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Influence of a liquid-filled compartment structure on the incoming shaped charge jet stability

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Defence Technology（防务技术） 2021年第2期17卷 571-582页

作者： X.D.zu z.X.Huang z.W.Guan X.C.yin y.m.zheng School of mechanical Engineering Nanjing University of Science and TechnologyXiaolingwei 200Nanjing 210094China School of Engineering University of LiverpoolLiverpoolL693GQUK Department of mechanics and Engineering Science Nanjing University of Science and TechnologyNanjing 210094China

Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and *** liquid-filled compartment structure can resist the shaped charge warhead *** paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact *** the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is *** interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also *** addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.

关键词： Compartment structure Shaped charge jet Shock wave Disturbance Stability

Assessment of clay stiffness and strength parameters using index properties

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Journal of Rock mechanics and Geotechnical Engineering 2018年第3期10卷 579-593页

作者： Sayed m.ahmed Structural Engineering Department Ain Shams University

A new approach is developed to determine the shear wave velocity in saturated soft to firm clays using measurements of the liquid limit, plastic limit, and natural water content with depth. The shear wave velocity is assessed using the site-specific variation of the natural water content with the effective mean stress. Subsequently, an iterative process is envisaged to obtain the clay stiffness and strength *** at-rest earth pressure coefficient, as well as bearing capacity factor and rigidity index related to the cone penetration test, is also acquired from the analyses. Comparisons are presented between the measured clay parameters and the results of corresponding analyses in five different case studies. It is demonstrated that the presented approach can provide acceptable estimates of saturated clay stiffness and strength parameters. One of the main privileges of the presented methodology is the site-specific procedure developed based on the relationships between clay strength and stiffness parameters, rather than adopting direct correlations. Despite of the utilized iterative processes, the presented approach can be easily implemented using a simple spreadsheet, benefiting both geotechnical researchers and practitioners.

关键词： Soft to firm clays Atterberg limits Shear wave velocity Small-strain shear modulus Constrained modulus Undrained shear strength Effective friction angle Cone penetration test

An Integrated Framework for Cloud Service Selection Based on BOm and TOPSIS

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Computers, materials & Continua 2022年第8期72卷 4125-4142页

作者： ahmed m.mostafa Computer and Systems Engineering Department Faculty of Engineering at HelwanHelwan UniversityCairo11795Egypt

many businesses have experienced difficulties in selecting a cloud service provider(CSP)due to the rapid advancement of cloud computing services and the proliferation of *** independent criteria should be considered when evaluating the services provided by different *** is a case of multi-criteria decision-making(mCDm).This paper presents an integrated mCDm cloud service selection framework for determining the most appropriate service provider based on the best only method(BOm)and technique for order of preference by similarity to ideal solution(TOPSIS).To obtain the weights of criteria and the relative importance of CSPs based on each criterion,BOm performs pairwise comparisons of criteria and also for alternatives on each criterion,and TOPSIS uses these weights to rank cloud *** evaluation and validation of the proposed framework have been carried out through a use-case model to prove its efficiency and ***,the developed framework was compared with the analytical hierarchical process(AHP),a popular mCDm approach,based on two perspectives:efficiency and *** to the research results,the proposed framework only requires 25%of the comparisons needed for the AHP ***,the proposed framework has a CR of 0%,whereas AHP has 38%.Thus,the proposed framework performs better than AHPwhen it comes to computation complexity and consistency,implying that it is more efficient and trustworthy.

关键词： Cloud computing(CC) multiple-criteria decision-making(mCDm) cloud service providers(CSPs) analytical hierarchical process(AHP) the best only method(BOm) technique for order of preference by similarity to ideal solution(TOPSIS)

mosquito autogeny in Aedes caspius （Diptera： Culicidae）： alterations of larval nourishments reservation upon bacterial infection

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Insect Science 2013年第4期20卷 472-484页

作者： Ashraf m. ahmed zoology Department College of Science King Saud University SaudiArabia zoology Department College of Science Minia UniversityEl-Minia Egypt

The present study recorded mosquito autogeny for the first time amongst Aedes caspius species in the Eastern region of Saudi Arabia. Laboratory rearing showed an obligatory autogenous species of Ae. caspius since it foregoes blood feeding during its first ovarian cycle, even in the presence of the hosts （CD mouse）, but produces its second egg batch only if ingested a blood meal. Both morphological and molecular identification confirmed that both autogenous and anautogenous strains belong to the same species of Ae. caspius. Data from biochemical analysis showed significant 2, 1.6, and 1.4 folds higher total carbohydrates, proteins, and lipids reserves respectively in the fourth larval instar of the autogenous strain compared to that of the anautogenous ones. In addition, exposing the fourth larval instars of autogenous strain to the infection stress by the mosquito larvicidal bacterium, Bacillus thuringiensis var kurstaki has significantly reduced total carbohydrates, proteins and lipids reserves by 29%, 35%, and 46%, respectively, at 12 h postinfection compared to those of uninfected ones. These reductions in nourishment reserves were more pronounced at 24 h postinfection in the case of proteins and lipids, but not carbohydrates. These results may indicate that bacterial infection is a health stress that significantly reduced nourishments reservation, which may interrupt the success of adult autogeny. However, the impact of infection-induced decline in larval nourishments reservation on successful adult autogeny is still to be investigated.

关键词： Aedes caspius anautogeny autogeny Bacillus thuringiensis nourishmentsreservation

Finite Element Prediction of the Thermal Conductivity of GNP/Al Composites

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Acta metallurgica Sinica(English Letters) 2022年第5期35卷 825-838页

作者： X.S.yang L.zhou K.y.Liu z.y.Liu Q.z.Wang B.L.Xiao z.y.ma School of Electromechanical and Automotive Engineering Yantai UniversityYantai264005China Shi-Changxu Innovation Center for Advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

A 3 D multi-scale finite element model was developed to predict the effective thermal conductivity of graphene nanoplatelet(GNP)/Al *** factors influencing the effective thermal conductivity of the GNP/Al composites were investigated,including the orientation,shape,aspect ratio,configuration and volume fraction of *** results show that GNPs shape has a little influence on the thermal conductivity of GNP/Al composites,and composites with elliptic GNPs have the highest thermal *** addition,with increasing the aspect ratio of GNPs,the thermal conductivity of GNP/Al composites increases and finally tends to be *** GNPs configuration strongly influences the thermal conductivity of GNP/Al composites,and the thermal conductivity of the composites with layered GNPs is the highest among the five *** effective thermal conductivity is sensitive to volume fraction of ***,when the volume fraction of layered GNPs reaches 1.54%,the thermal conductivity of GNP/Al composites is as high as 400 W/m *** findings of this study could provide a good theoretical basis for designing high thermal conductivity GNP/Al composites.

关键词： multi-scale finite element model Thermal conductivity GNP/Al composites Shape Aspect ratio Configuration

Exploring the uncertainties in theoretical predictions of nuclear β-decay half-lives

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Chinese Physics C 2021年第4期45卷 273-278页

作者： m.Shi J.y.Fang z.m.Niu School of mathematics and Physics Anhui Jianzhu UniversityHefei 230601China Key Laboratory of Architectural Acoustic Environment of Anhui Higher Education Institutes Hefei 230601China Key Laboratory of Advanced Electronic materials and Devices Anhui Jianzhu UniversityHefei230601China School of Physics and materials Science Anhui UniversityHefei 230601China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China

Nuclear β-decay half-lives are predicted based on an empirical formula and the mass predictions from various nuclear *** is found that the empirical formula can reproduce the nuclearβ-decay half-lives well,especially for short-lived nuclei with T_(1/2)mβ-decay energies and the parameters of the empirical formula are further *** is found that the uncertainties of the half-lives are relatively large for heavy nuclei and nuclei near the neutron-drip *** nuclei on the r-process path,the uncertainties for those with N=126 are about one order of magnitude,which are much larger than the uncertainties for those with N=50 and ***,theoretical uncertainties from the parameters of the empirical formula are relatively small for the nuclei on the r-process path,which indicates that the empirical formula is very suitable for predicting theβ-decay half-lives in r-process simulations.

关键词： βdecay nuclear mass r process

ImPROVED mETHOD OF PARTIAL SImILARITy OF BOUNDARy LAyER ALONG CURVED SURFACE

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Journal of Hydrodynamics 2001年第2期13卷 77-79页

作者： Sun, F.z. Shi, y.T. Sun, H.J. Ping, y.m. zhang, m.y. Inst. of Energy and Power Shandong Univ. Jinan 250061 China

The solution of boundary layer along a curved surface was discussed in this article. According to the principle of the theory of similarity, the method of partial similarity was proposed, in which the profile of object is divided into many tiny sections, the method of similarity was used in each section and the error in each section was fully considered. This method is proved to be feasible.

关键词： Cylinders (shapes) Differential equations Error analysis Surfaces

Effect of Ni Content on mechanical Properties and Corrosion Behavior of Al/Sn－9zn－xNi/Cu Joints

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Journal of materials Science & Technology 2012年第9期28卷 844-852页

作者： m.L.Huang N.Kang Q.zhou y.z.Huang Key Laboratory of Liaoning Advanced Welding and Joining Technology School of Materials Science&EngineeringDMian University of TechnologyDalian 116024China

The effects of Ni content on the microstructure and the wetting behavior of Sn-9zn-xNi solders on Al and Cu substrates, as well as the mechanical properties and electrochemical corrosion behavior of Al/Sn-9zn-xNi/Cu solder joints, were investigated. The microstructure of Sn-gzn-xNi revealed that tiny zn and coarsened Ni5zn21 phases dispersed in theβ-Sn matrix. The wettability of Sn-9zn-xNi solders on Al substrate was much better than that on Cu substrate. With increasing Ni content, the wettability on Cu substrate was slightly improved but became worse on Al substrate. In the Al/Sn-9zn-xNi/Cu joints, an Al4.2Cu3.2zn0.7 intermetallic compound （ImC） layer formed at the Sn-gzn-xNi/Cu interfaces, while an Al-zn-Sn solid solution layer formed at the Sn-9zn-xNi/Al interface. The mixed compounds of Ni3Sna and Al3Ni dispersed in the solder matrix and coarsened with increasing Ni content, thus leading to a reduction in shear strength of the Al/Sn-9zn- xNi/Cu joints. Al particles were segregated at both interfaces in the solder joints. The corrosion potentials of Sn-9zn-xNi solders continuously increased with increasing Ni content. The Al/Sn-9zn-0.25Ni/Cu joint was found to have the best electrochemical corrosion resistance in 5% NaCl solution.

关键词： Al-Cu disslmilar-metal solder joint Sn-9zn-xNi microstructure mechanicalproperties Electrochemical corrosion Corrosion potential

Violence toward emergency physicians: A prospective-descriptive study

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World Journal of Emergency medicine 2021年第2期12卷 111-116页

作者： Kasım Turgut Erdal yavuz mine Kayacıyıldız mehmet Kaan Poyraz Department of Emergency medicine Research and Training HospitalAdiyaman UniversityAdiyaman 02100Turkey

BACKGROUND: The highest rate of workplace violence occurs in the health sector, although most cases remain unreported. Emergency services face the majority of these incidents for many reasons, such as the patient profile, long waiting time, and overcrowding. We aimed to determine the characteristics and causes of violence toward emergency physicians. mETHODS: The acts of violence toward emergency physicians over a one-year period were prospectively recorded. After a violent incident took place, a third party separately interviewed the physician exposed to the violent behavior and the perpetrator who displayed this behavior. We examined the perpetrator's reasons for violence, their demographic characteristics, and the medical complaints of patients involved in such events to determine the characteristics and causes of ***: Of the violent acts investigated, 85.1% were verbal, and most were directed toward male doctors by the young male relatives of the patients. more than half of the violent acts occurred within the 15 minutes of presentation to emergency service(60.5%) and at off-hours(69.4%). Concerning the health insurance, 20.4% of the cases were covered by the free green card system, and a small number of the perpetrators of violence lived in rural areas(38.2%). The most common reason for violent behavior was the patients' or their relatives' dissatisfaction with the examination or treatment method(38.2%).CONCLUSIONS: Appropriate communication should be established with the patients, and they should be adequately informed about the treatments and interventions to be performed in order to prevent possible acts of violence.

关键词： Violence Emergency physician Emergency department