水合温度、胶用量和氯化钾用量对kappa-卡拉胶胶液黏度的影响

目的:实现kappa-卡拉胶在肉类制品、乳制品、甜点和果冻等食品工业领域以及药用无缝胶囊、烟用爆珠等领域的精准应用。方法:采用数显式黏度计对在不同水合温度、不同卡拉胶用量以及不同氯化钾用量下制备的kappa-卡拉胶胶液的黏度进行测定。结果:①水合温度对kappa-卡拉胶胶液的黏度具有较大的影响。随着水合温度的升高(固定水合时间1 h),kappa-卡拉胶胶液黏度下降。总体而言,kappa-卡拉胶用量越高,其黏度下降幅度越大。②kappa-卡拉胶胶液黏度随胶用量的增大而呈指数规律增加。③在低kappa-卡拉胶用量下,在试验所选用的KCl用量范围内,KCl用量对样品黏度的影响不大,但在高kappa-卡拉胶用量下,随着氯化钾用量的增大,样品的黏度有所增大。结论:水合温度、胶用量对kappa-卡拉胶的胶液黏度具有重要影响,氯化钾用量对黏度的影响相对较小。

气体组分变化对油井水合物生成温度的影响

近年来对于气井井筒水合物生成研究甚多,而对油井水合物的生成研究则较少,且由于在重力作用下油相将气、水两相隔开给水合物生成条件测试造成了困难。为此,将测定油气水三相水合物生成问题转化为原油脱出气与水生成水合物的问题,首先开展了油气水三相水合物生成条件测试实验,并以此为基础评价优选出了适用的水合物生成条件预测模型;然后结合油藏流体相图和井筒压力温度预测方法及采出井井流物天然气组成的动态相态数值模拟预测,讨论了天然气组成含量随井深的变化规律;最后采用井口、井深1000 m和井深1900 m处组分数据预测了井筒水合物生成温度剖面,验证了气体组分变化对井筒水合物生成温度的影响。实验及计算结果表明:不同含水率对水合物的生成条件并无影响,各模型中简化牛顿热力学模型误差为7.31%,预测精度相对较高;随井深增加,轻烃逐渐下降,重组分逐渐增大;最后指出,采用组分数据预测油井水合物生成温度剖面时,其数据选择尤为重要,否则可能导致预测的准确性降低。该研究成果对于准确预测油井水合物的生成条件具有重要的意义。

一种动力学天然气水合物抑制剂合成研究

研发低剂量水合物抑制剂部分代替传统热力学水合物抑制剂是目前水合物研究的热点之一。为提高聚N-乙烯基吡咯烷酮的性能,采用N-乙烯基吡咯烷酮与马来酸酐合成了聚合物MVP。利用四氢呋喃法研究了MVP的合成条件及对水合物的抑制效果。研究表明,以乙二醇丁醚为溶剂,双氧水为引发剂时,马来酸酐与N-乙烯基吡咯烷酮质量比为3∶4、反应温度(80～100)℃、反应时间9 h条件下合成MVP对水合物抑制效果良好。该条件下合成的MVP与聚N-乙烯基吡咯烷酮相比对水合物具有更好的抑制效果,相同加量下能够承受过冷度较聚N-乙烯基吡咯烷酮高3℃;最佳加量为0.7%,该加量下水合物生成温度从-2℃下降到-8.6℃。由于MVP性能受过冷度影响较大,研究发现MVP发挥作用的过冷度不能高于10℃。

水合法合成二氧化钛晶须工艺条件的探究

本文论述二氧化钛晶须的制备、并着重从酸性介质的选取、水合温度和水合比等方面讨论用水合法合成二氧化 钛晶须的最佳反应条件。

纯水体系二氧化碳水合物浆液流动特性的研究

为研究纯水体系下二氧化碳水合物浆液流动的特性,在高压环路中进行水合物的生成实验。分析二氧化碳水合物在气泡流、段塞流条件下的堵塞过程及机理;在环路堵塞后仍保持水浴降温,分析了堵塞后水合物的温度及生成速率的变化。结果表明:气泡流生成水合物的位置主要在管道顶部,以小气泡为核生长出的水合物层拦截液相中的絮状水合物逐步降低流通面积,顶部的水合物壳层坍塌堵住管路。段塞流中难以在顶部形成致密水合物层,常在气水界面附近生成片状水合物,与液相中的絮状水合物结合在一起,堵塞管路。环路堵塞后,对比不同条件水合物温度变化后发现,低压力下水合物温度升高迅速,生成速率更快;高压力下水合物温度升高缓慢,生成速率较慢。

飞灰/石灰脱硫剂制备及其宏观结构研究

测定了不同条件下制备的飞灰/石灰脱硫剂的比表面积、孔径及其分布,并分析了其宏观结构特点.结果表明,由飞灰和石灰水合制得的脱硫剂具有比飞灰或石灰大得多的比表面积.分别考察了飞灰/石灰比、水合温度、水合时间对脱硫剂宏观结构的影响.研究表明,最适宜的脱硫剂制备条件为飞灰/石灰比3∶1,水合温度60℃,水合时间4 h.

Variation in litter decomposition-temperature relationships between coniferous and broadleaf forests in Huangshan Mountain, China

A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes （Phenoloxidase, peroxidase, !5-glucosidase and endocellulase） and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.

多柔比星前体脂质体包封率测定及影响因素考察

目的测量自制多柔比星前体脂质体的包封率并对影响包封率的因素进行考察。方法葡聚糖凝胶层析法、紫外分光光度法测量多柔比星前体脂质体包封率。结果自制多柔比星前体脂质体包封率平均可达80.0%,稳定性良好。结论药脂比、膜材、水合温度等对多柔比星前体脂质体的包封率有较大的影响。

Coupled effect of cement hydration and temperature on rheological properties of fresh cemented tailings backfill slurry

The fluidity of fresh cemented tailings backfill（CTB） slurry depends on its rheological properties. Hence, it is crucial to understand the rheology of fresh CTB slurry, which is related to the cement hydration progress and temperature evolution within CTB mixtures. For this reason, a numerical model was developed to predict the evolution of the rheological properties of fresh CTB slurry under the coupled effect of cement hydration and temperature. Experiments were conducted to investigate the rheological behaviours of the fresh CTB slurry. By comparing the simulated results with the experimental ones, the availability of this developed model was validated. Thereafter, the model was used to demonstrate the coupled effect of cement hydration and temperature on the evolution of fresh CTB slurry＇s rheological properties, under various conditions（initial CTB temperature, cement to tailings ratio, and water to cement ratio）. The obtained results are helpful to better understanding the rheology of CTB slurry.

Thermal modeling of underwater friction stir welding of high strength aluminum alloy

The thermal modeling of underwater friction stir welding （FSW） was conddcted with a three-dimensional heat transfer model. The vaporizing characteristics of water were analyzed to illuminate the boundary conditions of underwater FSW. Temperature dependent properties of the material were considered for the modeling. FSW experiments were carried out to validate the calculated results, and the calculated results showed good agreement with the experimental results. The results indicate that the maximum peak temperature of underwater joint is significantly lower than that of normal joint, although the surface heat flux of shoulder during the underwater FSW is higher than that during normal FSW. For underwater joint, the high-temperature distributing area is dramatically narrowed and the welding thermal cycles in different zones are effectively controlled in contrast to the normal joint.

水胶炸药胶体稳定性的研究

介绍了水胶炸药的结构体系及影响水胶炸药胶体稳定性的因素。通过控制工艺条件、原材料及操作方式,完全可以改善炸药的交联状况,提高交联等级,从而稳固水胶炸药的爆炸性能。

Influence of Pore Size,Salinity and Gas Composition upon the Hydrate Formation Conditions

An experimental device was set up to study the hydrate formation conditions.Effects of pore size,salinity,and gas composition on the formation and dissociation of hydrates were investigated.The result indicates that the induction time for the formation of hydrates in porous media is shorter than that in pure water.The decrease in pore size,by decreasing the size of glass beads,increases the equilibrium pressure when the salinity and temperature are kept constant.In addition,higher salinity causes higher equilibrium pressure when the pore size and temperature are kept constant.It is found that the effects of pore size and salinity on the hydrate equilibrium are quite different.At lower methane concentration,the hydrate equilibrium is achieved at lower pressure and higher temperature.

Effects of Temperature Gradient and Cooling Rate on the Formation of Methane Hydrates in Coarse Sand

Temperature gradient and cooling rate have an obvious effect on formation of methane hydrate. The process for formation of methane hydrate in coarse sand is monitored to tmderstand the relationship between temperature gradient and cooling rate and nucleation, growth and distribution of methane hydrate by using the electrical resistivity method. The results show that the change of resistivity can better reflect the nucleation and growth and distribution of methane hydrate. Temperature gradient promotes the nucleation, formation, and formation rate of methane hydrate. At a temperature gradient of 0.11℃/cm, the rate of methane hydrate formation and saturation reaches a maximum. Cooling rate has little effect on the methane hydrate formation process. Judging from the outcome of final spatial distribution of methane hydrate, the cooling rate has an obvious but irregular effect in coarse sand. The effect of tempera^re gradient on distribution of methane hydrate in coarse sand is less than that of cooling rate. At a temperature gradient of 0.07℃/cm, methane hydrate is distributed uniformly in the sample. If the temperature gradient is higher or lower than this value, the hydrate is enriched in the upper layer of sample.

Vegetation/Soil Synthesis Water Index Using MODIS Data

In consideration of the spectral character of MODIS (Moderate Resolution Imaging Spectroradiometer) dataand the reflective spectrum of vegetation and soil, NDVI (Normalized Difference Vegetation Index) and NDWI (Nor-malized Difference Water Index) are deduced using one visible band (0.66μm) and two near-infrared bands (0.86μm,1.24 μm). Vegetation canopy temperature is derived using two thermal infrared bands (8.6 μm and 11μm). Then thevegetation/soil synthesis water index (VSWI) is acquired through analyzing the coupling character of three indexeswhich can reflect the water condition of vegetation. Finally, the synthesis index is verified by equivalent water contentof a single leaf. The matching results show that the synthesis index is directly proportional to the modeled data,which means that the vegetation water content can be reflected using the synthesis index effectively.

A New Method for Predicting the Decadal Component of Global SST

A simple approach that considers both internal decadal variability and the effect of anthropogenic forcing is developed to predict the decadal components of global sea surface temperatures (SSTs) for the three decades 2011-2040. The internal decadal component is derived by harmonic wave expansion analyses based on the quasiperiodic evolution of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO), as obtained from observational SST datasets. Furthermore, the external decadal component induced by anthropogenic forcing is assessed with a second-order fit based on the ensemble of projected SSTs in the experiments with multiple coupled climate models associated with the third Coupled Model Intercomparison Project (CMIP3) under the Intergovernmental Panels on Climate Change (IPCC) Special Reports on Emissions Scenario (SRES) A1B. A validation for the years from 2002 to 2010 based on a comparison of the predicted and the observed SST and their spatial correlation, as well as the root mean square error (RMSE), suggests that the approach is reasonable overall. In addition, the predicted results over the 50°S-50°N global band, the Indian Ocean, the western Pacific Ocean, the tropical eastern Pacific Ocean, and the North and the South Atlantic Ocean are presented.

Improving Energy Performance of Water Allocation Networks Through Appropriate Stream Merging

Water-using operations in the process industry have demands for water usually both on water quality and temperature, and the existing mathematical models of heat exchange networks cannot guarantee the energy performance of a water network optimal. In this paper, the effects of non-isothermal merging on energy performance of water allocation networks are analyzed, which include utility consumption, total heat exchange load, and number of heat exchange matches. Three principles are proposed to express the effects of non-isothermal merging on energy performance of water allocation networks. A rule of non-isothermal merging without increasing utility consumption is deduced. And an approach to improve energy performance of water allocation network is presented. A case study is given to demonstrate the method.

Effect of ageing temperature on precipitation of A1-Cu-Li-Mn-Zr alloy

The precipitation behaviors of an A1-Cu-Li-Mn-Zr alloy at different ageing temperatures （120, 160 and 200 ~C） were investigated using Vickers hardness measurements and transmission electron microscopy （TEM） characterization. Age hardening curves show an increase in precipitation kinetics with increasing ageing temperature. The results of TEM show that for the samples peak aged at 120 ~C, the amount of g＇ （A13Li）, GP zones/0＇ （A12Cu） and Z （A15Cu6Li2） phases is obviously higher than that of T1 （A12CuLi） precipitates; while the samples peak aged at 160 and 200 ~C are usually dominated by T1 phase with a minor fraction of GP zones/0＇ and g＇, and the Z phase almost does not form. In addition, quantitative analysis on the T1 platelets demonstrates that the samples peak aged at 200 ~C have larger plate diameter and smaller area fraction of T1, as compared to the samples peak aged at 160 ~C. Correspondingly, the possible reasons for such phenomena are discussed.

Preventing Coal and Gas Outburst Using Methane Hydration

According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in the coal seams to form hydrate. The paper analyzes the feasibility of forming the methane hydrate in the coal seam from the several sides, such as, temperature,pressure, and gas components, and the primary trial results indicate the problems should be settled before the industrialization appliance realized.

Effects of heat treatment conditions and Y-doping on structure and phase transition temperature of VO2 powders

The VO2 powders were prepared by hydrothermal synthesis.The effects of heat treatment conditions and Y-doping on the structure and phase transition temperature of VO2 were studied.The XRD,SEM and TEM results show that the heat treatment temperature has a significant effect on the crystal transformation of VO2 precursor.Increasing temperature is conducive to the transformation of precursor VO2(B)to ultrafine VO2(M).The Y-doping affects the structure of VO2.Y^3+can occupy the lattice position of V4+to form YVO4 solid solution,which can increase the cell parameters of VO2.Due to the lattice deformation caused by Y-doping,the aggregation of particles is prevented,and the grain is refined obviously.DSC curves show that Y-doping can reduce the phase transition temperature of VO2(M).After adding 9 at.%Y,the phase transition temperature can be reduced from 68.3 to 61.3℃.

Effects of temperature and phosphoric acid addition on the solubility of iron phosphate dihydrate in aqueous solutions

As important controlling factors for the synthesis of iron phosphate materials by liquid-phase precipitation, the solubilities of iron phosphate dihydrate were systematically measured at H3PO4 concentrations from 1.13 wt% to 10.7 wt% temperature from 298.15 to 363.15 K, and atmosphere pressure in this work. The solubility was found to increase 5 orders of magnitude or more with increasing the concentration of phosphoric acid, and de- crease 1 to 2 orders of magnitude with increasing the equilibrium temperature. The phosphoric acid addition and temperature were found to affect the solubility of iron phosphate dihydrate by the formation or dissociation of coordination species, which could further accelerate the phase transformation from the amorphous iron phosphate dihydrate to orthorhombic iron phosphate dehydrate by dissolution-recrystallization mechanism. The high dependences of the solubility of iron phosphate materials on HsPO4 concentration and temperature were also well predicted by calibration equations, which are meaningful for quantitatively understanding the precipitation process and sequential crystalline structure transformation and pursuing a rational strategy for syn- thesizing specific iron phosphate materials.