电子电气产品中挥发性有机化合物的释放量测定

采用小型释放舱-热脱附-气相色谱-质谱联用技术测定了电子电气产品中8种挥发性有机化合物（苯、甲苯、邻二甲苯、间二甲苯、对二甲苯、乙苯、乙酸丁酯和苯乙烯）的释放量.对一级脱附参数（一级脱附温度、一级脱附流量、一级脱附时间）、冷阱温度、捕集管脱附温度、脱附时间条件进行了优化,并进行了线性关系、回收率、精密度等试验.结果表明：本方法可用于测定电子电气产品中释放的8种常见的挥发性有机化合物的释放量,线性范围10-1000ng,当采样量为6L时,定量限为1.7μg/m3,回收率范围在89.5％-106％之间,相对标准偏差小于7％.     

环境样品中总汞测定方法的建立——吹扫-金柱捕集-(双柱)热脱附-冷原子荧光法

基于美国环境保护局(U.S.Environmental Protection Agency,USEPA)1631方法,自制双柱热脱附装置,以国产AF-610B型原子荧光仪为检测器,搭建吹扫-金柱捕集-(双柱)热脱附-冷原子荧光系统,用于测定环境样品中的总汞。对吹扫流速、吹扫时间和尾吹流速等实验参数进行了优化。双柱热脱附装置的脱附效率为99%—100%。在最优测定条件下,仪器检出限为5.0pg,海水测定的方法检出限为0.50ng/L,土壤、沉积物和红树样等固体样品测定的方法检出限为1.0ng/g。采用基底加标回收率法和参考样,验证了该系统的准确可靠性。结果表明,海水、土壤、沉积物和红树植物组织等样品的基底加标回收率均符合USEPA的限定范围,土壤参考样(ESS-4)和近海海洋沉积物参考样(GBW07314)的测定结果在参考值的可控范围内。该系统可满足环境样品中总汞测定的要求。     

大孔吸附树脂纯化杜仲叶加工剩余物中的京尼平苷酸

以杜仲叶加工剩余物为原料,研究(比较)了S-8、AB-8、D101和X-5 4种大孔吸附树脂对杜仲中的降血压活性成分京尼平苷酸(GPA)的吸附及脱附性能。以S-8型树脂吸附-水脱附工艺纯化GPA的优化工艺为:脱附剂用量300mL、脱附流速3mL/min、上柱液pH值1.0,脱附过程的最大影响因素为脱附剂流速,GPA的脱附率达89.64%,GPA含量由7.23%提高到45.18%。     

蓝色氧化钨吸附丙烯和氧的热脱附谱

在超高真空条件下,用对样品进行闪烁加热的方法测定了蓝色氧化钨WO_2.90吸附丙烯和氧的热脱附谱。发现在室温下,丙烯在蓝色氧化钨表面只有一个吸附态,对应于热脱附谱中在100℃附近出现一个脱附峰。实验测定的热脱附参数为n=1(一级脱附),脱附活化能E_D=10.1kcal/mol。温度升高,丙烯在蓝色氧化钨表面形成稳定吸附态的几率减小。在125℃以上,不能形成稳定的吸附态,蓝色氧化钨在室温下对氧的吸附并不明显,温度升高到300℃以上,WO_2.90 关键词：     

用热脱附谱研究氢在Si(100)清洁表面的吸附

用超高真空中对样品进行闪烁加热的方法,测量了Si(100)清洁表面吸附氢以后的热脱附谱。得到在室温下暴露氢时,低暴露量下只有一个脱附峰A,暴露量增大后,出现第二个脱附峰B。升高温度暴露氢,如在230℃以上暴露,热脱附谱中不出现B峰;在530℃以上暴露,则A,B峰均不出现。在室温下吸附氢后再加热退火,温度超过350℃,则热脱附谱中B峰不再存在;在530℃退火,则A峰也消失。热脱附的这些规律,使我们相信A峰和B峰分别对应于Si(100)表面的单氢化相和双氢化相的脱附。测量了它们的脱附活化能分别为52.9kcal/mol和14.5kcal/mol。从级数图证实了A峰的脱附属于一级脱附,但其机理并不与一般的一级或二级脱附机理相同。 关键词：     

独活浸膏的热裂解产物分析

采用在线热裂解-气相色谱质谱联用技术(Py-GC-MS),模拟卷烟燃吸状态,对独活浸膏进行热裂解,裂解产物经气相色谱-质谱联用仪分析。结果表明:独活浸膏的热裂解产物中共鉴定出51种成分,主要有5-羟甲基糠醛(29.00%)、甲氧基欧芹酚(18.79%)、(Z,Z)-9,12-亚油酸(5.76%)、(E)-2-甲基-2-丁烯酸(3.64%)、5-甲基糠醛(2.79%)、十六酸(2.67%)、2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(1.55%)、糠醛(1.29%)等致香物质,该结果为独活浸膏在卷烟中的应用提供理论依据。     

二阶导数同步荧光光谱测定卷烟主流烟气中的苯并(a)芘

研究了卷烟主流烟气粒相物中苯并(a)芘(BaP)的同步荧光及其一阶和二阶导数光谱, 发现二阶导数同步光谱可明显减少背景及BaP同系物对BaP测定的干扰。据此建立了一种固相萃取-二阶导数同步荧光光谱法测定卷烟主流烟气粒相物中BaP的新方法。方法检测限为0.2 ng·mL-1,平均回收率为80.2%～86.2%,相对标准偏差为2.64%～3.02%。     

3-硝基邻苯二甲酸系列稀土配合物的光谱学与热稳定性研究

在水-乙醇溶液中合成了稀土离子(RE=La, Nd, Eu, Tb, Er, Y)与3-硝基邻苯二甲酸(H₂L)的晶体化合物,并通过元素分析、红外光谱、紫外光谱、差热-热重分析对系列配合物RE₂L₂(HL)₂(H₂O)₆·2H₂O进行了系统的研究与表征。谱学研究结果与通过X衍射表征的晶体结构数据是一致的。配体3-硝基邻苯二甲酸具有两种配位模式。两个全脱质子的配体L2-以桥联-螯合形式与两个稀土离子配位,而另两个单脱质子的配体HL-利用其酸根(—COO-)和羧基(—COOH)分别与金属离子以端基螯合形式配位。红外数据证实了羧酸根(—COO-)和羧基(—COOH)的存在以及羧基(—COOH)与结晶水之间的氢键作用。差热-热重数据与化合物的组成结构非常吻合,配合物中的结晶水和配位水在150 ℃左右开始失去并吸热,配体则在400 ℃左右开始氧化分解。     

2,4-二氯苯酚气相色谱的内标法测定

邻苯二甲酸二甲酯作为内标物 ,乙酸酐作为衍生剂 ,气相色谱分离和测定 2 ,4 -二氯苯酚 ,检出限为 0 .2 mg/ L,相对标准偏差为 2 .97% ,结果令人满意。     

浊点萃取-分光光度法测定水环境中的痕量钴

利用阴离子表面活性剂十二烷基硫酸钠(SDS)和络合剂1-(2-吡啶偶氮)2-萘酚(PAN),加入HCI使SDS质子化,对钴进行浊点萃取,分光光度法测定水体中痕量钴.详细探讨了影响浊点萃取及测定灵敏度的因素.优化条件为:NaCl、HCI、PAN、SDS浓度分别为1.90mol/L、1.20mol/L、0.3umol/L、1.25%,60℃水浴50min、离心5min(3000r/min).在最佳条件下,钴的富集倍数为50倍,方法检出限为2.870ug/L,线性范围为16.7-83.3pg/L,RSD为0.96%-3.30%.该方法用于实际水样钴的富集和测定,结果令人满意.     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.