检索结果-南通市图书馆

Chemical modification of barite for improving the performance of weighting materials for water-based drilling fluids

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1期21卷 551-566页

作者： Li-Li Yang Ze-Yu liu Shi-bo Wang xian-Bo He Guan-Cheng Jiang jie Zhang MOE Key Laboratory of Petroleum Engineering State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Changping DistrictBeijing102249China MOE Key CNPC Drilling Research Institute Changping DistrictBeijing102206China

With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore *** this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite *** suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of *** viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same *** multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of *** sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was ***,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection *** work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.

关键词： Drilling fluids Weighting materials Filtration control Reservoir protection Stability property

Projected changes in Köppen-Trewartha climate zones under 1.5-4℃global warming targets over mid-high latitudes of Northern Asia using an ensemble of RegCM4 simulations

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第2期15卷 185-196页

作者： jie WU Xue-jie GAO xian-Bing TANG Filippo GIORGI School of Geography and Environmental Engineering Gannan Normal UniversityGanzhou 341000China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China University of Chinese Academy of Sciences Beijing 100049China The Abdus Salam International Centre for Theoretical Physics Trieste 34100Italy

Mid-high latitude Northern Asia is one of the most vulnerable and sensitive areas to global warming,but relatively less studied *** used an ensemble of a regional climate model(RegCM4)projections to assess future changes in surface air temperature,precipitation and Köppen-Trewartha(K-T)climate types in Northern Asia under the 1.5-4℃global warming ***4 is driven by five CMIP5 global models over an East Asia domain at a grid spacing of 25 *** of the present day(1986-2005)simulations shows that the ensembles of RegCM4(ensR)and driving GCMs(ensG)reproduce the major characters of the observed temperature,precipitation and K-T climate zones reasonably *** and more realistic spatial detail is found in RegCM4 compared to the driving GCMs.A general warming and overall increases in precipitation are projected over the region,with these changes being more pronounced at higher warming *** projected warming by ensR shows different spatial patterns,and is in general lower,compared to ensG in most months of the year,while the percentage increases of precipitation are maximum during the cold *** future changes in K-T climate zones are characterized by a substantial expansion of Dc(temperature oceanic)and retreat of Ec(sub-arctic continental)over the region,reaching∼20%under the 4℃warming *** most notable change in climate types in ensR is found over Japan(∼60%),followed by Southern Siberia,Mongolia,and the Korean Peninsula(∼40%).The largest change in the K-T climate types is found when increasing from 2 to 3℃.The results will help to better assess the impacts of climate change and in implementation of appropriate adaptation measures over the region.

关键词： Mid-high latitudes of Northern Asia Köppen climate zones Global warming targets Regional climate model

Effect of Ti Particles on the Microstructure and Mechanical Properties of AZ91 Magnesium Matrix Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 513-524页

作者： Lu Xiao Ting-Ting liu Yue Chu Bo Song jie Zhao xian-Hua Chen Kai-Hong Zheng Fu-Sheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China lntelligent Manufacturing and Automobile School Chongqing College of Electronic EngineeringChongqing 401331China School of Materials and Energy Southwest UniversityChongqing 400715China Science and Technology Research Institute of CNNC 404 Co.LTD Gansu 735100China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

Spherical micro-Ti particle(TiP)-reinforced AZ91 magnesium alloy composites were fabricated by semi-solid stirring assisted ultrasonic vibration,which were then subjected to hot *** microstructure results showed that the addition of Ti particles refined the grain size and decreased the texture intensity of the as-extruded AZ91 *** Al3Ti phase with a thickness of 100 nm formed at the Ti/Mg interface,which had a non-coherent relationship with the magnesium *** as-extruded 1 vol.%TiP/AZ91 composite exhibited the best comprehensive mechanical properties,with yield strength,ultimate tensile strength,and elongation at break of 366 MPa,456 MPa,and 14.6%,respectively,which were significantly higher than those of the AZ91 ***,the addition of Ti particles can improve the strength and ductility of the AZ91 alloy,demonstrating the value of magnesium matrix composites for commercial applications.

关键词： Magnesium matrix composites Ti particles Interface Mechanical properties

Hyperspectral image super resolution using deep internal and self-supervised learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CAAI Transactions on Intelligence Technology 2024年第1期9卷 128-141页

作者： Zhe liu xian-Hua Han Graduate School of Science and Technology for Innovation Yamaguchi UniversityYamaguchiJapan Graduate School of Artificial Intelligence and Science Rikkyo UniversityTokyoJapan

By automatically learning the priors embedded in images with powerful modelling ca-pabilities,deep learning-based algorithms have recently made considerable progress in reconstructing the high-resolution hyperspectral(HR-HS)*** previously collected large-amount of external data,these methods are intuitively realised under the full supervision of the ground-truth ***,the database construction in merging the low-resolution(LR)HS(LR-HS)and HR multispectral(MS)or RGB image research paradigm,commonly named as HSI SR,requires collecting corresponding training triplets:HR-MS(RGB),LR-HS and HR-HS image simultaneously,and often faces dif-ficulties in *** learned models with the training datasets collected simultaneously under controlled conditions may significantly degrade the HSI super-resolved perfor-mance to the real images captured under diverse *** handle the above-mentioned limitations,the authors propose to leverage the deep internal and self-supervised learning to solve the HSI SR *** authors advocate that it is possible to train a specific CNN model at test time,called as deep internal learning(DIL),by on-line preparing the training triplet samples from the observed LR-HS/HR-MS(or RGB)images and the down-sampled LR-HS ***,the number of the training triplets extracted solely from the transformed data of the observation itself is extremely few particularly for the HSI SR tasks with large spatial upscale factors,which would result in limited reconstruction *** solve this problem,the authors further exploit deep self-supervised learning(DSL)by considering the observations as the unlabelled training ***,the degradation modules inside the network were elaborated to realise the spatial and spectral down-sampling procedures for transforming the generated HR-HS estimation to the high-resolution RGB/LR-HS approximation,and then the reconstruction errors of the observations were formulated for mea

关键词： computer vision deep learning deep neural networks hyperspectral image enhancement

A short review of antibacterial Cu-bearing stainless steel:antibacterial mechanisms,corrosion resistance,and novel preparation techniques

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 Iron and Steel Research International 2024年第1期31卷 24-45页

作者： Shuai liu Han-jie Guo School of Artificial Intelligence Beijing Technology and Business UniversityBeijing100048China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials University of Science and Technology BeijingBeijing100083China

Cu-bearing stainless steel is widely used in the fields of food,medical and household sanitary equipment because of its surface finish and corrosion ***,the growth of bacteria on stainless steel leads to the formation of biofilms,which causes ***,the antibacterial property of stainless steel is a worthy research *** of breakthroughs in the field of corrosion resistance and antimicrobial properties are still ***,due to the scarcity of publications on the antibacterial mechanisms and processing methods of antibacterial Cu-bearing stainless steel,we review the current state of relevant research and *** toxicity of Cu,corrosion resistance mechanism of stainless steel,and antibacterial mechanism and preparation method of antibacterial stainless steel are *** addition,alloying,surface modification and other methods are found to have limitations in balancing the toxicity and antibacterial properties of copper and the relationship between the antibacterial properties and corrosion resistance of Cu-bearing stainless steel.A new preparation method of antibacterial stainless steel associated with selective laser melting(SLM)is *** is becoming a powerful additive manufacturing technology that can be used to manufacture customized and complex *** research status of SLM applied in antibacterial stainless steel preparation is ***,the future research direction of Cu-bearing antibacterial stainless steel is discussed.

关键词： Cu-bearing stainless steel Antibacterial Processing Additive manufacturing Corrosion resistance

Efficacy and safety of minimally invasive laparoscopic surgery under general anesthesia for ovarian cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2024年第9期12卷 1569-1577页

作者： xian Qin Chen Chen Yang liu xian-Hong Hua Jia-Yi Li Meng-jie Liang Fang Wu Department of Anesthesiology The First People's Hospital of Jiangxia DistrictWuhan 430200Hubei ProvinceChina Department of Obstetrics and Gynecology The First People's Hospital of Jiangxia DistrictWuhan 430200Hubei ProvinceChina

BACKGROUND Ovarian cancer is one of the most common malignant tumors in female reproductive system in the world,and the choice of its treatment is very important for the survival rate and prognosis of *** open surgery is the main treatment for ovarian cancer,but it has the disadvantages of big trauma and slow *** the continuous development of minimally invasive technology,minimally invasive laparoscopic surgery under general anesthesia has been gradually applied to the treatment of ovarian cancer because of its advantages of less trauma and quick ***,the efficacy and safety of minimally invasive laparoscopic surgery under general anesthesia in the treatment of ovarian cancer are still *** To explore the efficacy and safety of general anesthesia minimally invasive surgery in the treatment of ovarian *** The clinical data of 90 patients with early ovarian cancer in our hospital were analyzed *** to the different surgical treatment methods,patients were divided into study group and control group(45 cases in each group).The study group received minimally invasive laparoscopic surgery under general anesthesia for ovarian cancer,while the control group received traditional open surgery for ovarian *** European Organization for Research and Treatment of Cancer Quality of Life Questionnaire(EORTC QLQ-C30),clinical efficacy and safety of the two groups were *** The intraoperative blood loss,length of hospital stay,postoperative gas evacuation time,and postoperative EORTC QLQ-C30 score of the study group were significantly better than those of the control group(P<0.05).The incidence of postoperative complications in the study group was significantly lower than in the control group(P<0.05).The two groups had no significant differences in the preoperative adrenocorticotropic hormone(ACTH),androstenedione(AD),cortisol(Cor),cluster of differentiation 3 positive(CD3+),and clu

关键词： Early-stage ovarian cancer Efficacy Minimally invasive Laparoscopy Safety Surgery

Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第4期43卷 661-676页

作者： jie Wang Yun liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

Evaluation of transmission risk of respiratory particles under different ventilation strategies in an elevator

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第5期17卷 771-784页

作者： Liangyu Zhu xian Li Bujin Feng Fan liu School of Civil Engineering and Architecture Linyi UniversityLinyi276000China College of Agriculture Shandong Agricultural UniversityTaian271018China School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China

People in elevators are at risk of respiratory infection because the elevator cabin is crowded and has poor *** exhaled particles may be inhaled by the susceptible person,deposited on the surface and suspended in the elevator,which can result in direct and indirect ***,whether the air vent designs adopted in the elevator can effectively reduce the transmission risk of respiratory particles remains *** this study,the dispersion of particles under four common ventilation strategies used in the commercial elevator was investigated by proven computational fluid dynamics(CFD)*** flow field was simulated with the RNG κ-ξ turbulence model and the Lagrangian method was adopted to track particle *** effects of air vent layout and airflow rate on particle transmission were *** found that more than 50% of exhaled particles(average value)were suspended in the cabin and difficult to discharge under the investigated ventilation *** deposited fraction of particles on the susceptible person reached up to 39.14% for infiltration ventilation,which led to a high risk of contact *** the ventilation rate could not significantly reduce the inhalation proportion of particles due to the poor airflow distribution inside the elevator.A more proper ventilation strategy should be explored for the elevator to control transmission risk.

关键词： particle dispersion transmission risk elevator ventilation strategy computational fluid dynamics(CFD)

A compact bimorph rotary piezoelectric actuator with customized small power supply

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(Technological Sciences) 2024年第4期67卷 1185-1195页

作者： DENG jie liu DaQing WANG WeiYi liu Yingxiang School of Mechatronics and Engineering Harbin Institute of TechnologyHarbin 150001China

Inertial piezoelectric actuators are widely applied in precision devices with simple structure and accurate ***,existing inertial piezoelectric actuators still face the challenges of rollback motion and bulky power *** this work,an alternate excitation strategy and a customized small power supply for a bimorph rotary piezoelectric actuator(BRPA)are proposed to solve the *** BRPA prototype is designed with a bipedal symmetrical structure,measuring 35 mm in height and 32 mm in diameter,which has a maximum rotation velocity of 0.247 rad/s and a resolution of 0.66μ*** to the bipedal symmetrical structure,the friction directions between the driving feet and the rotor can be coordinated to suppress the *** rollback ratio is almost zero when the phase difference of the exciting signal is set as 180°.The customized power supply is designed and manufactured,whose size is 58 mm×56 mm×46 *** can output signals for the single step mode and the continuous mode,and they are adopted to excite BRPA to achieve a small stroke with one single step and a large stroke with continuous step,***,an experimental system for optical fiber alignment is developed based on the BRPA and the customized small power supply,the experiment has verified the practicability of this work in the precision fields,especially in the miniaturized precision systems.

关键词： inertial piezoelectric actuator customized small power supply single step mode continuous mode rollback suppression miniaturized precision system