检索结果-南通市图书馆

Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第3期21卷 205-212页

作者： Guan-yu Jiang Meng-wu wu xiao-guang yang Hui Wang Yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

Microstructural and thermal properties of coal measure sandstone subjected to high temperatures

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 2909-2921页

作者： Weijing xiao Dongming Zhang Shujian Li Mingyang wu School of Civil Engineering and Architecture East China Jiaotong UniversityNanchang330013China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400044China Yunnan Phosphate Chemical Group Co. Ltd.Kunming650600China National Engineering and Technology Research Center for Development and Utilization of Phosphate Resources Kunming650600China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

To study the microscopic structure,thermal and mechanical properties of sandstones under the influence of temperature,coal measure sandstones from Southwest China are adopted as the research object to carry out high-temperature tests at 25℃-1000℃.The microscopic images of sandstone after thermal treatment are obtained by means of polarizing microscopy and scanning electron microscopy(SEM).Based on thermogravimetric(TG)analysis and differential scanning calorimetric(DSC)analysis,the model function of coal measure sandstone is explored through thermal analysis kinetics(TAK)theory,and the kinetic parameters of thermal decomposition and the thermal decomposition reaction rate of rock are *** the uniaxial compression experiments,the stress‒strain curves and strength characteristics of sandstone under the influence of temperature are *** results show that the temperature has a significant effect on the microstructure,mineral composition and mechanical properties of *** particular,when the temperature exceeds 400℃,the thermal fracture phenomenon of rock is obvious,the activity of activated molecules is significantly enhanced,and the kinetic phenomenon of the thermal decomposition reaction of rock appears *** mechanical properties of rock are weakened under the influence of rock thermal fracture and mineral thermal *** research results can provide a reference for the analysis of surrounding rock stability and the control of disasters caused by thermal damage in areas such as underground coal gasification(UCG)channels and rock masses subjected to mine fires.

关键词： Rock mechanics Coal measure sandstone Micromorphology Thermal damage

Conservation genomics of the critically endangered Chinese pangolin

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2024年第10期67卷 2051-2061页

作者： Shichao Wei Huizhong Fan Wenliang Zhou Guangping Huang yan Hua Shibao wu xiao Wei Yiting Chen Xinyue Tan Fuwen Wei Jiangxi Province Key Laboratory of Conservation Biology College of ForestryJiangxi Agricultural UniversityNanchang 330045China Center for Evolution and Conservation Biology Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)Guangzhou 511458China Institute of Zoology Chinese Academy of SciencesBeijing 100101China Guangdong Provincial Key Laboratory of Silviculture Protection and UtilizationGuangdong Academy of ForestryGuangzhou 510520China School of Life Science South China Normal UniversityGuangzhou 510631China Terrestrial Wildlife Rescue and Epidemic Diseases Surveillance Center of Guangxi Nanning 530003China

The Chinese pangolin(Manis pentadactyla,MP)has been extensively exploited and is now on the brink of extinction,but its population structure,evolutionary history,and adaptive potential are ***,we analyzed 94 genomes from three subspecies of the Chinese pangolin and identified three distinct genetic clusters(MPA,MPB,and MPC),with MPB further divided into MPB1 and MPB2 *** divergence of these populations was driven by past climate *** MPB2 and MPC,recent human activities have caused dramatic population decline and small population size as well as increased inbreeding,but not decrease in genomic variation and increase in genetic load probably due to strong gene flow;therefore,it is crucial to strengthen in situ habitat management for these two *** contrast,although human activities have a milder impact on MPA,it is at high risk of extinction due to long-term contraction and isolation,and genetic rescue is urgently ***1 exhibited a relatively healthy population status and can potentially serve as a source ***,our findings provide novel insights into the conservation of the Chinese pangolin and biogeography of the mammals of eastern Asia.

关键词： Manis pentadactyla conservation genomics demographic history human activities conservation strategies

Expression and significance of pigment epithelium-derived factor and vascular endothelial growth factor in colorectal adenoma and cancer

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第3期16卷 670-686页

作者： Ye yang wu Wen Feng-Lin Chen Ying-Jie Zhang xiao-Cong Liu xiao-yan yang Shan-Shan Hu Ye Jiang Jing Yuan Digestive Diseases Chengdu Qingbaijiang District People's HospitalChengdu 610300Sichuan ProvinceChina Digestive Diseases Chengdu Second People’s HospitalChengdu 610000Sichuan ProvinceChina Graduate School Chengdu Medical CollegeChengdu 610000Sichuan ProvinceChina

BACKGROUND The incidence and mortality of colorectal cancer(CRC)are among the highest in the world,and its occurrence and development are closely related to tumor *** the balance between pigment epithelium-derived factors(PEDF)that inhibit angiogenesis and vascular endothelial growth factors(VEGF)that stimulate angiogenesis is broken,angiogenesis is out of control,resulting in tumor ***,it is very necessary to find more therapeutic targets for CRC for early intervention and later *** To investigate the expression and significance of PEDF,VEGF,and CD31-stained microvessel density values(CD31-MVD)in normal colorectal mucosa,adenoma,and *** In this case-control study,we collected archived wax blocks of specimens from the Digestive Endoscopy Center and the General Surgery Department of Chengdu Second People's Hospital from April 2022 to October *** cases of specimen wax blocks were selected as normal intestinal mucosa confirmed by electronic colonoscopy and concurrent biopsy(normal control group),50 cases of specimen wax blocks were selected as colorectal adenoma confirmed by electronic colonoscopy and pathological biopsy(adenoma group),and 50 cases of specimen wax blocks were selected as CRC confirmed by postoperative pathological biopsy after inpatient operation of general surgery(CRC group).An immunohistochemical staining experiment was carried out to detect PEDF and VEGF expression in three groups of specimens,analyze their differences,study the relationship between the two and clinicopathological factors in CRC group,record CD31-MVD in the three groups,and analyze the correlation of PEDF,VEGF,and CD31-MVD in the colorectal adenoma group and the CRC *** F test or adjusted F test is used to analyze measurement data ***-Wallis rank sum test was used between groups for ranked *** chi-square test,adjusted chi-square test,or Fisher's exact test were used to compare the rates betwe

关键词： Pigment epithelium-derived factors Vascular endothelial growth factor Microvessel density Colorectal adenoma Colorectal cancer Targeted therapy

Boosting oxygen vacancies by modulating the morphology of Au decorated In_(2)O_(3)with enhanced CO_(2)hydrogenation activity to CH_(3)OH

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第6期140卷 91-102页

作者： Ruxian Hou Jiewen xiao Qian wu Tianyu Zhang Qiang Wang Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China

CO_(2)hydrogenation to methanol has become one of the most promising ways for CO_(2)utilization,however,the CO_(2)conversion rate and methanol selectivity of this reaction still need to be improved for industrial *** we investigated the structure-activity relationship for CO_(2)conversion to methanol of In_(2)O_(3)-based catalysts by modulating morphology and decorating *** different Au/In_(2)O_(3)catalysts were prepared,their activity follow the sequence of Au/In_(2)O_(3)-nanosphere(Au/In_(2)O_(3)-NS)>Au/In_(2)O_(3)-nanoplate(Au/In_(2)O_(3)-NP)>Au/In_(2)O_(3)-hollow microsphere(Au/In_(2)O_(3)-HM).Au/In_(2)O_(3)-NS exhibited the best performance with good CO_(2)conversion of 12.7%,high methanol selectivity of 59.8%,and large space time yield of 0.32 g CH_(3)OH/(hr·gcat)at 300℃.The high performance of Au/In_(2)O_(3)-NS was considered as the presence of *** contributes to the creation of more surface oxygen vacancies,which further promoted the CO_(2)adsorption and facilitated CO_(2)activation to form the formate intermediates towards *** work clearly suggests that the activity of In_(2)O_(3)catalyst can be effective enhanced by structure engineering and Au decorating.

关键词： CO_(2)hydrogenation Methanol Au/In_(2)O_(3) Morphology Oxygen vacancies

Efficacy of scraping therapy on blood pressure and sleep quality in stage Ⅰ and Ⅱ essential hypertension: A systematic review and meta-analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Medicine 2024年第1期22卷 12-21页

作者： Zheng-gang Zhu Jian-ru Wang xiao-yan Pan School of Nursing Hunan University of Chinese MedicineChangsha 410208Hunan ProvinceChina School of Health Sciences Universiti Sains MalaysiaKubang Kerian 16150KelantanMalaysia Department of Cardiovascular Medicine the First Affiliated Hospital of Henan University of Chinese MedicineZhengzhou 450000Henan ProvinceChina

Background Scraping therapy is widely used in treating stage I and II essential hypertension in ***,there has been no systematic evaluation of the efficacy of scraping therapy on blood pressure and sleep quality in stage I and II essential *** strategy Seven electronic databases(PubMed,Scopus,Cochrane Library,Web of Science,EBSCO,China National Knowledge Infrastructure and Wanfang Data electronic databases)were searched from inception to December *** on the principle of combining subject words with text words,the search strategy was constructed around search terms for“scraping therapy,”“scraping,”“Guasha,”“Gua sha,”“hypertension,”and“high blood pressure”during the database *** criteria Randomized controlled trials(RCTs)were included if they recruited patients with stage I and II essential hypertension and included a scraping therapy *** intervention group received antihypertensive drugs and scraping therapy,while the control group only took antihypertensive *** extraction and analysis Review Manager 5.4.0 and STATA 15.1 were used to enter all the relevant outcome variables to conduct the *** quality of the selected RCTs was assessed using the PEDro *** sensitivity analysis was carried out by iteratively excluding individual studies and repeating the analysis to determine the stability of the findings and identify any studies with greater influence on the *** analysis was performed to find the source of *** plots were used to evaluate the publication bias of included *** Nine RCTs including 765 participants were ***-analysis showed that scraping therapy combined with medication had an advantage over the use of medication alone in lowering systolic blood pressure(mean difference[MD]=?5.09,95%confidence interval[CI]=?6.50 to?3.67,P<0.001)and diastolic blood pressure(MD=?2.66,95%CI=?3.17 to?2.14,P<0.001).Subgroup analysis showed tha

关键词： Scraping therapy Essential hypertension Efficacy Blood pressure Sleep quality Systematic review Meta-analysis

Kinetic Resolution of Racemic 4-Substituted Chroman-2-ones Through Asymmetric Lactone Hydrogenation

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第10期6卷 2560-2576页

作者： Xiong wu Hai-Tao Yue xiao-Dong Zuo xiao-Hui yang Pu-Cha yan Jian-Hua Xie Qi-Lin Zhou State Key Laboratory and Institute of Elemento-Organic Chemistry College of ChemistryFrontiers Science Center for New Organic MatterNankai UniversityTianjin 300071 Zhejiang Jiuzhou Pharmaceutical Co. Ltd.TaizhouZhejiang 318000

Esters are abundant in natural and synthetic products and their conversion into primary alcohols holds great importance in fine chemical ***,achieving asymmetric hydrogenation(AH)of racemic esters with remote stereocenters via kinetic resolution(KR)remains a formidable challenge due to the difficulties associated with discerning spatially distant *** address this issue,we have designed a hydroxy-assisted strategy that introduces a hydroxy group into racemicβ-aryl esters to facilitate hydrogenation and enhance chiral discrimination through a lactone *** employing chiral Ir-SpiroPAP catalysts,we achieved exceptional AH of racemic 4-substituted chroman-2-ones,lactone form of ortho-hydroxylatedβ-aryl esters,via KR,resulting in impressive selectivity factor(s)values of up to *** approach exhibited significant efficacy for racemic chroman-2-ones containingβ-aryl,alkenyl,alkynyl,and alkyl groups,enabling the synthesis of chiralγ-aryl primary alcohols and the recovery of chiralβ-aryl esters or chroman-2-ones,typically difficult to access using existing *** scalability and broad synthetic applications of this method were exemplified by successfully synthesizing chiral drugs(R)-fesoterodine and enrasentan,alongside various chiral intermediates essential for producing chiral drugs and natural *** promising results highlight the potential of this approach as a powerful tool for synthesizing valuable chiral compounds.

关键词： asymmetric hydrogenation chiralγ-aryl primary alcohols hydrogenation of esters iridium catalysts kinetic resolution

Research on casing deformation prevention technology based on cementing slurry system optimization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1231-1240页

作者： yan yan Meng Cai Wen-Hai Ma xiao-Chuan Zhang Li-Hong Han Yong-Hong Liu State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research InstituteXi©an710077ShaanxiChina College of Mechanical and Electrical Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Shale Gas Evaluation and Exploitation Key Laboratory of Sichuan Province Chengdu610095SichuanChina CNPC Daqing Oilfield Company Daqing163453HeilongjiangChina

The casing deformation prevention technology based on the optimization of cement slurry is proposed to reduce the casing deformation of shale oil and gas wells during hydraulic fracturing. In this paper, the fracture mechanism of hollow particles in cement sheath was firstly analyzed by discrete element method, and the effect of hollow particles in cement on casing deformation was investigated by laboratory experiment method. Finally, field test was carried out to verify the improvement effect of the casing deformation based on cement slurry modification. The results show that the formation displacement can be absorbed effectively by hollow particles inside the cement transferring the excessive deformation away from casing. The particles in the uncemented state provide deformation space during formation slipping. The casing with diameter of 139.7 mm could be passed through by bridge plug with the diameter of 99 mm when the mass ratio of particle/cement reaches 1:4. According to the field test feedback, the method based on optimization of cement slurry can effectively reduce the risk of casing deformation, and the recommended range of hollow microbeads content in the cement slurry is between 15% and 25%.

关键词： Cement slurry Hollow ceramsite Casing deformation Formation slip Field test

Research progresses on cathode materials of aqueous zinc-ion batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第10期97卷 237-264,I0005页

作者： Zengyuan Fan Jiawei Wang Yunpeng wu Xuedong yan Dongmei Dai Xing-Long wu Jilin Provincial Science and Technology Innovation Centre of Optical Materials and Chemistry Jilin Provincial International Joint Research Center of Photo-functional Materials and ChemistrySchool of Chemistry and Environmental EngineeringChangchun University of Science and TechnologyChangchun 130022JilinChina PMOE Key Laboratory for UV LightEmitting Materials and Technology School of PhysicsNortheast Normal UniversityChangchun 130024JilinChina Chongqing Research Institute Changchun University of Science and TechnologyChongqing 401135China Institute of Energy Storage and Conversion Technology College of Chemical EngineeringNingbo PolytechnicNingbo 315800ZhejiangChina School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007HenanChina

Electrochemical energy storage and conversion techniques that exhibit the merits such as high energy density,rapid response kinetics,economical maintenance requirements and expedient installation procedures will hold a pivotal role in the forthcoming energy storage technologies *** recent years,aqueous zinc-ion batteries(AZIBs)have garnered substantial attention as a compelling candidate for large-scale energy storage systems,primarily attributable to their advantageous featu res encompassing cost-effectiveness,environmental sustainability,and robust safety ***,one of the primary factors hindering the further development of AZIBs originates from the challenge of cathode ***,the three mainstream types of mainstream cathode materials,in terms of manganese-based compounds,vanadium-based compounds and Prussian blue analogues,surfer from the dissolution of Mn~(2+),in the low discharge voltage,and the low specific capacity,*** strategies have been developed to compensation the above intrinsic defects for these cathode materials,including the ionic doping,defect engineering,and materials ***,this review first provides a systematic summarization of the zinc storage mechanism in AZIBs,following by the inherent merit and demerit of three kind of cathode materials during zinc storage analyzed from their structure characteristic,and then the recent development of critical strategies towards the intrinsic insufficiency of these cathode *** this review,the methodologies aimed at enhancing the efficacy of manganese-based and vanadium-based compounds are emphasis ***,the article outlines the future prospective directions as well as strategic proposal for cathode materials in AZIBs.

关键词： Aqueous zinc-ion batteries Cathode materials Optimization strategies