DMC聚醚的降解研究

研究DMC聚醚 (双金属催化剂的聚环氧丙烷 )的降解现象 .讨论了各种因素对降解的影响 ,以及降解中不饱和度的变化情况 .实验表明 ,DMC聚醚的降解与自由基有关 ,降解在常温下 1 5天后开始发生 ,在抗氧剂存在下受到抑制 .加入抗氧剂 1 0 1 0和 61 8可使聚醚得以稳定储存     

Removal of fine powders from film surface. II. Effect of operating parameters on the removal efficiency

In the previous paper, a novel fine particle removal system composed of a corona-discharge neutralizer, a pulse-jet air unit and an image processing system has been developed and applied to the removal of fine particles from film surface. We have calculated the van der Waals and electrostatic forces between particle and film and then reported that the electrostatic force influenced the adhesion characteristics significantly and thus the elimination of electrostatic charge should be necessary for the effective removal of fine particles. In this paper, we have modified the corona-discharge neutralizer for getting much better removal performance. The effect of operating parameters on the removal efficiency was investigated experimentally. The ratio of fine particle remained on the film surface after removal experiment as a function of particle size was measured. It was found that fine particles smaller than 15 microm, which were impossible to remove by other conventional techniques, could be almost completely removed. This method is anticipated to be used in the capsule filling, film packaging and tabletting processes for prevention of stain on lens of video automatic inspection machines, unpredictable movement of electronic devices, and deteriorates of product quality.     

A survey of 222Rn concentrations in dwellings of Turkey

As part of a national program to determine public exposure to natural radiation, indoor air ²²²Rn concentrations were determined in dwellings of Turkey. The ²²²Rn concentrations were measured with time-integrating passive nuclear etched track detectors in 27 provincial centers. The indoor radon concentrations were found to be in the range of 10-380 Bq^.m^-3. This revised version was published online in August 2006 with corrections to the Cover Date.     

The effect of ph and gas composition on the bubble fractionation of proteins

Studies were conducted to establish the effect of the variation of environmental factors on the separation occurring in protein systems, resulting from bubble fractionation in a bioreactor. The measure of separation was selected to be the separation ratio. This is defined to be the ratio of either the top or the middle position concentration in the vessel to the bottom concentration of the vessel. Invertase and α-amylase were the two “model” enzymes considered. It was observed that, under certain conditions, i.e., a combination of the nature of the sparging gas and the medium pH, varying degrees of protein separation were achieved. The pH of the system dramatically influenced the separation. It was found that the best separation occurred at a certain pH, assumed to be at or close to thepI of the protein in question. Furthermore, it was observed that systems sparged with CO₂ exhibited greater separation than systems sparged with air. In fact, in the case of invertase, almost threefold separation was observed at the top port when the solution was sparged with CO₂.     

半干法烟气脱硫喷嘴的雾化特性研究

利用FAM型衍射式激光测粒仪，对双流体石灰浆液雾化喷嘴的雾化特性进行了试验研究，得到了预测雾滴平均粒径的经验公式，分析了气耗率、石灰浆液浓度等参数对雾化粒径分布和雾化角的影响规律。结果表明，气液质量比增大，浆液液滴平均直径(SMD)减小；浆液浓度增加，液滴平均直径增加。气液质量比在0.05～0.3的范围内可获得良好的雾化效果，雾化粒径一般在20 μm～100 μm。喷嘴的雾化角较小，一般在20°～25°之间。气液质量比增加，雾化角减小；而石灰浆浓度对雾化角影响较小。     

Preparation of ZnO nanoparticles in a reverse micellar system and their photoluminescence properties

ZnO nanoparticles with spherical morphology and narrow size distribution were obtained by calcination of Zn(OH)2 nanoparticles, which were prepared in a polyethylene glycol mono-4-nonylphenyl ether (NP-5)/cyclohexane reverse micellar system and incorporated into polyurea (PUA) via an in situ polymerization of hexamethylene diisocyanate (HDI). The resulting ZnO nanoparticles demonstrated a near-UV emission and a green emission, the intensity ratio of which depended on calcination conditions. For the nanoparticles studied, the calcination atmosphere influenced remarkably the photoluminescence properties such as intensity ratio of the near-UV emission to green emission, rather than the size, morphology, and crystallinity of the ZnO nanoparticles. The green emission decreased by calcination in O2 flow but increased by calcination in N2 flow, as compared with the case calcined in air flow. This finding suggests that the green emission is enhanced with the increase of the number of oxygen vacancies of the ZnO nanoparticles and thus the photoluminescence properties of the nanoparticles were successfully controlled by the calcination condition, without changing the size and morphology.     

Heavy metal contamination in street dusts of Istanbul (Pendik to Levent) E-5 highway

Street dust composition is an important environmental parameter that should be considered in investigations of environmental pollution originating from traffic. In this study, fifty-six samples of street dusts were collected during the period December 2003-April 2004 from Pendik to Levent on E-5 highway in Istanbul, Turkey. Analyses were determined by graphite furnace atomic absorption spectrometry after digestion using USEPA, 1996 (Method 3050B). The mean concentration levels of Pb, Mn, Zn, Ni, Cd and Cu were found to be 368.3, 747.8, 431.2, 27.1, 0.3 and 191.1 microg/g respectively. Pb, Cu, Zn and Mn mean concentrations in studied areas were higher than levels of these heavy metals according to USEPA (1992) and Republic of Turkey Ministry of Environment and Foresty (2003). Highly significant correlations except for Mn were found between the number of vehicles and heavy metal concentrations.     

甲苯溶剂中聚丁二烯基锂缔合度测定

本工作是甲苯-丁二烯-丁基锂聚合体系研究的一部份。在甲苯溶剂中进行聚丁二烯基锂缔合度测定,在国内外文献上尚未见报导,通过实验可以看出,聚丁二烯基锂甲苯溶液的平均缔合度,在引发剂浓度>1×10^-3mol/1范围内等于或大于2,此外用粘度法测定聚丁二烯基锂的缔合度时,如果剪切速度在12～450see^-1之间,测量结果不受剪切的影响。     

太原东山煤地下气化模型试验研究

通过地下气化模型试验，获得了东山煤地下气化过程的一般规律。进行了东山煤空气气化及纯氧-水蒸气气化试验，研究了鼓风量及气氧比对煤气组成的影响、气化过程的稳定性以及试验条件下的煤层气化速率变化，进行了纯氧-水蒸气地下气化的物料衡算。试验结果表明，东山煤空气气化可以生产低热值空气煤气，鼓风量会影响空气煤气的组成；纯氧-水蒸气地下气化可以获得合格的二甲醚合成原料气，但需根据气化工作面的移动及煤气组成变化，采用移动点供风气化维持气化过程连续稳定进行。气化过程的物料衡算可以用来预测气化煤气的基本组成。气氧比影响煤气组成变化，试验条件下适宜的气氧比范围为1.8～2.2。气化工作面扩展速率在供风点附近出现最大值，变化平稳，瘦煤地下气化具有较高的稳定性。     

Continuous-flow isotope analysis of the deuterium/hydrogen ratio in atmospheric hydrogen

A convenient method is described for analyzing the deuterium/hydrogen (D/H) ratio of atmospheric molecular hydrogen (H(2)) based on mass spectrometric isotope-ratio monitoring. The method requires small amounts of air ( approximately 300 mL STP), is operated on-line, and comprises four steps: (1). the condensation of the air matrix at approximately 40 K; (2). the collection of the non-condensed components of the air sample (H(2), Ne, He, and traces of N(2)) in a 5 A molecular sieves pre-concentration trap at approximately 63 K; (3). gas chromatographic purification of H(2) in a flow of He; and (4) quantification of the D/H ratio in an isotope-ratio mass spectrometer. The precision of the determination of the D/H ratio is better than 2 per thousand, which is comparable to, or better than, that obtained by conventional duel-inlet off-line analysis. There are, however, discrepancies relative to the D/H ratios determined by conventional duel-inlet analysis. This is due to differences in peak shape between reference and sample air, depending on the amount of H(2) injected. Consequently, calibration runs are required. After the calibration of the system, we obtained an accuracy of 1.5 per thousand, so that the accumulated uncertainty is estimated to be less than 4 per thousand. The method also allows determination of the H(2) concentration, with an uncertainty estimated to be 2%.     

Spinodal instability and pattern formation in thin liquid films confined between two plates

The instability, morphology and pattern formation engendered by the van der Waals force in a thin liquid film of thickness h confined between two closely placed solid surfaces (at distance d > h) are investigated based on nonlinear 3D simulations. The initial and the final stages of dewetting and pattern formation are found to be crucially dependent on the volumetric (thickness) ratio of air and liquid and its deviation from the location of the maximum of the spinodal parameter versus volumetric ratio curve. On a low energy surface, relatively thinner films and wider air gaps favor initial dewetting of the lower plate by the formation of holes, whereas thicker films with thinner air gaps initially evolve by the formation of columns/bridges that join the upper plate. In the later stage of evolution, the initial holes in thinner films evolve into columns/drops, while a rapid coalescence of columns in the thicker films eventually causes formation of holes. Thus, a phase inversion, either from liquid-in-air to air-in-liquid dispersion or vice versa, occurs during the final stages of evolution. A thin film confined between two high-energy solid surfaces forms columns (bridges) only when its mean thickness, h0, is greater than a critical thickness (hc) or the air gap is smaller than a critical distance. The patterns can be aligned by using a topographically patterned confining surface. Conditions on pattern periodicity, amplitude, and the volumetric ratio of air and liquid in the gap are explored for the formation of various types of ordered patterns including annular rings of columns, concentric ripples, parallel channels and a rectangular array of complex features. The results are of significance in soft lithographies such as LISA, soft stamping and capillary force lithography.     

程序升温还原法研究氧化对煤中硫形态及结构的影响

用程序升温还原法研究了三种不同硫含量的煤被空气和HNO3氧化后含硫气体的逸出规律。结果表明，空气和HNO3氧化后，尽管煤中有机硫总量变化不大，但煤中H2S的释放量有所下降，而COS和SO2的生成量明显增加，这说明氧化作用使得煤中弱的有机硫变成S=O和SO2结构。与以往的研究结果不同的是，发现CS2的生成与FeS密切相关，同时对HNO3氧化后的煤来说，CS2的生成主要以气相中H2S和COS的反应为主。空气氧化后煤中CS2的生成量与原煤的差不多，但HNO3氧化后煤中释放出的CS2有所下降。提出通过（COS+SO2）/H2S的比值来研究煤及其中硫被氧化的程度，并对比了不同煤种及氧化后样品的气相含硫化合物发现：随变质程度的提高和煤中噻吩硫含量的增加，煤被氧化的程度下降。对同一煤种而言，HNO3的氧化程度要高于空气氧化的。     

Investigation of uranium and thorium concentrations in the fluorite beds of Anatolia by using solid state nuclear track detectors

Uranium and thorium concentrations of fluorite samples taken from the main fluorite beds of Anatolia (Turkey) have been determined by fission fragment radiography using solid state nuclear track detectors (SSNTDs). The fissionable elements concentration of the fluorite samples were found to be 10^–4–10^–7 g/g. The Th/U ratio, obtained for all the fluorite samples, is found to be characteristic for the location of the samples. Some correlations between the concentration of Th and those of lanthanites and concentration of U and that of Mo or Zr are observed.     

Statistical estimate for evaluation of vitrified radioactive wastes

The evaluation of experimental results by methods of mathematical statistics enabled us to derive a number of conclusions on the leachability of vitrified radioactive wastes. Practical application of this procedure requires that the ratio of Na and K concentrations in the solution should be independent of the leaching time. The actual value of this ratio is influenced, above all, by the properties of the glass matrix. These results confirm the assumption that the Na/K correlation found could be extended for the determination of the Na/¹³⁷ Cs concentration ratio. This finding was used for the application of a In-In correlation, while evaluating the quality of vitrified radioactive wastes products.     

Study of the thermal decomposition of solids in a fluidized bed,III

The influence of the air humidity upon the thermal decomposition of diammonium hydrogen phosphate was studied in a fluidized bed, under isothermal conditions. It was found that the increase of the decomposition rate is influenced directly by the partial pressure of the water vapour in the air, and indirectly by the working temperature. The moisture effect is explained by the salt hydrolysis in the water condensed on the grain surface. The energy of activation of the thermal decomposition decreases when the air humidity increases.     

Continuous shipboard sampling system for determination of triple oxygen isotopes and O2/Ar ratio by dual-inlet mass spectrometry

A continuous shipboard sampling system was developed for the determination of the isotopic composition of the triple oxygen isotopes and oxygen to argon (O(2)/Ar) ratios in dissolved air. In this system, dissolved air is separated by a hollow fiber membrane degassing module. This system collects dissolved air quantitatively and rapidly. The sample flow rate through the membrane is critical for the fractionation of the oxygen isotopes and the O(2)/Ar ratio and should be < 2 mL/min. Fractionation of oxygen between the liquid and gas phase of the air-saturated water was found to be similar to that of earlier reports. The advantages of this method over existing techniques include rapid collection of samples (30 min/sample), high efficiency in extraction of gases from the liquid phase, and the lack of a sample preparation step (e.g. degassing).     

Pneumatically tunable optofluidic 2 × 2 switch for reconfigurable optical circuit

We presented a pneumatically tunable 2 × 2 optofluidic switch for on-chip light routing that was controlled by compressed air. The device was fabricated with an optically clear elastomer-polydimethylsiloxane (PDMS)-by soft-lithography. The optical switching is realized with a tunable air-gap mirror by which the light is deflected due to total internal reflection in the bypass state. When the device is subjected to high pressure, the air gap collapses and hence the light will be switched to the crossover state. The device had a switching speed of more than 5 Hz and an extinction ratio of 8 dB. This switch can be readily integrated with other microfluidic circuits. We demonstrated a simple reconfigurable optical waveguide circuit for dual-channel microfluidic spectroscopy measurement on a chip.     

Simultaneous liquid chromatographic determination of 39 polycyclic aromatic hydrocarbons in indoor and outdoor air and application to a survey on indoor air pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.     

Stimulation of the Germination and Early Growth of Tomato Seeds by Non-thermal Plasma

The influence of non-thermal plasma on tomato seeds has been investigated using a fluidized bed dielectric barrier discharge generated in air. It was found that plasma-treated seeds germinate faster than untreated ones. Plasma slightly enhanced germination rate and considerably influenced growth parameters. Seedling length and weight are significantly higher than those of untreated seeds. The influence of plasma exposure is more visible on the plant roots, which are substantially longer and more branched. An increase in weight of 20–40% was observed for the plants grown from treated seeds as compared to the control ones. The best results are obtained for relatively short plasma exposure, while too long treatment appears to be detrimental to the seeds.