检索结果-南通市图书馆

Journal of Materials Science & Technology 2021年第25期84卷 49-58页

作者： x.c.Li J.x.Zhao J.H.cong R.D.K.Misra x.M.Wang x.L.Wang c.J.Shang collaborative Innovation center of Steel Technology University of Science and Technology BeijingBeijing 100083China Department of Metallurgical Materials and Biomedical EngineeringUniversity of Texas at El Paso500 W.University AvenueEl PasoTX 79968USA

Gradient boosting decision tree(GBDT)machine learning(ML)method was adopted for the first time to automatically recognize and conduct quantitative statistical analysis of boundaries in bainitic microstructure using electron back-scatter diffraction(EBSD)*** spite of lack of large sets of EBSD data,we were successful in achieving the desired accuracy and accomplishing the objective of recognizing the *** with a low model accuracy ofxis-angle pair as characteristic features,the accuracy of the model was significantly enhanced to about 88%when the Euler angle was converted to overall misorientation angle(OMA)and specific misorientation angle(SMA)and considered as important *** this model,the recall score of prior austenite grain(PAG)boundary was~93%,high angle packet boundary(OMA>40°)was~97%,and block boundary was~96%.The derived outcomes of ML were used to obtain insights into the ductile-to-brittle transition(DBTT)***,ML modeling approach suggested that DBTT was not determined by the density of high angle grain boundaries,but significantly influenced by the density of PAG and packet *** study underscores that ML has a great potential in detailed recognition of complex multi-hierarchical microstructure such as bainite and martensite and relates to material performance.

关键词： Machine learning Feature engineering Automatic recognition Lath structure crystallography

光谱参数在青藏高原东北缘尖扎盆地风成红黏土古气候记录中的应用

在线全文

学校读者我要写书评

暂无评论

中国科学：地球科学 2024年第6期54卷 1980-1995页

作者：符超峰田菊娥徐新文宋友桂左俊王凤陈琳李鹏飞强小科长安大学地球科学与资源学院西安710054 中国科学院地球与环境研究所黄土与第四纪地质国家重点实验室西安710061 西北大学城市与环境学院西安710069 中国科学院第四纪科学与全球变化卓越创新中心西安710061

反射光谱测量具有快速、廉价和无损的特点,可提供岩石和沉积物所含矿物的重要信息.通过测量青藏高原东北缘晚中新世红黏土沉积物的反射光谱,旨在寻找一种可以快速获取古气候变化信息的方法.利用尖扎盆地红黏土沉积物的可见光/近红外(VN... 详细信息

反射光谱测量具有快速、廉价和无损的特点,可提供岩石和沉积物所含矿物的重要信息.通过测量青藏高原东北缘晚中新世红黏土沉积物的反射光谱,旨在寻找一种可以快速获取古气候变化信息的方法.利用尖扎盆地红黏土沉积物的可见光/近红外(VNIR)和短波红外(SWIR)波段的光谱数据,分析了它们与传统古气候指标黏土矿物含量和环境磁学参数的关系.结果表明, VNIR参数D500、D900、R500和R900(其中D和R分别代表500nm和900nm附近吸收峰的深度和反射率)与磁化率、频率磁化率和深海氧同位素关系密切,且它们对温度较为敏感.VNIR参数的频谱分析结果表明,它们可以反映气候在轨道时间尺度上的变化. SWIR参数AS1400、D1400/D1900、D1900(其中AS代表1400nm附近吸收峰的不对称性)与伊利石和蒙脱石的相对含量有关,且它们对风化强度更敏感.尖扎盆地风成红黏土沉积物的光谱参数可以反映~8.5Ma青藏高原隆升引起的区域气候变化和~7.2Ma的全球气候变冷事件.因此,光谱参数可作为反映区域和全球气候变化的古环境指标.

关键词：可见光/近红外光谱短波红外光谱古气候指标红黏土青藏高原

Photoionisation detection of a single Er3+ ion with sub-100-ns time resolution

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第4期11卷 38-45页

作者： Yangbo Zhang Wenda Fan Jiliang Yang Hao Guan Qi Zhang xi Qin changkui Duan Gabriele G.de Boo Brett c.Johnson Jeffrey c.Mc callum Matthew J.Sellars Sven Rogge chunming Yin Jiangfeng Du cAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China cAS center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China centre of Excellence for Quantum computation and communication Technology School of Physics University of New South Wales centre of Excellence for Quantum computation and communication Technology School of Engineering RMIT University centre of Excellence for Quantum computation and communication Technology School of Physics University of Melbourne centre of Excellence for Quantum computation and communication Technology Research School of Physics and Engineering Australian National University

Efficient detection of single optical centres in solids is essential for quantum information processing, sensing and single-photon generation *** this work,we use radio-frequency（RF） reflectometry to electrically detect the photoionisation induced by a single Er3+ion in *** high bandwidth and sensitivity of the RF reflectometry provide sub-100-ns time resolution for the photoionisation *** this technique,the optically excited state lifetime of a single Er3+ion in a Si nano-transistor is measured for the first time to be 0.49±0.04μ*** results demonstrate an efficient approach for detecting a charge state change induced by Er excitation and *** approach could be used for fast readout of other single optical centres in solids and is attractive for large-scale integrated optical quantum systems thanks to the multi-channel RF reflectometry demonstrated with frequency multiplexing techniques.

关键词： single optical centres erbium ions RF reflectometry photoionisation detection

Postbiotics from Saccharomyces cerevisiae fermentation stabilize microbiota in rumen liquid digesta during grain-based subacute ruminal acidosis(SARA) in lactating dairy cows

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2024年第5期15卷 2059-2080页

作者： Junfei Guo Zhengxiao Zhang Le Luo Guan Ilkyu Yoon Jan c.Plaizier Ehsan Khafipour Department of Animal Science University of ManitobaWinnipegMB R3T 2N2Canada Present Address:college of Food and Biological Engineering Jimei UniversityXiamenFujian 361021China Department of Agriculture Food and Nutrition DepartmentUniversity of AlbertaEdmontonAB T6G 2R3Canada Faculty of Land and Food Systems University of British ColumbiaVancouverBC V6T 1Z4Canada Diamond V Cedar RapidsIA 52404United States Present Address:cargill Animal Nutrition 15407 McGinty Road WestWayzataMN 55391USA

Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host *** study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(ScFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SARA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after *** groups included a control diet or diets supplemented with postbiotics(ScFPa,14 g/d Original xPc;ScFPb-1x,19 g/d Nutri Tek;ScFPb-2x,38 g/d Nutri Tek,Diamond V,cedar Rapids,IA,USA).Grain-based SARA challenges were conducted during week 5(SARA1)and week 8(SARA2)after parturition by replacing 20%DM of the base total mixed ration(TMR)with pellets containing 50%ground barley and 50%ground *** DNA from rumen liquid samples was subjected to V3–V416S r RNA gene amplicon *** of rumen microbiota were compared among treatments and SARA *** Both SARA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic *** SARA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence *** with ScFP postbiotics,in particular ScFPb-2x,enhanced the robustness of the rumen *** ScFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SARA *** ScFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of Ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SARA and SARA *** with S

关键词： Postbiotics Rumen microbiota Saccharomyces cerevisiae fermentation products SARA

Bulk nanocrystalline W-Ti alloys with exceptional mechanical properties and thermal stability

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第19期114卷 16-28页

作者： H.x.xue x.c.cai B.R.Sun x.Shen c.c.Du x.J.Wang T.T.Yang S.W.xin T.D.Shen clean Nano Energy center State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao 066004China cSSc 723rd Research Institute China State Shipbuilding Corporation LimitedYangzhou 225000China

Nanocrystalline(Nc)W metals and alloys often exhibit higher radiation tolerance and strength than their coarse-grained ***,their thermal stability is low,making it difficult to achieve bulk Nc W metals and alloys by consolidation using conventional techniques such as pressure-less sintering,hot-explosive-compaction sintering,and spark plasma *** we report the synthesis and mechanical properties of bulk Nc W_(100-x)Ti_(x)(x=10 at.%-30 at.%)alloys prepared by consolidating mechanically alloyed Nc powders under a high-temperature/high-pressure *** 20 at.%-30 at.%Ti largely improves the sinterability of Nc W-Ti alloy *** room-temperature microhardness and compressive yield strength of consolidated bulk Nc W_(80)Ti_(20) alloy are∼16.9 and 6.0 GPa,respectively,which are mainly caused by grain boundary strengthening and significantly higher than those of previously reported W and W *** ultimate compressive strength of bulk Nc W_(80)Ti_(20) measured between 900 and 1100°c deceases with increasing *** behavior can be explained by the activation of Rachinger grain boundary *** grain growth is observed in bulk Nc W_(80)Ti_(20) after compression at 1000°*** calculation suggests that it is the segregation of Ti at grain boundaries that decreases the specific grain boundary free energy and makes the Nc W_(80)Ti_(20) alloy thermodynamically stable.

关键词： Nanocrystalline W-Ti alloys Segregation Grain boundary energy Strength Hardness

Homotopy analysis solutions for the asymmetric laminar flow in a porous channel with expanding or contracting walls

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2011年第2期27卷 208-214页

作者： x.-H. Si L.-c. Zheng x.-x. Zhang Y. chao Applied Science School University of Science and Technology Beijing 100083 Beijing China Department of Mechanical Engineering University of Science and Technology Beijing100083 Beijing China Research Institute of chemical Defense of the EL.A 102205 Beijing China

In this paper, the asymmetric laminar flow in a porous channel with expanding or contracting walls is investigated. The governing equations are reduced to ordinary ones by using suitable similar transformations. Homotopy analysis method （HAM） is employed to obtain the expres- sions for velocity fields. Graphs are sketched for values of parameters and associated dynamic characteristics, especially the expansion ratio, are analyzed in detail.

关键词： Homotopy analysis method · Expanding or contracting wall · Asymmetric laminar flow · Porous channel · Expansion ratio

数字减影血管造影引导下经鞘管内钳夹活检辅助诊断肺动脉梗阻性疾病

在线全文

学校读者我要写书评

暂无评论

中国介入影像与治疗学 2024年第7期21卷 390-392页

作者：侯荣娜周学良宋梦瑶张程智孙占国方毅韩新巍焦德超郑州大学第一附属医院放射介入科河南郑州450052

目的观察数字减影血管造影(DSA)引导下经鞘管内钳夹活检辅助诊断肺动脉梗阻性疾病的有效性及其安全性。方法回顾性分析16例因肺动脉梗阻性疾病而接受经股静脉途径钳夹活检患者资料,记录其临床表现,以取材满足病理学诊断所需为技术成功... 详细信息

目的观察数字减影血管造影(DSA)引导下经鞘管内钳夹活检辅助诊断肺动脉梗阻性疾病的有效性及其安全性。方法回顾性分析16例因肺动脉梗阻性疾病而接受经股静脉途径钳夹活检患者资料,记录其临床表现,以取材满足病理学诊断所需为技术成功;根据病理学结果诊断恶性病变,将活检病理为良性且其后半年及以上病情无明显变化,或手术病理良性者归为良性病变,二者均不符合为“未确诊”。记录钳夹活检操作时间、技术成功率、诊断效能、并发症及活检前、后肺动脉压改变。结果 16例中,9例表现为间断胸闷、4例胸痛伴胸闷、2例胸痛、1例无明显症状;10例病灶位于左肺、6例位于右肺,增强cT显示病变肺动脉内存在充盈缺损。对16例共行16次钳夹活检,平均操作时间(31.02±6.02)min,技术成功率100%。10例恶性肿瘤中,1例肺癌钳夹活检结果呈假阴性;6例良性病变中,钳夹活检均正确诊断。活检后2例出现一过性胸痛伴胸闷加重,均经对症治疗后缓解。活检前[(53.38±14.28)mmHg]、后[(53.69±14.15)mmHg]肺动脉压差异无统计学意义(P>0.05)。结论 DSA引导下经鞘管内钳夹活检能安全、有效地辅助诊断肺动脉梗阻性疾病。

关键词：肺动脉血管造影术数字减影活组织检查

Layered Machinable and Electrically conductive Ti_2Alc and Ti_3Alc_2 ceramics:a Review

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第5期26卷 385-416页

作者： x.H. Wang Y.c. Zhou Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China

Ti2Alc and Ti3Alc2 are the most light-weight and oxidation resistant layered ternary carbides belonging to the MAx *** review highlights recent achievements on the processing,microstructure,physical,mechanical and chemical properties of these two machinable and electrically conductive ***2Alc and Ti3Alc2 display superior properties such as fracture toughness,electrical and thermal conductivities,and oxidation resistance over their binary *** paper provides a comprehensive overview of the processing-microstructure-property correlations of these two *** fields of applications for Ti2Alc and Ti3Alc2 are *** addition,we point out methods for further improving their properties in some specific applications through appropriate structural design and modification.

关键词： MAx phases Ti2Alc Ti3Alc2 Machinable ceramics

Influence of a liquid-filled compartment structure on the incoming shaped charge jet stability

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第2期17卷 571-582页

作者： x.D.Zu Z.x.Huang Z.W.Guan x.c.Yin Y.M.Zheng School of Mechanical Engineering Nanjing University of Science and TechnologyXiaolingwei 200Nanjing 210094China School of Engineering University of LiverpoolLiverpoolL693GQUK Department of Mechanics and Engineering Science Nanjing University of Science and TechnologyNanjing 210094China

Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and *** liquid-filled compartment structure can resist the shaped charge warhead *** paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact *** the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is *** interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also *** addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.

关键词： compartment structure Shaped charge jet Shock wave Disturbance Stability

Optimization of performance of the KM2A full array using the crab Nebula

在线全文

学校读者我要写书评

暂无评论

chinese Physics c 2024年第6期48卷 169-178页

作者：曹臻 F.Aharonian 安琪阿西克古白云翔包逸炜 D.Bastieri 毕效军毕玉江蔡金庭曹晴曹文羽曹喆常进常劲帆陈尚明陈恩生陈亮陈林陈龙陈明君陈玛丽陈起辉陈素弘陈天禄陈阳程宁程耀东崔明阳崔树旺崔晓红崔昱东戴本忠代洪亮戴子高单增罗布 D.della Volpe 董绪强段凯凯樊军辉范一中方军方堃冯存峰封莉冯少辉丰晓婷冯有亮 S.Gabici 高博高川东高林青高启高卫高伟康葛茂茂耿利斯 G.Giacinti 龚光华苟全补顾旻皓郭福来郭晓磊郭义庆郭莹莹韩毅昂何会海贺昊宁何佳银何新波何钰 M.Heller 贺远强侯博文侯超侯贤胡红波胡铨胡世聪黄代绘黄天奇黄文俊黄性涛黄晓渊黄勇黄志成季筱璐贾焕玉贾康江琨姜晓巍姜泽军金敏康明铭柯通 D.Kuleshov.K.Kurinov 李兵兵李澄李骢李丹李飞李海波李会财李华阳李军李剑李捷李凯李文龙李文莲李秀荣李昕李一卓李哲黎卓梁恩维梁云峰林苏杰刘冰刘成刘栋刘虎刘海东刘佳刘江来刘金艳刘茂元柳若愚刘四明刘伟刘怡刘以农鲁睿罗晴吕洪魁马伯强马玲玲马欣华毛基荣闵振 W.Mitthumsiri 穆慧君南云程 A.Neronov 区子维庞彬宇 P.Pattarakijwanich 裴致远齐孟尧祁业情乔冰强秦家军 D.Ruffolo A.Sáiz D.Semikoz 邵澄宇邵琅 O.Shchegolev 盛祥东舒富文宋慧超 Yu.V.Stenkin V.Stepanov 苏扬孙秦宁孙晓娜孙志斌谭柏轩唐庆文唐泽波田文武王超王昌贝王广威王洪光王惠惠王建成汪凯王利苹王玲玉王培汉王冉王为王祥高王祥玉王阳王玉东王岩谨王忠海王仲翔王振王铮韦大明魏俊杰魏永健文韬吴超勇吴含荣武莎吴雪峰吴雨生席邵强夏捷夏君集项光漫肖迪泫肖刚辛广广辛玉良邢祎熊峥徐东莲徐仁峰徐仁新徐伟立薛良闫大海颜景志颜田杨朝文杨帆杨冯帆杨何文杨佳盈杨莉莉杨明洁杨睿智杨深邦姚玉华姚志国叶一锰尹丽巧尹娜游晓浩游智勇于艳红袁强岳华曾厚敦曾婷轩曾玮查敏张彬彬张丰张海明张恒英张建立张丽霞张力张鹏飞张佩佩张瑞张少博张少如张寿山张潇张笑鹏张云峰张毅张勇赵兵赵静赵雷赵立志赵世平郑福周斌周浩周佳能周猛周平周荣周勋秀祝成光祝凤荣朱辉朱科军左雄 LHAASO collaboration Key Laboratory of Particle Astrophyics&Experimental Physics Division&computing center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese Academy of Sciences Beijing 100049China Tianfu cosmic Ray Research center Chengdu 610000China Dublin Institute for Advanced Studies 31 Fitzwilliam Place2 DublinIreland Max-Planck-Institut for Nuclear Physics P.O.Box 10398069029 HeidelbergGermany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of china Hefei 230026China School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China center for Astrophysics Guangzhou UniversityGuangzhou 510006China Hebei Normal University Shijiazhuang 050024China Key Laboratory of Dark Matter and Space Astronomy&Key Laboratory of Radio Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory for Research in Galaxies and cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China Key Laboratory of cosmic Rays(Tibet University) Ministry of EducationLhasa 850000TibetChina National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Physics and Astronomy(Zhuhai)&School of Physics(Guangzhou)&Sino-French Institute of Nuclear Engineering and Technology(Zhuhai) Sun Yat-sen UniversityZhuhai 519000&Guangzhou 510275China School of Physics and Astronomy Yunnan UniversityKunming 650091China Département de Physique Nucléaire et corpusculaire Facultéde SciencesUniversitéde Genève24 Quai Ernest Ansermet1211 GenevaSwitzerland Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China APc Universit'e Paris Cit'eCNRS/IN2P3CEA/IRFUObservat

The full array of the Large High Altitude Air Shower Observatory(LHAASO)has been in operation since July *** its kilometer-square array(KM2A),we optimized the selection criteria for very high and ultrahigh energyγ-rays using data collected from August 2021 to August 2022,resulting in an improvement in significance of the detection in the crab Nebula of approximately 15%,compared with that of previous *** the implementation of these new selection criteria,the angular resolution was also significantly improved by approximately 10%at tens of *** aspects of the full KM2A array performance,such as the pointing error,were also calibrated using the crab *** resulting energy spectrum of the crab Nebula in the energy range of 10-1000 TeV are well fitted by a log-parabola model,which is consistent with the previous results from LHAASO and other experiments.

关键词： γ-ray crab Nebula significance