库车山前低返速固井钻井液低剪切流变特性研究

针对塔里木库车山前超高压气井四开低返速固井过程中钻井液实际处于低剪切流动状态和现场采用全剪切速率流变测试数据拟合其流变模式和流变参数的不足,研究了库车山前钻井液在低返速固井过程中的低剪切速率范围、对应的流变模式和流变参数及其对注水泥环空流动摩阻系数的影响。研究结果表明,在低返速固井过程中,钻井液的剪切速率明显小于1022 s^(−1)(600 r/min),且对应的流变模式及流变参数与全剪切速率范围内的差异巨大,导致基于二者的注水泥环空摩阻系数也存在较大的差异,从而影响对注水泥环空压力计算的精确控制。为此,对低返速固井,应根据其低剪切速率范围内的流变模式和流变参数计算环空流动压耗,控制固井排量,提高低返速防漏固井的成功率。

Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel(Prymnesiophyceae) isolated from the South China Sea

Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth ofP. globosa （Is） was 60 μmol/（m^2·s）, which was lower than those of other harmful algal species （70-114μmol/（m^2·s））. A moderate growth rate of 0.22/d was observed at 2 μmol/（m^2·s） （the minimum irradiance in the experiment）, and photo-inhibition did not occur at 230 μmol/（m^2·s） （the maximum irradiance in the experiment）. Exposed to 42 different combinations of temperatures （10- 31 ℃） and salinities （10-40） under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24℃ and 35, and 27℃ and 40. The optimum growth rates （〉0.80/d） were observed at temperatures ranging from 24 to 27℃ and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20℃ to 31℃ and salinities from 20 to 40, it could not grow at temperatures lower than 15℃ or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain ofP. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year.

Analysis of penetration acceleration signal based on wavelet transformation

In order to analyze the composition and frequency distribution of acceleration signal in the process of projectile penetrating,this paper uses wavelet transform to decompose penetration acceleration signal to get the distribution of penetration acceleration signal in different frequency bands.Compared with the ideal acceleration signal curve and its characteristics,it can be concluded that the frequency range of the acceleration signal in the axis of the projectile and the vibration frequency range of the projectile are 31.25-62.5kHz and 62.5-125 kHz,respectively.Finally,the penetration acceleration signal curve is obtained by Simulink.

Pyrolysis of Huadian oil shale by electrical heating on different heating rates

The electrical heating experiments on oil shale sample from Huadian of Jilin were carried out by the pyrolysis method at three different heating rate 2℃/min, 5 ℃/min and 10 ℃/min in the temperature range of 30℃ -750℃. Heating rate 2 ℃/rain is considered low, while intermediate one covers the range 5 ℃/min and high heating rate is 10℃/min. The controlling parameters studied were the final pyrolysis temperature and the influence of the heating rate as well as type. The heating rate has an important effect on the pyrolysis of oil shale and the amount of residual carbon obtained therefore. It is found that increasing the heating rate and py- rolysis temperature also increases the production of oil and the total weight loss. Higher heating rates resulted in higher rates of accumulation. The rate of oil and water collection passed through the maximum of different heat- ing rates at different pyrolysis temperatures. Heating rate affected density, oil conversion and oil yield.

Kinetics of esterification of methanol and acetic acid with mineral homogeneous acid catalyst

In this work, esterification of acetic acid and methanol to synthesize methyl acetate in a batch stirred reactor is studied in the temperature range of 305.15–333.15 K. Sulfuric acid is used as the homogeneous catalyst with concentrations ranging from 0.0633 mol·L-1to 0.3268 mol·L-1. The feed molar ratio of acetic acid to methanol is varied from 1:1 to 1:4. The influences of temperature, catalyst concentration and reactant concentration on the reaction rate are investigated. A second order kinetic rate equation is used to correlate the experimental data. The forward and backward reaction rate constants and activation energies are determined from the Arrhenius plot.The developed kinetic model is compared with the models in literature. The developed kinetic equation is useful for the simulation of reactive distillation column for the synthesis of methyl acetate.

Creep behavior of ageing hardened Mg-10Gd-3Y alloy

Tensile creep behaviors of the ageing hardened Mg-10Gd-3Y alloy(referred to GW103)were investigated at temperatures up to 300℃.The extruded-T5 specimen exhibited high creep resistance,i.e.the low steady-state creep rate and long creep rupture time,while the better creep properties were observed in the cast-T6 one.The low steady-state creep rate of 1.71×10- 9s -1is obtained at 200℃and 80 MPa for the extruded-T5 GW103 alloy.In addition,the microstructure development of GW103-T5 alloy was also examined after creep exposure at different temperatures.On the other hand,the stress exponent and activation energy were studied in the temperature range of 200-300℃for the extruded-T5 specimens,and the creep mechanism was also discussed.

Hot-compression behavior of Al alloy 5182

Hot-compression of aluminum alloy 5182 was carried out on a Gleeble- 1500 thermo-simulator at deformation temperature ranging from 350 ℃ to 500 ℃ and at strain rate from 0.01 s^-1 to 10 s^-1 with strain range from 0.7 to 1.9. The microstructures and macro-textures evolution under different conditions were investigated by polarized optical microscopy and X-ray diffraction analysis, respectively. The basic trend is that the hot-compression stress increases with the decrease of temperature and increase of strain rate, which is revealed and elucidated in terms of Zener-Hollomon parameter in the hyperbolic sine equation with the hot-deformation activation energy of 143.5 kJ/mol. An empirical constitutive equation is proposed to predict the hot-deformation behavior under different conditions. As deformation temperature increases up to 400 ℃, at strain rate over 1 s^-1, dynamic recrystallization （DRX） occurs. Cube orientation { 100} （001） is detected in the recrystallized sample after hot-compression.

Kinetics of the Reaction Between Boron Trifluoride Methanol Complex and Sodium Methoxide to Produce Enriched ^(10)B Methylborate

The relation of boron trifluoride concentration with conductivity in boron trifluoride methanol solution(BF_3-CH_3OH)was power exponent fitted in low concentration range. The kinetics of the reaction between boron trifluoride methanol complex and sodium methoxide to produce enriched ^(10)B methylborate was proposed based on a detailed mechanism study, and was verified by acid-base titration method and conductivity method. It was found that this reaction is first order reaction and the rate constant is 0.022 min^(-1) at 338 K(65 ℃), the activity energy is 65 k J/mol. In addition, it was found that the conductivity method is more feasible to measure the kinetic curve than acid-base titration method.

Effects of Temperature on the Deposition Rate of Supersaturated Silicic Acid on Ca-type Bentonite Tsuyoshi Sasagawa, Taiji Chida and Yuichi Niibori

Na-type bentonite is commonly used as a tunnel backfilling material to prevent groundwater and radionuclide migration during the construction of a geological disposal system for high-level radioactive waste in Japan. However, host rock fractures with strong water flow can develop groundwater paths in the backfilling material. Especially, the alteration to Ca-type bentonite causes degradation of the barrier performance and accelerates the development of groundwater paths. Additionally, using cementitious materials gradually changes pH between 13 and 8. High alkaline groundwater results in high solubility of silicic acid; therefore, silicic acid is eluted from the host rock. Downstream, in the low alkaline area, the groundwater becomes supersaturated in silicic acid. This acid is deposited on Ca-type bentonite, thus leading to the clogging of the groundwater paths. In the present study, we investigate the silicic acid deposition rate on Ca-type bentonite under 288-323 K for depths greater or equal to 500 m. The results indicate that temperature does not affect the silicic acid deposition rate up to 323 K. However, in this temperature range, the deposition of silicic acid on Ca-type bentonite in backfilled tunnels results in clogging of the flow paths.

Kinetic analysis of experiment data for the formation of C.I.Acid Blue 9 leuco compound

A systematic study of the synthesis of C.I.Acid Blue 9 leuco compound in water is reported.The kinetic analysis of experimental data for the condensation reaction between 2-formylbenzenesulfonic acid sodium and N-ethyl-N-(3'-sulfonic acid benzyl) aniline obtained at four different temperatures ranging between 85 and 100°C is discussed.It is shown that the reaction followed second-order rate kinetics.The overall rate constant(k) increased with the increase of temperature.On the basis of the value of k,activation energy(E_a) of the reaction was evaluated.Importantly,it is found that reactant concentration has great effect on the formation of C.I.Acid Blue 9 leuco compound,implying that it is not enough to improve the conversion of N-ethyl-N-(3'-sulfonic acid benzyl) aniline by only prolonging reaction time in the late period of the reaction.

多维应力状态下裂纹扩展规律研究

通过对具有预裂纹的圆柱形带缺口试件的高温低周疲劳试验，并借助于带有非硬化区的双曲面模型程序，进行了轴对称问题的循环应力、应变计算。研究表明三维应力状态下，裂纹扩展速率ｄａ／ｄＮ可用当量Ｊ积分范围ΔＪｅｑ及当量应变能密度ΔＷｅｑ进行表征。

Study Rheological Behavior for Rapeseed Oils

Rheological behavior of this article presents rapeseed oil. Dynamic viscosity of rapeseed oil was determined at temperatures between 40 ℃-90 ℃ and shear rates ranging from 3.3-120 s1. All types of oils studied Bingham fluid behavior in the temperature range from 313-363 K. Correlation coefficients have similar values to one for all oils studied.

Hydrolysis Kinetics of 2-Pyridinecarboxamide, 3-Pyridinecarboxamide and 4-Pyridinecarboxamide in High-Temperature Water

A kinetic study is reported here on hydrolysis of three pyridinecarboxamides in high-temperature water in the temperature range of 190-250℃ at 8 MPa. 2-Pyridinecarboxamide, 3-pyridinecarboxamide and 4-pyridinecarboxamide hydrolyze to corresponding picolinic acids. 2-Picolinic acid is further decarboxylated to pyridine. Experiments at different temperatures show that the first-order rate constants display an Arrhenius behavior with activation energies of （110.9 ±2.3）, （70.4 ± 2.1） and （61.4 ± 1.8）kJ.mo1-1 for 2- pyridinecarboxamide, 3-pyridinecarboxamide and 4-pyridinecarboxamide, respectively. These kinetic parameters for pyridinecarboxamide hydrolysis are more reliable and accurate than those from the consecutive hydrolysis of cyanopyridines.

Modulating the mean residence time difference of wide-size particles in a fluidized bed

For non-catalytic gas-solid reaction, it is desirable to match the mean residence time （MRT） of particles and complete conversion time （tc） in a fluidized bed. In this study, the MRT differences （MRT ratios） between the coarse particles and the fine particles were investigated in a continuous fluidized bed with a side exit by varying the superficial gas velocity, feed composition and particle size ratio, The results show that the MRT ratio increases firstly and then decreases with increasing the gas velocity. By controlling the gas velocity and the feed composi tion of coarse particles, the MRT ratio can be modulated from 1.8 to 10.5 at the gas velocity of 1.0 m-s -1 for the binary mixture with the size ratio of 2.2. The MRT ratio can reach to - 12 at the gas velocity of 1.2 m. s for the particle size ratio of 3.3. The present study has endeavored to obtain fundamental data for an effective plant operation to meet the need of synchronously complete conversion of particles with different sizes during the film diffusion controlling reaction.

Analysis and evaluation of band-limited ray tracing method

From the analysis and the contrast of band-limited ray tracing method based on Kirchhoff integral, it was found that the method performs many approximations in the derivation process and omits the derivative term of the phase factor in the Kirchhoff integral. Numerical calculations and analysis show that the omission of cor-relation terms in Kirchhoff integrals has a non-negligible effect on the calculation results, and the different terms in the Kirchhoff integral have different effects on different frequency ranges. The method can be applied to ve-locity models containing complex interfaces without changing waves and continuous media. the velocity model and can be extended to elastic waves and continuous media.

Hot compression deformation characteristics of Mg-Mn alloys

The hot deformation behaviors of solution treated Mg-1.8Mn-0.4Er-0.2Al alloys were investigated by means of compression tests on Gleeble-1500 in strain rate range of 0.01-10s-1,deformation temperature range of 250-450℃ and a true strain of 0.6.The constitutive relationships among flow stress,strain rate and deformation temperature were described by Arrhenius-type equations,based on the fact that the material constants could be calculated under a wide range of strains.The results show that the flow stress of the experimental alloy decreases with temperature increasing and strain rate decreasing.Under the experimental conditions,the products of constant α and n in the constitutive equation are stable within certain strains,and the deformation activation energy ranges from 160 to 220 kJ/mol.It is proved that the values of calculated flow stress are close to the experimental results with average error of 2.01%.

温控双轴转台的电控设计与实现

针对温控双轴转台的功能要求介绍了转台开发的主要技术难点,进行电控系统设计并通过分析与实验,最终达到用户指标需求。

Theoretical study of mechanism and kinetics for the addition of hydroxyl radical to phenol

The reaction mechanism and kinetics for the addition of hydroxyl radical （OH） to phenol have been investigated using the hybrid density functional （B3LYP） method with the 6-31＋＋G（2dp, 2dr） basis set and the complete basis set （CBS） method using APNO basis sets, respectively. The equilibrium geometries, energies, and thermodynamics properties of all the stationary points along the addition reaction pathway are calculated. The rate constants and the branching ratios of each channel are evaluated using classical transition state theory （TST） in the temperature range of 210 to 360 K, to simulate temperatures in all parts of the troposphere. The ortho addition pathway is dominant and accounts for 99.8%-96.7% of the overall adduct products from 210 to 360 K. The calculated rate constants are in good agreement with existing experimental values. The addition reaction is irreversible.