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Chinese Journal of Chemical Engineering 2018年第5期26卷 1012-1021页

作者： muhammad Sarfraz m. ba-Shammakh Department of Polymer and Process Engineering University of Engineering and Technology Lahore 54890 Pakistan Department of Chemical Engineering King Fahd University of Petroleum and Minerals Dhahran 31261 Saudi Arabia

Water stable mixed-matrix membranes(mmms) were developed to help control the global warming by capturing and sequestrating carbon dioxide(CO_2) from post-combustion flue gas originated from burning of fossil *** of different compositions were prepared by doping glassy polymer Ultrason? S 6010(US) with nanocrystals of zeolitic imidazolate frameworks(ZIF-300) in varying degrees. Solution-casting technique was used to fabricate various mmms to optimize their CO_2 capturing performance from both dry and wet gases. The prepared composite membranes indicated enhanced filler-polymer interfacial adhesion, consistent distribution of nanofiller, and thermally established matrix configuration. CO_2 permeability of the membranes was enhanced as demonstrated by gas sorption and permeation experiments performed under both dry and wet conditions. As compared to neat Ultrason? membrane, CO_2 permeability of the composite membrane doped with 40 wt% ZIF-300 nanocrystals was increased by four times without disturbing CO_2/N_2 ideal selectivity. In contrast to majority of previously reported membranes, key features of the fabricated mmms include their structural stability under humid conditions coupled with better and unaffected gas separation performance.

关键词： Hydrophobic mmms ZIF-300 Gas permeation CO2 capture Permselectivity

The effect of propagation delay on the dynamic evolution of the Bitcoin blockchain

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Digital Communications and Networks 2020年第2期6卷 157-166页

作者： moustapha ba mODAL’X(Laboratoire de modélisation aléatoire)of UniversitéParis Nanterre(Paris X) MODAL’X is the Mathematics and Computer Sciences laboratory of UniversitéParis Nanterre(Paris X)ministerial label EA 3454UFR SEGMIdépartement Mathématiques-Informatique200 avenue de la République92000NanterreFrance

This paper analyzes the selfish-mine strategy in the Bitcoin blockchain introduced in 2013 by *** and *** strategy could be used by a colluding pool of miners to earn more than their fair share of the mining revenue and in consequence to force other honest miners to join them to decrease the variance of their revenues and make their monthly revenues more *** is a very dangerous dynamic that could allow the rogue pool of miners to go toward a majority by accumulating powers of news adherents and control the entire *** that the propagation delay of information between any two miners in the network,which is not negligible and follows a normal distribution with mean proportional to the physical distance between the two miners,and a constant variance independent of others'delays,we prove that no guarantee can be given about the success or failure of the selfish-mine attack because of the variability of information propagation in the network.

关键词： Blockchain Bitcoin mining Selfish-mine attack Propagation delay of information

移植物厚度对角膜内皮失代偿行简易后弹力层角膜内皮移植效果的影响

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中国组织工程研究 2025年第6期29卷 1199-1207页

作者：巴颜红高明宏陈颖欣中国人民解放军北部战区总医院辽宁省沈阳市110000

背景:研究表明较薄移植物视力恢复更快、排斥风险更低,国内缺乏对内皮移植术后不同植片厚度的临床疗效分析,因此,确定最佳移植物厚度对于提高手术疗效至关重要。目的:评价简易后弹力层剥离内皮角膜移植术后不同植片厚度对视力恢复及其... 详细信息

背景:研究表明较薄移植物视力恢复更快、排斥风险更低,国内缺乏对内皮移植术后不同植片厚度的临床疗效分析,因此,确定最佳移植物厚度对于提高手术疗效至关重要。目的:评价简易后弹力层剥离内皮角膜移植术后不同植片厚度对视力恢复及其他预后指标的影响。方法:选取2013年1月至2023年2月在北部战区总医院接受简易后弹力层剥离内皮角膜移植手术治疗的角膜内皮失代偿患者共72例(72眼),其中薄植片组(m)32例(32眼),厚植片组(≥100μm)40例(40眼)。随访1年,观察两组术前及术后1,3,6,12个月的最佳矫正视力,术后1年角膜内皮细胞数、角膜植片透明度、术后并发症、植片生存情况。结果与结论:①两组患者术后视力较术前均有显著提高,薄植片组患者术后3个月最佳矫正视力优于厚植片组(P0.05);③两组患者继发性青光眼、植片免疫排斥、植片移位等术后并发症发生率比较差异无显著性意义(P>0.05);④两组术后1年植片生存率比较差异无显著性意义(93.8%,92.3%,P>0.05);⑤结论:简易后弹力层剥离内皮角膜移植术是一种安全有效的角膜内皮移植手术方式,其术后疗效与传统后弹力层剥离内皮角膜移植术相似,而且植片植入方式更为简便。较薄植片能够更早提供最佳矫正视力,更早完成角膜重塑,因此在治疗角膜内皮失代偿疾病时,优先选择薄移植物来提高恢复时间。

关键词：后弹力层撕除角膜内皮移植术角膜内皮失代偿继发性青光眼植片移位原发移植失败植片排斥角膜内皮细胞数角膜移植

Characterization of Arithmetic Functions that Preserve the Sum-of-squares Operation

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Acta mathematica Sinica,English Series 2014年第4期30卷 689-695页

作者： Bojan baI Department of mathematics and Informatics University of Novi Sad

We characterize all functions f ： N → C such that f（m^2 ＋ n^2） = f（m）^2 ＋ f（n）^2 for all m, n ∈ N. It turns out that all such functions can be grouped into three families, namely f ≡ 0, f（n） = ±n （subject to some restrictions on when the choice of the sign is possible） and f（n） =±l/2（again subject to some restrictions on when the choice of the sign is possible）.

关键词： Arithmetic function functional equation sum of squares

Enzymatic Synthesis of Polycaprolactone:Effect of Immobilization mechanism of CALB on Polycaprolactone Synthesis

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Journal of Renewable materials 2018年第6期6卷 619-629页

作者： Yasemin Kaptan.m.Sc Yüksel Avcıbaşı-Güvenilir Istanbul Technical University Department of Chemical EngineeringIstanbul Technical University34469Maslak-Istanbul

Surface-modified rice husk ash was used as an inorganic support material for immobilization of Candida antarctica lipase B.(3-aminopropyl)trimethoxysilane was used for surface *** of CALB was performed via both physical adsorption and *** synthesis was carried out by using these immobilized enzymes,free enzyme and Novozyme 435®.molecular weight distribution of polymer samples was obtained by gel permeation chromatography(GPC)and chain structures of the polymer samples were observed by hydrogen nuclear magnetic resonance(1H-NmR).The highest monomer conversion is generally obtained by using cross-linked enzyme,around 90%.PDI values for all polymer samples were approximately 1.5 which can be considered as *** general cross-linked enzymes were better than physically adsorbed enzymes in terms of average molecular *** can be concluded that PCL can be synthesized with these immobilized enzymes with high molecular weight and low PDI values.

关键词： Candida antarctica lipase B cross-linking physical adsorption Polycaprolactone rice husk ash

On the Space bv_p(F) of Sequences of p-bounded Variation of Fuzzy Numbers

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Acta mathematica Sinica,English Series 2008年第7期24卷 1205-1212页

作者： zer TALO Feyzi ba■AR Fatih niversitesi Fen-Edebiyat FakltesiMatematik BlmBykekmece Kamps 34500-stanbulTrkiye

Recently, the space bvp of real or complex numbers consisting of all sequences whose differences are in the space lp has been studied by basar, Altay [Ukrainian math. J. 55（1）（2003）, 136-147], where 1 ≤ p ≤ ∞. The main purpose of the present paper is to introduce the space bvp（F） of sequences of p-bounded variation of fuzzy numbers. moreover, it is proved that the space bvp（F） includes the space lp（F） and also shown that the spaces bvp（F） and lp（F） axe isomorphic for 1 ≤ p ≤∞. Furthermore, some inclusion relations have been given.

关键词： sequence of fuzzy numbers space of difference sequences isomorphic spaces and inclusion relations

Surface nanostructure formation mechanism of 45 steel induced by supersonic fine particles pombarding

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Journal of University of Science and Technology Beijing 2008年第5期15卷 561-567页

作者： Dema ba Shining ma Changqing Li Fanjun meng Department of Remanufacture Engineering Academy of Armored Force Engineering Beijing 100072 China

By means of supersonic fine particles bombarding （SFPB）,a nanostructured surface layer up to 15 μm was fabricated on a 45 steel plate with ferrite and pearlite phases. To reveal the grain refinement mechanism of SFPB-treated 45 steel,microstructure features of various sections in the treated surface were systematically characterized by X-ray diffraction （XRD）,scanning electron microscopy （SEm） and transmission electron microscopy （TEm）. Grain size increases with an increase of depth from the treated surface. Plastic deformation and grain refinement processes are accompanied by an increase in strain. Plastic deformation in the proeutectoid ferrite phases has precedence over the pearlite phases. Grain refinement in the ferrite phases involves： the onset of dislocation lines （Dls）,dislocation tangles （DTs） and dense dislocation walls （DDWs） in the original grains; the formation of fine lamellar and roughly equiaxed cells separated by DDWs; by dislocation annihilation and rearrangement,the transformation of DDWS into subboundaries and boundaries and the formation of submicron grains or subgrains; the successive subdivision of grains to finer and finer scale,resulting in the formation of highly misoriented nano-grains. By contrast,eutectoid cementite phase accommodated strain in a sequence as follows： onset of elongated,bended and shear deformation under deformation stress of ferrites,short and thin cementites with a width of about 20-50 nm and discontinuous length were formed. Shorter and thinner cementites were developed into ultra-fine pieces under the action of high density dislocation and strains. At the top surface,some cementites were decomposed under severe plastic deformation. Experimental evidences and analysis indicate that surface nanocrystallization of 45 steel results from dislocation activities,high strains and high strain rate are necessary for the formation of nanocrystallites.

关键词： surface nanocrystallization grain refinement mechanism microstructure 45 steel

Zeolite usage as source of silica to produce cordierite in mgO–Al_2O_3–SiO_2 system

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Journal of Advanced Ceramics 2018年第4期7卷 370-379页

作者： Tu?ba Tun? PARLAK A.?ükran DEmIRKIRAN Department of metallurgical and materials Engineering Faculty of EngineeringSakarya UniversityEsentepe Campus

In this study, natural zeolite was used as source of silica to produce cordierite. mgO and Al_2O_3 were added to zeolite to obtain the cordierite stoichiometry. mixture of these raw materials was mechanically activated for different durations. The mechanically activated powder mixture was characterized using XRD, DSC, SEm, specific surface area, and particle size analyzer. The pycnometer method was used to measure the densities of mechanically activated powder mixtures. mechanically activated for 60 min powder mixture was sintered at 1150–1350 ℃ for 1 h. The sintering behavior of the samples was determined by measuring the linear shrinkage, density, and apparent porosity. The phases in the sintered samples were identified by XRD. Cordierite and spinel phases were detected for sintered at a temperature higher than 1150 ℃ but corundum accompanied to cordierite and spinel at 1150 ℃. The microstructure of the samples was examined using both SEm and AFm. The sintering behavior and microstructural properties of the samples changed with an increase in the sintering temperature. As the apparent porosity increased with increasing sintering temperature, linear shrinkage and density values decreased. Density values were determined as 2.31–2.69 g/cm^3 depending on the temperature. The grains coarsened at higher temperature and the average grain size depending on the temperature was 1.34–1.96 μm. From the results optimum sintering temperature was determined as 1250 ℃. Dense material was produced at a temperature as low as 1250 ℃ using zeolite as raw material.

关键词： mechanical activation sintering zeolite cordierite

Acoustic-electrical properties and rock physics models for shale-oil formations:prediction of reservoir properties of interbedded sandstone and shale layers

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Applied Geophysics 2022年第4期19卷 485-502,603页

作者： Pang meng-Qiang ba Jing Wu Chun-Fang Carcione José maria müller Tobias School of Earth Science and Engineering Hohai UniversityNanjingu211000China Bochum University of Applied Sciences D-44801 BochumGermany Shanghai Technical Institute of Electronics and Information Shanghai201411China National Institute of Oceanography and Applied Geophysics(OGS) SgonicoTrieste 34010

In recent years,the Yanchang shale-oil formations of the Ordos basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water discriminations,have been the key targets of unconventional oil/gas resource exploration and development in the relevant *** joint acoustic-electrical(AE)properties can be used to interpret reservoir lithology,mineralogy,pore structure,and fluid *** conduct tests of thin section analysis,X-ray diff raction,and ultrasonic and electrical experiments at diff erent pressures and saturation degrees,cores from the shale-oil formations in the Q area of the basin are *** variations in AE properties with respect to clay content,porosity,pressure(microfracture),and saturation are *** experimental results indicate that the rock physics behaviors of sandstones with diff erent clay contents vary *** AE properties of clean sandstones are basically dependent on the microfractures(pressure),while for muddy sandstones,the clay content is an important factor affecting the *** target reservoir consists of interbedded sandstone and shale *** AE equivalent medium equations and the Gurevich theory are applied to establish the joint models for the diff erent lithologies and simulate the variations in AE properties with respect to fluid type,pore structure,and mineral *** three-dimensional joint templates of clean and muddy sandstones,as well as shale,are developed based on the elastic and electrical attributes and then calibrated using the experimental and well-log *** reservoir properties are estimated with the templates and validated by the log *** results indicate that the joint templates based on lithology characteristics can eff ectively characterize the properties of interbedded sandstone and shale ***,the combined application of AE data provides more beneficial informatio

关键词： shale-oil formations acoustic-electrical(AE)properties interbedded layers clay content pore structure rock physics model

Influence of Solid Fraction on Gravity Segregation of Sn in A1-20Sn Alloy Casting

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Journal of materials Science & Technology 2000年第6期16卷 577-580页

作者： Zhang, P. Du, Y.H. Zeng, D.B. Cui, J.Z. ba, L.m. Dep. of mechanical Eng. Tsinghua Univ. Beijing 100084 China

The influence of solid fraction of Al-20Sn alloy mushy on gravity segregation of Sn in casting was studied . The relationship between solid fraction and the temperature of alloy mushy and that between solid fraction of alloy mushy and size of Sn particle in ingot were determined. The results show that the relationship between solid fraction and the temperature of alloy mushy was fs=1683-4.86t+0.003 5t2. The extent of gravity segregation of Sn in casting reduced gradually with the increase of solid fraction of alloy mushy. When solid fraction of alloy mushy was larger than 40%, the gravity segregation of Sn in casting could be removed basically, and the relationship between solid fraction of alloy mushy and size of Sn particle in ingot was s=-0.64fs+70.8.

关键词： metal casting