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Quantitative prediction and ranking of the shock sensitivity ofexplosives via reactive molecular dynamics simulations

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Defence Technology（防务技术） 2022年第5期18卷 843-854页

作者： Kun yang Lang Chen dan-yang liu De-shen Geng Jian-ying Lu Jun-ying Wu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

A deep understanding of explosive sensitivities and their factors is important for safe and reliable ***,quantitative prediction of the sensitivities is ***,reactive molecular dynamics simulation models for high-speed piston impacts on explosive supercells were *** were also performed to investigate shock-induced reactions of various high-energy *** fraction of reacted explosive molecules in an initial supercell changed linearly with the propagation distance of the shock-wave *** corresponding slope could be used as a reaction rate for a specific shock-loading *** rates that varied with the shock-loading pressure exhibited two-stage linearities with different *** two inflection points corresponded to the initial and accelerated reactions,which respectively correlated to the thresholds of shock-induced ignition and ***,the ignition and detonation critical pressures could be *** sensitivity could then be a quantitative prediction of the critical *** accuracies of the quantitative shock sensitivity predictions were verified by comparing the impact and shock sensitivities of common explosives and the characteristics of anisotropic shock-induced *** dynamics simulations quantitatively predict and rank shock sensitivities by using only crystal structures of the ***,this method will enable the design and safe use of explosives.

关键词： Explosive Shock sensitivity Quantitative prediction Reactive molecular dynamics simulation

Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive

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Defence Technology（防务技术） 2021年第2期17卷 327-337页

作者： dan-yang liu Pin Zhao Serene Hay-Yee Chan Huey Hoon Hng Lang Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China School of Materials Science and Engineering Nanyang Technological University639798Singapore

Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same ***,the near-detonation zone effects of reaction between Nano-Al with detonation products remain *** this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser *** fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by *** the numerical simulations based on the calculated afterburn energy and experimental results,the parameters in the detonation equation of state describing the Nano-Al reaction characteristics were *** study found that when the 170 nm Al content is from 0%to 15%,every 5%increase of aluminum resulted in about a 1.3%decrease in detonation *** pressure gauge measurement showed no significant enhancement in detonation *** detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14%and 8%higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation *** the recording time of about 10 ms throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12%and 2.9 ms higher

关键词： Nano-sized aluminum Detonation reaction zone Explosive metal acceleration Thermodynamic equilibrium calculation Laser interferometry

Hypersonic impact flash characteristics of a long-rod projectile collision with a thin plate target

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Defence Technology（防务技术） 2021年第2期17卷 375-383页

作者： Yi-jiang Xue Qing-ming Zhang dan-yang liu Ren-rong Long yang-yu Lu Tian-fei Ren Liang-fei Gong State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

Impact flash occurs when objects collide at supersonic speeds and can be used for real-time damage assessment when weapons rely on kinetic energy to destroy ***,the mechanism of impact flash remains unclear.A series of impact flash experiments of flat-head long-rod projectiles impacting thin target plates were performed with a two-stage light gas *** impact flash spectra for 6061 aluminum at 1.3e3.2 km/s collision speeds were recorded with a high-speed camera,a photoelectric sensor,and a time-resolved *** intensity of the impact flash exhibited a pulse characteristic with *** intensity(I)increased with impact velocity(V0)according to IfVn 0,where n?4.41 for V0>2 km/***,for V02 km/s,a continuous spectrum(thermal radiation background)was observed and increased in intensity with ***,for V0<2 km/s,only atomic line spectra were *** was no aluminum spectral lines for V0<2 km/s,which indicated that it had not been *** initial intense flash was emission from excited and ionized ambient gases near the impact surface,and had little relationship with shock temperature rise,indicating a new mechanism of impact flash.

关键词： Hypersonic impact flash Radiation intensity Impact flash mechanism Environmental luminescence

Comparison of the performance of MS enteroscope series and Japanese double-and single-balloon enteroscopes

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World Journal of Gastroenterology 2022年第13期28卷 1329-1337页

作者： Jin-Hua liu dan-yang liu Yong-Feng Yuan Xue-Jun Sun Shu-Mei Shan The First Affiliated Hospital of Xi'an Jiaotong University Xi'an 710061Shaanxi ProvinceChina Affiliated Dalian Municipal Friendship Hospital of Dalian Medical University Dalian 116001Liaoning ProvinceChina Department of Endocrinology Affiliated Dalian Municipal Friendship Hospital of Dalian Medical UniversityDalian 116001Liaoning ProvinceChina College of Computer Science and Technology Harbin Institute of TechnologyHarbin 150001Heilongjiang ProvinceChina General Manager Office Dalian Ming Sheng Technology Development Co.Ltd.Dalian 116001Liaoning ProvinceChina

BACKGROUND Small intestine disease endangers human health and is not easy to locate and *** To observe the effect of the MS series of small intestine endoscopes on the gastrointestinal tract,the changes in serum gastrin levels and intestinal tissue,and the time required for the *** In vivo experiments in 20 Living pigs were conducted,Bowel preparation was routinely performed,Intravenous anesthesia with propofol and ketamine was applied,the condition of the small intestine was observed and the detection time of the MS series of small intestine endoscopes were recorded,The changes in intestinal tissue using the MS series of small intestine endoscopes observed and compared before and after the examination,Venous blood(3-5 mL)from pigs was collected before and after the experiment;changes in intestinal tissue after use of the MS series of small intestine endoscopes observed after *** completion of each type of small intestine endoscope experiment,the pigs were allowed to rest and the next type of small intestine endoscope experiment was performed after 15 days of normal *** detection time data of the single-balloon small intestine endoscope and doubleballoon small intestine endoscope were collected from four *** One case of Ascarislumbricoides,one of suspected Crohn’s disease,one small intestinal diverticulum and one anesthesia accident were observed in *** small intestine showed no differences in the MS series of small intestine endoscopes and there were no differences in serum gastrin between the groups(P>0.05).The time required for inspection was recorded,and the overall detection time for the Japanese small intestine endoscopes was approximately 1.68±0.16 *** Intestinal ascariasis is a common disease in *** pigs have abnormal intestinal *** continuous upgrade and improvement,the MS-3 and MS-4 small intestine endoscope appear superior in terms of detection time.

关键词： Intestinal ascariasis Intestinal variation Crohn’s disease Serum gastrin Small intestine endoscope

Cu/Li Ratio on the Microstructure Evolution and Corrosion Behaviors of Al–xCu–yLi–Mg Alloys

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1201-1216页

作者： dan-yang liu Jin-Feng Li Yong-Cheng Lin Peng-Cheng Ma Yong-Lai Chen Xu-Hu Zhang Rui-Feng Zhang School of Materials Science and Engineering Central South UniversityChangsha 410083China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education Central South UniversityChangsha 410083China Aerospace Research Institute of Materials and Processing Technology Beijing 100076China

The microstructure evolution and the corrosion feature of Al–x Cu– y Li–Mg alloys( x : y = 0.44, 1.65 and 4.2) were systematically investigated under the same artificial aging conditions. The relationships between types of precipitates and mechanical performance, as well as electrochemical behaviors, were discussed. Our results show that different types of precipitates can be obtained in alloys with different Cu/Li mass ratios, which significantly influences the mechanical performance of the alloys and substantial corrosion behaviors. Specifically, the analogous corrosion evolution in the aging Al– x Cu– y Li–Mg alloys was first ascertained to be derived from the growth mechanism of the precipitates at the grain boundary(GB). Moreover, a small number of GB precipitates can be obtained in the aged alloy with the lowest Cu/Li mass ratio, thereby resulting in the largest intergranular corrosion resistance. A higher proportion of the GB T1 phase in the continuous precipitates induces higher corrosion sensitivity in alloy with a high Cu/Li mass ratio.

关键词： Al–Cu–Li–Mg alloy Cu/Li mass ratio Microstructure evolution Corrosion behaviors

Influence of Pre-deformation on Aging Precipitation Behavior of Three Al–Cu–Li Alloys

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Acta Metallurgica Sinica(English Letters) 2017年第2期30卷 133-145页

作者： Jin-Feng Li Zhi-Hao Ye dan-yang liu Yong-Lai Chen Xu-Hu Zhang Xiu-Zhi Xu Zi-Qiao Zheng School of Materials Science and Engineering Central South University Changsha 410083 China Aerospace Research Institute of Materials and Processing Technology Beijing 100076 China

The influence of pre-deformation on aging precipitates of three near peak-aged Al–Cu–Li alloys,1460 alloy with a low Cu/Li ratio（1.46）,2050 alloy with a high Cu/Li ratio（4.51） and 2A96 alloy with a medium Cu/Li ratio（2.97）,was *** strength of the aged alloys is enhanced by the *** effectiveness of pre-deformation on precipitates is dependent on the alloy＇s *** increasing the pre-deformation,the population density of T1（Al2Cu Li） precipitates increases in all three Al–Cu–Li alloys and their diameter decreases in 2050 and 2A96 alloys,and the greatest effectiveness is observed in 2A96 *** pre-deformation also increases the population density of θ＇（Al2Cu）precipitates and decreases their diameter in 2050 and 2A96 Al–Li alloys,but the effectiveness is smaller compared to that on T1 *** 1460 alloy subjected to two-step aging at 130 ℃ for 20 h followed by 160 ℃ for 12 h,the main precipitates are δ＇（Al3Li）.At 2%–6% pre-deformation,GP-I zones form and pre-deformation displays little *** percentage pre-deformation promotes θ＇＇/θ＇ precipitation and increases their population density.

关键词： Al-Li alloy Pre-deformation Aging Precipitates

Advancements in adipose-derived stem cell therapy for skin fibrosis

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World Journal of Stem Cells 2023年第5期15卷 342-353页

作者： Yu-Xin liu Jia-Ming Sun Chia-Kang Ho Ya Gao Dong-Sheng Wen yang-dan liu Lu Huang Yi-Fan Zhang Department of Plastic and Reconstructive Surgery Shanghai Ninth People's HospitalShanghai Jiao Tong UniversityShanghai 200011China

Pathological scarring and scleroderma,which are the most common conditions of skin fibrosis,pathologically manifest as fibroblast proliferation and extracellular matrix(ECM)*** proliferation and ECM hyperplasia lead to fibrotic tissue remodeling,causing an exaggerated and prolonged wound-healing *** pathogenesis of these diseases has not been fully clarified and is unfortunately accompanied by exceptionally high medical needs and poor treatment ***,a promising and relatively low-cost treatment has emerged-adipose-derived stem cell(ASC)therapy as a branch of stem cell therapy,including ASCs and their derivatives-purified ASC,stromal vascular fraction,ASC-conditioned medium,ASC exosomes,etc.,which are rich in sources and easy to *** have been widely used in therapeutic settings for patients,primarily for the defection of soft tissues,such as breast enhancement and facial *** the field of skin regeneration,ASC therapy has become a hot research topic because it is beneficial for reversing skin *** ability of ASCs to control profibrotic factors as well as anti-inflammatory and immunomodulatory actions will be discussed in this review,as well as their new applications in the treatment of skin *** the long-term effect of ASC therapy is still unclear,ASCs have emerged as one of the most promising systemic antifibrotic therapies under development.

关键词： Adipose-derived stem cell Cicatrix,hypertrophic Keloid Scleroderma,localized Stromal vascular fraction Exosomes

Effects of nasal continuous positive airway pressure treatment on insulin resistance and ghrelin levels in non-diabetic apnoeic patients with coronary heart disease

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Chinese Medical Journal 2013年第17期126卷 3316-3320页

作者： yang dan liu Zhi-hong ZHAO Qing LUO Qin State Key Laboratory of Cardiovascular Disease Fu Wai Hospital National Centre for Cardiovascular Diseases Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100037 China

Background Obesity is a common risk factor for several diseases. Obesity related hormone and increased insulin resistance （IR） may contribute to the effects of obstructive sleep apnoea on cardiovascular consequences. We investigated ghrelin and IR in non-diabetic apnoeic patients with stable coronary heart disease and assessed the effects of continuous positive airway pressure （CPAP）. Methods Plasma ghrelin, glucose and insulin were measured in 22 patients with CPAP and 22 matched controls without CPAP at baseline and three months. Indexes including homeostasis model assessment IR （HOMA IR）, HOMA S and HOMA β were calculated for the assessment of IR, insulin sensitivity and pancreatic β cell function. Results At three months follow-up, plasma ghrelin levels and HOMA IR in CPAP group were significantly decreased （P=0.002 and 0.046, respectively） while those in control group increased significantly （P=0.012 and 0.009, respectively）. Significant moderate correlations were found between ghrelin vs. HOMA IR and ghrelin vs. HOMA S after CPAP, however, for those without CPAP, no significant associations were observed. Conclusions Short-term effective continuous positive airway pressure had a significant effect on lowering plasma ghrelin levels and IR, but not body fat. Further large scale and longer term studies are warranted to corroborate these findings.

关键词： obstructive sleep apnoea coronary heart disease continuous positive airway pressure homeostasis model assessment ghrelin

Microstructures evolution and mechanical properties disparity in 2070 Al-Li alloy with minor Sc addition

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Transactions of Nonferrous Metals Society of China 2018年第11期28卷 2152-2162页

作者： dan-yang liu Jie-xia WANG Jin-feng LI School of Materials Science and Engineering Central South UniversityChangsha 410083China Science and Technology on High Strength Structural Materials Laboratory Central South UniversityChangsha 410083China

The microstructures and mechanical properties of Al-3.35Cu-1.2Li-0.4Mg-0.4Zn-0.3Mn-0.1Zr （mass fraction, %） alloywith Sc addition or free Sc were investigated through tensile test, SEM, EPMA and TEM. The addition of 0.082% （mass fraction） Scelement leads to the formation of Cu-rich and Sc-contained nano-sized Al3（ScZr） particles and W phase particles. The Al3（ScZr）particles can inhibit recrystallization to a certain extent and impede recrystallized grain growth during solution treatment. It is foundthat W phase cannot dissolve in supersaturated solid solution during the solution heat treatment, and the Cu content in thesolutionized matrix is decreased, which causes a decrease in the fraction of Cu-contained strengthening precipitates with T1 （Al2CuLi）and θ＇（Al2Cu） under T8 aging condition. Due to the formation of the W phases, the small Sc addition causes a little reduction in thestrength.

关键词： Al-Li alloy Sc addition microstructure mechanical properties