矿化剂浓度和温度对水热法合成氧化锌晶体形态的影响

采用水热法，通过改变矿化剂浓度和温度合成了具有不同形态的氧化锌晶体。在较低的温度(350℃)，填充度为35％。矿化剂KOH浓度小于2mol／L时，只合成了氧化锌微晶。当矿化剂KOH浓度大于3mol/L时，合成出多种形态氧化锌晶体，大的晶体达到几十到几百微米，小晶体仅几微米。当矿化剂KOH浓度从4mol／L增加到5mol／L时，晶体的大小没有明显改变。在高矿化剂条件下合成的晶体显露完整的晶面结构，主要显露柱面m{1010}、锥面p{1011}、负极面O面{0001}，有时也显露Zn面{0001}。晶体表面出现斑坑，显示出晶体的表面缺陷。在430℃，填充度为35％，矿化剂KOH浓度大于1．5moL／L时。合成了多种形态氧化锌晶体，大晶体有几十到几百微米，小晶体仅几微米。当矿化剂KOH浓度为2mol／L，KBr浓度为lmol/L时，最大晶体的长度达到1mm。矿化剂KOH浓度为4mol/L时，晶体没有增大。粒度较大的氧化锌晶体形状多为六棱锥体，显露柱面m{1010}、锥面p{1011}、负极面O面{0001}。晶体表面光滑，完整性好。质量高于350℃时合成的晶体。     

基体溶液改进-原子荧光法测定食品中的汞

探讨改进基体溶液双道原子荧光光谱法测定食品样品中的汞。样品消解后用6mol/L盐酸、硫脲+抗坏血酸(50g/L)作为基体溶液进行仪器测定。本方法检出限0.051μg/g,最低检出质量浓度0.10μg/L,相对标准偏差为7.45%、6.76%,回收率为88.6%—113.2%。方法具稳定性好、灵敏度高、检出限低等优点。     

光度法测定浮法玻璃下表面渗锡

研究了用二溴苯基羟基荧光酮比色法测定浮法玻璃下表面渗锡的反应条件。在0.2mol/L盐酸介质中,OP乳化剂（聚乙二醇对异辛基苯基醚）存在时,锡与该试剂形成橘黄色螯合物,最大吸收波长513nm,表观摩尔吸光系数为1.20×10^5L.mol^-1.cm^-1,锡的质量浓度在0—8μg/25mL范围内符合比耳定律。反应选择性好,不经分离直接测定浮法玻璃下表面渗锡。回收率试验在93.01%—106.85%之间。     

3D多孔FeC_2O_4/石墨烯电极用于高性能25 V水系非对称超级电容器（英文）

本文制备的三维多孔结构FeC_2O_4/石墨烯复合材料,在不添加粘结剂时可作为超级电容器电极.复合材料由大孔石墨烯和微介孔FeC_2O_4组成.通常,水分解电压为1.23 V,对于以水系为电解液的不对称超级电容器,电压窗口限制为2V.当以FeC_2O_4/rGO水凝胶作为负极,以纯rGO水凝胶作为正极时,在KOH(1.0mol/L)电解质中不对称超级电容器电压窗为1.7 V,在中性Na_2SO_4(1.0 mol/L)电解质中可达到2.5 V,相应地,组装的非对称电容器性能优异,能量密度为59.7 Wh/kg.通过将具有微介孔结构的金属氧化物与石墨烯相结合,制备在不添加导电剂和粘合剂时直接用于组装不对称超级电容器的电极材料.     

聚丙烯酸钠增敏抑制高碘酸钠氧化夜蓝褪色光度法测定痕量锡

建立了聚丙烯酸钠增敏抑制高碘酸钠氧化夜蓝褪色光度法测定痕量锡的新方法。该方法基于聚丙烯酸钠增敏锡 ( )抑制高碘酸钠氧化夜蓝褪色反应 ,在最佳条件下 ,锡 ( )的含量在 0 .2 0— 2 .0 μg/L范围内与 ΔA值呈线性关系 ,其校准曲线的回归方程 ΔA=0 .0 0 788+ 0 .10 9CSn( ) (μg/L) ,r=0 .9992 ,检出限(L D) =1.1× 10 -11g/m L。本方法用于测定人发样品和水样中的锡含量 ,其相应的回收率为 10 0 .3%和10 0 .0 %。相对标准偏差为 3.4 %和 3.2 %。     

光泽精化学发光体系的研究与应用

对光泽精化学发光体系的动力学性质、荧光光谱、化学发光光谱及化学发光机理进行研究和探讨。详细研究了光泽精 - H2 O2 - Co( )流动注射化学发光体系的最佳分析条件。结果表明 ,当光泽精 (L c)为 2 .5×10 - 5mol/L、H2 O2 为 0 .5 mol/L、Na OH为 0 .4 mol/L、CTMAB为 2 .0× 10 - 5mol/L时 ,测定 Co( )的校准曲线线性范围为 0 .0 5— 2 0 0μg/m L ,检出限为 0 .0 1μg/m L。对 10μg/m L Co( )连续测定 7次 ,相对标准偏差为 1.7%。     

铋膜电极电位溶出法测定水果罐头中的痕量Sn2+

研究了同位镀铋膜法制备铋膜电极测定痕量Sn2+的电位溶出法。在0.1mol/L HAc-NaAc缓冲溶液(pH 4.8)中,通过开路富集于-1.2V进行电沉积,Sn2+与Bi3+被还原为单质富集于电极表面,在铋膜电极的电催化作用下再进行电位溶出,于-0.61V左右单质锡被氧化为Sn2+获得一灵敏的氧化溶出峰,其浓度与峰值成线性关系,线性范围为0.1—5.0mg/L,该方法的最低检出限为0.03mg/L(3σ)。利用该电极测定了水果罐头中痕量Sn2+的含量,并与国标方法作对比实验,结果表明该方法可用于实际样品分析。     

连续氢化法电感耦合等离子体发射光谱同时测定生物样品中痕量硒、砷、锡、锑

本文叙述用氢化法电感耦合等离子体发射光谱同时测定生物样品中痕量硒、砷、锡、锑的方法。比较了浓度为2.88mol/L,4.8mol/L和6.0mol/L的HCl对Se,As,Sn,Sb,Hg和Ge谱线强度的影响,也比较了NaBH_4溶液中VC对测定Se,As,Sb,Sn,Hg和Ge的影响。在4.8mol/L HCl浓度下,在1％NaBH_4溶液中加0.5％VC,HY-ICP-AES的检出限是:Se 0.3ng/ml,As 2.5ng/ml,Sn 5.0ng/ml,sb 0.4ng/ml,Hg 0.3ng/ml,Ge 8.0ng/ml。用国家标准物质GBW09101来检验本方法的准确性,得到的se,As,Sn和Sb结果良好。     

一种在弱酸性介质中有电化学发光性能的鲁米诺衍生物

报道了一种鲁米诺的衍生物-3-(1-乙酰丙酮偶氮)苯二甲酰肼在酸性介质中的电化学发光行为,该化合物与鲁米诺类似,发生两步电化学氧化反应,但其氧化电位较鲁米诺低约0.5V,在氧化铟锡玻璃电极上具有良好的电化学发光性能,有效地避免了氧化铟锡玻璃电极本身的发光干扰.不仅在碱性介质中具有较高的电化学发光效率,而且在酸性介质中也产生较稳定的电化学发光,在1.0×10-6mol/L以上浓度,电化学发光强度与浓度有良好的线性关系.     

邻苯二酚荧光光谱法测定铁(Ⅲ)的研究

基于铁(Ⅲ)对荧光试剂邻苯二酚的荧光熄灭,建立了测定微量铁的荧光分析方法.在0.3mol/L的HCl介质中,最大激发与发射波长分别为277nm和313nm,铁的荧光强度与浓度呈良好的线性关系,测定铁浓度的线性范围为1.59×10-5-1.26×10-3mol/L,检出限为7.14×10-6mol/L,常见的共存离子不干扰测定.本方法用于环境水中铁(Ⅲ)的测定,结果满意.     

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.     

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.     

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.     

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].     

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.     

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.     

Real-time restoration of rotational blurred image using gradient-loading

The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix.Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image.By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then.Gradientloading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading.Compared with the approach using least square filtering, its peak signal-to-noise ratio (PSNR) is improved from 3.18 to 6.46dB, while the computing time is reduced to 1/2-1/3.Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

Real-time, continuous-wave terahertz imaging by a pyroelectric camera

Real-time, continuous-wave terahertz (THz) imaging is demonstrated. A 1.89-THz optically-pumped farinfrared laser is used as the illumination source, and a 124 × 124 element room-temperature pyroelectric camera is adopted as the detector. With this setup, THz images through various wrapping materials are shown. The results show that this imaging system has the potential applications in real-time mail and security inspection.