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Designing multilayer diamond like carbon coatings for improved mechanical properties

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Journal of Materials Science & Technology 2021年第6期65卷 108-117页

作者： Mohammad Sharear Kabir zhifeng zhou Zonghan Xie Paul Munroe School of Materials Science and Engineering University of New South WalesSydneyNSW.2052Australia mineAlloy Institute for Frontier MaterialsDeakin UniversityWaum PondsVIC3217Australia Advanced Coatings Applied Research Laboratory Department of Mechanical and Biomedical EngineeringCity University of Hong Kong.KowloonHong KongChina School of Mechanical Engineering University of AdelaideSA5005Australia School of Engineering Edith Cowan University.WA6027Australia

New multilayer coatings were produced by incorporating alternating soft and hard DLC layers enabled by varying the bias voltage during deposition process while maintaining a constant hard-to-soft layer thickness *** coatings were deposited onto a Cr/Cr Cxgraded layer by closed field unbalanced magnetron sputtering(CFUBMS).The cross-sectional analysis of the coatings showed that the multilayer coatings possess sharp interfaces between the soft and hard layers with the hard to soft layer thickness ratio(1:1.33)constant in all the *** analysis uncovered the increasing sp^(3)character of the DLC coatings as a result of decreasing ID/IGratio and increasing full width at half maximum(FWHM)values of the G band peak induced supposedly by an increase in bias voltage during hard layer *** tests showed an increase in hardness of the DLC coatings which can be correlated with the increase in the sp^(3)content of the coatings as well as decreasing sp^(2)-C cluster size,as calculated from the ID/***,the coatings exhibited excellent plastic deformation resistance and adhesion strength upon microindentation and scratch testing,*** further investigations are required to assess coating durability,the multilayer design could offer the DLC coatings with a rare opportunity to combine the high hardness with damage resistance with a constant bilayer thickness and without the need to introduce complex multilayer system.

关键词： Diamond like carbon(DLC) Closed field unbalanced magnetron sputtering(CFUBMS) sp^(3)Character Nanoindentation Plastic deformation resistance Scratch adhesion behaviour

Do land utilization patterns affect methanotrophic communities in a Chinese upland red soil?

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Journal of Environmental Sciences 2010年第12期22卷 1936-1943页

作者： Yong Zheng Xinzhan Liu Limei Zhang zhifeng zhou Jizheng He State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Key Laboratory of Systematic Mycology and Lichenology Institute of Microbiology Chinese Academy of Sciences Beijing 100101 China

Soil samples were collected from three plots under different land utilization patterns including degradation, farming, and restoration. The abundances of methanotrophs were quantified using real-time polymerase chain reaction （PCR） based on the pmoA and 16S rRNA genes, and the community fingerprint was analyzed using denaturing gradient gel electrophoresis （DGGE） aiming at pmoA gene. Significantly lower 16S rRNA and pmoA genes copies were found in the degradation treatment than in farming and restoration. Higher abundances of Type I than those of Type II methanotrophs were detected in all treatments, The treatment of farming was clearly separated from degradation and restoration according to the DGGE profile by cluster analysis. The lowest diversity indices were observed in the F （farming plot）, suggesting that the community structure was strongly affected by farming activities. There were significantly positive correlations between the copy numbers of pmoA also Type II-related 16S rRNA genes and soil available K content. Strong negative and positive correlations were found between Type I and soil pH, and available P content, respectively. We concluded that the vegetation cover or not, soil characteristics including pH and nutrients of P and K as a result of anthropogenic disturbance may be key factors affecting methanotrophic communities in upland soil.

关键词： DGGE land utilization methanotrophs prnoA real-time PCR

Responses of activities, abundances and community structures of soil denitrifiers to short-term mercury stress

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Journal of Environmental Sciences 2012年第3期24卷 369-375页

作者： zhifeng zhou Yuanming Zheng Jupei Shen Limei Zhang Yurong Liu Jizheng He State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Graduate School of Chinese Academy of Sciences Beijing 100039China College of Resources and Environment Southwest UniversityChongqing 400716China

The responses of activities, abundances and community structures of soil denitrifiers to mercury （Hg） stress were investigated through a short-term incubation experiment. Four soil treatments with different concentrations of Hg （CK, Hg25, Hg50, and Hg100, denoted as 0, 25, 50, and 100 mg Hg/kg dry soil, respectively） were incubated for 28 days. Soil denitrification enzyme activity （DEA） was measured at day 3, 7 and 28. The abundances and community structures of two denitrification concerning genes, nirS （cd1-nitrite reductase gene） and nosZ （nitrous oxide reductase gene）, were analyzed using real-time PCR and denaturing gradient gel electrophoresis （DGGE）. Results showed that soil DEA was significantly stimulated in the treatments of Hg25 and Hg50 compared with others at day 7. Meanwhile, no difference in the abundances of soil nirS and nosZ was found between Hg spiked treatments and CK, except the lower abundance of nirS （P 〈 0.05） in the Hg added treatments compared with that in the CK at day 28. The community structures of denitrifiers based on nirS gene presented obvious change at day 7 along with the Hg additions, however, no variation was found in all treatments based on the nosZ gene. The results indicated that Hg （Hg25 and Hg50） had a strongly short-term stimulation on soil DEA, and nirS gene is more sensitive than nosZ gene to Hg stress.

关键词： Hg denitrification enzyme activity nirS nosZ DGGE real-time PCR

Tomographic imaging of P wave velocity structure beneath the region around Beijing

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Earthquake Science 2009年第4期22卷 403-408页

作者： zhifeng Ding Xiaofeng zhou Yan Wu Guiyin Li Hong Zhang Institute of Geophysics China Earthquake Administration Beijing 100081 China

The three-dimension crustal and upper mantle structures in the region around Beijing were studied by seismic tomography. We used the P wave arrival times from local and teleseismic events. These events were recorded by 250 stations of the North China Seismic Array and 108 stations of the Beijing Telemetry Seismic Network. 118 869 P wave arrivals from 10 285 local events and 12 189 P wave arrivals from 107 teleseismic events were used in the inversion. We obtained the 3-D P wave velocity structure of the crust and upper mantle with the horizontal resolution of 0.3° in the studied region. The tomographic imaging shows the remarkably heterogeneous velocity variation. The velocity anomalies are in well agreement with the geological structure in the shallow crust. The different relationships between seismic activities and velocity anomalies may imply the different seismogenic structure and mechanism. Beneath the Moho under Taihangshan mountain and Yanshan mountain, we found the high velocity anomalies deep to 120 km and 200 km, respectively. The deep high velocity zone may be explained by the existence of the mountain root under Yanshan mountain. The high velocity anomalies in the upper mantle of North China basin may be the relics of the de-rooting from the former craton mantle lithosphere.

关键词： crustal and upper mantle structure Beijing seismic tomography

Recycle use of phosphorous mixer extractant to extract indium

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Rare Metals 2003年第2期22卷 91-94页

作者： XU Xiulian, XU zhifeng, and zhou FayingFaculty of Material and Chemical Engineering, Southern Institute of Metallurgy, Ganzhou 341000, China (Received 2002-01-30) Faculty of Material and Chemical Engineering Southem Institute of Metallurgy Ganzhou 341000

The stripping and regeneration of the loaded organic phase of phosphorousmixer extractant (PPD) were studied. The mixed solutions (3 mol/L HCl +2 mol/L ZnC1_2) were used asthe stripping agent and more than 99 percent of indium can be stripped after three-stage strippingwhen the volume ratio of organic phase to stripping agent is 1:1. The organic phase can he recycledto use alter regeneration with HCl. The parallel contrast experiments with D_2EHPA (di-2-ethyl hexylphosphoric acid) were carried out under the same conditions. The results show that the mixerextractant has good reusability and the stripping and regeneration of PPD are superior to those ofD_2EHPA.

关键词： hydrometallurgy solvent extraction single-factor experiment indium phosphorous mixer extractant (PPD)

Application of extracorporeal therapies in critically ill COVID-19 patients

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2021年第9期22卷 701-717页

作者： zhifeng zhou Huang KUANG Yuexian MA Ling ZHANG Department of Nephrology Kidney Research InstituteWest China HospitalSichuan UniversityChengdu 610041China Renal Division Peking University First HospitalPeking University Institute of NephrologyKey Laboratory of Renal DiseaseMinistry of Health of ChinaBeijing 100034China Department of Nephrology Hospital of Chengdu University of Traditional Chinese MedicineChengdu 610072China

The coronavirus disease 2019(COVID-19)pandemic is a major public health event caused by severe acute respiratory syndrome coronavirus 2(SARS-Co V-2).COVID-19 has spread widely all over the world.A high proportion of patients become severely or critically ill,and suffer high mortality due to respiratory failure and multiple organ ***,providing timely and effective treatment for critically ill patients is essential to reduce overall *** plasma therapy and pharmacological treatments,such as aerosol inhalation of interferon-α(IFN-α),corticosteroids,and tocilizumab,have all been applied in clinical practice;however,their effects remain *** studies have shown that extracorporeal therapies might have a potential role in treating critically ill COVID-19 *** this review,we examine the application of continuous renal replacement therapy(CRRT),therapeutic plasma exchange(TPE),hemoadsorption(HA),extracorporeal membrane oxygenation(ECMO),and extracorporeal carbon dioxide removal(ECCO2 R)in critically ill COVID-19 patients to provide support for the further diagnosis and treatment of COVID-19.

关键词： Coronavirus disease 2019(COVID-19) Critical illness Cytokine release syndrome(CRS) Acute kidney injury(AKI) Extracorporeal therapy

High cut-off membranes in patients requiring renal replacement therapy:a systematic review and meta-analysis

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Chinese Medical Journal 2023年第1期136卷 34-44页

作者： zhifeng zhou Huang Kuang Fang Wang Lu Liu Ling Zhang Ping Fu Division of Nephrology Kidney Research InstituteWest China Hospital of Sichuan UniversityChengduSichuan 610041China Division of Nephrology Peking University First HospitalPeking University Institute of NephrologyKey Laboratory of Renal DiseaseMinistry of Health of ChinaBeijing 100034China Preventive Medicine West China School of Public HealthSichuan UniversityChengduSichuan 610041China

Background:Whether high cut-off(HCO)membranes are more effective than high-flux(HF)membranes in patients requiring renal replacement therapy(RRT)remains *** aim of this systematic review was to investigate the efficacy of HCO membranes regarding the clearance of inflammation-related mediators,β2-microglobulin and urea;albumin loss;and all-cause mortality in patients requiring ***:We searched all relevant studies on PubMed,Embase,Web of Science,the Cochrane Library,and China National Knowledge Infrastructure,with no language or publication year *** reviewers independently selected studies and extracted data using a prespecified extraction *** randomized controlled trials(RCTs)were *** estimates of standardized mean differences(SMDs)or weighted mean differences(WMDs)and risk ratios(RRs)were obtained by fixed-effects or random-effects *** analyses and subgroup analyses were performed to determine the source of ***:Nineteen RCTs involving 710 participants were included in this systematic *** with HF membranes,HCO membranes were more effective in reducing the plasma level of interleukin-6(IL-6)(SMD-0.25,95%confidence interval(CI)-0.48 to-0.01,P=0.04,I 2=63.8%);however,no difference was observed in the clearance of tumor necrosis factor-α(TNF-α)(SMD 0.03,95%CI-0.27 to 0.33,P=0.84,I 2=4.3%),IL-10(SMD 0.22,95%CI-0.12 to 0.55,P=0.21,I 2=0.0%),or urea(WMD-0.27,95%CI-2.77 to 2.23,P=0.83,I 2=19.6%).In addition,a more significant reduction ratio ofβ2-microglobulin(WMD 14.8,95%CI 3.78 to 25.82,P=0.01,I 2=88.3%)and a more obvious loss of albumin(WMD-0.25,95%CI-0.35 to-0.16,P<0.01,I 2=40.8%)could be observed with the treatment of HCO *** all-cause mortality,there was no difference between the two groups(risk ratio[RR]1.10,95%CI 0.87 to 1.40,P=0.43,I 2=0.0%).Conclusions:Compared with HF membranes,HCO membranes might have additional benefits on the clearance of IL-6 andβ

关键词： High cut-off High-flux Renal replacement therapy Randomized controlled trials Meta-analysis