检索结果-南通市图书馆

有色矿冶 1992年第2期8卷 35-37页

作者： c.r.edwards 李蔚强

在矿物加工和金属提取工业中,回收的产品不仅给生产厂家带来经济效益、提高资源的利用率,而且还能保护环境。目前,回收副产品对执行环保规章是至关重要的。本文叙述了从原为尾矿废渣中回收副产品成功的三种工艺操作,同时,介绍了它们的... 详细信息

在矿物加工和金属提取工业中,回收的产品不仅给生产厂家带来经济效益、提高资源的利用率,而且还能保护环境。目前,回收副产品对执行环保规章是至关重要的。本文叙述了从原为尾矿废渣中回收副产品成功的三种工艺操作,同时,介绍了它们的工艺流程。

关键词：尾矿废渣有价金属回收

Understanding the initial use stage of cement mortar lining in drinking water distribution systems:Silicon and aluminum as stability indicators

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第1期135卷 495-505页

作者： Qiaozhi Liu Yuan Zhuang Guiwei Li Yao Zhang Marc A.edwards Baoyou Shi Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of chinese Academy of Sciences Beijing 100049China civil and Environmental Engineering Virginia TechBlacksburgVA 24061USA

The cement mortar lining(cML)of commonly used ductile iron pipes can severely deteriorate the drinking water quality at the initial stage of use,but the behavioral characteristics of different elements release from the cML in this stage is still *** this study,dynamic immersion experiments with new cement mortar lined ductile iron pipe reactors were conducted under different feed water hardness and alkalinity *** results showed that the release of alkaline substances from the cML at the initial stage of use could strongly influence the pH of water,which consequently greatly impacted the release/precipitation behaviors of calcium,aluminum and *** pH and aluminum concentration of the effluent water could reach 11.5 and 700μg/L within 24 hr of hydraulic retention time,respectively,under conditions of relatively lower hardness and *** to the pH elevation,calcium carbonate precipitation could occur even at much lower feed water *** the aluminum and silicon could keep release from the cML in soluble form at different hardness and alkalinity levels,and their release rate depended on the amount of calcium carbonate ***,aluminum and silicon were more suitable as indicators of the corrosion intensity at the initial stage of cML use rather than the traditional calcium carbonate precipitation *** feed water hardness and alkalinity levels for mitigating the initial intense corrosion of cML were proposed:hardness>40 mg/L(cacO_(3)),alkalinity>100 mg/L(cacO_(3)).

关键词： cement mortar lining Hardness Alkalinity Elemental release Drinking water supply

Learning from Neighbors and Differentiating Export Quality

在线全文

学校读者我要写书评

暂无评论

china & World Economy 2024年第4期32卷 1-32页

作者： Qiming Liu Bin Qiu Huw edwards Bo Gao School of Economics and Management Southeast UniversityChina Business school Loughborough UniversityUK

This paper explores how learning from neighboring firms affects new exporters' product quality. It builds a Bayesian learning model to study how new exporters revise their prior beliefs about foreign customers' preferences for product quality from neighboring pioneering exporters. The model shows that a new exporter improves its product quality when it receives a positive quality-preference signal from its neighbors. The learning process of a firm depends on the number of neighbors, the level and heterogeneity of their export quality, and its own prior knowledge of the market. Highly disaggregated firm–product–country level transaction data provide robust evidence for this. The results also suggest that the impact of neighboring signals on a new exporter's quality can be channeled through the importation of high-quality intermediate inputs and more fixed investment. Learning effects are heterogeneous across firms and learning can influence other aspects of export performance.

关键词： Bayesian learning export quality information spillovers uncertainty

Mantle avalanches in a Venus-like stagnant lid planet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第5期8卷 686-702页

作者： Madeleine c.Kerr Dave r.Stegman Institute of Geophysics and Planetary Physics Scripps Institution of Oceanography University of California

Stagnant lid planets are characterized by a globe-encircling, conducting lid that is thick and strong, which leads to reduced global surface heat flows. consequently, the mantles of such planets can have warmer interiors than Earth, and interestingly, a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose, 2002; Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014; Dannberg et al, 2022). Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite, at pressures corresponding to410 km and 520 km depth in Earth, respectively, it instead transforms into a mineral assemblage of wadsleyite, majorite, and ferropericlase(WMF), and then to majorite + ferropericlase(MF), before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014). convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips) forming within the mobile rheological sublayer under the rigid lid. Using ASPEcT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo, we show that under certain conditions, the small drips can pond atop the WMF-MF mineral phase transition. The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni, 2022). Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al., 2022; Li rP et al.,2024), the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle. Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed

关键词： Venus mantle avalanches numerical modelling phase transitions

Effects of dust controls on respirable coal mine dust composition and particle sizes:case studies on auxiliary scrubbers and canopy air curtain

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of coal Science & Technology 2024年第3期11卷 86-101页

作者： F.Animah c.Keles W.r.reed E.Sarver Department of Mining and Minerals Engineering Virginia Polytechnic Institute&State UniversityBlacksburgVAUSA National Institute of Occupational Safety and Health(NIOSH) PittsburghPAUSA

control of dust in underground coal mines is critical for mitigating both safety and health *** decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal *** studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(cAcs)to reduce respirable dust in key operator *** detailed dust characterization was not a focus of such studies,this is a growing area of *** preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter cAc on respirable dust composition and particle size *** this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive *** indicate that dust composition was not appreciably affected by either scrubber or the ***,the wet scrubber and cAc appeared to decrease the overall particle size *** an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return *** from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.

关键词： respirable dust Dust control SEM–EDX Scrubber canopy air curtain Silica

Investigations of nuclear chirality at iThemba LABS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第2期19卷 7-38页

作者： r.A.Bark E.A.Lawrie c.Liu S.Y.Wang iThemba Laboratory for Accelerator Based Sciences National Research FoundationP.O.Box 722Somerset-West 7129South Africa Department of Physics University of the Western CapePrivate Bag X177535BellvilleSouth Africa Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China

Progress in the studies of chirality in atomic nuclei at iThemba LABS is *** regions of chirality,around mass 80 and 190 have been discovered using the AFrODITE array,specifically in the nuclei^(74)As,^(78,80,82)Br,^(81)Kr,and^(193,194,198)*** phenomena have been observed,including multiple chiral bands in the same nucleus,the coexistence of octupole correlations and nuclear chirality,and the coexistence of pseudo spin and nuclear *** best example of chiral degeneracy to date was found in ^(194)*** level scheme of ^(106)Ag has been revisited and interpreted in terms of two-and four-quasiparticle *** using the particle-rotor model have shown that the fingerprints of chirality in the two-quasiparticle system only can occur in an idealised model *** systems with a higher number of quasiparticles,the calculations showed that nuclear chirality can persist.

关键词： chirality high-spin states particle-rotor model

cannabinoids and endocannabinoids as therapeutics for nervous system disorders:preclinical models and clinical studies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural regeneration research 2024年第4期19卷 788-799页

作者： r.Scott Duncan Sean M.riordan Matthew c.Gernon Peter Koulen Department of Ophthalmology School of MedicineUniversity of Missouri Department of Biomedical Sciences School of MedicineUniversity of Missouri

cannabinoids are lipophilic substances derived from cannabis sativa that can exert a variety of effects in the human *** have been studied in cellular and animal models as well as in human clinical trials for their therapeutic benefits in several human *** of these include central nervous system(cNS)diseases and dysfunctions such as forms of epilepsy,multiple sclerosis,Parkinson’s disease,pain and neuropsychiatric *** addition,the endogenously produced cannabinoid lipids,endocannabinoids,are critical for normal cNS function,and if controlled or modified,may represent an additional therapeutic avenue for cNS *** review discusses in vitro cellular,ex vivo tissue and in vivo animal model studies on cannabinoids and their utility as therapeutics in multiple cNS *** addition,the review provides an overview on the use of cannabinoids in human clinical trials for a variety of cNS *** and endocannabinoids hold promise for use as disease modifiers and therapeutic agents for the prevention or treatment of neurodegenerative diseases and neurological disorders.

关键词： anandamide cannabidiol cannabinoid endocannabinoid epilepsy multiple sclerosis neurodegeneration neuroprotection tetrahydrocannabinol

Efficient guiding and focusing of intense laser pulse using periodic thin slits

在线全文

学校读者我要写书评

暂无评论

Matter and radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu T.W.Huang K.Jiang c.N.Wu H.Peng P.c.hen r.Li H.B.Zhuo c.T.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

Summarizing the evidence for robotic-assisted bladder neck reconstruction: Systematic review of patency and incontinence outcomes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Urology 2024年第3期11卷 341-347页

作者： Tenny r.Zhang Ashley Alford Lee c.Zhao Department of Urology NewYork-Presbyterian Hospital/Weill Cornell MedicineNew YorkNYUSA Department of Urology NYU Langone Medical CenterNew YorkNYUSA

Objective:Bladder neck contracture and vesicourethral anastomotic stenosis are difficult to manage endoscopically,and open repair is associated with high rates of *** recent years,there have been increasing reports of robotic-assisted bladder neck reconstruction in the ***,existing studies are small,heterogeneous case *** objective of this study was to perform a systematic review of robotic-assisted bladder neck reconstruction to better evaluate patency and incontinence ***:We performed a systematic review of PubMed from first available date to May 2023 for all studies evaluating robotic-assisted reconstructive surgery of the bladder neck in adult *** in non-English,author replies,editorials,pediatric-based studies,and reviews were *** of interest were patency and incontinence rates,which were pooled when ***:After identifying 158 articles on initial search,we included only ten studies that fit all aforementioned criteria for robotic-assisted bladder neck *** were case series published from March 2018 to March 2022 ranging from six to 32 men,with the median follow-up of 5e23 months.A total of 119 patients were included in our analysis.A variety of etiologies and surgical techniques were *** rates ranged from 50%to 100%,and pooled patency was 80%(95/119).De novo incontinence rates ranged from 0%to 33%,and pooled incontinence was 17%(8/47).Our findings were limited by small sample sizes,relatively short follow-ups,and heterogeneity between studies.

关键词： Bladder neck continence Incontinence Patency Posterior urethra reconstructive surgery robotic surgery Stenosis Stricture Surgical outcome

chronic effects of stretching on range of motion with consideration of potential moderating variables:A systematic review with meta-analysis

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 Sport and Health Science 2024年第2期13卷 186-194页

作者： Andreas Konrad Shahab Alizadeh Abdolhamid Daneshjoo Saman Hadjizadeh Anvar Andrew Graham Ali Zahiri reza Goudini chris edwards carina Scharf David George Behm Institute of Human Movement Science Sport and HealthGraz UniversityGraz A-8010Austria School of Human Kinetics and recreation Memorial University of NewfoundlandSt.John’sNL A1C 5S7Canada Department of Sport Injuries and corrective Exercises Faculty of Sport SciencesShahid Bahonar University of KermanKerman 76169-13439Iran

Background:It is well known that stretch training can induce prolonged increases in joint range of motion(rOM).However,to date more information is needed regarding which training variables might have greater influence on improvements in ***,the purpose of this metaanalysis was to investigate the effects of stretch training on rOM in healthy participants by considering potential moderating variables,such as stretching technique,intensity,duration,frequency,and muscles stretched,as well as sex-specific,age-specific,and/or trained state-specific adaptations to stretch ***:We searched through PubMed,Scopus,Web of Science,and SportDiscus to find eligible studies and,finally,assessed the results from 77 studies and 186 effect sizes by applying a random-effect ***,by applying a mixed-effect model,we performed the respective subgroup *** find potential relationships between stretch duration or age and effect sizes,we performed a ***:We found a significant overall effect,indicating that stretch training can increase rOM with a moderate effect compared to the controls(effect size=-1.002;Z=-12.074;95%confidence interval:-1.165 to-0.840;proup analysis showed a significant difference between the stretching techniques(p=0.01)indicating that proprioceptive neuromuscular facilitation and static stretching produced greater rOM than did ballistic/dynamic ***,there was a significant effect between the sexes(p=0.04),indicating that females showed higher gains in rOM compared to ***,further moderating analysis showed no significant relation or ***:When the goal is to maximize rOM in the long term,proprioceptive neuromuscular facilitation or static stretching,rather than ballistic/dynamic stretching,should be *** to consider in future research as well as sports practice is that neither volume,intensity,nor frequency of stretching were

关键词： Flexibility Long-term stretching Stretch training