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Relationships between distribution characteristics of ceramic fragments and anti-penetration performance of ceramic composite bulletproof insert plates

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Defence Technology（防务技术） 2023年第1期19卷 103-110页

作者： Wen-hao Yu Wei-ping Li Yi-fan Shangguan xin-yang ji Tian Ma Guo-qing Wu School of Materials Science and Engineering Beihang UniversityBeijing100191China Institute of Quartermaster Engineering Technology of PLA Academy of Military Science Beijing100010China China Linyi High-tech Zone Shuanghang Material Technology Co. Ltd.Linyi276000China

Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates(CCBIPs),distribution characteristics of ceramic fragments within a specific size range were analyzed for different Armor Piercing Incendiary(API)and shot *** quantitatively evaluate the effect of energy absorption for ceramic plates,a model of energy absorption during penetration for CCBIPs was established based on statistics of the size distribution of ceramic fragments(SDCF).Variation in the SDCF and its influence on energy absorption for CCBIPs were *** results indicate that the distribution feature of ceramic fragments in the range of 0.25-2.25 mm is Gaussian *** with Type 56 of API(56-API),ceramic fragments formed by 53-API with higher kinetic energy possess more quantity and more concentrated distribution,whose average equivalence size decreases by 6.5%,corresponding to increasing by 83.9%of estimated energy ***,the ability of CCBIPs to resist the third shot is significantly weakened,whose estimated energy absorption decreases by 58.8%compared with the first *** concentrated distribution and fewer fragments are formed after the third shot,the average equivalence size of ceramic fragments increases by 6.9%,which may attribute to the micro-cracks induced by the previous two shots.

关键词： Bulletproof insert plate Ceramic fragment Statistic Energy absorption Anti-penetration performance

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Disseminated hydatid disease in the orbit and central nervous system

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International Journal of Ophthalmology(English edition) 2021年第9期14卷 1457-1459页

作者： Ming-Shen Ma Fan Su Yan Hei Mei-Yan Feng xin-ji yang Orbital Diseases Institute Chinese People’s Liberation Army General HospitalBeijing 100853China Department of Ophthalmology Affiliated Hospital of Inner Mongolia Medical UniversityHohhot 010050Inner Mongolia Autonomous RegionChina

Dear Editor,We are writing to present a rare case of disseminated hydatid disease(HD)in the orbit and central nervous system(CNS)leading to visual dysfunction,and an improved surgical *** rare case demonstrates intracranial multiple hydatid cysts encroaching and penetrating the orbital wall leading to orbital hydatid *** reducing the cyst volume may be an excellent option to avoid rupture of orbital hydatid cyst.

关键词： technique. nat system

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Accurate simulations of pure-viscoacoustic wave propagation in tilted transversely isotropic media

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Petroleum Science 2024年第2期21卷 866-884页

作者： Qiang Mao jian-Ping Huang xin-Ru Mu ji-Dong yang Yu-jian Zhang Geosciences Department China University of Petroleum(East China)Qingdao266580ShandongChina Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao266207ShandongChina

Forward modeling of seismic wave propagation is crucial for the realization of reverse time migration(RTM) and full waveform inversion(FWI) in attenuating transversely isotropic media. To describe the attenuation and anisotropy properties of subsurface media, the pure-viscoacoustic anisotropic wave equations are established for wavefield simulations, because they can provide clear and stable wavefields. However, due to the use of several approximations in deriving the wave equation and the introduction of a fractional Laplacian approximation in solving the derived equation, the wavefields simulated by the previous pure-viscoacoustic tilted transversely isotropic(TTI) wave equations has low accuracy. To accurately simulate wavefields in media with velocity anisotropy and attenuation anisotropy, we first derive a new pure-viscoacoustic TTI wave equation from the exact complex-valued dispersion formula in viscoelastic vertical transversely isotropic(VTI) media. Then, we present the hybrid finite-difference and low-rank decomposition(HFDLRD) method to accurately solve our proposed pure-viscoacoustic TTI wave equation. Theoretical analysis and numerical examples suggest that our pure-viscoacoustic TTI wave equation has higher accuracy than previous pure-viscoacoustic TTI wave equations in describing q P-wave kinematic and attenuation characteristics. Additionally, the numerical experiment in a simple two-layer model shows that the HFDLRD technique outperforms the hybrid finite-difference and pseudo-spectral(HFDPS) method in terms of accuracy of wavefield modeling.

关键词： Pure-viscoacoustic TTI wave equation Attenuation anisotropy Seismic modeling Low-rank decomposition method

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A reweighted damped singular spectrum analysis method for robust seismic noise suppression

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Petroleum Science 2024年第3期21卷 1671-1682页

作者： Wei-Lin Huang Yan-xin Zhou yang Zhou Wei-jie Liu ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206China SINOPEC Geophysical Research Institute Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis Damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

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First-Principles Studies of Structural Evolutions in Cathode Materials LiMO_(2)(M=Co,Mn,Ni)

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Chinese Physics Letters 2024年第10期41卷 129-136页

作者： Yufeng Sun xin-Gao Gong ji-Hui yang Key Laboratory for Computational Physical Sciences(MOE) Department of PhysicsFudan UniversityShanghai 200433China Shanghai Qizhi Institution Shanghai 200232China

We explore the structural evolutions of stoichiometric LiMO_(2)using the first-principles calculations combined with the cluster expansion *** automatically obtain the ground state structures of the stoichiometric LiMO_(2)by just considering the cation orderings in the quasi rock-salt structures and the following structural relaxations due to both the atomic size mismatches and the Jahn–Teller *** point out that,on the one hand,the cation orderings are mainly determined by the nearest,the second nearest,and the third nearest cation interactions and can be obtained from the‘phase diagram’we have built using the relative strengths of effective cluster interaction(ECI).On the other hand,the structural relaxations are dominated by the crystal field splitting(CFS)energies,i.e.,structures with larger CFS energies are more *** calculating the ECIs and CFS energies for various structures of LiMO_(2),we clearly show how ECI and CFS play roles in determining the structural evolution mechanism of these systems.

关键词： method. relaxation cluster

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Volume-averaged modeling of multiphase solidification with equiaxed crystal sedimentation in a steel ingot

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China Foundry 2024年第3期21卷 229-238页

作者： Xiao-lei Zhu Shuang Cao Rui Guan ji yang Zhe Ning xin-gang Ai Sheng-li Li xin-cheng Miao The key Laboratory of Material Forming and Structure Property Control Anshan 114051LiaoningChina State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009LiaoningChina School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

Macrosegregation is a critical factor that limits the mechanical properties of *** impact of equiaxed crystal sedimentation on macrosegregation has been extensively studied,as it plays a significant role in determining the distribution of alloying elements and impurities within a *** improve macrosegregation in steel connecting shafts,a multiphase solidification model that couples melt flow,heat transfer,microstructure evolution,and solute transport was established based on the volume-averaged Eulerian-Eulerian *** this model,the effects of liquid phase,equiaxed crystals,columnar dendrites,and columnar-to-equiaxed transition(CET)during solidification and evolution of microstructure can be considered *** sedimentation of equiaxed crystals contributes to negative macrosegregation,where regions between columnar dendrites and equiaxed crystals undergo significant A-type positive macrosegregation due to the ***,noticeable positive macrosegregation occurs in the area of final solidification in the *** improvement in macrosegregation is beneficial for enhancing the mechanical properties of connecting *** mitigate the thermal convection of molten steel resulting from excessive superheating,reducing the superheating during casting without employing external fields or altering the design of the ingot mold is indeed an effective approach to control macrosegregation.

关键词： ingot casting multiphase solidification model equiaxed crystal sedimentation microstructure macrosegregation

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Experimental and numerical investigation of two blended blade and endwall configurations

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Chinese Journal of Aeronautics 2024年第9期37卷 150-163页

作者： Tongtong MENG xin LI Ling ZHOU Lucheng ji Institute for Aero Engine Tsinghua UniversityBeijing 100084China Schoolof Aerospace Engineering Bejing Institute of TechnologyBeijing 0081China

The Blended Blade and Endwall(BBEW)technique has proven to be effective in control-ling the intersection of boundary layer in corner region of the compressor *** this study,the experiment and analysis of two different BBEW designs are ***,based on a linear cas-cade with 0.7 Mach number inflow,two different configurations,BBEW 1 and BBEW 2,are well ***,according to the experimental result,control effects of these two BBEW configu-rations are validated and compared subsequently under various working *** results demonstrate a reduction in total pressure loss of 12.8%and 29%at the design point for BBEW 1 and BBEW 2,***,the BBEW technique proves effective in suppressing the development of the boundary layer and preventing corner *** by detailed numerical analysis,improvements around the corner region,especially for the boundary layer,are extracted to show the mechanisms and distinctions between the two *** results indicate that BBEW 1 significantly restrains the development of boundary layer before separation occurs,while BBEW 2 directly controls the strength and scale of the corner separation.

关键词： Aerodynamic Computational fluid dynamic Experiment Corner separation Blended Blade and Endwall(BBEW)

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A molecular insight into coke formation process of vacuum residue in thermal cracking reaction

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Petroleum Science 2024年第3期21卷 2130-2138页

作者： ji-Guang Li xin Guo Huan-Di Hou Heavy Oil Processing Department Sinopec Research Institute of Petroleum Processing Co.LtdBeijing100083China

Understanding the coking behaviors has been considered to be really essential for developing better vacuum residue processing technologies.A battery of thermal cracking tests of typical vacuum residue at 410℃ with various reaction time were performed to evaluate the coke formation *** total yields of ideal components including naphtha,atmospheric gas oil(AGO)and vacuum gas oil(VGO)of thermal cracking reactions increased from 10.89%to 40.81%,and the conversion ratios increased from8.05%to 43.33%with increasing the reaction time from 10 to 70 *** asphaltene content increased from 12.14%to a maximum of 22.39%and then decreased,and this maximum of asphaltene content occurred at the end of the coking induction *** asphaltenes during the coking induction period,at the end and after coking induction period of those tested thermal cracking reactions were characterized to disclose the structure changing rules for coke formation process,and the coke formation pathways were discussed to reveal the coke formation process at molecular level.

关键词： Vacuum residue Thermal cracking Asphaltene Coking induction period Sulfur Nitrogen

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Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1370-1374页

作者： Xiao-Lei Yin Zhi-yang ji Xiu-xin Li Xue-Mei Liang Shu-xing ji Department of Ophthalmology the 305 Hospital of PLABeijing 100017China Department of Ophthalmology Daping HospitalArmy Medical UniversityChongqing 400042China Department of Medical Administration the 305 Hospital of PLABeijing 100017China

Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the *** causes blurred vision at any distance and includes corneal,lenticular,and retinal *** surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery *** development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of ***,three surgical approaches can be *** placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be *** or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism *** are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is *** toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal *** IOLs implantation can correct 1.0-4.5 D of corneal *** IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 *** approaches can be used alone or in combination.

关键词： cornea astigmatism cataract surgery peripheral corneal relaxing incisions toric intraocular lens

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Elaborate Design of Two Novel Fluorescent Zinc-based Metal-Organic Frameworks for Highly Efficient Tetracycline Antibiotics Detection

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Chemical Research in Chinese Universities 2024年第3期40卷 499-507页

作者： TAO He ji Chengshan ZHANG jian YIN Yuanyuan jiA Wenwen jiANG xin XU jie yang Yulin MIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001P.R.China

The abuse of tetracycline antibiotics has caused great harm to human health and *** inexpensive,convenient and sensitive methods for the detection of tetracycline antibiotics is highly ***,based on the H_(4)ddp ligand[H_(4)ddp=3-(3,5-dicarboxyphenyl)pyridine-2,6-dicarboxylic acid],two novel zinc-based metal-organic frameworks(MOFs){[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn1-ddp)and{[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn2-ddp)were successfully designed by delicate structural *** Zn1-ddp and Zn2-ddp exhibited excellent water and chemical stability and showed excellent fluorescence quenching performance for tetracycline ***,the more advanced framework structure and better fluorescent performance make Zn1-ddp more sensitive than Zn2-ddp in fluorescent detection with a detection limit of 0.29µmol/L for tetracycline(TC),0.09µmol/L for doxycycline(DOX),0.10µmol/L for minocycline(MIN)and metacycline(MEL),0.19µmol/L for chlortetracycline(CTC),and 0.67µmol/L for oxytetracycline(OTC)among tetracycline *** fluorescence quenching mechanism of Zn1-ddp and Zn2-ddp for tetracycline antibiotics detection was deeply *** reasons for the superior detection performance of Zn1-ddp over Zn2-ddp were also analyzed in depth through Fourier transform infrared spectrophotometry(FTIR),X-ray photoelectron spectroscopy(XPS)analysis and framework structure *** developed method opens up a new perspective for antibiotics detection based on zinc-based MOFs.

关键词： Water system Metal-organic framework Fluorescent detection Tetracycline antibiotic

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