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Self-Lubricating PEO Coating on an Al Alloy Produced by Vacuum Impregnation Post-treatment

Acta Metallurgica Sinica(English Letters) 2015年第8期28卷 965-974页

作者： Ling Hong Dong wang Guang-Dong Bian Lin-Lin wang Shu-gen Hu College of Mechanical Engineering Zhejiang University Zhejiang Wanliyang Transmission Co. Ltd. College of Engineering Zhejiang Normal University

The objective of this research was to develop a novel self-lubricating coating on an AA6061 aluminum *** coatings were prepared by the plasma electrolytic oxidation（PEO） process using 50-, 500-, and 1000-Hz pulsed direct current, respectively. The as-deposited coatings were then post-treated using two different methods, viz., ultrasonic vibration-aided vacuum oil impregnation（UVOI） and oil impregnation under ambient pressure（OIAP）. After posttreatment, an oil-containing, self-lubricating top layer was formed on the coatings. The effects of the coatings＇ surface morphologies and structures on their oil-holding capabilities were discussed. The results revealed that coatings prepared with higher frequency had a greater oil-holding capacity using OIAP post-treatment, while those prepared with lower frequency had a greater oil-containing capability using UVOI post-treatment. These phenomena are related to the morphologies of the coatings produced with various current modes. The tribological properties of the coatings before and after post-treatments were investigated by pin-on-disc sliding wear tests. Due to the formation of a lubricant-containing top layer, the post-treatment coatings had a lower friction coefficient and improved wear resistance compared with the asdeposited coatings. In addition, the coatings after UVOI treatment had better wear performance than those post-treated using the OIAP process. Among all coatings, the coating produced with a 50-Hz pulsed current followed by UVOI posttreatment achieved the lowest friction coefficient（0.03） and best wear resistance when sliding against a Si3N4 ceramic counterface. This study indicates that a novel self-lubricating coating can be prepared by a PEO process combined with vacuum oil impregnation post-treatment.

关键词： Tribological properties Self-lubricating coating Plasma electrolytic oxidation process Oil impregnation Vacuum

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The Influence of Seasonal Snow on Soil Thermal and Water Dynamics under Different Vegetation Covers in a Permafrost Region

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Journal of Mountain Science 2014年第3期11卷 727-745页

作者： HANG Juan wang gen-xu GAO Yong-heng wang Yi-bo College of Earth and Environmental Sciences Lanzhou University Institute of Mountain Hazards and Environment Chinese Academy of Sciences

Seasonal snow is one of the most important influences on the development and distribution of permafrost and the hydrothermal regime in surface soil. Alpine meadow, which constitutes the main land type in permafrost regions of the Qinghai-Tibet Plateau, was selected to study the influence of seasonal snow on the temperature and moisture in active soil layers under different vegetation coverage. Monitoring sites for soil moisture and temperature were constructed to observe the hydrothermal processes in active soil layers under different vegetation cover with seasonal snow cover variation for three years from 2010 to 2012. Differences in soil temperature and moisture in areas of diverse vegetation coverage with varying levels of snow cover were analyzed using active soil layer water and temperature indices. The results indicated that snow cover greatly influenced the hydrothermal dynamics of the active soil layer in alpine meadows. In the snow manipulation experiment with a snow depth greater than 15 cm, the snow cover postponed both the freeze-fall and thawrise onset times of soil temperature and moisture in alpine LC(lower vegetation coverage) meadows and of soil moisture in alpine HC(higher vegetation coverage) meadows; however, the opposite response occurred for soil temperatures of alpine HC meadows,where the entire melting period was extended by advancing the thaw-rise and delaying the freeze-fall onset time of the soil temperature. Snow cover resulted in a decreased amplitude and rate of variation in soil temperature, for both alpine HC meadows and alpine LC meadows, whereas the distinct influence of snow cover on the amplitude and rate of soil moisture variation occurred at different soil layers with different vegetation coverages. Snow cover increased the soil moisture of alpine grasslands during thawing periods. The results confirmed that the annual hydrothermal dynamics of active layers in permafrost were subject to the synergistic actions of both snow cover

关键词： Permafrost Snow cover Vegetationcover Active soil layer Hydrothermal dynamics Synergistic action

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MEBS: Uncovering Memory Life-Cycle Bugs in Operating System Kernels

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Journal of Computer Science & Technology 2021年第6期36卷 1248-1268页

作者： gen Zhang Peng-Fei wang Tai Yue Xu Zhou Kai Lu College of Computer National University of Defense TechnologyChangsha 410073China

Allocation,dereferencing,and freeing of memory data in kernels are coherently *** widely exist real cases where the correctness of memory is *** incorrectness in kernel memory brings about significant security issues,e.g.,information *** memory allocation,dereferencing,and freeing are closely related,previous work failed to realize they are closely *** this paper,we study the life-cycle of kernel memory,which consists of allocation,dereferencing,and *** in them are called memory life-cycle(MLC)*** propose an in-depth study of MLC bugs and implement a memory life-cycle bug sanitizer(MEBS)for MLC bug *** an interprocedural global call graph and novel identification approaches,MEBS can reveal memory allocation,dereferencing,and freeing sites in *** constructing a modified define-use chain and examining the errors in the life-cycle,MLC bugs can be ***,the experimental results on the latest kernels demonstrate that MEBS can effectively detect MLC bugs,and MEBS can be scaled to different *** than 100 new bugs are exposed in Linux and FreeBSD,and 12 common vulnerabilities and exposures(CVE)are assigned.

关键词： software security operating system memory life-cycle static analysis vulnerability detection

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Hemodynamics and vasoactive substance levels during renal congestion that occurs in the anhepatic phase of liver transplantation

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World Journal of Gastroenterology 2015年第18期21卷 5482-5487页

作者： Zhong-Xin Li Man-Cai wang you-Cheng Zhang Jie Mao Mo Chen Rui Ni Feng-Xian Wei gen-Nian wang Ling-Yi Zhang Department of Hepatology Lanzhou University Second Hospital Hepato-Biliary-Pancreatic Institute Lanzhou University Second Hospital Department of general Surgery Lanzhou University Second Hospital

AIM: To explore hemodynamics and vasoactive substance levels during renal vein congestion that occurs in the anhepatic phase of liver ***: New Zealand rabbits received ligation of the hepatic pedicle, supra-hepatic vena cava and infrahepatic vena cava [anhepatic phase group(APH); n = 8], the renal veins(RVL; n = 8), renal veins and hepatic pedicle [with the inferior vena cava left open)(RVHP; n = 8)], or a sham operation(SOP; n = 8). Hemodynamic parameters(systolic, diastolic, and mean arterial blood pressures) and the levels of serum bradykinin(BK) and angiotensin Ⅱ(ANGII) were measured at baseline(0 min), and 10 min, 20 min, 30 min, and 45 min after the surgery. Correlation analyses were performed to evaluate the associations between hemodynamic parameters and levels of vasoactive ***:All experimental groups(APH,RVL,and RVHP)showed significant decreases in hemodynamic parameters(systolic,diastolic,and mean arterial blood pressures)compared to baseline levels,as well as compared to the SOP controls(P<0.05 for all).In contrast,BK levels were significantly increased compared to baseline in the APH,RVL,and RVHP groups at all time points measured(P<0.05 for all),whereas no change was observed in the SOP *** were no significant differences among the experimental groups for any measure at any time *** analyses revealed that systolic,diastolic,and mean arterial blood pressures were all negatively correlated with BK levels,and positively correlated with ANGII levels in the APH,RVL,and RVHP groups(P<0.05 for all).CONCLUSION:In the anhepatic phase of orthotopic liver transplantation,renal vein congestion significantly impacts hemodynamic parameters,which correlate with serum BK and ANGII levels.

关键词： Hemodynamics Renal vein congestion Orthotopic liver transplantation Anhepatic phase Vasoactive substances

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Effects of scleral encircling surgery on vitreous cavity length and diopter

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International Journal of Ophthalmology(English edition) 2016年第4期9卷 572-574页

作者： Zi-Cheng Zhu gen-Jie Ke Yue-Chun Wen Zhang-you Wu Department of Ophthalmology Anhui Provincial HospitalAnhui Medical University

AIM： To observe the changes of vitreous cavity length and diopter after scleral encircling（SE） produce.·METHODS： This prospective study included 68 eyes of68 non-consecutive patients with macula-off retinal detachment who were operated by SE surgery. The corneal refractive power, ocular axial length and diopter were measured by keratometer, A-mode ultrasonic meter and computed dioptometer.· RESULTS： There was no significant difference in corneal refractive power among preoperative and post operative 1, 3 and 6mo（0.57±0.54 D at pre-surgery; 0.72±0.26 D at 1mo; 0.71 ±0.34 D at 3mo; 0.69 ±0.31 D at 6mo;all P 〉0.05）. Axial lengths were obviously lengthened,especially in vitreous cavity length（17.87 ±3.09 mm,19.69 ±3.12 mm, 18.97 ±3.56 mm, 18.76 ±3.47 mm, 18.68 ±3.42 mm at pre-surgery, 1wk, 1, 3 and 6mo postoperatively,P 〈0.05） and diopter also increased at beginning and then recovered gradually. After 1 and 3 mo, axial length（vitreous cavity length） and myopia were more and in higher degree than before surgery.·CONCLUSION： The change of postoperative vitreous cavity length is the main factor that results in the changes of axial length and then makes the change of diopter.

关键词： sclera encircling vitreous cavity length diopter axial length

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Grass-livestock balance based grassland ecological carrying capability and sustainable strategy in the Yellow River Source National Park, Tibet Plateau, China

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Journal of Mountain Science 2021年第8期18卷 2201-2211页

作者： YU Hui LIU Bin-tao wang gen-xu ZHANG Tong-zuo YANG Yan LU Ya-qiong XU you-xue HUANG Min YANG Yi ZHANG Lv Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu610041China Northwest Institute of Plateau Biology Chinese Academy of SciencesKey Laboratory of Adaptation and Evolution of Plateau BiotaXining810001China Qinghai Grassland general Station Xining810001China University of Chinese Academy of Sciences Beijing100049China Sichuan Institute of Land Science and Technology(Sichuan Satellite Application Technology Center) Chengdu610045China

The Yellow River Source National Park(YRSP)is one of the most sensitive and fragile ecological regions in the *** historical intensive grazing and climate change have resulted in ecological degradation that threatens the wildlife and *** the sustainable strategy is urgent for policy makers to meet the demands for wild ungulates and *** our study,the grassland ecological carrying capability(GECC)was assessed based on the updated grass-livestock balance that considered the grass competition from wild *** balances between grass and livestock,and GECC and grassland pressure index(GPI)in the YRSP were measured through overlay analysis and geostatistic *** results showed that:(1)the ratio of livestock to wild ungulates in the research area was approximately 4.56:1,in which the proportion of livestock was 81.75%and the actual number of livestock was 33.84×104 standard sheep units;(2)Under the scenario of minimum grazing utilisation rate,the theoretical grazing capacity and GECC were 37.83×104 standard sheep units and−0.13,*** the maximum grazing utilisation rate,the theoretical grazing capacity and GECC were 41.93×104 standard sheep units and−0.21,*** GECC in both scenarios were both less than 0,the grassland was considered to be in surplus and the livestock was not ***,GPI in the two scenarios were 0.87 and 0.79,respectively,both of which exceeded the warning line of *** on GECC,we recommend that the sustainable strategy in YRSP is either to increase the supplementary feeding about 6.40×104 standard sheep units or reduce the grazing livestock by about 3.50×10^(4) standard sheep units.

关键词： Yellow River Source National Park Grassland ecological carrying capability Grasslivestock balance

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A new method for determination of antithrombotic activity of egg white protein hydrolysate by microplate reader

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Chinese Chemical Letters 2007年第4期18卷 449-451页

作者： Wan gen Yang Zhang wang Shi Ying Xu School of Food Science ＆ Technology Southern Yangtze University Wuxi 214036 China

A new method for the determination of antithrombotic activity of egg white protein hydrolysate （EWPH） was developed using a microplate reader. Reaction was carried out at 37℃and pH 7.2 with fibrinogen concentration 0.1%. Microplate reading was conducted at 405 nm. Inhibition rate of EWPH on thrombin activity showed linearity （R2 = 0.9971）, when the inhibition rate was in the range of 10-90%. The lower limit of detection （LLD, at 99.7% probability） and the biological limit of detection （BLD, at 99.7% probability） of the method were 10.643 and 40 mg/mL, respectively. The repeatability standard deviation （R.S.D.） was 1.08%. The standard deviation of the method was ±0.027 AT-U.

关键词： Egg white protein hydrolysate Antithrombotic activity Microplate reader

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Separation of Insecticidal Ingredient of Paecilomyces cicadae (Miquel) Samson

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Agricultural Sciences in China 2007年第11期6卷 1352-1358页

作者： CHAI Yi-qiu JIN Yi-wei CHEN Guan-ju LIU you-gao LI Xiao-la wang gen-e Zhejiang Institute of Subtropical Crops Wenzhou 325005 P.R.China

In this study, the insecticidal active substance of the fruiting body of Paecilomyces cicadae （Miquel） Samson that can kill the larvae of Plutella xylostella （Lepidoptera： Plutellidae） was isolated and purified by combined separation with biology experiments for the first time. By means of bioactive guided isolation of 40% ethanol-H2O, dichloromethane, ethyl acetate, n-butyl ethanol, macroporous adsorption resin column, high performance liquid chromatography, and sephadex A-20 column, the insecticidal active compound was purified,and a white powder compound was obtained. The compound was active against the third instar larvae ofP. xylostella in 24, 48, and 72 h at the concentration of 10.0 mg mL-1 with a corrective mortality of （95.1 ± 1.8）, （97.7 ± 1.6）, and （99.1 ± 1.7）%, respectively. The compound was strongly sensitive to the larvae. It was stable at acid environment, and was not sensitive to pepsin, and other chracteristics were studied.

关键词： Paecilomyces cicadae (Miquel) Samson Plutella xylostella (Lepidoptera: Plutellidae) extracts of the fruitbody insecticidal activity

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Antibacterial gas therapy: Strategies, advances, and prospects

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Bioactive Materials 2023年第5期23卷 129-155页

作者： Tian-Yu wang Xiao-Yu Zhu Fu-gen Wu State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast University2 Sipailou RoadNanjing210096PR China

One of the challenges posed by current antibacterial therapy is that the expanded and massive use of antibiotics endows bacteria with the ability to resist almost all kinds of ***,developing alternative strategies for efficient antibacterial treatment is urgently *** gas therapy has attracted much attention in the past *** oxide(NO),carbon monoxide(CO),sulfur dioxide(SO2),hydrogen sulfide(H_(2)S),and hydrogen(H_(2))are not only known as endogenous signaling molecules,but also play critical roles in many pathological *** gases are considered as attractive bactericidal agents because they are able to kill bacteria,disperse biofilms,and promote bacteria-infected wound healing while avoiding *** this review,we discuss the bactericidal properties of these gases,as well as the recent advances of gas-involving systems in antibacterial,antibiofilm,and wound treatment ***,we summarize various gas donors utilized in antibacterial *** hope this review will shed new light on the future design and applications of advanced antibacterial gas therapy.

关键词： Antibacterial Antibiofilm Gas therapy Gas donor Nitric oxide

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Multi-VMs Intrusion Detection for Cloud Security Using Dempster-shafer Theory

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Computers, Materials & Continua 2018年第11期57卷 297-306页

作者： Chak Fong Cheang Yiqin wang Zhiping Cai gen Xu Faculty of Information Technology Macao University of Science and TechnologyMacao College of Computer National University of Defense TechnologyChangsha410073China

Cloud computing provides easy and on-demand access to computing resources in a configurable *** flexibility of the cloud environment attracts more and more network services to be deployed on the cloud using groups of virtual machines(VMs),instead of being restricted on a single physical *** more and more network services are deployed on the cloud,the detection of the intrusion likes Distributed Denialof-Service(DDoS)attack becomes much more challenging than that on the traditional servers because even a single network service now is possibly provided by groups of VMs across the cloud *** this paper,we propose a cloud-based intrusion detection system(IDS)which inspects the features of data flow between neighboring VMs,analyzes the probability of being attacked on each pair of VMs and then regards it as independent evidence using Dempster-Shafer theory,and eventually combines the evidence among all pairs of VMs using the method of evidence *** the traditional IDS that focus on analyzing the entire network service externally,our proposed algorithm makes full use of the internal interactions between VMs,and the experiment proved that it can provide more accurate results than the traditional algorithm.

关键词： Intrusion detection cloud computing Dempster-Shafer theory evidence fusion

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