检索结果-南通市图书馆

ChemPhysMater 2024年第3期3卷 329-340页

作者： Patrick Ndouka Ndouka Stephane Kenmoe Jacques Richard mache elie Acayanka Dick Hartmann Douma Ralph Gebauer Patrick Mountapmbeme Kouotou Department of Chemistry Faculty of SciencesUniversity of MarouaP.O.Box 814 MarouaCameroon Department of theoretical Chemistry University of Duisburg-EssenD-45141 EssenGermany Department of Mining engineering School of Geology and Mining EngineeringUniversity of NgaoundéréP.O.Box 115 MeigangaCameroon Department of Inorganic Chemistry Faculty of ScienceUniversity of YaoundéIP.O.Box 812 YaoundéCameroon Groupe de Simulations Numériques en Magnétisme et Catalyse Facultédes Sciences et TechniquesUniversitéMarien NgouabiB.P.69 BrazzavilleCongo the Abdus Salam International Centre for theoretical Physics(ICtP) 34151 TriesteItaly National Advanced School of engineering of Maroua University of MarouaP.O.Box 46 MarouaCameroon Higher Institute of Agriculture WoodWater and EnvironmentUniversity of EbolowaP.O.Box 118 EbolowaCameroon

In this study,Mn_(3)O_(4) spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn_(3)O_(4) exhibited a tetragonal spinel structure,and fourier transformed infrared(ftIR)spectroscopy identified surfaceadsorbed functional *** electron microscopy(SeM)and the specific surface area analyses by Brunauer−emmett−teller(Bet)revealed a porous,homogeneous surface composed of strongly agglomerated spherical grains with an estimated average particle size of∼35 nm,which corresponded to a large specific surface area of∼81.5 m^(2)/g.X-ray photoelectron spectroscopy(XPS)analysis indicated that Mn_(3)O_(4) was composed of metallic cations(Mn^(4+),Mn_(3)+,and Mn^(2+))and oxygen species(O_(2)−,OH−and CO_(3)2−).the optical bandgap energy is∼2.55 *** of the catalytic performance of the Mn_(3)O_(4) SPs indicated t90 conversion of CH4 to CO_(2) and H2O at 398℃ for gas hourly space velocity(GHSV)of 72000 mL^(3) g^(−1) h^(−1).this observed performance can be attributed to the cooperative effects of the smallest spherical grain size with a mesoporous structure,which is responsible for the larger specific surface area and available surface-active oxygenated *** cooperative effect of the good reducibility,higher ratio of active species(OLat/OAds),and results of density functional theory(Dft)calculations suggested that the total oxidation of CH4 over the mesoporous Mn_(3)O_(4) SPs might take place via a two-term process in which both the Langmuir−Hinshelwood and Mars−van Krevelen mechanisms are cooperatively involved.

关键词： Sol-gel Manganese oxide Catalytic oxidation Methane Langmuir−Hinshelwood mechanism Mars−van Krevelen route two−term process

来源：

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

the effects of local variations in conditions on carbon storage and release in the continental mantle

引用

National Science Review 2024年第6期11卷 22-36页

作者： Stephen f.foley Chunfei Chen Dorrit e.Jacob School of Natural Sciences Macquarie University Research School of earth Sciences Australian National University State Key Laboratory of Geological Processes and Mineral Resources School of Earth Sciences China University of Geosciences

Recent advances indicate that the amount of carbon released by gradual degassing from the mantle needs to be revised upwards, whereas the carbon supplied by plumes may have been overestimated in the *** in rock types and oxidation state may be very local and exert strong influences on carbon storage and release mechanisms. Deep subduction may be prevented by diapirism in thick sedimentary packages,whereas carbonates in thinner sequences may be subducted. Carbonates stored in the mantle transition zone will melt when they heat up, recognized by coupled stable isotope systems(e.g. Mg, Zn, Ca). there is no single ‘mantle oxygen fugacity’, particularly in the thermal boundary layer(tBL) and lowermost lithosphere, where very local mixtures of rock types coexist. Carbonate-rich melts from either subduction or melting of the uppermost asthenosphere trap carbon by redox freezing or as carbonate-rich dykes in this zone. Deeply derived, reduced melts may form further diamond reservoirs, recognized as polycrystalline diamonds associated with websteritic silicate minerals. Carbon is released by either edge-driven convection,which tears sections of the tBL and lower lithosphere down so that they melt by a mixture of heating and oxidation, or by lateral advection of solids beneath rifts. Both mechanisms operate at steps in lithosphere thickness and result in carbonate-rich melts, explaining the spatial association of craton edges and carbonate-rich magmatism. High-pressure experiments on individual rock types, and increasingly on reactions between rocks and melts, are fine-tuning our understanding of processes and turning up unexpected results that are not seen in studies of single rocks. future research should concentrate on elucidating local variations and integrating these with the interpretation of geophysical signals. Global concepts such as average sediment compositions and a uniform mantle oxidation state are not appropriate for small-scale processes; an increa

关键词： lithospheric mantle carbonate melts deep carbon cycle craton destruction continental rifts

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Converting tRex-RGB green-channel data to 557.7 nm auroral intensity:Methodology and initial results

引用

earth and Planetary Physics 2024年第1期8卷 258-274页

作者： Jun Liang D.M.Gillies e.Spanswick e.f.Donovan University of Calgary CalgaryT2N 1N4Canada

the recently deployed transition Region explorer(tRex)-RGB(red-green-blue)all-sky imager(ASI)is designed to capture“true color”images of the aurora and *** the 557.7 nm green line is usually the brightest emission line in visible auroras,the green channel of a tRex-RGB camera is usually dominated by the 557.7 nm *** this rationale,the tRex mission does not include a specific 557.7 nm imager and is designed to use the RGB green-channel data as a proxy for the 557.7 nm *** this study,we present an initial effort to establish the conversion ratio or formula linking the RGB green-channel data to the absolute intensity of 557.7 nm auroras,which is crucial for quantitative uses of the RGB *** illustrate two approaches:(1)through a comparison with the collocated measurement of green-line auroras from the tRex spectrograph,and(2)through a comparison with the modeled green-line intensity according to realistic electron precipitation flux measurements from low-earth-orbit satellites,with the aid of an auroral transport *** demonstrate the procedures and provide initial results for the tRex-RGB ASIs at the Rabbit Lake and Lucky Lake *** RGB response is found to be *** conversion ratios or formulas between RGB green-channel data and the green-line auroral intensity are given and can be applied immediately by tRex-RGB data *** methodology established in this study will also be applicable to the upcoming SMILe ASI mission,which will adopt a similar RGB camera system in its deployment.

关键词： tRex RGB green-line aurora auroral transport model

来源：

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

Inflow and outflow permeability tests in a very soft clay under low stresses

引用

Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3270-3283页

作者： J.W.S.Vargas f.A.B.Danziger f.R.Lopes t.Lunne federal University of Rio de Janeiro Rio de JaneiroBrazil Norwegian Geotechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the BAt probe at SarapuíII soft clay test site are presented.A description of the BAt permeability test is provided,discussing its advantages and shortcomings,especially in the case of very soft clays under low *** pressures were monitored during probe installation and were found to be slightly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investigated after the usual saturation procedure provided an unsatisfactory pore pressure response during probe *** show that the vacuum saturation procedure provides adequate response during installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating that careful execution of the test can lead to good test repeatability regardless of the loading *** sequences of alternated inflow and outflow tests have yielded similar results,indicating that soil reconsolidation and filter clogging were negligible in the tests *** are presented concerning the relationship between index parameters and the in situ coefficient of permeability for SarapuíII clay,which plot outside the range of existing databases.

关键词： Permeability test Soft clay BAt probe Inflow and outflow tests

来源：

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

All-electron basis sets for H to Xe specific for ZORA calculations:Applications in atoms and molecules

引用

Chinese Physics B 2024年第8期33卷 238-246页

作者： C.S.Gomes f.e.Jorge A.Canal Neto Departamento de fisica Universidade Federal do Espirito Santo29075-910 VitoriaESBrazil Departamento de fisica Instituto de Ciencias Exatas e BiologicasUniversidade Federal de Ouro Preto Campus Universitario Morro do Cruzeiro35402-136 Ouro PretoMGBrazil

A segmented basis set of quadruple zeta valence quality plus polarization functions(QZP)for H through Xe was developed to be used in conjunction with the ZORA *** set was augmented with diffuse functions to describe electrons farther away from the nuclei *** the ZORA-CCSD(t)/QZP-ZORA theoretical model,atomic ionization energies and bond lengths,harmonic vibrational frequencies,and atomization energies of some molecules were *** addition of core-valence corrections has been shown to improve the agreement between theoretical and experimental results for molecular *** atomization energies,a similar observation emerges when considering spin-orbit *** the augmented QZP-ZORA set,static mean dipole polarizabilities of a set of atoms were calculated and compared with previously published recommended and experimental *** evaluations of the ZORA and Douglas–Kroll–Hess Hamiltonians were made for each property studied.

关键词： QZP-ZORA and AQZP-ZORA basis sets elements from H to Xe CCSD(t)method atomic and molecular properties

来源：

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

New trends in diagnosis and management of gallbladder carcinoma

引用

World Journal of Gastrointestinal Oncology 2024年第1期16卷 13-29页

作者： efstathios t Pavlidis Ioannis N Galanis theodoros e Pavlidis ^(nd)Propedeutic Department of Surgery Hippokration General HospitalSchool of MedicineAristotle University of ThessalonikiThessaloniki 54642Greece

Gallbladder(GB)carcinoma,although relatively rare,is the most common biliary tree cholangiocarcinoma with aggressiveness and poor *** is closely associated with cholelithiasis and long-standing large(>3 cm)gallstones in up to 90%of *** other main predisposing factors for GB carcinoma include molecular factors such as mutated genes,GB wall calcification(porcelain)or mainly mucosal microcalcifications,and GB polyps≥1 cm in *** is made by ultrasound,computed tomography(Ct),and,more precisely,magnetic resonance imaging(MRI).Preoperative staging is of great importance in decisionmaking regarding therapeutic *** staging is based on MRI findings,the leading technique for liver metastasis imaging,enhanced three-phase Ct angiography,or magnetic resonance angiography for major vessel *** is also necessary to use positron emission tomography(Pet)-Ct or ^(18)f-fDG Pet-MRI to more accurately detect metastases and any other occult deposits with active metabolic *** laparoscopy may detect dissemination not otherwise found in 20%-28.6%of *** treatment is needed,including surgical resection,targeted therapy by biological agents according to molecular testing gene mapping,chemotherapy,radiation therapy,and *** is of great importance to understand the updated guidelines and current treatment *** extent of surgical intervention depends on the disease stage,ranging from simple cholecystectomy(t1a)to extended resections and including extended cholecystectomy(t1b),with wide lymph node resection in every case or IV-V segmentectomy(t2),hepatic trisegmentectomy or major hepatectomy accompanied by hepaticojejunostomy Roux-Y,and adjacent organ resection if necessary(t3).Laparoscopic or robotic surgery shows fewer postoperative complications and equivalent oncological outcomes when compared to open surgery,but much attention must be paid to avoiding *** addition to surgery,novel targe

关键词： Biliary tract neoplasms extrahepatic cholangiocarcinoma Gallbladder carcinoma Gallbladder diseases Biliary tree diseases Gastrointestinal malignancies

来源：

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

Management of obstructed colorectal carcinoma in an emergency setting:An update

引用

World Journal of Gastrointestinal Oncology 2024年第3期16卷 598-613页

作者： efstathios t Pavlidis Ioannis N Galanis theodoros e Pavlidis 2nd Propedeutic Department of Surgery Hippokration General HospitalSchool of MedicineAristotle University of ThessalonikiThessaloniki 54642Greece

Colorectal carcinoma is common,particularly on the left *** 20%of patients,obstruction and ileus may be the first clinical manifestations of a carcinoma that has advanced(stage II,III or even IV).Diagnosis is based on clinical presentation,plain abdominal radiogram,computed tomography(Ct),Ct colonography and positron emission tomography/*** best management strategy in terms of short-term operative or interventional and long-term oncological outcomes re-mains *** the most common left-sided obstruction,the first choice should be either emergency surgery or endoscopic decompression by self-expen-dable metal stents or *** operative plan should be either one-stage or two-stage ***-stage resection with on-table bowel decompression and irrigation can be accompanied or not accompanied by proximal defunctioning stoma(colostomy or ileostomy).Primary anastomosis is more convenient but has increased risks of anastomotic leakage and ***-stage resection(Hart-mann’s procedure)is safer and the most widely used despite temporally affecting quality of *** control surgery in high-risk frail patients is less frequently performed since it can be successfully substituted with endoscopic stenting or *** the less common right-sided obstruction,one-stage surgical resection is more beneficial than endoscopic *** role of minimally invasive surgery(laparoscopic or robotic)is a subject of *** laparoscopic-assisted management is advantageous to some extent but requires much expertise due to inherent difficulties in dissecting the distended colon and the risk of rup-ture and subsequent septic *** decompressing stent as a bridge to elective surgery more substantially decreases the risks of morbidity and mortality than emergency surgery for decompression and has equivalent medium-term overall survival and disease-free survival *** combination with neoadjuvant chemotherapy or radiation may have a p

关键词： Acute abdomen Obstructive ileus Colorectal carcinoma emergency surgery Colectomy Intraluminal metal stents

来源：

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

美国页岩油气地质特征及勘探开发进展

引用

石油勘探与开发 2024年第4期51卷 807-828页

作者： MCMAHON t P LARSON t e ZHANG t SHUSteR M 美国德克萨斯大学奥斯汀分校杰克逊地质科学学院经济地质局奥斯汀78758-4445德克萨斯州美国

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比... 详细信息

基于美国页岩油气勘探开发历程的回顾,对主要页岩盆地的地质演化、主要页岩层系的油气地质特征及勘探开发进展进行系统梳理和总结。美国重要页岩盆地的富烃页岩主要发育于6个地质时期:中奥陶世、中—晚泥盆世、早石炭世(中—晚密西西比世)、早二叠世、晚侏罗世和晚白垩世(塞诺曼期—土伦期),构造沉积环境主要包括克拉通内盆地、前陆盆地和被动大陆边缘盆地。古生界富烃页岩主要分布于以下6个盆地:阿巴拉契亚盆地(尤蒂卡页岩和马塞勒斯页岩)、阿纳达科盆地(伍德福德页岩)、威利斯顿盆地(巴肯页岩)、阿卡马盆地(费耶特维尔页岩)、沃思堡盆地(巴内特页岩)和二叠盆地(狼营组和斯帕瑞组/骨泉组页岩)。中生界富烃页岩主要发育在西墨西哥湾盆地(海恩斯维尔组和鹰滩组)和落基山盆地群(以丹佛和粉河盆地的尼尔布拉勒组页岩为主)。通过对各页岩区带的详细分析发现,页岩的岩相和矿物成分存在差异,“页岩储层”并非只是页岩,很多情况下页岩油气还产自粉砂岩和碳酸盐岩等多种岩石类型。美国的页岩油气资源丰富,页岩油地质资源量超过0.246×1012 t,页岩气地质资源量超过290×1012 m3。在开启“页岩革命”的水平井水力压裂技术出现之前,美国经过了长达20年的勘探开发实践和理论技术积累。自2007年至2023年,美国页岩油气产量从约11.2×104t/d油当量增加到超过300.0×104t/d油当量,2017年页岩油气产量超过了常规油气,2023年在油气总产量中的占比增加到60%以上。页岩油气的开发主要得益于钻完井技术的改进,“立体开发”的攻关,以及重复压裂、提高原油采收率和“U”形井等技术的应用。基于美国丰富的页岩资源基础和技术的不断进步,页岩油气的产量将继续为全美的油气生产做出更大贡献。

关键词：美国页岩油页岩气页岩储层非常规储层油气产量资源评价

来源：

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

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

引用

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

来源：

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

Current considerations on intraductal papillary neoplasms of the bile duct and pancreatic duct

引用

World Journal of Gastroenterology 2024年第10期30卷 1461-1465页

作者： efstathios t Pavlidis Ioannis N Galanis theodoros e Pavlidis 2^(nd) Propedeutic Department of Surgery Hippokration General HospitalSchool of MedicineAristotle University of ThessalonikiThessaloniki 54642Greece

Pancreatobiliary intraductal papillary neoplasms(IPNs)represent precursors of pancreatic cancer or bile duct cholangiocarcinoma that can be detected and *** advances in diagnostic methods,identifying these premalignant lesions is still challenging for treatment *** imaging,biomarkers and molecular tests for genomic alterations can be used for diagnosis and *** intervention in combination with new chemotherapeutic agents is considered the optimal treatment for malignant *** balance between the risk of malignancy and any risk of resection guides management policy;therefore,treatment should be individualized based on a meticulous preoperative assessment of high-risk *** of the bile duct is more aggressive;thus,early diagnosis and surgery are *** conservative management of low-risk pancreatic branch-duct lesions is safe and effective.

关键词： Biliary tree diseases Pancreatic cystic neoplasms Biliary tract neoplasms extrahepatic cholangiocarcinoma Pancreatic adenocarcinoma

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：