检索结果-南通市图书馆

Aqueous-phase hydrogenation of levulinic acid over carbon layer protected silica-supported cobalt-ruthenium catalysts

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2021年第10期34卷 114-122页

作者： lihua qian Guojun Lan Xiaoyan Liu Zhenqing Li Ying Li Institute of Industrial Catalysis Zhejiang University of TechnologyHangzhou 310014China

The hydrogenation of levulinic acid(LA)to c-valerolactone(GVL)by using water as solvent is a crucial process in the production of fine chemicals from *** ultrathin carbon layer coating CoRu bimetallic catalyst supported on silica(CoRu@C/SiO2)is prepared by using tannis-ligated cobalt-ruthenium complex on silica as precursors,and applied for catalyzed synthesis of GVL from *** of the synergistic effect between cobalt and ruthenium,the addition of small amounts of Ru to Co catalysts can increase the catalytic activity in the aqueous hydrogenation of *** ultrathin carbon layer covered on the CoRu bimetallic catalyst can greatly reduce the leaching of active *** CoRu@C/SiO2 catalyst achieves high stability and is reused up to 5 runs without significant loss of performance in aqueous hydrogenation of levulinic acid.

关键词： Levulinic acid Hydrogenation Cobalt-ruthenium Synergistic effect Carbon coating

Geochronology and Geochemistry of the Granites from the Longtoushan Hydrothermal Gold Deposit in the Dayaoshan Area,Guangxi:Implication for Petrogenesis and Mineralization

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2019年第2期30卷 309-322页

作者： lihua qian Jianqing Lai Lifang Hu Rong Cao Shilong Tao Bei You Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of EducationSchool of Geosciences and Info-physicsCentral South University

The gold mineralization in the Longtoushan hydrothermal gold deposit is concentrated within the contact zone of the granitic complex. Whole rock geochemistry and in-situ U-Pb and Hf isotopic data were used to constrain the genesis and age of the granites and related Cu-Au mineralization in the Longtoushan Deposit. The granites mainly consist of the granite porphyry, rhyolite porphyry, porphyritic granite and quartz porphyry. LA-ICP-MS U-Pb dating of zircons from the granite porphyry, rhyolite porphyry and quartz porphyry indicates that they intruded from ca. 94 to 97 Ma. These intrusions exhibit similar trace element characteristics, i.e., right-dipping REE patterns, depletion of Ba, Sr, P and Ti, and enrichment of Th, U, Nd, Zr and Hf. The εHf(t) values of zircons from the granite porphyry, rhyolite porphyry and quartz porphyry range from-26.81 to-8.19,-8.12 to-5.33, and-8.99 to-5.83, respectively, suggesting that they were mainly derived from the partial melting of the Proterozoic crust. The Cu-Au mineralization is mainly related to the rhyolite porphyry and porphyritic granite, respectively. The Longtoushan granites were most likely formed in a post-collisional extensional environment, and the deposit is a part of the Late Yanshanian magmatism related mineralization in the Dayaoshan area and its adjacent areas.

关键词： Longtoushan gold deposit rhyolite porphyry zircon U-Pb dating Hf isotopes petrogenesis Cu-Au mineralization

Ammonium Metavanadate Fabricated by Selective Precipitation of Impurity Chemicals on Inorganic Flocculants

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2023年第4期11卷 1951-1961页

作者： Bo Shi Dandan Zhu Pengxiang Lei Ximin Li Hengbo Xiao lihua qian Shandong Aluminum Industry Corporation Limited ZiboChina Petroleam&Natural Gas Transport Corporation of China WuhanChina School of Chemistry and Chemical Engineering Hubei University of TechnologyWuhanChina School of Physics Huazhong University of Science and TechnologyWuhanChina

High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage ***_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the ***,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the *** this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost ***,high purity NH_(4)VO_(3)is produced by the crystallization from the purified *** screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,***_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude *** purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.

关键词： Ammonium metavanadate flocculating agent phosphate arsenate cooling precipitation vanadium slag bayer alumina liquor

Chemical and boron isotopic compositions of tourmaline in the Longtoushan hydrothermal gold deposit, Guangxi, China:implications for gold mineralization

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 2019年第2期38卷 277-291页

作者： lihua qian Jianqing Lai Shugen Zhang Lifang Hu Rong Cao Shilong Tao Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education School of Geosciences and Info-Physics Central South University

The Longtoushan hydrothermal gold deposit is located in the southwestern region of the Dayaoshan *** is widespread in the Longtoushan gold deposit and is mainly distributed in the rhyolite porphyry and associated cryptoexplosive breccia. The spatial distribution of tourmaline enrichment is similar to that of the gold orebody. Feldspar has been largely replaced by tourmaline in the rhyolite porphyry and cryptoexplosive *** microprobe analysis revealed that tourmalines in the Longtoushan deposit belong mainly to the alkali group and partly to the X-vacant group; they mostly fell in the schorl-dravite series field. Two distinct sets of dominant substitutions were observed: MgFe_(-1) and Al□(NaR2+)-1,where R = Fe, Mg. In addition, minor substitutions include(CaMg)(NaAl)_(-1) and FeAl_(-1). The calculated d11 B value for the mineralizing fluids ranged from-12.8 to-9.7%,which is typical of S-type granites, and boron-enriched fluids predominantly derived from rhyolitic melt. Part of the tourmaline from the rhyolite porphyry crystallized during the magmatic-hydrothermal stage, whereas most tourmalines from the deposit formed in the post-magmatic hydrothermal stage. The tourmalines were deposited from a relatively reduced and acidic fluid system, and the gold predominantly precipitated during the post-magmatic hydrothermal stage in the Longtoushan deposit.

关键词： Longtoushan gold deposit Tourmaline Oreforming fluids Boron isotopes

Origin and the Hardening Mechanism of Twinned Lenticular Martensite in a Fe-33Ni Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2023年第6期36卷 899-905页

作者： Yong Li Zuohua Wang lihua qian Jian Zhao Wu Zhang Ping Wei Hongwang Zhang National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical EngineeringYanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China School of Physics Huazhong University of Science and TechnologyWuhan 430074China China Copper Huazhong Copper Cooperation Limited Huangshi 435004China College of Weaponry Engineering Naval University of EngineeringWuhan 430033China

The twinned substructure of lenticular martensite in a quenched Fe–33Ni alloy was *** contrary to the traditional viewpoint that the twinned laths come from{112}deformation twins and show insignificant hardening,we demonstrate that they are actually originated from the twinned Kurdjumov Sachs(KS)variants and can give rise to 3–4 times hardening up to~420 HV(~130 HV for the starting sample).The underlying mechanisms responsible for the propensity for twinned variants and the carbon-independent hardening for Fe–Ni system were discussed.

关键词： Twinned variants Midrib Lenticular martensite Hardening mechanism Fe-33Ni

Self-Supported Nanoporous Gold with Gradient Tin Oxide for Sustainable and Efficient Hydrogen Evolution in Neutral Media

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 Renewable Materials 2020年第2期8卷 133-151页

作者： Xianglong Lu Tianshui Yu Hailing Wang Ruichun Luo Pan Liu Songliu Yuan lihua qian School of Physics Huazhong University of Science and TechnologyWuhan430074China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200030China

Hydrogen evolution reaction(HER)in neutral medium suffers from slow kinetics as compared to that in alkaline or acidic conditions,owing to larger Ohmic loss and low proton *** we report that a self-supported nanoporous Au-SnO_(x)(NP Au-SnO_(x))catalyst with gradient tin oxide surface could significantly enhance HER activity in neutral buffer solution(0.2 M PBS).The NP Au-SnO_(x)catalyst exhibits a low onset overpotential of 38 mV and a small Tafel slope of 79 mV dec^(−1).The current density of 10 mA cm^(−2)is manifested at an overpotential as low as 148 mV,representing the comparable performance of Pt/C *** high catalytic activity can retain at least 10 hours without any detectable *** superior HER activity is proposed to originate from the gradient SnO_(x)structure and metal/oxide interfaces in nanoporous ***,the X-ray photoelectron spectroscopy reveals that the gradient oxide in the ligament is remarkably stable during long-term reaction.

关键词： Nanoporous metals electrocatalysts hydrogen evolution reaction neutral electrolyte gradient oxide structure

Ultrasensitive strain gauge with tunable temperature coefficient of resistivity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2016年第5期9卷 1346-1357页

作者： Lizhi Yi Weihong Jiao Changming Zhu Ke Wu Chao Zhang lihua qian Shuai Wang Yingtao Jiang Songliu Yuan School of Physics Huazhong University of Science and Technology Wuhan 430074 China Flexible Electronics Research Center Huazhong University of Science and Technology Wuhan 430074 China School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan 430074 China Nevada Nanotechnology Center & Department of Electrical and Computer Engineering University of Nevada Las Vegas Nevada 89154-4026 USA

We demonstrate an ultrasensitive strain gauge based on a discontinuous metal film with a record detection limit as low as 8.3 × 10^-6. Constructed by well-tunable crevices on the nanometer scale within the film, this gauge exhibits an ultrafast dynamic response to vibrations with a frequency range of 1 Hz to 10 kHz. More importantly, the temperature coefficient of resistivity （TCR） of the metal film is tunable owing to the cancellation effect caused by the possibility of tunneling across the nanoscale crevices （showing a negative temperature dependence） and the electron conduction within the metal islands （showing a positive temperature dependence）. Consequently, a nullified TCR is achievable when the crevice size can be precisely controlled. Thus, a fabrication strategy to precisely control the nanoscale crevices was developed in this study through the real-time tracking of the electrical conductivity during thermal evaporation. The ultrasensitive strain gauge with a tunable thermal drift introduces numerous opportunities for precision devices and wearable electronics with superior reliability.

关键词： strain gauge flexible gauge Au nanoparticle sound-wave detection radial-artery detection electron tunneling

Nanoporous Au-Sn with solute strain for simultaneously enhanced selectivity and durability during electrochemical CO2 reduction

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 Materials Science & Technology 2020年第8期36卷 154-160页

作者： Xianglong Lu Tianshui Yu Hailing Wang lihua qian Ruichun Luo Pan Liu Yao Yu Lin Liu Pengxiang Lei Songliu Yuan School of Physics Huazhong University of Science and TechnologyWuhan430074China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai200030China School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan430074China School of Chemistry and Chemical Engineering Hubei University of TechnologyWuhan430068China

Electrochemical carbon dioxide reduction meditated by metallic catalysts suffers from restricted selectivity and competition from hydrogen evolution, which sensitively depends on ambiguous contributions of alloying and strain state in bimetallic catalysts. Herein, nanoporous Au-Sn(NPAS) containing trace tin solute in Au lattices is delicately designed to convince real strain effect, while eliminating other undesirable factors, such as alloying, crystal facets and surface composition. Compared with nanoporous gold(NPG), the NPAS with a solute strain of ~2.2% enables more efficient CO2-to-CO conversion, with an efficiency as high as 92% at-0.85 V versus reversible hydrogen electrode(vs. RHE), and the high activity can retain for more than 8 h. The combination of HRTEM and surface valence band photoemission spectra reveals that the tensile strain on the surface of 3 D nanoporous structure promotes the catalytic activity by shifting up the d-band center and strengthening the adsorption of key intermediate *COOH. A small amount of Sn solute in the nanoporous alloy can prevent ligament coarsening effectively and improve the electrochemical stability.

关键词： Nanoporous metals Electrocatalysts Electrochemical carbon dioxide reduction Strain effect

Controllable defects implantation in MoS2 grown by chemical vapor deposition for photoluminescence enhancement

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第8期11卷 4123-4132页

作者： Ke Wu Zhe Li Jibo Tang Xianglong Lv Hailing Wang Ruichun Luo Pan Liu lihua qian Shunping Zhang Songliu Yuan School of Physics Huazhong University of Science and Technology Wuhan 430074 China School of Physics and Technology Center for Nanoscience and Nanotechnology and Key Laboratory of Artificial Micro- nndIVano-Structures of Ministry of Education Wuhan University Wuhan 430072 China The Institute for Advanced Studies Wuhan University Wuhan 430072 China Flexible Electronics Research Center Huazhong University of Science and Technology Wuhan 430074 China Department of Materials Science and Engineering Shanghai Jiaotong University Shanghai200240 China

Photoluminescence （PL） of transition metal dichalcogenides （TMDs） can be engineered by controlling the density of defects, which provide active sites for electron-hole recombination, either radiatively or non-radiatively. However, the implantation of defects by external stimulation, such as uniaxial tension and irradiation, tends to introduce local damages or structural non-homogeneity, which greatly degrades their luminescence properties and impede their applicability in constructing optoelectronic devices. In this paper, we present a strategy to introduce a controllable level of defects into the MoS2 monolayers by adding a hydrogen flow during the chemical vapor deposition, without sacrificing their luminescence characteristics. The density of the defect is controlled directly by the concentration of hydrogen. For an appropriate hydrogen flux, the monolayer MoS2 sheets have three times stronger PL emission at the excitonic transitions, compared with those samples with nearly perfect crystalline structure. The defect-bounded exciton transitions at lower energies arising in the defective samples and are maximized when the total PL is the strongest. However, the B exciton, exhibits a monotonic decline as the defect density increases. The Raman spectra of the defective MoS2 reveal a redshift （blueshift） of the in-plane （out-of-plane） vibration modes as the hydrogen flux increases. All the evidence indicates that the generated defects are in the form of sulfur vacancies. This study renders the high-throughput synthesis of defective MoS2 possible for catalysis or light emitting applications.

关键词： chemical vapor deposition(CVD) MoS2 hydrogen,sulfur vacancy defect-bounded exciton photoluminescenceenhancement,Raman shifts