm-1处的振动峰最强, 1124、1320、1372和1459 cm-1处的四个振动峰较弱, 952、1242 cm-1处的二个振动峰强度居中。位于650 cm-1附近的拉曼峰源自于酪氨酸、鸟嘌呤的振动, 952 cm-1属于缩氨酸基团C=C的伸缩振动,1124 cm-1是蛋白质的C-N和C-C伸缩振动引起的, 1242 cm-1则归属于是酰胺 III蛋白的振动, 1320 cm-1是蛋白质的CH变形振动, 1372 cm-1是由酪氨酸振动引起的, 1459 cm-1则是蛋白质的CH2变形振动。     

FTIR分析脉冲电场和热处理后的大豆分离蛋白结构变化

采用自行研制的脉冲电场设备,利用傅里叶变换红外光谱(FTIR)比较研究了脉冲电场(PEF)和热处理对大豆分离蛋白(SPI)分子结构的影响.结果表明:50 kV·cn-1的脉冲场强处理引起SPI分子内和分子间氢键增强,分子中C-O-O糖苷键伸缩振动和P=O,P-O-C伸缩振动增强,且其增加值与PEF处理时间呈正相关.研究发现较短时间(1 600 μs)PEF处理导致了SPI分子结构中α-螺旋和β-折叠分别减少了5.9%和0.7%,β-转角和侧链结构分别增加了7.5%和9.6%;处理时间延长至2 400 μs,其α-螺旋和β-折叠减少量增至6.0%和5.6%.对比而言,热处理对SPI分子结构中C-O-O糖精苷键伸缩振动和P=O,P-O-C伸缩振动的影响程度较大,而对蛋白质二级结构影响程度较小:90℃热处理30 min,α-螺旋和β-折叠分别减小5.1%和6.6%,β-转角结构增加19.1%.由此可以认为PEF和热处理对SPI的影响机理是不一样的.     

荧光偏振法研究脉冲电场对酿酒酵母细胞膜流动性影响

以DPH(1,6-二苯基-1,3,5-己三烯)为荧光探剂,采用荧光偏振法探讨了脉冲电场(0～25 kV·cm-1,0～266 ms)对酿酒酵母细胞膜流动性影响。经5 kV·cm-1电场处理后,酿酒酵母细胞膜的流动性显著减小,并且随电场强度和处理时间的增加而减小;通过平板计数法和紫外分光光度计法分别检测了脉冲电场对酿酒酵母细胞存活对数及膜通透性影响。结果显示,5 kV·cm-1虽然只能使少量的酵母致死,却能使酵母细胞膜的通透性显著增加,膜流动性显著降低。并且细胞的存活率随电场强度增大而减小,细胞膜的通透性随电场强度增大而增大。这表明细胞膜的流动性降低与细胞膜的通透性升高成正相关,与细胞的存活率成负相关。由此推测脉冲电场在对酿酒酵母灭菌过程中,细胞膜是其作用的一个关键位点,膜流动性减小,细胞膜通透性增强,是细胞死亡的主要原因。     

Inactivation of Bucillus Stearothermophilus by pulsed electricfield

B. Stearothermophilus remains alive even under intense electric field, since spores formed are highly resistant to damage from electric field effects. This paper describes the effects of pulsed electric field on B. Stearothermophilus (ATCC no, 12980). An aqueous suspension of B. Stearothermophilus spores was placed between parallel planar electrodes and subjected to pulsed electric fields of up to 189 kV/cm, which are obtained from a high-voltage pulsed voltage generator. Either a Blumlein generator or a magnetic compression circuit with a semiconductor opening switch was used as the pulsed voltage generator. The spores that survived the treatment were detected by a colony counting method. The growth activities were measured using a microbial calorimetry technique. The temperature and pH of the spore suspension remained unchanged during the treatment. It was found that the growth activity of B. Stearothermophilus was affected by the pulsed electric field. while no remarkable lethal effect was observed in the range of up to 40 kV/cm     

脉冲电场防治水生生物附着

为探究脉冲电场对防治水生生物附着效果的影响因素,确定有效防治附着生物所需的最低电场条件,搭建了脉冲电场试验平台,通过人工脉冲形成线产生近似方波的脉冲,统计不同条件下大型溞死亡率和形态结构发生的变化,通过函数拟合得到了脉冲电场诱导死亡率与电场强度、总等效处理时间、脉冲注入能量密度之间的函数关系,并以某干渠工程为例介绍了脉冲电场防治大型溞的参数选取原则和平台搭建方法。结果表明,脉冲电场对大型溞的处理效果与电场强度、总等效处理时间和脉冲注入能量密度都呈正相关关系。电场强度介于0.5～1.5 kV/cm之间时,电场强度每增加0.5 kV/cm,诱导死亡率增加35%左右。电场强度高于2.0 kV/cm、总等效处理时间大于900μs或脉冲注入能量密度高于80 J/L时,脉冲电场都可以产生80%以上的诱导死亡率。     

炸药爆轰合成纳米金刚石的拉曼光谱和红外光谱研究

用负氧平衡炸药爆轰法合成纳米金刚石,并用粉末X射线衍射(XRD)仪、激光Raman光谱仪和红外光谱仪等分析仪器对其结构进行表征。XRD结果表明,纳米金刚石为立方结构,由于其内部结构的高密度缺陷、杂质原子的夹杂使谱线偏离,晶格常数比静压合成的大颗粒金刚石大0.72%。由于金刚石晶粒细小,Raman光谱特征峰产生宽化,并且向小波数方向偏移了3 cm-1,此外在纳米金刚石中还含有极少量的石墨。红外光谱测试结果中,3 422 cm-1吸收峰为O—H伸缩振动峰;在1 634 cm-1出现了H₂O的弯曲振动峰,表明在纳米金刚石样品粉末中含有水分;2 930和2 857 cm-1是CH₂的反对称和对称伸缩振动吸收峰;2 971 cm-1是CH₃的反对称伸缩振动吸收峰,说明样品中存在极少量的碳氢化合物;1 788 cm-1吸收峰为CO伸缩振动吸收峰。文章从纳米金刚石的生成机理上分析了产生这些峰位的原因,结果表明纳米金刚石属于Ⅰ型金刚石,在它之中含有ⅠaA型和Ⅰb型金刚石,ⅠaA型金刚石的含量比Ⅰb型金刚石多。     

脉冲电场对木瓜蛋白酶影响的荧光光谱分析

木瓜蛋白酶溶液在电场强度为50 kV·cm-1,频率1 500 Hz,脉冲宽度40 μs的脉冲电场下接受19 800个脉冲处理后,其活性降低了56.5％。文章采用荧光偏光光谱对处理前后的样品进行了分析。 处理后酶样的荧光强度明显大于处理前,在峰值位置其荧光强度增加超过50％,峰位从342 nm移到了346 nm左右,其荧光偏振幅度明显减小。由此推断出木瓜蛋白酶经脉冲电场处理后酶蛋白的α-螺旋结构松散拉伸,分子内部的氨基酸残基暴露于分子表面,并有部分发生离解游离于溶液中,导致活性部位的结构发生变化,最终导致酶失活。     

台湾蓝玉髓的振动光谱表征

蓝玉髓是中国台湾所产的名贵宝石之一,素有"台湾蓝宝"的美誉.文章通过红外吸收光谱和激光拉曼光谱,对不同颜色及质地的台湾蓝玉髓的振动光谱特征进行了研究.结果表明,台湾蓝玉髓均显示典型的石英质玉石的振动光谱特征.其红外吸收光谱主要表现为:1 250～1 110 cm-1为最强吸收区,属Si-O非对称伸缩振动,800～600 cm-1间中等强度的吸收窄带,由Si-O-Si对称伸缩振动致,Si-O弯曲振动位于600～300 cm-1内.台湾蓝玉髓样品的激光拉曼光谱散射峰主要分布在499 cm-1,464 cm-1和214～208cm-1处,分别归属为"Moganite"石英中的Si-O对称弯曲振动、Si-O弯曲振动和[SiO4]的旋转振动或平移振动.     

Study on temperature & EMF co-effects on insulin conformation and biological functions by fluorescence and Raman spectroscopy

Our previous studies had suggested that the intercellular signal molecule might be an important target of electromagnetic fields. Insulin, an intercellule signal molecule, plays a critical role in transferring life information. The studies on effects of pulsed electric fields (PEF) on insulin molecule are meaningful for explaining the mechanism of biological effects of electromagnetic fields. The PEF, which we used, with its highest electric field (2 x 10(6) V x m(-1)) coupled into the insulin buffer, was about 1 V x cm(-1) cm, with a repeating frequency of 50 Hz. In the present study, the changes of insulin conformation induced by PEF were studied by fluorescence spectroscopy. Insulin solution was exposed to 50 Hz PEF with different electric field intensities for 5-35 min, which caused a time-and dose-dependent decrease in fluorescence intensities of insulin. Further, insulin solution was exposed to PEF at different temperatures to investigate the effects of PEF co-operated with temperature on insulin. The results indicated that the difference in temperature (about 5 degrees C) could induce conflict results, which is due to the effects of PEF co-operated with temperature rather than only to the effect of temperature. The authors calculated that the increase in temperature induced by PEF was 0.07 degrees C (less than 0.1 degrees C). So the effects of PEF were scarcely explained by thermal effects, it belongs to "non-thermal effects" of electric fields. So it was concluded that temperature is a considerably important factor in "non-thermal effects" of electric fields, and the ignorance of variety of temperature probably result in the contrary conclusion. Further, Raman spectroscopy was used to investigate the details of structure of insulin treated by PEF co-operated with temperature. The results of Raman spectroscopy verified the effects of PEF co-operated with temperature on insulin. And the reductions of the S-S band intensity at 510 cm(-1), the skeletal C-C stretch band intensity at 934 cm(-1), and the content of the secondary structure of the alpha helix were observed. Both S--S linkages and alpha helix structure were important to the stabilization of insulin conformation. Modification of insulin may change the biological activity either by reducing the affinity of the hormone for the receptor or by decreasing the ability of the complex, when formed, to elicit a biological response.     

Magnetic resonance imaging of electroconvection in a polar organic solvent

Molecular motion in the polar organic solvent nitrobenzene induced by an electric field is studied by magnetic resonance imaging. Rf pulse sequences that correlate images obtained at two different times under conditions of both continuous and pulsed electric fields are introduced. The resultant image correlation spectra indicate that the time scale of motion in a 9.6 kV/cm electric field is tens of milliseconds. Comparison of the results to an analytic solution for the Fokker-Planck probability function for one-dimensional bounded diffusion yields an electric field dependent effective diffusion coefficient for perdeuterated nitrobenzene of D = 1.08 x 10(-5) cm(2)/s + (3.33 x 10(-3) cm(4)/kV(2)s) E(2) at room temperature. Characteristics of this electroconvection and its consequences for combining multidimensional nuclear magnetic resonance with electrical orientation are also discussed.     

Electric field effect in pulsed laser deposition of epitaxial ZnO thin film

We have developed a new system in which thin films can be pulsed laser deposited under an external electric field. Application of 1 kV high voltage to a thin metal wire placed 1 mm above an edge of a 14 mm long substrate distributes electric fields ranging from 4500 V/cm at the left to 50 V/cm at the right side of the substrate. The crystallinity of the ZnO thin film was remarkably improved in the area where the electric field higher than +100 V/cm was applied during the film deposition. Thus, the film growth of ZnO with a strong polarity along the c-axis was verified to depend on an external electric field. PACS 61.10.Nz; 68.55.-a; 72.80.Ga; 78.55.-m; 78.55.-Et