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Elemental sulfur in northern South China Sea sediments and its significance

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Science China Earth Sciences 2015年第11期58卷 2271-2278页

作者： LIN qi WANG JiaSheng FU ShaoYing lu hongFeng BU qingTao LIN RongXiao SUN fei State Key Laboratory of Biogeology and Environmental Geology School of Earth Science China University of Geosciences Guangzhou Marine Geological Survey qingdao Institute of Marine Geology

Elemental sulfur(ES) is one of the intermediates in the inorganic sulfur cycle and thus plays a key role in the fractionation of stable sulfur isotopes in different reservoirs and the marine environment. In this study, solid ES is discovered in sediments near the Jiulong Methane Reef in the northern South China Sea by scanning electron microscopy and Raman spectroscopy. Combining the morphology and distribution of ES, pyrite concentrations, and sulfur isotopes, we conclude that:(1) solid ES coexists with pyrite microcrystals and sulfide(oxyhydr)oxides as well as clay minerals, and they are mainly distributed on the surface of mineral aggregates;(2) ES mainly occurs within and near the sulfate-methane transition zone(SMTZ) despite little morphological diversity;(3) ES formation might be related to hydrogen sulfide oxidation and is therefore linked with fluctuations in the SMTZ. Within the SMTZ, hydrogen sulfide is produced and pyrite precipitates because of enhanced anaerobic oxidation of methane coupled with dissimilatory sulfate reduction. This enhances the efficiency of the inorganic sulfur cycle and provides favorable conditions for ES formation. The discovery of solid ES in sediments near the Jiulong Methane Reef suggests an important relationship with SMTZ fluctuations that could have implications for the evolution of methane hydrate in the South China Sea.

关键词： elemental sulfur sulfate-methane transition zone shallow sediments northern South China Sea

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Solid-State Interfacial Reaction between Eutectic Au-Ge Solder and Cu/Ni(P)/Au Metalized Ceramic Substrate and Its Suppression

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Journal of Materials Science & Technology 2015年第5期31卷 445-452页

作者： F.q.Lang h.Yamaguchi h.Nakagawa h.Sato Advanced Power Electronics Research Center(ADPERC) National Institute of Advanced Industrial Science and Technology(AIST).Central 21-1-1UmezonoTsukubaIbaraki 305-8568.Japan

Eutectic Au-12 Ge solder was employed to bond the SiC power devices to a Si3N4/Cu/Ni（P）/Au multilayered *** high-temperature reliability of the bond was investigated in detail at 200,250,300 and 330 ℃,*** and Ni5Ge3intermetallic compounds（IMCs） were identified at the Au-12Ge/Ni（P） interface by micro X-ray diffraction（μXRD） and scanning electron microscopy（SEM）equipped with energy dispersive X-ray analysis（EDX）.The growth of the Ni-Ge IMCs was dominated by Ni5Ge3layer,which formed at the Ni5Ge3/NiGe interface by outward diffusion of Ni from the Ni（P） *** activation energy of the total Ni-Ge IMCs growth was 66 kJ/*** shear strength of the bond was tested at both 25 ℃ and the aging temperatures,*** shear strength decreased slightly after aging at 200 and 250 ℃.The shear strength tested at 250 ℃ was 46 MPa after aging at 250 ℃ for 3000 *** shear strength aged at 300 and 330 ℃ rapidly decreased with aging time due to the rapid growth of the *** slow down the interfacial reaction between the high temperature solder and the Ni（P）layer,an approximately 200 nm-thick Ta/TaN/Ta new diffusion barrier（DB） was deposited on the *** by transmission electron microscopy（TEM） equipped with EDX,reveals that the Ta/TaN/Ta DB was bonded well to the Ni（P） layer and the *** temperature storage test at 330 ℃ for1500 h reveals that the bond of the SiC devices maintained its high shear strength of approximately56 MPa without *** new DB effectively suppressed the interfacial reaction between the Au-12 Ge solder and the Ni（P） layer of the substrate.

关键词： high-temperature solder Interfacial reaction Activ

Engineering electronic structures of titanium vacancies in Ti_(1-x)O_(2)nanosheets enables enhanced Li-ion and Na-ion storage

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Green Energy & Environment 2022年第4期7卷 734-741页

作者： huiqin Wang Fengchu Zhang Jing Xia fei lu Bo Zhou Ding Yi Xi Wang Key Laboratory of luminescence and Optical Information Ministry of EducationDepartment of PhysicsSchool of ScienceBeijing Jiaotong UniversityBeijing100044China Institute of Molecular Plus Tianjin UniversityTianjin300072China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China

Up to now,three kinds of ion-storage mechanisms are summarized towards anode materials in lithium/sodium-ion batteries,but they have low capacity and poor cyclic ***,it is necessary to develop a new approach to optimize ion ***,we report an adsorption/desorption storage route through engineering electronic structure of cation-deficient Ti_(1-x)O_(2)***_(1-x)O_(2)nanosheets indeed exhibit higher capacity(332.1 mA h g^(-1)vs.137.7 mA h g^(-1)for LIBs,195.7 mA h g^(-1)vs.111 mA h g^(-1)for SIBs),and more stable cyclic performance(296 mA h g^(-1)vs.99 mA h g^(-1)for LIBs,178.1 mA h g^(-1)vs.80.2 mA h g^(-1)for SIBs after 100 cycles)at 0.1 A g^(-1)than TiO_(2)*** analysis and density functional theory(DFT)calculations reveal that electronic structures of vacancy within Ti_(1-x)O_(2) nanosheets encourage a novel adsorption-desorption storage *** results highlight the benefits of the engineered electronic structures within electrode material and implement novel ion-storage mechanism towards broad energy storage applications.

关键词： Titanium vacancy Titania nanosheet Electronic structure Ion storage Storage mechanism

Dispatchable Region for Active Distribution Networks Using Approximate Second-order Cone Relaxation

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CSEE Journal of Power and Energy Systems 2023年第6期9卷 1999-2007页

作者： Zhigang Li Wenjing huang J.h.Zheng q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

Uncertainty in distributed renewable generation threatens the security of power distribution *** concept of dispatchable region is developed to assess the ability of power systems to accommodate renewable generation at a given operating *** DC and linearized AC power flow equations are typically used to model dispatchable regions for transmission systems,these equations are rarely suitable for distribution *** achieve a suitable trade-off between accuracy and efficiency,this paper proposes a dispatchable region formulation for distribution networks using tight convex *** cone relaxation is adopted to reformulate AC power flow equations,which are then approximated by a polyhedron to improve ***,an efficient adaptive constraint generation algorithm is employed to construct the proposed dispatchable *** studies on distribution systems of various scales validate the computational efficiency and accuracy of the proposed method.

关键词： Dispatchable region distribution system renewable power generation second-order cone relaxation uncertainty

Synergistic Effect of Dual-Doped Carbon on MO_(2)C Nanocrystals Facilitates Alkaline hydrogen Evolution

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Nano-Micro Letters 2023年第10期15卷 101-111页

作者： Min Zhou Xiaoli Jiang Weijie Kong hangfei Li fei lu Xin Zhou Yagang Zhang School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731People’s Republic of China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054People’s Republic of China College of Physical Science and Technology Yangzhou UniversityYangzhou 225002People’s Republic of China Department of Chemical Engineering Polytechnique MontrealMontrealQC H3C 3A7Canada

Molybdenum carbide(MO_(2)C)materials are promising electrocatalysts with potential applications in hydrogen evolution reaction(hER)due to low cost and Pt-like electronic ***,their hER activity is usually hindered by the strong hydrogen binding ***,the lack of water-cleaving site's makes it difficult for the catalysts to work in alkaline ***,we designed and synthesized a B and N dual-doped carbon layer that encapsulated on MO_(2)C nanocrystals(MO_(2)C@BNC)for accelerating hER under alkaline *** electronic interactions between the MO_(2)C nanocrystals and the multiple-doped carbon layer endow a near-zero h adsorption Gibbs free energy on the defective C atoms over the carbon ***,the introduced B atoms afford optimal h_2O adsorption sites for the water-cleaving ***,the dual-doped MO_(2)C catalyst with synergistic effect of non-metal sites delivers superior hER performances of a low overpotential(99 mV@10 mA cm^(-2))and a small Tafel slope(58.1 mV dec^(-1))in 1 M KOh ***,it presents a remarkable activity that outperforming the commercial 10%Pt/C catalyst at large current density,demonstrating its applicability in industrial water *** study provides a reasonable design strategy towards noble-metal-free hER catalysts with high activity.

关键词： Molybdenum carbide hydrogen evolution reaction Dual-doped Synergistic effect Superior performances

Pt nanoclusters modified porous g-C_(3)N_(4)nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

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Chinese Journal of Chemical Engineering 2024年第2期66卷 40-50页

作者： Yi-fei Liang Jin-Rong lu Shang-Kun Tian Wen-quan Cui Li Liu hebei Provincial Key Laboratory of Environmental Photocatalytic and Electrocatalytic Materials College of Chemical EngineeringNorth China University of Science and TechnologyTangshan 063210China

For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild *** attention has been paid to gC_(3)N_(4)as a promising photocatalyst for the generation of *** improve the separation of photogenerated charge,porous nanosheet g-C_(3)N_(4)was modified with Pt nanoclusters(Pt/g-C_(3)N_(4))through impregnation and following photo-induced *** catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)N_(4).The strong interactions of Pt-N in Pt/g-C_(3)N_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes *** addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into h_(2)and CO_(2)via formaldehyde and *** study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

关键词： Water reforming of methanol Photocatalysis g-C_(3)N_(4) Pt nanoclusters hydrogen production

Comparing Ordinary Kriging and Regression Kriging for Soil Properties in Contrasting Landscapes

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Pedosphere 2010年第5期20卷 594-606页

作者： q.ZhU h.S.LIN Department of Crop and Soil Sciences 116 ASI BuildingThe Pennsylvania State UniversityUniversity ParkPA 16802(USA)

The accuracy between ordinary kriging and regression kriging was compared based on the combined consideration of sample size,spatial structure,and auxiliary variables(terrain indices and electromagnetic induction surveys) for a variety of soil properties in two contrasting landscapes(agricultural ***).When spatial structure could not be well captured by point-based observations(e.g.,when the ratio of sample spacing over correlation range was > 0.5),or when a strong relationship existed between target soil properties and auxiliary variables(e.g.,their R2 was > 0.6),regression kriging(RK) was more accurate for interpolating soil properties in both landscapes ***,ordinary kriging(OK) was *** depth and wetness condition did not appear to affect the selection of kriging for soil moisture interpolation,because they did not significantly change the ratio of sample spacing over correlation range and the relationship with the auxiliary *** of a smaller ratio of elevation change over total study area(E/A = 1.2) and multiple parent materials in the agricultural land,OK was generally more accurate in that *** contrast,a larger E/A ratio of 6.8 and a single parent material led to RK being preferable in the steep-sloped forested *** results from this study can be useful for selecting kriging for various soil properties and landscapes.

关键词： geostatistics soil moisture spatial interpolation spatial structure

MATRIX INVESTIGATION ON ISAIChEV ORIENTATION RELATIONShIP

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 185-190页

作者： Sheng, Z.q. Xiao, h. Nuclear Power Inst of China Chengdu China

By means of TEM technique the orientation relationships of cementite, precipitated from islands of granular bainite during tempering, with ferrite have been observed. By calculating the eigenvalues and eigenvectors of transformation matrix, Isaichev relationship has been analyzed. The results indicate that Isaichev relationship is indeed the sum of Kurdjumov-Sachs relationship and Pitsch relationship, so the viewpoint that the cementite with Isaichev relationship precipitates from austenite, instead of ferrite, was confirmed. Moreover, the matrix calculation shows that three reported orientation relationships among austenite, ferrite and cementite in pearlitic transformation cannot be simultaneously valid. (Edited author abstract) 4 Refs.

关键词： Carbides Crystal orientation Eigenvalues and eigenfunctions Nuclear reactors Pearlitic transformations Phase transitions

Risk management for sulfur dioxide abatement under multiple uncertainties

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Frontiers of Earth Science 2016年第1期10卷 87-107页

作者： C. DAI W. SUN q. TAN Y. LIU W.T. lu h.C. GUO College of Environmental Science and Engineering Peking University Beijing 100871 China Institute for Energy Environment and Sustainable Communities University of Reginal Regina Saskatchewan S4S 7H9 Canada College of Water Resources & Civil Engineering China Agricultural University Beijing 100083 China

In this study, interval-parameter programming, two-stage stochastic progranaming （TSP）, and conditional value-at-risk （CVaR） were incorporated into a general optimization framework, leading to an interval-parameter CVaR-based two-stage programming （ICTP） method. The ICTP method had several advantages：（i） its objective function simultaneously took expected cost and risk cost into consideration, and also used discrete random variables and discrete intervals to reflect uncertain properties; （ii） it quantitatively evaluated the right tail of distributions of random variables which could better calculate the risk of violated environmental standards; （iii） it was useful for helping decision makers to analyze the trade-offs between cost and risk; and （iv） it was effective to penalize the second-stage costs, as well as to capture the notion of risk in stochastic programming. The developed model was applied to sulfur dioxide abatement in an air quality management system. The results indicated that the ICTP method could be used for generating a series of air quality management schemes under different risk-aversion levels, for identifying desired air quality management strategies for decision makers, and for considering a proper balance between system economy and environmental quality.

关键词： risk management conditional value-at-risk,interval optimization two-stage programming uncertainty,air quality management