木瓜中多糖和微量元素含量分析

苯酚 -硫酸光度法和原子吸收分光光度法分别测定了木瓜中多糖和微量元素的含量。多糖测定的相关系数为 0 .994 3,平均含糖量为 1 0 .4 9%;微量元素测定回收率为 97.1 %— 1 0 5 .9%,RSD为 2 .4 7%—7.6 0 %。本方法简单可靠 ,适用于木瓜及其制品的常规检测。     

亚叶酸钙与对硝基酚荷移反应的研究

本文主要研究了在水溶液中亚叶酸钙与对硝基酚发生荷移反应生成稳定的 1∶ 1络合物 ,络合物的最大吸收波长为 4 0 2 .2 nm,表观摩尔吸光系数为 ε=5 .2 5 5× 10 2 L· mol-1· cm-1,线性范围为 5 0—12 0 0 μg/ m L。回收率为 99.5 8%— 10 2 .6 0 % ,相对标准偏差为 1.4 3%。方法简单、快速、准确度高 ,可用于亚叶酸钙制剂含量的测定。     

化妆品中铅、镉含量的测定

原子吸收光谱法测定了化妆品中的铅和镉 ,铅和镉分别在 0 .5 0— 10 .0 0 μg·m L-1和 0 .2 0— 8.0 0 μg·m L-1范围内有良好的线性关系 ,相关系数分别为 r=0 .9989和 r=0 .9997;标准偏差分别为 RSD≤1.6 7%和 RSD≤ 4 .71% ;标准加入法测定铅和镉的回收率分别为 93.5 %— 10 6 .0 %和 94 .0 %— 10 5 .5 %。方法简单 ,结果准确。     

火焰原子吸收光谱法测定粤东第一温泉中钾、钠、钙、锰和锌

用火焰原子吸收光谱法测定粤东第一温泉源头水中的钾、钠、钙、锰和锌。测定结果为 :钾 2 .5 5 4mg/ L、钠 2 4 2 .0 mg/ L、钙 74 .4 0 mg/ L、锰 1 .0 78mg/ L、锌 0 .96 0 0 mg/ L,RSD1 .2 1 %— 2 .5 6 %,回收率 98.3%— 1 0 1 .1 %。     

分光光度法测定发酵液中果糖的含量

针对微生物转化发酵液体系的特征 ,用分光光度法测定其中果糖的含量。校准曲线回归方程为 y=2 6 .2 3x 0 .0 0 7,相关系数为 0 .9991 ;1 0倍量葡萄糖和 1 0倍量甘露醇的存在对果糖测定基本无干扰 ;发酵液中果糖测定的加标回收率为 99.1 %— 99.8%。     

抗坏血酸基体改进剂-石墨炉原子吸收法测定尾矿砂中铂

本文以抗坏血酸 (Vc)为基体改进剂 ,建立了石墨炉原子吸收法直接测定尾矿砂中微量铂的方法 ,并对不同基体改进剂的作用机理作了初步探讨。此方法的特征质量为 1 .3× 1 0 -10 g;检出限为 1 .9× 1 0 -12 g;线性范围为 2— 5 0 0 ng· m L-1;样品的加标回收率为 1 0 0 .7%— 1 0 4 .0 %。     

硫化银体系共振散射光谱研究及分析应用

Triton X- 1 0 0存在下 ,在碱性介质中 ,Ag 与 S2 -形成 Ag2 S微粒 ,Ag 与 S2 -反应体系的共振光散射(RLS)明显增强 ,建立了水中痕量银的测定方法。Ag 浓度在 0 .0 1 1— 6 .0 0 μg/ m L范围内具有良好的线性关系 (r=0 .9992 )。方法检出限 3.5 6 ng/ m L;相对标准偏差 0 .5 3%— 1 .97%;样品加标回收率 92 .82 %—1 0 6 .0 0 %。方法简便 ,测定体系抗干扰的效果好 ,灵敏度高。     

分光光度法测定镧汞齐中的镧

以偶氮胂 为显色剂 ,氯乙酸 -氢氧化钠为缓冲溶液 ,用分光光度法直接测定镧汞齐中镧含量。最佳的显色酸度为 p H2 .8— 3.0 ,最佳测定波长为 6 6 0 nm。镧含量在 0— 75 μg/ 2 5 m L范围内吸光度符合比耳定律 ,线性回归方程为 A=- 0 .0 2 4 8+0 .0 132 C,相关系数 r=0 .9992 ,配合物的摩尔吸光系数 ε为 4 .2 8×10 4L· mol-1· cm-1,回收率为 97.3%— 10 3.6 %。本法显色稳定性好 ,灵敏度高 ,操作简便 ,快速     

磷钼杂多酸-结晶紫分光光度法测定高纯氯化铯中微量磷

以 4 -叔丁基 - 2 (α-甲苄基 )苯酚 (t- BAMBP)萃取分离基体铯 ,磷钼杂多酸与结晶紫染料生成离子缔合物 ,在聚乙烯醇存在下 ,在水溶液中显色。在波长 5 45 nm处 ,其摩尔吸光系数可达 2 .0 1× 10 5L· mol-1·cm-1。方法的回收率为 97%— 10 1% ,相对标准偏差为 0 .8%— 2 .7%。     

反相高效液相色谱法同时测定动物组织中苯并咪唑类兽药残留量

本文建立了高灵敏度的苯并咪唑的测定方法 ,通过对实验条件的优化 ,采用反相高效液相色谱法同时测定动物组织中的苯亚砜苯咪唑 (oxfendazole)、噻苯咪唑酯 (cambendazole)、丙苯咪唑 (albendazole)及苯硫达唑 (fenbendazole) 4种苯并咪唑类兽药残留量。测定方法的相关系数 r>0 .9999,检出限为0 .0 1mg/ kg,线性范围为 0 .0 5— 10 .0 mg/ L ,精密度为 2 .1%— 7.3% ,回收率为 74 .8%— 90 .2 %     

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].     

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.     

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.