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mechanisms behind the environmental sensitivity of carbon fiber reinforced polytetrafluoroethylene(PTFE)

Friction 2024年第5期12卷 997-1015页

作者： Pontus JOHANSSON P.mARKLUND m.bjORLING Y.SHI Division of machine Element LuleåUniversity of TechnologyLuleåSE-97187Sweden

Carbon fiber reinforced polytetrafluoroethylene (CF/PTFE) composites are known for their exceptional tribological performance when sliding against steel or cast iron in inert gas environments. Compared to experiments in humid air, about an order of magnitude lower wear rate and several times lower coefficient of friction have been reported for tests conducted in dry nitrogen and hydrogen. moreover, trace moisture has been shown to affect the friction and wear significantly of this tribosystem, although a possible effect of oxygen cannot be ruled out due to uncertainties regarding the oxygen concentrations. While several studies have pointed out the environmental sensitivity of CF/PTFE, the understanding of the underlying mechanisms are very limited. The objective of this research is to investigate the individual and combined effect of oxygen and moisture on the tribological behavior of CF/PTFE sliding against steel. Additionally, this study aims to elucidate the underlying mechanisms that govern the environmental sensitivity of the system. Climate-controlled three-pin-on-disc experiments were conducted in nitrogen atmospheres at various concentrations of oxygen and moisture. The tribological results clearly demonstrate that both moisture and oxygen contribute to increased friction and wear. However, the adverse effect was much more pronounced for oxygen than moisture. A qualitative method was developed to estimate the tribofilm coverage on the CF/PTFE surface. Results showed strong correlation between high coverage of strongly adhered tribofilm and low wear rate. moreover, a loosely adhered tribofilm was observed on top of the CF/PTFE surface in presence of moisture. FTIR analysis indicated that the loosely adhered tribofilm found in the moisture-enriched environment contained a significant amount of adsorbed water, which may explain the lower coefficient of friction in presence of moisture compared to oxygen. The adsorbed water in the loosely adhered tribofilm could be an indication of moisture-driven lubricatio

关键词： polymer composite tribofilm tribochemistry atmosphere

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Conventional Geothermal Systems and Unconventional Geothermal Developments: An Overview

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Open Journal of Geology 2024年第2期14卷 196-246页

作者： maryam Khodayar Sveinbjörn björnsson Consultant and Researcher in Geosciences Reykjavík Iceland Formerly at National Energy Authority of Iceland Reykjavík Iceland

This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. medium-temperature (mT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at m depth (Enhanced Geothermal Systems (EGS), drilling below brittle-ductile transition zones and under geothermal fields), or by the Oil & Gas industry (Advanced Geothermal Systems, heat recovery from hydrocarbon wells or reservoirs, Superhot Rock Geothermal, and millimeter-wave drilling down to 20 Km). Their primary aim is electricity generation, relying on closed-loops, but EGS uses fractures for heat exchange with earthquake risks during fracking. Unconventional approaches could be everywhere, with shallow geothermal already functional. The deeper and hotter unconventional alternatives are still experimental, overcoming costs and technological challenges to become fully commercial. meanwhile, the conventional geothermal resources remain the most proven opportunities for investments and development.

关键词： Conventional Geothermal Systems Unconventional Geothermal Developments Shallow and Deep Closed-Loops Enhanced Geothermal Systems Supercritical and millimeter-Wave Drilling

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Application of novel constrained friction processing method to produce fine grained biomedical mg-Zn-Ca alloy

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Journal of magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong Fu Junjun Shen Uceu F.H.R.Suhuddin björn Wiese Yuanding Huang min Wang Jorge F.dos Santos Jean Pierre Bergmann Benjamin Klusemann Solid State materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Functional magnesium materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of materials Laser Processing and modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied materials and manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CFP)”,was investigated.Via CFP,defect-free mg-Zn-Ca rods with greatly refined grains and high mechanical properties were produced.Compared to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process cycle.The compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear deformation.From the base material to the rod,the material experienced three stages,i.***.deformation by the tool,upward flow with additional tilt,followed by upward transportation.The microstructural evolution was revealed by“stop-action”technique.The microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing magnesium alloys microstructure mechanical properties Grain refinement Plastic deformation

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more abundant and healthier meat:will the mSTN editing epitome empower the commercialization of gene editing in livestock?

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Science China(Life Sciences) 2022年第2期65卷 448-450页

作者： Xiaolong Wang björn Petersen Key Laboratory of Animal Genetics Breeding and Reproduction of Shaanxi ProvinceCollege of Animal Science and TechnologyNorthwest A&F UniversityYangling 712110China Institute of Farm Animal Genetics Friedrich-Loeffler-Institute(FLI)Mariensee 31535Germany

In recent years,various gene-edited crops and livestock have been developed to find rapid and unconventional solutions to boost agriculture,animal breeding,environmental sustain-ability,and animal welfare.In the animal production field,significant gene-edited livestock with economic beneficial traits,like the mSTN-edited double muscles,can be com-mercialized on a large scale to benefit more people with real need.Nutritional demand for animal proteins increases an-nually with improvement of living conditions in modern societies and developing countries.Additionally,the number of people with special needs for healthier meat(with high-protein and low-fat)is growing(e.g.,elderly patients with cardio/cerebrovascular diseases).With steady global en-vironmental deterioration,increasing human population,growing food demand,continuous disease outbreaks,and concerns regarding animal welfare。

关键词： abundant crops breeding

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Search for the doubly heavy baryons Ωbc~0 and Ξbc~0 decaying to Λc~+π~- and Ξc~+π~-

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Chinese Physics C 2021年第9期45卷 14-25页

作者： R.Aaij C.Abellán Beteta T.Ackernley B.Adeva m.Adinolfi H.Afsharnia C.A.Aidala S.Aiola Z.Ajaltouni S.Akar J.Albrecht F.Alessio m.Alexander A.Alfonso Albero Z.Aliouche G.Alkhazov P.Alvarez Cartelle S.Amato Y.Amhis L.An L.Anderlini A.Andreianov m.Andreotti F.Archilli A.Artamonov m.Artuso K.Arzymatov E.Aslanides m.Atzeni B.Audurier S.Bachmann m.Bachmayer J.J.Back P.Baladron Rodriguez V.Balagura W.Baldini J.Baptista Leite R.J.Barlow S.Barsuk W.Barter m.Bartolini F.Baryshnikov J.m.Basels G.Bassi B.Batsukh A.Battig A.Bay m.Becker F.Bedeschi I.Bediaga A.Beiter V.Belavin S.Belin V.Bellee K.Belous I.Belov I.Belyaev G.Bencivenni E.Ben-Haim A.Berezhnoy *** D.Berninghoff H.C.Bernstein C.Bertella A.Bertolin C.Betancourt F.Betti Ia.Bezshyiko S.Bhasin J.Bhom L.Bian m.S.Bieker S.Bifani P.Billoir m.Birch F.C.R.Bishop A.Bitadze A.Bizzeti m.bj?rn m.P.Blago T.Blake F.Blanc S.Blusk D.Bobulska J.A.Boelhauve O.Boente Garcia T.Boettcher A.Boldyrev A.Bondar N.Bondar S.Borghi m.Borisyak m.Borsato J.T.Borsuk S.A.Bouchiba T.J.V.Bowcock A.Boyer C.Bozzi m.J.Bradley S.Braun A.Brea Rodriguez m.Brodski J.Brodzicka A.Brossa Gonzalo D.Brundu A.Buonaura C.Burr A.Bursche A.Butkevich J.S.Butter J.Buytaert W.Byczynski S.Cadeddu H.Cai R.Calabrese L.Calefice L.Calero Diaz S.Cali R.Calladine m.Calvi m.Calvo Gomez P.Camargo magalhaes A.Camboni P.Campana A.F.Campoverde Quezada S.Capelli L.Capriotti A.Carbone G.Carboni R.Cardinale A.Cardini I.Carli P.Carniti L.Carus K.Carvalho Akiba A.Casais Vidal G.Casse m.Cattaneo G.Cavallero S.Celani J.Cerasoli A.J.Chadwick m.G.Chapman m.Charles Ph.Charpentier G.Chatzikonstantinidis C.A.Chavez Barajas m.Chefdeville C.Chen S.Chen A.Chernov V.Chobanova S.Cholak m.Chrzaszcz A.Chubykin V.Chulikov P.Ciambrone m.F.Cicala X.Cid Vidal G.Ciezarek P.E.L.Clarke m.Clemencic H.V.Cliff J.Closier J.L.Cobbledick V.Coco J.A.B.Coelho J.Cogan E.Cogneras L.Cojocariu P.Collins T.Colombo L.Congedo A.Contu N.Cooke G.Coombs G.Corti C.m.Costa Sobral B.Couturier D.C.Craik J.Crkovská m.Cruz Torres R.Currie C.L.Da Silva E.Dall’Occo J.Dalseno C.D’Amb AGH-University of Science and Technology Faculty of Computer Science Electronics and Telecommunications AGH-University of Science and Technology Faculty of Physics and Applied Computer Science Aix marseille Univ CNRS/IN2P3 CPPM Budker Institute of Nuclear Physics (SB RAS) Cavendish Laboratory University of Cambridge Center for High Energy Physics Tsinghua University Centro Brasileiro de Pesquisas Físicas (CBPF) DS4DS La Salle Universitat Ramon Llull Departamento de Fisica Universidad Nacional de Colombia Department of Physics and Astronomy University of Manchester Department of Physics and Astronomy Uppsala University Department of Physics University of Oxford Department of Physics University of Warwick European Organization for Nuclear Research (CErn) Fakult?t Physik Technische Universit?t Dortmund Guangdong Provencial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University H.H. Wills Physics Laboratory University of Bristol Hangzhou Institute for Advanced Study UCAS Hanoi University of Science Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences Horia Hulubei National Institute of Physics and Nuclear Engineering I.Physikalisches Institut RWTH Aachen University ICCUB Universitat de Barcelona INFN Laboratori Nazionali di Frascati INFN Sezione di Bari INFN Sezione di Bologna INFN Sezione di Cagliari INFN Sezione di Ferrara INFN Sezione di Firenze INFN Sezione di Genova INFN Sezione di milano INFN Sezione di milano-Bicocca INFN Sezione di Perugia INFN Sezione di Pisa INFN Sezione di Roma La Sapienza INFN Sezione di Roma Tor Vergata Imperial College London Institut für Physik Universit?t Rostock Institute Of High Energy Physics (IHEP) Institute for High Energy Physics NRC Kurchatov Institute (IHEP NRC KI) Institute for Nuclear Research of the National Academy of Sciences (KINR) Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS) Institute of Nuclear Physics Moscow State University (SINP MSU) Institute of Part

The first search for the doubly heavy Ωbc~0 baryon and a search for the Ξbc~0 baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb-1.The baryons are reconstructed via their decays to ∧c~+π~-andΞc~+π~-.No significant excess is found for invariant masses between 6700 and 7300 meV/c2,in a rapidity range from2.0 to 4.5 and a transverse momentum range from 2 to 20 meV/c.Upper limits are set on the ratio of the Ωbc~0 andΞbc~0 production cross-section times the branching fraction to ∧c~+π~-(Ξc~+π~-) relative to that of the ∧b~0(Ξb~0) baryon,for different lifetime hypotheses,at 95% confidence level.The upper limits range from 0.5×10-4to 2.5×10-4for theΩbc~0→∧c~+π~-(Ξbc~0→∧c~+π~-) decay,and from 1.4×10-3to 6.9×10-3for the Ωbc~0→Ξc~+π~-(Ξbc~0→Ξc~+π~-) decay,depending on the considered mass and lifetime of the Ωbc~0(Ξbc~0) baryon.

关键词： B physics quarkonium spectroscopy heavy quark production

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Toward implantable devices for angle-sensitive,lens-less,multifluorescent,single-photon lifetime imaging in the brain using Fabry-Perot and absorptive color filters

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Light(Science & Applications) 2022年第2期11卷 197-211页

作者： Adriaan J.Taal Changhyuk Lee Jaebin Choi björn Hellenkamp Kenneth L.Shepard Columbia University-Department of Electrical Engineering 500W.120th St.Mudd 1310New York 10027 NYUSA Korea Institute of Science and Technology-Brain Science Institute 5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea

Implantable image sensors have the potential to revolutionize neuroscience.Due to their small form factor requirements;however,conventional filters and optics cannot be implemented.These limitations obstruct highresolution imaging of large neural densities.Recent advances in angle-sensitive image sensors and single-photon avalanche diodes have provided a path toward ultrathin lens-less fluorescence imaging,enabling plenoptic sensing by extending sensing capabilities to include photon arrival time and incident angle,thereby providing the opportunity for separability of fluorescence point sources within the context of light-field microscopy(LFm).However,the addition of spectral sensitivity to angle-sensitive LFm reduces imager resolution because each wavelength requires a separate pixel subset.Here,we present a 1024-pixel,50μm thick implantable shank-based neural imager with color-filtergrating-based angle-sensitive pixels.This angular-spectral sensitive front end combines a metal–insulator–metal(mIm)Fabry–Perot color filter and diffractive optics to produce the measurement of orthogonal light-field information from two distinct colors within a single photodetector.The result is the ability to add independent color sensing to LFm while doubling the effective pixel density.The implantable imager combines angular-spectral and temporal information to demix and localize multispectral fluorescent targets.In this initial prototype,this is demonstrated with 45μm diameter fluorescently labeled beads in scattering medium.Fluorescent lifetime imaging is exploited to further aid source separation,in addition to detecting pH through lifetime changes in fluorescent dyes.While these initial fluorescent targets are considerably brighter than fluorescently labeled neurons,further improvements will allow the application of these techniques to in-vivo multifluorescent structural and functional neural imaging.

关键词： filters lifetime angle

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Effects of different forms of nitrogen addition on microbial extracellular enzyme activity in temperate grassland soil

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Ecological Processes 2022年第1期11卷 483-490页

作者： Lili Dong björn Berg Weiping Gu Zhengwen Wang Tao Sun Erguna Forest-Steppe Ecotone Research Station Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Forest Sciences University of Helsinki00014 HelsinkiFinland Section of Biology University of Gävle80176 GävleSweden Key Laboratory of Forest Ecology and management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China

Background:Nitrogen(N)deposition alters litter decomposition and soil carbon(C)sequestration by influencing the microbial community and its enzyme activity.Natural atmospheric N deposition comprises of inorganic N(IN)and organic N(ON)compounds.However,most studies have focused on IN and its effect on soil C cycling,whereas the effect of ON on microbial enzyme activity is poorly understood.Here we studied the effects of different forms of externally supplied N on soil enzyme activities related to decomposition in a temperate steppe.Ammonium nitrate was chosen as IN source,whereas urea and glycine were chosen as ON sources.Different ratios of IN to ON(Control,10:0,7:3,5:5,3:7,and 0:10)were mixed with equal total amounts of N and then used to fertilize the grassland soils for 6 years.Results:Our results show that IN deposition inhibited lignin-degrading enzyme activity,such as phenol oxidase(POX)and peroxidase(PER),which may restrain decomposition and thus induce accumulation of recalcitrant organic C in grassland soils.By contrast,deposition of ON and mixed ON and IN enhanced most of the C-degrading enzyme activities,which may promote the organic matter decomposition in grassland soils.In addition,theβ-N-acetyl-glucosaminidase(NAG)activity was remarkably stimulated by fertilization with both IN and ON,maybe because of the elevated N availability and the lack of N limitation after long-term N fertilization at the grassland site.meanwhile,differences in soil pH,soil dissolved organic carbon(DOC),and microbial biomass partially explained the differential effects on soil enzyme activity under different forms of N treatments.Conclusions:Our results emphasize the importance of organic N deposition in controlling soil processes,which are regulated by microbial enzyme activities,and may consequently change the ecological effect of N deposition.Thus,more ON deposition may promote the decomposition of soil organic matter thus converting C sequestration in grassland soils into a C source.

关键词： Inorganic N deposition Organic N deposition Soil microbial biomass microbial enzyme activity Decomposition Grassland

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The SNAPc complex mediates starvation-induced trans-splicing in Caenorhabditis elegans

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Journal of Genetics and Genomics 2022年第10期49卷 952-964页

作者： Xinhao Hou Chengming Zhu mingjing Xu Xiangyang Chen Cheng Sun björn Nashan Shouhong Guang Xuezhu Feng The First Affiliated Hospital of USTC Division of Life Sciences and MedicineSchool of Life SciencesMinistry of Education Key Laboratory for Membraneless Organelles&Cellular DynamicsThe USTC RNA InstituteDepartment of Obstetrics and GynecologyBiomedical Sciences and Health Laboratory of Anhui ProvinceUniversity of Science and Technology of ChinaHefeiAnhui 230001China CAS Center for Excellence in molecular Cell Science Chinese Academy of SciencesHefeiAnhui 230027China

Dietary restriction usually suppresses biosynthesis but activates catabolic pathways in animals.However,the short-term starvation enhances biosynthetic activities and promotes ribosomal biogenesis in adult Caenorhabditis elegans.The mechanism underlying the processes remains largely unknown.Here,we find that the short-term starvation enhances the SL1 trans-splicing of translation-related genes in adult C.elegans by transcriptome analysis.The small nuclear rnA-activating protein complex(SNAPc)promotes SL rnA production and mediates starvation-induced trans-splicing.TOFU-5,a core factor in the upstream sequence transcription complex(USTC)essential for pirnA production,is also involved in the starvationinduced trans-splicing processes.Knocking down components of the SNAPc complex and tofu-5 extends worm survival under starvation conditions.Taken together,our study highlights the importance of SL transsplicing in the nutrition response and reveals a mechanism of the survival regulation by food deprivation via SNAPc and TOFU-5.

关键词： Trans-splicing SNAPc tofu-5 Starvation C.elegans

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■^(−)_(b)→J/ψΛK^(−)衰变中一个J/ψΛ结构的迹象与■^(−)激发态的发现

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Science Bulletin 2021年第13期66卷 1278-1287,M0003页

作者： R.Aaij C.Abellán Beteta T.Ackernley B.Adeva m.Adinolfi H.Afsharnia C.A.Aidala S.Aiola Z.Ajaltouni S.Akar J.Albrecht F.Alessio m.Alexander A.Alfonso Albero Z.Aliouche G.Alkhazov P.Alvarez Cartelle S.Amato Y.Amhis L.An L.Anderlini A.Andreianov m.Andreotti F.Archilli A.Artamonov m.Artuso K.Arzymatov E.Aslanides m.Atzeni B.Audurier S.Bachmann m.Bachmayer J.J.Back S.Baker P.Baladron Rodriguez V.Balagura W.Baldini J.Baptista Leite R.J.Barlow S.Barsuk W.Barter m.Bartolini F.Baryshnikov J.m.Basels G.Bassi B.Batsukh A.Battig A.Bay m.Becker F.Bedeschi I.Bediaga A.Beiter V.Belavin S.Belin V.Bellee K.Belous I.Belov I.Belyaev G.Bencivenni E.Ben-Haim A.Berezhnoy *** D.Berninghoff H.C.Bernstein C.Bertella E.Bertholet A.Bertolin C.Betancourt F.Betti Ia.Bezshyiko S.Bhasin J.Bhom L.Bian m.S.Bieker S.Bifani P.Billoir m.Birch F.C.R.Bishop A.Bizzeti m.bj┆rn m.P.Blago T.Blake F.Blanc S.Blusk D.Bobulska J.A.Boelhauve O.Boente Garcia T.Boettcher A.Boldyrev A.Bondar N.Bondar S.Borghi m.Borisyak m.Borsato J.T.Borsuk S.A.Bouchiba T.J.V.Bowcock A.Boyer C.Bozzi m.J.Bradley S.Braun A.Brea Rodriguez m.Brodski J.Brodzicka A.Brossa Gonzalo D.Brundu A.Buonaura C.Burr A.Bursche A.Butkevich J.S.Butter J.Buytaert W.Byczynski S.Cadeddu H.Cai R.Calabrese L.Calefice L.Calero Diaz S.Cali R.Calladine m.Calvi m.Calvo Gomez P.Camargo magalhaes A.Camboni P.Campana A.F.Campoverde Quezada S.Capelli L.Capriotti A.Carbone G.Carboni R.Cardinale A.Cardini I.Carli P.Carniti L.Carus K.Carvalho Akiba A.Casais Vidal G.Casse m.Cattaneo G.Cavallero S.Celani J.Cerasoli A.J.Chadwick m.G.Chapman m.Charles Ph.Charpentier G.Chatzikonstantinidis C.A.Chavez Barajas m.Chefdeville C.Chen S.Chen A.Chernov S.-G.Chitic V.Chobanova S.Cholak m.Chrzaszcz A.Chubykin V.Chulikov P.Ciambrone m.F.Cicala X.Cid Vidal G.Ciezarek P.E.L.Clarke m.Clemencic H.V.Cliff J.Closier J.L.Cobbledick V.Coco J.A.B.Coelho J.Cogan E.Cogneras L.Cojocariu P.Collins T.Colombo L.Congedo A.Contu N.Cooke G.Coombs G.Corti C.m.Costa Sobral B.Couturier D.C.Craik J.Crkovská m.Cruz Torres R.Currie C.L.Da Silva E.Dall’ Centro Brasileiro de Pesquisas Físicas(CBPF) Rio de JaneiroBrazil Universidade Federal do Rio de Janeiro(UFRJ) Rio de JaneiroBrazil Center for High Energy Physics Tsinghua UniversityBeijingChina School of Physics State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijingChina University of Chinese Academy of Sciences BeijingChina Institute Of High Energy Physics(IHEP) BeijingChina Institute of Particle Physics Central China Normal UniversityWuhanHubeiChina Univ.Grenoble Alpes Univ.Savoie Mont BlancCNRSIN2P3-LAPPAnnecyFrance UniversitéClermont Auvergne CNRS/IN2P3LPCClermont-FerrandFrance Aix marseille Univ CNRS/IN2P3CPPMMarseilleFrance UniversitéParis-Saclay CNRS/IN2P3IJCLabOrsayFrance Laboratoire Leprince-ringuet(llr) PalaiseauFrance LPNHE Sorbonne UniversitéParis Diderot Sorbonne Paris CitéCNRS/IN2P3ParisFrance I.Physikalisches Institut RWTH Aachen UniversityAachenGermany Fakultät Physik Technische Universität DortmundDortmundGermany max-Planck-Institut für Kernphysik(mPIK) HeidelbergGermany Physikalisches Institut Ruprecht-Karls-Universität HeidelbergHeidelbergGermany School of Physics University College DublinDublinIreland INFN Sezione di Bari BariItaly INFN Sezione di Bologna BolognaItaly INFN Sezione di Ferrara FerraraItaly INFN Sezione di Firenze FirenzeItaly INFN Laboratori Nazionali di Frascati FrascatiItaly INFN Sezione di Genova GenovaItaly INFN Sezione di milano-Bicocca MilanoItaly INFN Sezione di milano MilanoItaly INFN Sezione di Cagliari MonserratoItaly Universita degli Studi di Padova Universita e INFNPadovaPadovaItaly INFN Sezione di Pisa PisaItaly INFN Sezione di Roma Tor Vergata RomaItaly INFN Sezione di Roma La Sapienza RomaItaly Nikhef National Institute for Subatomic Physics AmsterdamNetherlands Nikhef National Institute for Subatomic Physics and VU University Amsterdam AmsterdamNetherlands Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences KrakówPoland AGH-University of Science and Techno

夸克和胶子组成的粒子统称强子,其中包含4个或以上组分夸克的强子被称为奇异强子.目前实验上发现的奇异强子最多包含5个夸克,称为五夸克态.对五夸克态的深入研究可以检验对强相互作用的理解.利用质心能量为7、8和13 TeV,总积分亮度9 fb^... 详细信息

夸克和胶子组成的粒子统称强子,其中包含4个或以上组分夸克的强子被称为奇异强子.目前实验上发现的奇异强子最多包含5个夸克,称为五夸克态.对五夸克态的深入研究可以检验对强相互作用的理解.利用质心能量为7、8和13 TeV,总积分亮度9 fb^(−1)的质子-质子对撞数据,大型强子对撞机底夸克实验(LHCb)采用全谱分析的方法,研究了■^(−)_(b)→J/ψΛK^(−)衰变过程中的共振态结构.实验发现J/ψΛ系统中存在质量约为4.46 meV/c^(2)的共振结构存在的迹象,其显著程度为3.1倍标准偏差,性质与五夸克态相符.这是实验上首次观测到包含奇异夸克的五夸克态的存在证据,为五夸克态的理论研究和后续的实验探索提供了重要的依据.除此之外,实验还精细测量了ΛK−系统中部分共振态的共振参数,精度远高于当前世界平均值,这对加深传统重子谱学的认识有着重要的意义.

关键词：大型强子对撞机强相互作用五夸克态共振结构奇异夸克强子组分夸克重子谱

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Norwegian oil and gas storage in rock caverns-Technology based on experience from hydropower development

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Journal of Rock mechanics and Geotechnical Engineering 2021年第2期13卷 479-486页

作者： bjørn Nilsen Department of Geoscience and Petroleum Norwegian University of Science and Technology(NTNU)TrondheimNorway

Underground storage in rock caverns is widely used in Norway for many different petroleum products,such as crude oil,fuel,propane and butane.Basically,the caverns for such storages are unlined,i.***.containment is ensured without using any steel lining or membrane.The main basis for the storage technology originates from the extensive hydropower development in Norway.As part of this activity,about 4500 km of tunnels and shafts have been excavated,and around 200 large powerhouse caverns have been constructed.The hydropower tunnels are mainly unlined,with hydrostatic water pressure on unlined rock of up to 1000 m.Some of the projects also include air cushion chambers with volumes of up to 1×10^(5)m^(3)and air pressure up to 7.7 mPa.many lessons which are valuable also for underground oil and gas storage have been learnt from these projects.For a storage project to become successful,systematic,well planned design and ground investigation procedures are crucial.The main steps of the design procedure are first to define the optimum location of the project,and then to optimize orientation,shape/geometry and dimensions of caverns and tunnels.As part of the procedure,ground investigations have to be carried out at several steps integrated with the progress of design.The investigation and design procedures,and the great significance of these for the project to become successful will be discussed.Case examples of oil and gas storage in unlined rock caverns are given,illustrating the relevancy of experience from high-pressure hydropower projects for planning and design of unlined caverns for oil and gas storage.

关键词： Underground storage Oil Gas Liquefied petroleum gas(LPG) Hydropower Air cushion chamber

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