浅谈蒽醌法生产双氧水影响氢化工艺的几个因数

介绍了蒽醌法生产双氧水工艺中氢化的工艺条件,指出了氢气分压和纯度、氢化温度、氢化液循环、工作液中水分含量、工作液中过氧化氢含量和循环工作液碱度对氢化工艺的影响,并给出了最佳设计参数。

PECVD制备氢化非晶硅薄膜的氢含量研究

采用等离子增强化学气相沉积工艺在硅片上制备a-Si:H薄膜,用傅里叶变换红外光谱仪测试薄膜的红外光谱吸收峰。研究了衬底温度、工艺压强和氢气稀释比对a-Si:H薄膜中氢含量的影响。结果表明,随着衬底温度升高,氢含量显著减小;压强增大时,氢含量也增大;氢气稀释比增大,氢含量反而减小。选择适当的工艺参数,可以控制a-Si:H薄膜的氢含量,从而改善a-Si:H薄膜性能和微结构。研究结果对低温多晶硅制造工艺也有一定的指导意义。

Hydrogenation of Silicon Tetrachloride in Microwave Plasma

This study investigated the hydrogenation of silicon tetrachloride （SIC14） in microwave plasma. A new launcher of argon （Ar） and hydrogen （Ha） plasma was introduced to produce a non-thermodynamic equilibrium activation plasma. The plasma state exhibited a characteristic temperature related to the equilibrium constant, which was termed ＂Reactive Temperature＂ in this study. Thus, the hydrogenation of SIC14 in the plasma could easily be handled with high conversion ratio and very high selectivity to trichlorosilane （SiHC13）. The effects of SiC14/Ar and H2/Ar ratios on the conversion were also investigated using a mathematical model developed to determine the op- timum experimental parameters. The highest hydrogenation conversion ratio was produced at a H2/SiCl4 molar ratio of 1, with mixtures of SICl4 and H2 to Ar molar ratio of 1.2 to 1.4. In this plasma, the special system pressure and incident power were required for the highest energy efficiency of hydrogenating SIC14, while the optimum system pressure varies from 26.6 to 40 kPa depending on input power, and the optimum feed gas （He and SiCI4） molar en- ergy input was about 350 kJ. mo1-1.

Three-Dimensional Structure of Optimal Nonlinear Excitation for Decadal Variability of the Thermohaline Circulation

The decadal variability of the North Atlantic thermohaline circulation(THC) is investigated within a three-dimensional ocean circulation model using the conditional nonlinear optimal perturbation method. The results show that the optimal initial perturbations of temperature and salinity exciting the strongest decadal THC variations have similar structures: the perturbations are mainly in the northwestern basin at a depth ranging from 1500 to 3000 m. These temperature and salinity perturbations act as the optimal precursors for future modifications of the THC, highlighting the importance of observations in the northwestern basin to monitor the variations of temperature and salinity at depth. The decadal THC variation in the nonlinear model initialized by the optimal salinity perturbations is much stronger than that caused by the optimal temperature perturbations, indicating that salinity variations might play a relatively important role in exciting the decadal THC variability. Moreover, the decadal THC variations in the tangent linear and nonlinear models show remarkably different characteristics, suggesting the importance of nonlinear processes in the decadal variability of the THC.

A non-invasive method for gastrointestinal parameter monitoring

AIM: To propose a new, non-invasive method for monitoring 24-h pressure, temperature and pH value in gastrointestinal tract.METHODS: The authors developed a miniature, multifunctional gastrointestinal monitoring system, which comprises a set of indigestible biotelemetry capsules and a data recorder.The capsule, after ingested by patients, could measure pressure, temperature and pH value in the gastrointestinal tract and transmit the data to the data recorder outside the body through a 434 MHz radio frequency data link. After the capsule passed out from the body, the data saved in the recorder were downloaded to a workstation via a special software for further analysis and comparison.RESULTS: Clinical experiments showed that the biotelemetry capsules could be swallowed by volunteers without any difficulties. The data recorder could receive the radio frequency signals transmitted by the biotelemetry in the body. The biotelemetry capsule could pass out from the body without difficulties. No discomfort was reported by any volunteer during the experiment. In vivo pressure and temperature data were acquired.CONCLUSION: A non-invasive method for monitoring 24-h gastrointestinal parameters was proposed and tested by the authors. The feasibility and functionality of this method are verified by laboratory tests and clinical experiments.

Effect of NaOH treatment on combustion performance of Xilinhaote lignite

The combustion characteristics of NaOH treated and untreated Xilihaote lignite was investigated by thermogravimetric analysis.The relationship between physico-chemical properties,including the ash content,oxygen-containing functional groups,mean pore diameter and specific surface area and combustion performance,was also studied in this paper.Combustion kinetic parameters were calculated through Coasts Redfern Method.The results show that ignition of treated samples takes place at higher temperature compared to raw lignite,and peak temperature also occurs at higher temperature.The maximum combustion rate of the sample,which was treated by 0.01 mol/L NaOH lignite,was the biggest.Reaction orders of 0.6,2.0,and 0.8 were found to be effective mechanism for definite three temperature regions.Average activation energies of these three temperature regions of XLHTR,XLHT0.01,XLHT0.50 and XLTH1.00 are 19.17,23.87,10.77,and 10.93 kJ/mol,respectively.Treatment of lignite with NaOH can reduce the reactivity of lignite at proper concentration.

Effect of calcination temperatures on photocatalytic H_(2)O_(2)-production activity of ZnO nanorods

Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.

Effect of cobalt loading on reducibility, dispersion and crystallite size of Co/Al_2O_3 Fischer-Tropsch catalyst

Co/Al2O3 Fischer-Tropsch synthesis catalysts with different cobalt loadings were prepared using incipient wetness impregnation method. The effects of cobalt loading on the properties of catalysts were studied by means of X-ray diffraction （XRD）, temperature programmed reduction （TPR）, hydrogen temperature programmed desorption （H2-TPD） and O2 titration. Co-support compound formation can be detected in catalyst system by XRD. For the Co/Al2O3 catalysts with low cobalt loading, CoAl2O4 phase appears visibly. Two different reduction regions can be presented for Co/Al2O3 catalysts, which belong to Co3O4 crystallites （reduction at 320 ℃） and cobalt oxide-alumina interaction species （reduction at above 400 ℃）. Increasing Co loading results in the increase of Co3O4 crystallite size. The reduced Co/Al2O3 catalysts have two adsorption sites, and cobalt loading greatly influences the adsorption behavior. With the increase of cobalt loading, the amount of low temperature adsorption is increased, the amount of high temperature adsorption is decreased, and the percentage reduction and cobalt crystallite size are increased.

Hydrogenation reaction characteristics and properties of its hydrides for magnetic regenerative material HoCu_2

The hydrogenation reaction characteristics and the properties of its hydrides for the magnetic regenerative material HoCu_2(CeCu_2-type) of a cryocooler were investigated. The XRD testing reveals that the hydrides of HoCu_2 were a mixture of Cu, unknown hydride Ⅰ, and unknown hydride Ⅱ. Based on the PCT(pressure-concentration-temperature) curves under different reaction temperatures, the relationships among reaction temperature, equilibrium pressure, and maximum hydrogen absorption capacity were analyzed and discussed. The enthalpy change ΔH and entropy change ΔS as a result of the whole hydrogenation process were also calculated from the PCT curves. The magnetization and volumetric specific heat capacity of the hydride were also measured by SQUID magnetometer and PPMS, respectively.

Influence of Synthesis Temperature on Phosphate Adsorption by Zn-Al Layered Double Hydroxides in Excess Sludge Liquor

A group of Zn-Al layered double hydroxides (LDHs) were synthesized at different temperatures from 25-90 °C in order to investigate the influence of synthesis temperature on characteristics of the LDHs and their phosphate adsorption behaviour. The results reveal that an increase in the synthesis temperature generally improves the specific surface area of the sample and the phosphate adsorption capacity. The significantly enhanced crystallin- ity of the Zn-Al-30, synthesized at 30 °C, leads to a remarkable decrease in the specific surface area and consequently a poor phosphate adsorption capacity. It is suggested that the surface adsorption plays an important role in the phosphate uptake by the Zn-Al LDHs. Zn-Al-70 presents a relatively higher crystallinity and a lower specific surface area, compared with Zn-Al-60 and Zn-Al-80, but the highest phosphate adsorption capacity, indicating that surface adsorption is only one of the pathways for phosphate removal. The phosphate adsorption by the Zn-Al follows a pseudo-second-order kinetic equation. The adsorption isotherms fit Langmuir models, and the maximum a dsorption capacities of the Zn-Al-25, Zn-Al-50 and Zn-Al-70 are estimated to be 17.82, 21.01 and 27.10 mg·g-1 adsorbent, respectively.

Applying Study of Hydrogen Storage Alloy

Hydrogen is an important source of energy.The natural resouces of hydrogen is plenty and it gives us lots of heat, and it is dean. One of difficulties of developing hydrogen sources of energy is hydrogen storage. Hydrogen storage tank is either dangous or a little of capacity. Liquid hydrogen occupys small space. Liquefaction temperature of hydrogen is -253℃ and need better heat insulation protection, the volumn and weight of heat insulation layer are equal to hydrogen storage tank. Hydrogen storage utillizing hydrogen storage material is a very safety, economical and effective method. Hydrogen storage material is either a medium of sofid hydrogen storage or is negative pole active material of Ni-H battery,and is the one of key technoloy of fuel and Ni-H battery, it is an important material of new sources of energy too.Nanotechnology is introduced Mg-matrix hydrogen storage alloy and is achieved progress gteatly,but hydrogen storage alloy need be mode further improvment on applying investigation.

Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

A central composite experimental design and response surface method were used to investigate the combined effects of water temperature(18–34℃) and copper ion concentration(0.1–1.5 mg/L) on the catalase(CAT) activity in the digestive gland of C rassostrea ariakensis. The results showed that the linear effects of temperature were significant(P <0.01), the quadratic effects of temperature were significant( P <0.05), the linear effects of copper ion concentration were not significant(P >0.05), and the quadratic effects of copper ion concentration were significant(P <0.05). Additionally, the synergistic effects of temperature and copper ion concentration were not significant(P >0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

Ecological Costs Applied in the Bleaching of Cotton： A Study for an Optimized Process

The aim of this paper was to study three variables in hydrogen peroxide bleaching of cotton fabrics： the amount of hydrogen peroxide （H2O2）, peroxide stabilizer （Na2SiO3） and the process temperature. The factorial planning of two levels and three factors was done in order to obtain an optimized recipe for subsequent comparison with commons recipes used in industry. Were evaluated the brightness （DL）, energy consumption （dQ）, H2O2 residual （Rox）, processing time and ecological costs.

Oxidative desulfurization performance optimization of tert- amyl hydroperoxide

The desulphurization experiment of oil-soluble oxidant tert-amyl hydroperoxide with dibenzothiophene dissolved in decalin as model-oil was researched. Characterisation on oxidation product was made, and dibenzothiophene removal rate was computed. The influence factors of the oxidative reaction regent amount and the condtions of reaction temperature and reaction time were optimized and compared. The best reaction condition was reaction temperature 90℃, reaction time 3 h, ratio of oxygen to sulfur 4：1, catalyst amount 0.12 g. Dibenzothiophene removal rate reached 97% in this reaction condition.

High Temperature Catalytic Hydrogenation of Acetone over Raney Ni for Chemical Heat Pump

Exothermic hydrogenation reaction of acetone is an important part of an IAH-CHP, and the performance of IAH-CHP is affected directly by this reaction. This paper studies the influence of space velocity, temperature, hydrogen flow rate and pressure on conversion and selectivity experimentally. The byproducts are analyzed and classified into three types: hydrogenation product, cracking products and condensation products. Both the conversion and selectivity of this reaction have the same trend with the change of space velocity, temperature and hydrogen flow rate, and has the opposite trend with the change of pressure. As the space velocity increases, the conversion curve is a gradual decline parabola but the selectivity curve is close to a straight line. Hydrogen flow rate has a more obvious influence on conversion than temperature, whereas on selectivity the situation is opposite. High pressure increases the conversion of acetone to all products, but the increment of byproducts is more than that of isopropanol, so the selectivity decreases as pressure increases.

Hydrogen bonding in hydrogenated amorphous silicon thin films prepared at different precursor gas temperatures with undiluted silane

Hydrogen bonding configurations and hydrogen content in hydrogenated amorphous silicon (a-Si:H) thin films prepared at different precursor gas temperatures with undiluted silane have been investigated by means of Fourier transform infrared (FTIR) spectroscopy.The results show that the gas temperature before precursor gases entering the glow-discharge zone re-markably influences the hydrogen bonding configurations and the hydrogen content in a-Si:H thin films.The hydrogen content decreases from 18% down to 11% when increasing the gas temperature from room temperature (RT) to 433 K.Meanwhile,the clustered hydrogen at the physical film surface or at the internal surfaces of the microvoids decreases,indicating that a-Si:H thin films are densified at higher precursor gas temperatures.For a-Si:H thin films deposited at gas temperature of 433 K,the isolated silicon-hydrogen bonding configuration is predominant in the testing films.

Air-promoted selective hydrogenation of phenol to cyclohexanone at low temperature over Pd-based nanocatalysts

Attaining high activity with high selectivity at low temperature is challenging in the selective hydrogenation of phenol to cyclohexanone due to its high activation energy （Ea, 55-70 kJ/mol）. Here we report a simple and efficient strategy for phenol hydrogenation catalyzed by Pd in aqueous phase at 30 ℃ by introducing air to promote the catalysis. With the assistance of air, 〉99% conversion and 〉99% selectivity were achieved over Pd（111）/Al2O3 with an overall turnover frequency （TOF） of 621 h-1, -80 times greater than that of the state-of-art Pd catalyst at 30 ℃. Mechanism studies revealed that phenol was activated to generate phenoxyl radicals. The radicals were yielded from the reaction between phenol and hydroxyl radicals in the presence of hydrogen, oxygen and protic solvent on Pd. The phenoxyl pathway resulted in a low apparent Ea （8.2 kJ/mol） and thus high activity. More importantly, this strategy of activating substrate by air can be adapted to other Pd based catalysts, offering a new thinking for the rational design of cyclohexanone production in industry.

Grand canonical Monte Carlo simulation for hydrogen uptakes based on nanoporous NaBH_4

A new hydrogen storage route of 3D nanoporous sodium borohydride (NPSB) generated by removing special atoms is proposed in this work. Three different size pores of NPSB-1 (7), NPSB-2 (10) and NPSB-3 (14) are presented, and the hydrogen storage capacities of these NPSBs are simulated by employing a grand canonical Monte Carlo (GCMC) procedure for a temperature range of 77-298 K and a pressure range of 0.1-100 bar. The effects of pore diameter, temperature and pressure on the hydrogen adsorption have been examined. The results show that the adsorption of hydrogen decreases and increases with increasing temperature and hydrogen pressure, respectively. It also reflects that the hydrogen adsorption capacities at higher pressures are dependent on pore diameter, while independent of pore diameter at lower pressures.