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Paired-Pd(Ⅱ) centers embedded in HKUST-1 framework: Tuning the selectivity from dimethyl carbonate to dimethyl oxalate

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Journal of Energy Chemistry 2022年第4期31卷 233-240页

作者： hong-Zi Tan Zhe-Ning Chen Kai-qiang Jing Jing Sun Yu-Ping Xu Ning-Ning Zhang Zhong-Ning Xu guo-Cong guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Chemistry&Chemical Engineering Shandong University of TechnologyZibo 255049ShandongChina School of Chemistry and Chemical Engineering Liaocheng UniversityLiaocheng 252000ShandongChina

CO oxidative coupling to dimethyl oxalate(DMO) is the most crucial step in coal to ethylene glycol. Pdbased supported catalysts have been verified effective for generating DMO, but concomitant generation of dimethyl carbonate(DMC) is always unavoidable. It is generally accepted that Pd(0) is the active species for producing DMO, while Pd(II) for DMC. However, density functional theory calculations have proposed that the selectivity to DMO or DMC highly depends on the space state of Pd species rather than its oxidative state. It is thus urgently desired to develop high-efficient catalysts with well-defined structure,and further to elucidate the structure-performance relationship. In this work, HKUST-1 with unique structure of paired-Cu(Ⅱ) centers was chosen as ideal support to construct the catalysts with respective paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers via in situ Pd species doping. In despite of featuring Pdδ+(δ≈2) oxidation state, the synthesized paired-Pd(Ⅱ)/HKUST-1 catalyst still exhibited DMO as dominant product(90.8% of DMO selectivity). For isolated-Pd(Ⅱ)/HKUST-1 catalyst, however, the main product was DMC(84.8% of DMC selectivity). Based on catalyst characterizations, the structures of paired-Pd(Ⅱ) centers and isolated-Pd(Ⅱ) centers were determined. DMO was generated from the coupling of adjacent *COOCH;intermediates adsorbed on paired-Pd(Ⅱ) centers, while DMC was produced from the reaction between methyl nitrite and the *COOCH;intermediates formed on isolated-Pd(Ⅱ) centers. Current work is the first MOFs-based catalyst with well-defined structure being applied in CO oxidative coupling reaction, which not only sheds light on the structure-performance relationship, but also inspires the potential of using MOFs as tunable platform to design high-efficient catalysts in heterogeneous catalysis.

关键词： CO Methyl nitrite Oxidative coupling Dimethyl oxalate Paired-Pd(Ⅱ)centers HKUST-1

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Effects of Ni content and tempering temperatures on microstructure and properties of medium-carbon cast steel

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Journal of Iron and Steel Research International 2023年第8期30卷 1524-1536页

作者： Xiao-bo Cui Tian-long Liu Zhi-bin Zheng Zhi-qiang guo Kai-hong Zheng Pei-xian Han School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina Institute of New Materials Guangdong Academy of SciencesNational Engineering Research Center of Powder Metallurgy of Titanium and Rare MetalsGuangdong Provincial Key Laboratory of Metal Toughening Technology and ApplicationGuangzhou 510651GuangdongChina Guangdong Provincial Iron Matrix Composite Engineering Research Center Guangzhou 510651GuangdongChina Jiangxi Lianfeng Investment Casting Co. Ltd.Yichun 336300JiangxiChina

The microstructure evolution and properties of medium-carbon cast steel alloyed with different Ni contents after tempering at various temperatures have been *** addition of 0.47-1.59 wt.%Ni content results in the formation of 16%-36% retained austenite(RA).The blocky and irregular-polygonal RA mainly forms along the prior austenite grain boundaries,and the tempering temperature does not affect the RA *** hardness of medium-carbon cast steel is affected by the precipitation of carbides and the hardness of *** RA content is the main cause of intergranular impact rupture and low impact *** long-strip carbides formed after tempering at 320℃ would further reduce the impact energy of medium-carbon cast *** tempering at 220 and 380℃,the increase in impact energy is attributed to the formation of rod-like and spherical carbides and the low-carbon *** the medium-carbon cast steel with high impact energy,its impact-abrasive wear resistance is more ***-cutting and delamination are the primary wear mechanisms.

关键词： Medium-carbon cast steel Ni content Tempering temperature Hardness Impact energy Impact-abrasive wear resistance

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In Situ Experiments on Supporting Load Effect of Large-span Deep Tunnels in Hard Rock

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Journal of Mountain Science 2013年第6期10卷 1125-1136页

作者： HE Ben-guo ZHU Yong-quan SUN Ming-lei LIU hong-yan ZHANG Zhi-qiang School of Civil Engineering Shijiazhuang Tiedao University Department of Civil and Environmental Engineering Colorado School of Mines School of Civil Engineering Southwest Jiaotong University

A section of the Nanliang high speed railway tunnel on Shijiazhuang-Taiyuan high-speed passenger railway line in China was instrumented and studied for its mechanical properties and performances. The cross section for the tunnel was300 m2and is classified as the largest cross section for railway tunnels in China. Through in situ experimental studies, mechanistic properties of the tunnel were identified, including the surrounding rock pressure, convergences along tunnel perimeter and safety of primary support and lining *** on the field measured data, the surrounding rock pressure demand for large-span deep tunnel in hard rock is recommended as double peak type in the vertical direction and fold line type was recommended for horizontal pressure. The results suggested that Promojiyfakonov's theory was most close to the monitored value. Specific recommendations were also generated for the use of bolts in tunnel *** simulation was used to evaluate the safety of the tunnel and it confirmed that the current design can satisfy the requirement of the current code.

关键词： Large-span tunnel Railway tunnel Surrounding rock pressure Load distribution In situ experiment

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Optimization study and design of scintillating fiber detector for DT neutron measurements on EAST with Geant4

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Nuclear Science and Techniques 2022年第11期33卷 33-45页

作者： Wei-Kun Chen Li-Qun Hu guo-qiang Zhong Bing hong Rui-Jie Zhou Kai Li Li Yang Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Hefei Comprehensive National Science Center Institute of EnergyHefei 230031China School of Mechanical and Vehicle Engineering West Anhui UniversityLuan 237012China

Real-time monitoring of the 14-MeV D-T fusion neutron yield is urgently required for the triton burnup study on the Experimental Advanced Superconducting Tokamak (EAST). In this study, we developed an optimal design of a fast-neutron detector based on the scintillating fiber (Sci-Fi) to provide D-T neutron yield through Geant4simulation. The effect on the detection performance is concerned when changing the number of the Sci-Fis embedded in the probe head, minimum distance between the fibers, length of the fibers, or substrate material of the probe head. The maximum number of scintillation photons generated by the n/γ source particles and output by the light guide within an event (event:the entire simulation process for one source particle) was used to quantify the n/γ resolution of the detector as the main basis. And the intrinsic detection efficiency was used as another evaluation criterion. The results demonstrate that the optimal design scheme is to use a 5 cm probe head whose substrate material is pure aluminum, in which 463 Sci-Fis with the same length of 5 cm are embedded, and the minimum distance between the centers of the two fibers is 2 mm. The optimized detector exhibits clear directionality in the simulation, which is in line with the expectation and experimental data provided in the literature. This study presents the variation trends of the performance of the SciFi detector when its main parameters change, which is beneficial for the targeted design and optimization of the Sci-Fi detector used in a specific radiation environment.

关键词： Sci-Fi detector Optimal design n/c resolution Intrinsic detection efficiency Geant4

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A Cross-linked Polyethylene with Recyclability and Mechanical Robustness Enabled by Establishment of Multiple Hydrogen Bonds Network via Reactive Melt Blending

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Chinese Journal of Polymer Science 2023年第7期41卷 1104-1114页

作者： hong-Da Mao Ting-Ting Zhang Zhen-You guo Dong-Yu Bai Jie Wang Hao Xiu qiang Fu College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu610065China Chongqing University Key Laboratory of Micro/Nano Materials Engineering and Technology Chongqing University of Arts and SciencesChongqing402160China Hubei Huifu Nanomaterial Co. LTD.Yichang443007China

Physical cross-linking by hydrogen-bonds (H-bonds), providing a good combination of application properties of thermosets and processability of thermoplastics, is a potential strategy to resolve the recycling problem of traditional chemically cross-linked polyethylene. However, ureidopyrimidone (UPy), the most widely used H-bonding motif, is unfavorable for large-scale industrial application due to its poor thermal stability. In this work, H-bonds cross-linked polyethylene was successfully prepared by reactive melt blending maleic anhydride grafted polyethylene (PE-g-MAH) with 3-amino-1,2,4-triazole (ATA) to form amide triazole ring-carboxylic acid units. Triazole ring can easily generate multiple H-bonds with carboxylic acid and amide. More importantly, these units are more thermal stable than UPy due to the absence of unstable urea group of UPy. The introduction of H-bonds cross-linking leads to an obvious improvement in mechanical properties and creep resistance and a good maintain in thermal properties and recyclability. Furthermore, the reinforcement effect monotonically improves with increasing the density of H-bonds. The obtained good properties are mainly attributed to largely enhanced interchain interactions induced by H-bonds cross-linking and intrinsic reversibility of H-bonds. This work develops a novel way for the simple fabrication of H-bonds cross-linked PE with high performance through reactive melt blending.

关键词： Cross-linked polyethylene Hydrogen bonds Recyclability

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Carbon-hydrogen activation in China

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Science China Chemistry 2015年第8期58卷 1245-1248页

作者： Zhang-Jie Shi guo-qiang Lin College of Chemistry and Molecular Engineering Peking University Shanghai Institute of Organic Chemistry Chinese Academy of Sciences

Transition metal catalyzed C-H Functionalization is one of the most important and challenging research fields in or- ganic chemistry and has rapidly evolved in recent decades. Some recent achievements in the field include i） minimizing the pre-activation procedures of substrates, ii） reducing waste production, and iii） shortening synthetic steps by de- veloping direct activations and straightforward transfor- mations of C-H bonds. With the rapid developments in chemistry and the continuous support of the Chinese gov- ernment, Chinese chemists have played important roles in this emerging field in the past two decades. To stimulate the continued success of Chinese chemists, this work provides an intensive account of the current status of this important field in China's Mainland.

关键词： Activation analysis Transition metals

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Research on the flow stability and noise reduction characteristics of quasi-periodic elastic support skin

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Defence Technology（防务技术） 2024年第3期33卷 222-236页

作者： Lu Chen Shao-gang Liu Dan Zhao Li-qiang Dong Kai Li Shuai Tang Jin Cui hong guo Department of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin150001China

To enhance flow stability and reduce hydrodynamic noise caused by fluctuating pressure,a quasiperiodic elastic support skin composed of flexible walls and elastic support elements is proposed for fluid noise *** arrangement of the elastic support element is determined by the equivalent periodic distance and quasi-periodic *** this paper,a dynamic model of skin in a fluid environment is *** influence of equivalent periodic distance and quasi-periodic coefficient on flow stability is *** results suggest that arranging the elastic support elements in accordance with the quasi-periodic law can effectively enhance flow ***,the hydrodynamic noise calculation results demonstrate that the skin exhibits excellent noise reduction performance,with reductions of 10 dB in the streamwise direction,11 dB in the spanwise direction,and 10 dB in the normal *** results also demonstrate that the stability analysis method can serve as a diagnostic tool for flow fields and guide the design of noise reduction structures.

关键词： Flow stability Quasi-period Flexible wall Elastic support element Hydrodynamic noise

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Weighted gene co-expression network analysis identiffes potential regulators in response to Salmonella Enteritidis challenge in the reproductive tract of laying ducks

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Journal of Integrative Agriculture 2022年第8期21卷 2384-2398页

作者： ZHANG Yu LUO Shu-wen HOU Li-e GU Tian-tian ZHU guo-qiang Wanwipa VONGSANGNAK XU Qi CHEN guo-hong Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education Yangzhou UniversityYangzhou 225009P.R.China Jiangsu Key Laboratory of Zoonosis Yangzhou UniversityYangzhou 225009P.R.China Department of Zoology Faculty of ScienceKasetsart UniversityBangkok 10900Thailand

Salmonella Enteritidis(SE)is a zoonotic and vertically transmitted pathogen,often colonized in the reproductive tract of adult poultry,which can result in direct contamination of eggs and threaten human *** studies have revealed that some pattern recognition receptors and resistance genes were involved in regulating immune responses to SE invasion in ***,the role of these immune response genes was not independent,and the interactions among the genes remained to be further *** this study,SE burden and colonization were determined in reproductive tissue after the ducks were SE-infected,and RNA-sequencing was performed to construct co-expression networks by weighted gene co-expression network analysis(WGCNA).The result showed that SE could be isolated from 22% of infected-birds in any segment of the reproductive tract and the SE was readily colonized in the stroma,small follicle,isthmus,and vagina of the reproductive tracts in morbid *** top central,highly connected genes were subsequently identified three specific modules in the above four tissues at the defined cut-offs(P<0.01),including 60 new candidate regulators and 125 transcription ***,those 185 differentially expressed genes(DEGs)in these modules were ***,the hub genes(TRAF3,CXCR4 and IL13RA1)were identified to act with many other genes through immune response pathways including NF-kappaB,Toll-like receptor,steroid biosynthesis,and p53signaling *** data provide references that will understand the immune regulatory relationships during SE infection,but also assist in the breeding of SE-resistant lines through potential biomarkers.

关键词： duck Salmonella Enteritidis reproductive tract infection-related genes WGCNA

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Phase Structures of Microemulsions Determined by the Steady-State Fluorescence Method

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Chinese Chemical Letters 2001年第12期12卷 1109-1112页

作者： guo Quan SHAO qiang SHEN hong Zhi MAO Gan Zuo LI Wei Can ZHANG Key Lab for Colloid and Interface Chemistry of State Education Ministry Shandong UniversityJinan 250100 Hefei Institute of Economics and Technology Hefei 230052 不详

The steady-state fluorescence method has been tentatively used to determine the phase structures of microemulsion systems consisting of cetyltrimethylammonium bromide (CTAB), n-butanol (n-C4H9OH), octane (n-C8H18), and water. The excimer/monomer intensity ratio (I-e/I-m) of pyrene has demonstrated that the various structures in the microemulsion phase region can be distinguished. The results are consistent with electrical conductivity data already reported.

关键词： phase structure fluorescence microemulsion CTAB pyrene

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Modeling the Migration of Soluble Methanol in Unsaturated Soil Zone

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Pedosphere 2007年第3期17卷 366-372页

作者： LI hong LI Xin-Gang HUANG guo-qiang JIANG Bin School of Chemical Engineering and Technology Tianjin University Tianjin 300072 （China） National Engineering Research Center for Distillation Technology Tianjin 300072 （China）

A combined model of solute transport and water flow was developed to simulate the migration of methanol, a soluble organic chemical, in unsaturated soil zone. The solute transport equation considered convective-dispersive transport in the liquid phase as well as diffusion in the gas phase. The effect of rainfall and evapotranspiration on transport was considered at the boundary conditions of the governing equations. Data on the characteristics of a loam soil and the climatic conditions in southern California were also introduced to compare the results with those from a study in the USA in which the profiles of methanol distribution and water content in the soil zone at different times had been depicted. This comparison showed that there was good agreement between the two studies. The results showed that methanol contamination reached a depth of about 250 cm after 8 760 h. In contrast, if rainfall and evapotranspiration were not considered, the depth was only about 140 cm. The model therefore confirmed that rainfall strongly affected solute transport.

关键词： evapotranspiration methanol rainfall solute transport model

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