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A study on the surface overpressure distribution and formation of a double curvature liner under a two-point initiation

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Defence Technology（防务技术） 2022年第1期18卷 148-157页

作者： Jie Liu Xi Chen Zhong-hua du Nanging Vocational University of Industry Technology Nanjing210023China Nanjing University of Science and Technology Nanjing.210094China

The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this *** on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were *** dimensional numerical simulations of the formation process of the EFP with *** well as the ability to penetrate 45#steel were performed using LS-DYNA software,and the EFP ve locity,the penetration ability,and the forming were assessed via experiments and x_ray *** experimental results coincides with those of the *** indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintai ning the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the cnitical *** distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the qJ detonation pressure was greater than 2.5,2,and 15was approximately 0.66 mm,132 mm,and 3.3 mm,*** noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μ*** penetration depth of the EFP into a 45#steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFP,increasing the penetration resistance of the ***,the structural size of the unit charge and the liner can be further optimized to reduce resist ance to increase the penetration ability of the EFP.

关键词： Unit-shaped charge Double curvature liner Regular oblique reflection Two-point initiation Pene tra tion Numerical simulation

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蛋白质在分离纯化中保持稳定的方法及应用

天津轻工业学院学报 2002年第1期17卷 21-24页

作者：苏俊张国政刘忠华路福平杜连祥天津轻工业学院食品工程系天津300222

从正常生物基质中提取各种蛋白质需要有特定的条件 ,如果不能满足这些条件 ,蛋白质将很快的失去其生物学活性。本论文从两个方面讨论了在分离纯化中保持蛋白质的稳定的方法 :即通过添加稳定剂 (例如 :共溶剂 ,金属离子 ,蛋白酶抑制剂等 ... 详细信息

从正常生物基质中提取各种蛋白质需要有特定的条件 ,如果不能满足这些条件 ,蛋白质将很快的失去其生物学活性。本论文从两个方面讨论了在分离纯化中保持蛋白质的稳定的方法 :即通过添加稳定剂 (例如 :共溶剂 ,金属离子 ,蛋白酶抑制剂等 )及操作条件的优化 (例如 :低温、适宜 p H等 )。经实验证明均可获得满意的结果。

关键词：分离纯化活性蛋白质稳定方法稳定剂

Temperature-stable dielectric properties from 100 to 375℃ in system (K0.495Na0.495La0.01)(Nb0.997Cu0.0075)O3-Bi(Mg0.5Zr0.5)O3

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Rare Metals 2019年第12期38卷 1193-1198页

作者： hua-Lei Cheng Li-Fang Zhao Jian Xiao Peng Gao ping Wen Wan-Cheng Zhou Hong-Liang du Shaanxi Key Laboratory of Phytochemistry Department of ChemistryBaoji University of Arts and SciencesBaoji 721013China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

(1-x)(K(0.495)Na(0.495)La(0.01))(Nb(0.997)Cu(0.0075))O3-xBi(Mg(0.5)Zr(0.5))O3(abbreviated as KNLNC-xBMZ) ceramics were designed and *** phase transition,microstructure and electrical properties of the ceramics were *** phase structures of the ceramics transform from orthorhombic to pseudocubic phases and the grain sizes decrease gradually with BMZ content(x) ***,BMZ additions can significantly enhance the dielectric temperature stability and decrease the dielectric loss of ceramics over a relatively broad temperature ***-0.02 BMZ ceramics exhibit high dielectric permittivity(εr=1542) and small variation(Δεr/ε(r150℃)≤±15%)in dielectric permittivity from 100 to 375℃,and low dielectric loss(tanδ≤2%) in the temperature range of 100-350℃,which suggests that this ceramic is a candidate for high-temperature capacitor application.

关键词： (K(0.5)Na(0.5))NbO3 Lead-free Microstructure Dielectric properties Elevated temperature stability

Paleo-environmental evolution based on high-resolution phytolith since 26 ka B. P. in huanghe River Delta

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Acta Oceanologica Sinica 2016年第1期35卷 79-85页

作者： LI ping du Jun du Na GAO Wei The First Institute of Oceanography State Oceanic Administration College of Environmental Science and Engineering Ocean University of China International College Qingdao University

The huanghe River Delta is one of the world＇s large rivers, the huanghe River Delta paleoenvironmental evolution in the huanghe River has been a hot issue since the Last Glacial. Based on the core time series established by combining AMS 14C dating of Core DYZK1 sediments in submerged of huanghe River Delta and acoustic sequence on sub-bottom profile, phytolith analyses are carried out on 96 sediment samples. The grain size parameters, magnetic susceptibility are combined with the vertical changes of biostratum to reconstruct the paleo-sedimentary and climatic conditions in the huanghe River Delta. The study results show that there is a significant vertical change law in the index parameters, and that sedimentary environment of huanghe River Delta experienced an evolutionary process of fluvial facies-sealand transition facies-tidal flat facies-neritic facies- delta facies since 26.0 ka B. P.. The phytolith analyses results are as following. Firstly, The phytoliths are divided into lanceolate, smooth-elongated, spiny-elongated, rondel, long rectangular, bulliform and other types. In different sedimental environment, the phytolith content changes regularly, indicating that the phytolith assembles in the same sedimentary environment has a certain degree of stability. Secondly, The lanceolate, smooth-elongated and spiny-elongated categories of phytoliths have greater contents in the tidal flat facies and delta deposition, while have a smaller contents in the neritic facies and fluvial facies environment. Thirdly, Through comparative analysis of variation coefficient, the content of major phytolith categories in the sediment has a greater change amplitude in the sealand transition facies and fluvial facies deposition, while being more stable in the tidalflat facies and delta facies deposition.

关键词： K huanghe River Delta core DYZK1 phytolith sedimentary facies

Differential Polymorphic Transformation Behavior of Polybutene-1 with Multiple Isotactic Sequences

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Chinese Journal of Polymer Science 2020年第2期38卷 164-173,I0007页

作者： Ya-ping Ma Wei-ping Zheng Chen-Guang Liu hua-Feng Shao hua-Rong Nie Ai-hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) Qingdao University of Science and Technology

For the solid-solid transformation from form Ⅱ to form Ⅰ of isotactic polybutene-1(iPB),the temperature dependence of form Ⅰ nucleation and growth was deemed to control the transformation ***,the relationship between formⅠ formation and form Ⅱ disappearance in the transformation process is not *** this work,the spontaneous crystal transformation from form Ⅱ to Ⅰ of iPB with 81 mol%mmmm sequence concentration is studied firstly by tracking the two processes,the decay of form Ⅱ and the yielding of form Ⅰ in a wide range of temperature spanning from 0℃ to 50℃ and in a long transformation time ranging from 5 min to 65 days with in situ FTIR and *** the literature reports,the decay rate of form Ⅱ is firstly found to be lower than the yielding rate of form Ⅰ at all studied temperatures,especially at low transition *** is attributed to the amorphous chains which locate near crystal lamella participating into the nucleation of form Ⅱ.The regular chain folding and growth of i PB form Ⅰ from amorphous chains containing short isotactic sequences also lead to an increase in crystallinity of form Ⅰ compared with that of initial form Ⅱ crystallized at 60℃.An increase in the annealing temperature results in decrease in crystallinity and increase in lamellae thickness of i PB formⅠ.

关键词： Polybutene-1 Polymorphic transformation Isotactic sequence Crystallinity Lamellae thickness

Research on the Pitting Mechanism of Dispersion-Strengthened High-Strength Steel Under Wet-Dry Cycling in a Marine Environment

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Journal of Ocean University of China 2021年第6期20卷 1459-1468页

作者： LI ping GENG Yanming du Min The Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationCollege of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100China

due to the wet-dry cycling in the ocean tidal zone,the supply of dissolved oxygen and salt-containing particles were sufficient,so the corrosion was *** corrosion was a common form of localized *** paper studied the pitting corrosion mechanism of dispersion-strengthened high-strength steel under different wet-dry ratio *** Impedance Spectroscopy was used to study the changes of corrosion rate and electric double layer structure of the dispersionstrengthened high-strength *** electron microscope,Raman spectroscopy,electron probe microanalysis and laser confocal scanning microscope were used to observe the corrosion product morphologies,analyze the corrosion product compositions,analyze the secondary distribution of alloy elements in the corrosion products and analyze the pitting information of the steel after the corrosion products were *** results showed that the degree of the steel corrosion was slight when the wetting time was longer,the size and depth of the corrosion pits on the surface were *** was because the environment with longer wetting time made the corrosion products *** this environment,the conversion ofγ-FeOOH to Fe3O4 was *** addition,it could also promote the alloying elements to be more concentrated in the rust *** above phenomena hindered the further corrosion of the matrix by dissolved oxygen and Cl−in the seawater.

关键词： marine dispersion-strengthened high-strength steel wet-dry cycling pitting rust

Application of multiwalled carbon nanotubes treated by potassium permanganate for determination of trace cadmium prior to flame atomic absorption spectrometry

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Journal of Environmental Sciences 2007年第10期19卷 1266-1271页

作者： XIAO Jun-ping ZHOU Qing-xiang BAI hua-hua Department of Chemistry University of Science and Technology Beijing Beijing 100083 China Henan Key Laboratory for Environmental Pollution Control School of Chemistry and Environmental Sciences Henan Normal University Xinxiang 453007 China

In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes （MWCNTs） and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity （R^2=0.9992） over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.

关键词： multiwalled carbon nanombes (MWCNTs) solid-phase extraction flame atomic absorption spectrometry

Fatigue Properties of Supersteel for Automobiles

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Journal of Iron and Steel Research International 2006年第6期13卷 57-59,65页

作者： du Lin-xiu ZHANG Zhong-ping TIAN Yu-wei LIU Xiang-hua WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004Liaoning China Hot Rolled Strip Plant Panzhihua Steel Panzhihua 617062 Siehuan China Teehnology Center Benxi Steel Group Benxi 117000 Liaoning China

The fatigue properties of 400 MPa grade supersteel, plain low carbon steel SS400 and microalloyed steel Q340TM were investigated through tensile-compression fatigue experiment with R =- 1. The results indicate that the fatigue limit of the 400 MPa supersteel is higher than that of SS400 steel and close to that of the 340TM steel. According to the analysis of fatigue fracture, the fatigue striations of supersteel SS400 is thinner than that of SS400 steel and 340TM steel, and grain refinement can increase the fatigue limit.

关键词： supersteel grain refinement fatigue property

A New Lower Bound on the Potential-Ramsey Number of Two Graphs

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Acta Mathematicae Applicatae Sinica 2021年第1期37卷 176-182页

作者： Jin-zhi du Jian-hua YIN School of Science Hainan UniversityHaikou 570228China

A nonincreasing sequenceπ=(d1,…,dn)of nonnegative integers is a graphic sequence if it is realizable by a simple graph G on n *** this case,G is referred to as a realization ofπ.Given a graph H,a graphic sequenceπis potentially H-graphic ifπhas a realization containing H as a *** graphs G1 and G2,the potential-Ramsey number rpot(G1,G2)is the smallest integer k such that for every k-term graphic sequenceπ,eitherπis potentially G1-graphic or the complementary sequenceπ=(k-1-dk,…,k-1-d1)is potentially *** 0≤k≤[t/2],denote Kt-k to be the graph obtained from Kt by deleting k independent *** k=0,Busch et al.(Graphs Combin.,30(2014)847-859)present a lower bound on rpot(G,Kt)by using the 1-dependence number of *** this paper,we utilize i-dependence number of G for i≥1 to give a new lower bound on rpot(G,Kt-k)for any k with 0≤k≤[T/2].Moreover,we also determine the exact values of rpot(Kn,Kt-k)for 1≤k≤2.

关键词： graphic sequence potential-Ramsey number