Spark plasma sintering is a rapid, low⁃temperature, high⁃density sintering technique that facilitates the fabrication of dense compacts while mitigating excessive grain growth and insufficient densification. This study systematically investigated the effects of sintering pressure on the microstructure and thermophysical properties of Al⁃0.6Si composites prepared by spark plasma sintering. The results show that sintering pressure strongly influences the properties of high⁃silicon aluminum composites. At a sintering pressure of 40 MPa, the Al⁃0.6Si composite exhibits the densest microstructure and the smallest average silicon⁃phase size. Its thermal conductivity is 130.35 W/(m·K), thermal expansion coefficient is 8.51×10⁻⁶ K⁻¹, Vickers hardness is 329.2 HV, density is 2.394 3 g/cm³, and relative density reaches 96.93%. These results demonstrate that optimizing the sintering pressure is an effective route to preparing high⁃performance composites for electronic packaging and provides process guidance for their fabrication.

Due to the high storage capacity and multiple electron?transfer chemistry of sulfur (S), Li?S battery with virtues of high theoretical capacity/energy density, eco?friendliness and abundant supply has been considered as one of the most promising candidates for next?generation battery systems. The capacity of Li?S battery is much higher than that of traditional metal oxide cathode?based lithium?ion battery, which is regarded as the highest capacity of solid?state cathode?materials at current stage. As a vital component of Li?S battery, separator plays a profound role in resolving crucial issues (e.g., shuttling effect, volume expansion, poor conductivity and metal dendrites, etc.) of Li?S battery. So far, some pioneering works have been reported in the exploration of separators for Li?S battery. On this basis, covalent organic frameworks (COFs), possessing the advantages of low density, high porosity, well?defined structure, designable structure and functions, is a kind of potential materials for the functional modification of Li?S battery separators. This review will summarize the reported works about COFs in Li?S battery separators including their structural characteristics, preparation?methods, application forms and battery properties. It will also provide a brief perspective for the applications of COFs in Li?S battery separators and hope that it might give new insights for scientists in related fields.

Based on the discrete element method, the transport and internal force problem of the double screw conveyor was studied by using the discrete element analysis EDEM software. According to the Hertz contact theory, the contact models of material particles and devices were established, and the influence of the double screw conveyor on the transportation characteristics of the material particles under different physical and geometric parameters was analyzed.The results show that the movement of particles in the conveyor is mainly in a straight line, with the circumferential movement as the auxiliary； the change of the wheelbase has a great influence on the material conveying characteristics of the conveyor. With the increase of the wheelbase, the mass flow rate increases gradually, and the particle force in the central area decreases gradually.

In this paper, a novel hydrophobic modified cationic polyacrylamide flocculant P(AM⁃DAC⁃APG) was successfully synthesized by copolymerization of acrylamide (AM) as the main monomer, acryloxyethyl trimethyl ammonium chloride (DAC) as the cationic monomer and alkyl glycoside (APG) as the hydrophobic monomer, initiated by low⁃pressure ultraviolet light. FTIR, SEM and 1H⁃NMR were used to observe and analyze its chemical structure and surface morphology. The effects of other factors such as total monomer concentration and initiator concentration on the polymerization were studied. Optimum polymerization conditions were confirmed as total monomer concentration of 35.0%, initiator concentration of 0.2%, illumination time of 90 min, m（AM）/m（DAC）of 3, hydrophobic monomer concentration of 2.0%, urea concentration of 3.0%. The novel hydrophobic modified polyacrylamide flocculant with intrinsic viscosity and cationic charge density of 1 384.8 mL/g and 5.091 mmol/g was obtained under these conditions.

MnFe2O4/TiO2 Fenton⁃like photocatalyst was successfully prepared by sol⁃gel method, the structure and morphology of the sample were characterized by XRD, SEM and UV⁃vis. MB was used as the target pollutant for degradation, and the photocatalytic properties of products with different doping amounts were investigated in visible light. The results show that: The degradation rate of TMF Fenton⁃like photocatalytic reaction to MB is up to 96.8%, under the optimum conditions, in the iodine⁃tungsten lamp with a light source of 300 W, the doping amount of MnFe2O4 to TiO2 is 2%, the mass of catalyst is 60 mg, pH=11, and the concentration of H2O2 is 8 mmol/L . Under the same conditions, compare with the undoped pure TiO2, the catalytic performance of MnFe2O4/TiO2 for MB under visible light is significantly improved.

The channel prediction of Fuyu reservoir has been always highly emphasized. Using the conventional seismic attribute to predict channel is difficult to achieve the precision requirements because of the complex fault and the fast lithofacies phase in Fuyu reservoir. Aiming at this weak problem, the method of combing gray correlation analysis and support vector machines is used to establish a set of technical process which is suitable for the prediction of fluvial reservoirs under complicated geological conditions. In Fuyu test area in X reservoir of Daqing oilfield as an example, firstly, conventional seismic attribute of sedimentary unit dimensionless, obtained by the method of gray correlation analysis of the seismic attribute correlation factor, the greater the degree of correlation, indicating that the response probability of attribute river is higher. On this basis, the optimal correlation factor sequence a accumulation of large properties, first order accumulative sequence is generated, used as the input into the support vector machine training sample, so as to complete construction of support vector machine river forecast model. Drilling confirms that the prediction based on Gray Correlation Support Vector Machine has a larger coincidence rate of drilling. Combined with the superiority of seismic inversion to predict the channel sand boundary, supplemented by data of core, well logging and mud logging data to complete sedimentary microfacies in X Test Area Fuyu reservoir. Meanwhile, drilling further confirms the reliability of predicting channel and then the industrial oil flow well is successfully obtained. The results of comprehensive research show that this method is suitable for high channel prediction accuracy. It can be used as a better channel prediction method under complicated geological conditions.

This paper studied the preparation of a kind of environmentally friendly aluminum alloy wire passivation solution. During the experiments, the composition of the passivation solution has been studied, and the optimum content of each component has been achieved. In addition, the effect of passivation technical conditions on the passivation performance has been examined. The results show the optimal composition of passivation solution as follows: 6%~8% of w(sulfuric acid), 4%~6% of w(sodium sulfate),6×1 0-4~8×1 0-4、 of w(copper sulfate), and 2%~3% of w(urea); the optimal passivation technical condition is: passivation temperature 30~40 ℃, and passivation time 10~20 s.For the aluminum alloy wire,the performance of the passivation solution was comparable to the chromate passivation solution passivation.

Aiming at the leakage and diffusion problems of the 35 MPa ultrahigh pressure gas pipeline in densely populated area, the FLUENT software in the threedimensional numerical simulation was used under different climate conditions in the deep buried gas pipeline leak case. And the axial and surface safety area of the hydrogen sulfide and methane was provided when the ultrahigh pressure gas pipeline had leaked under the conditions of different wind speeds. Because of the buoyancy, the natural gas developed in the upward form during the process of diffusion. The wind speed and pressure had different effects on the diffusion process under the different environments. The result was that as the wind speed and pressure was higher, the natural gas was spread to the farther distance. This increased the lowest explosive limit and alerted the concentration range of the natural gas. The research result could provide the effective basis to the stuffs and security management in leakage spot.

Highpressure steam injection method is the major method of exploitation of heavy oil reservoir. In steam injection pipe network, the fluid in steam, liquid and solid phases scoured the bend and led to leakage. Based on the turbulence models, multiphase flow models, discrete phase models and erosion models ,and considering the mutual coupling of the different phases, the numerical simulation of the flow of the three phases in the bend flow was established. The results show that in the steam injection pipelines，as bending degree of the bent pipe increased， the distribution and wall wear area of the liquid phases and particle phases moved backwards step by step，and the value increased accordingly. Moreover, the increase of liquidphase volume fraction in the pipe wall could effectively reduce the surface corrosion of the solid phase.

A chlorinefree composite as oilwell cement early strength agent named LL was developed. Combining organic acids A, alcohol amines B and nitrate compound C in a certain ratio, the compressive of cement stone in 6 h as the strength examining index can be designed in optimization test using the orthogonal method. The optimum formula determined by orthogonal was as follows: the weight of organic acids D is 1.0% based on cement，the weight of alcohols amines E is 0.04%，the weight of nitrates F is 4%. Under the optimum proportion, and the performance test of early strength agent LL was carried out after its addition of 2.5% in the cement. The ratio of the thickening time of early strength agent LL slurry to cement slurry is 0.436 less than 0.5, and the compressive strength of cement stone 6 h (39 ℃ and atmospheric pressure) is 11.0 MPa more than 4.0 MPa, they are all meeting the requirement of early strength agent industry standard SY/T5504.4—2008. And it has a good compatibility with the homemade retarders MAM, dispersants FASA and fluid loss AS.

In flow measurement field, the differential pressure flowmeter was used widely. Adopting highprecision calibration system to calibration differential pressure flowmeter，the flow coefficient of the flowmeter was obtained. And the error analysis of the flow coefficient with scientific method was made to draw calibration result and its error accuracy. The results show that the measurement errors of the flowmeter followed the standard, and the flowmeter could be used for the actual measurement in the field.

In Gas injection pipeline the erosion wear of solid particle in cone throttling element was an important factor for causing failure. In this paper, made by the method of computational fluid dynamics finite volume was used for the numerical simulation of the erosion abrasion and the degree to erosion abrasion and the relationship of the shear stress with the injection volume, particle diameter and the particle content change were researched. The results showed that as the particle diameter increased, the tube wall wear relatively focused on the high speed area, the degree to the cone wear was increased. When the flow rate increased, erosion rate and shear stress were increased. And when the particle concentration increased, the quantity of the erosion abrasion was increased. So the research to the throttling element antifriction corrosion study and throttling element failure prediction would provide the theory guidance.

Spiral separator has the characteristics of simple structure, light weight and wellseparated effect, which becomes one of the commonest centrifugal separator currently. CFD method was used to simulate wateroil separation in spiral pipe under the condition of a variety of entrance velocities and cross section shapes, and obtained a wateroil separation result that for a spiral pipe with circular cross section shape, the separation effect became sharper as the velocity increased, and too fast or too slow velocity both impacted the effect. When they were equal cross section areas, circular had a better effect than laddershaped and square cross sections. Based on the numerical simulation, the result provided a certain theoretical basis for spiral pipe technology.

The contents of eleven mineral elements（Mg，Al，Ca，Mn，Fe，Cu、Zn，K，Na，Co and Pb） in twentythree green tea samples from different areas were analyzed by microwave plasma torch atomic emission spectrometry (MPTAES). Then principal component analysis (PCA) and cluster analysis (CA) were applied to differentiate the geographical origins of these tea. The result indicated that This method can discriminate the geographical origins of these tea from AnHui、ZheJiang、SiChuan and JiangXi, the classification performance was clearly, the content of the mineral elements in teas were good chemical descriptors for differentiating their geographical origins.

As the cement slurry hydration speed is slow, the curing time is long and the increase of cement early compressive strength is slow in the low temperature cementing of conductor and surface casing, it is easy to result in oil, gas and water invasion which impairs cementing quality and operation safety. In view of the fact that the accelerator is lack in cementing of low temperature shallow formation currently at home, some accelerators have poor effectiveness and significant negative impact on slurry rheology etc, a new compound accelerator WSA1 was selected by laboratory study. The performance of slurry that mixed WSA1 was systematically evaluated. The result shows that the accelerator WSA1 can enhance the hydration of oil well cement, shorten the thickening time of cement slurry and significantly improve the early compressive strength of cementstones, which all accord with the requirement of the accelerator evaluation criterion. When WSA1 addition amount is 3%, the thickening time of cement slurry can be shortened more than 50%, the 6 h strength of cementstones enhanced from 3.2 MPa to 11.3 MPa and the 24 h strength of cementstones enhanced from 24.3 MPa to 46.1 MPa. Accelerator WSA1 is a kind of highperformance compound accelerator, which can be used in low temperature shallow formation and has no effect on the initial consistency and rheological parameter of cement slurry. 

Adsorption removal of basic nitrogen compounds in the shale diesel with USY molecular sieves was investigated. The effect of adsorption time, temperature and adsorbent/oil weight ratio on the nitrogen removal rate was studied, and found that highest nitrogen removal rate (30.73%) are obtained under the following conditions: the adsorbent to oil weight ratio of 0.03, the adsorption temperature of 120 ℃, the adsorption time of 30 min. Simultaneously, the static equilibrium adsorption capacity can reach 27.2 mg/g. After regenerated for several cycles, the removal rate of basic nitrogen compounds is still more than 25%. Adsorption kinetics suggested that adsorption denitrogenation follows the second-order equation.

The measurement uncertainty was estimated for the determination of calcium and magnesium in milk using microwave plasma torch atomic emission spectrometry (MPT-AES) and the uncertainty parameters were discussed and compared in detail. The results show that the "whole method" performance parameters, such as precision and recovery, and sampling are the three main contributors to uncertainty. In addition, the content of calibration solution is the main contributor to measurement uncertainty in the determination of magnesium. When coverage factor k=2 and confidence level approximately 95%, the expanded uncertainties were determined as 18.6 and 3.2 mg/L for Ca and Mg, respectively.

AMPS, diethanolamine, and calium nitrate as materials of early-strength accelerator were prepared and characterized. Orthogonal experiment was utilized to optimize optimum content of early-strength accelerator. The samples were characterized with powder X-ray diffraction (XRD) and SEM. It is shown that when the weight of 5% early agents were introduced, the 1, 3 and 7 d of cement strength improved by 15.2%、14.3%、16.7%, respectively, which is also a further development in the high temperature.

The AS fluid loss additive was formulated with sodium lignosulfonate and the copolymers obtained by radical polymerization with AMPS and AM as raw material. Orthogonal tests were designed for optimizing the synthetic process of the fluid loss additive AS, and the performance of this fluid loss additive was systematically evaluated. API filtration in saturated salt solution at 150 ℃ is 96 mL; API filtration can be controlled within 50 mL when adding AS between 3% and 8% (weight percentage) at 120 ℃; Meanwhile AS has good compatibility with other additives. Sodium bicarbonate was used to adjust the PH and discharge oxygen of device used in the synthesis process. No nitrogen was needed as protective gas, which simplified the synthesis process. The sodium lignosulfonate derives from the wastewater of paper mill, so it not only reduces the cost but also protects the environment.

The thickening agent of graft copolymer was synthesized by carboxymethyl starch (CMS) and acrylamide (AM) under the condition of initiator. The optimum synthesis conditions were investigated by orthogonal experiment design. The structure of the product which was obtained under the best reaction conditions was characterized by FT-IR, and the salt sensitivity and temperature stability, shear stability and anti-ageing of the graft copolymer solution in different slurry were measured by rotational viscometer. The results show that the viscosity can reach 280 mPa·s under the reaction conditions as follows: the reaction temperature 60 ℃, the reaction time 7 h, the mass ratio of CMS to AM 1∶6 and the initiator addition amount 0.9%. The CMS-AM graft copolymer in different slurry shows excellent the salt sensitivity and temperature stability, shear stability and anti-ageing, which can satisfy the needs of oil field fracturing fluid for thickening agent.

The method for the determination of copper, zinc, manganese, iron, magnesium, calcium in wild pine tea by microwave plasma torch-atomic emission spectrometry (MPT-AES) was developed. The effect of nitric acid concentration in the sample solution and co-ionized elements on the emission intensity of copper, zinc, manganese, iron, magnesium and calcium was investigated in detail. The experimental conditions were optimized and showed that the detection limits of metal Cu, Zn, Mn, Fe, Mg and Ca are 3.6, 7.7, 6.1, 14.1, 0.5 and 0.9 ng/mL, respectively, and the RSD of the method is between 1.05%～6.46%, the recoveries are 97.25%～103.37%. This demonstrated that the proposed method is simple, accuracy and efficient, providing a well-established analytical method．

The symplectic geometry characterization of second order singular J- symmetric differential operators was investigated. By constructing different quotient spaces, self-adjoint extensions of second order J- symmetric differential operators were studied using the method of symplectic geometry. Then classification and description of complete J-Lagrangian submanifold corresponding with self-adjoint domains of second order differential operators were obtained.

 

The conventional fuzzy C means clustering algorithm couldn't consider any spatial information, and it is no good to noise image segmentation. In order to overcome this shortcoming, a fuzzy C-means clustering algorithm using spatial information for image segmentation was proposed. The new algorithm could make full use of pixels neighborhood feature by improving the membership function, furthermore local information and non local information were introduced in dissimilarity of data and clustering center. Experimental results show that this method is effective in image segmentation, and has better performance of resisting noise.

Flavonoids were extracted from codonopsis pilosula with microwave-assisted method, and its content was determined by spectrophotograpy. Two methods with NaNO2-Al(NO3)3 or AlCl3 as the chromogenic agent were performed and the precision, stability, reproducibility and recovery ratio of the two methods were studied. The results show that the AlCl3 colorimetric determination of flavonoids in codonopsis pilosula was simple, convenient, accurate and reliable as compared with the NaNO2-Al(NO3)3 colorimetric determination method.

 

 

Ordinary alloy steel samples were digested in a microwave digestion system. The parameters of microwave digestion (including system of acid, time, power, and pressure) were optimized. Extraction method was used to eliminate the interference of Cu、Fe、Mn ion on Ni from the ordinary alloy steel samples. The nickel content in the samples was determined by ordinary pressure spectroscopy method. The relative error of microwave digestion is less than 1.67% and the RSD(n=5) is less than 1.24%. It is less than general method that is relative error of 2.67% and RSD（n=5）of 3.72%.

The cucumber seed oil was obtained by Soxhlet extraction with the seed as the raw material. Soxhlet extraction of oils from cucumber-seed was studied with single factor test, and the yield of cucumber-seed oils was the evaluation index. The influences of extracting solvent, extracting temperature, extracting time, the rate of raw material , and solvent on the yield of cucumber-seed oils were investigated respectively. The optimal conditions of Soxhlet method were obtained: extracting temperature is 68.5 ℃, extracting time is 8 h, the mass concentration of cucumber-seed oil is 0.071 g/mL, optimal extracting solvent is n-hexane. The oil yield reaches 40.38% under the optimal conditions.

The content of copper, zinc and nickel in waste active muddy soil were measured by microwave digestion-fire atomic absorption spectrometry（FAAS）, and the optimization condition was studied. The results are compared with that of acid digestion at atmosphere. The results of the above two method are similar. The experiment results show that two steps are suggested in microwave digestion. Microwave power is 340 W, constant time is 10 min, and microwave pressure is 0.4 MPa and 0.45 MPa in each step, respectively. Linear range of copper, zinc, nickel is 0～20，0～12 and 0～25 mg/L respectively. Detection limit of copper, zinc, nickel is 0.300 0，0.030 7 and 0.010 6 mg/L respectively. Average recovery of copper, zinc, nickel in waste active muddy soil samples is 97.6%,98.9% and 96.5% respectively, and relative standard deviation is 1.74%,0.95% and 1.00% respectively.