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Prognositic value of anoikis and tumor immune microenvironment-related gene in the treatment of osteosarcoma
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作者 WANG Dong DENG Qing +7 位作者 PENG Yi TONG Zhaochen LI Zixin HUANG Liping ZENG Jin LI Jinsong MIAO Jinglei CHEN Shijie 《中南大学学报(医学版)》 CAS CSCD 北大核心 2024年第5期758-774,共17页
Objective:Osteosarcoma is a highly aggressive primary malignant bone tumor commonly seen in children and adolescents,with a poor prognosis.Anchorage-dependent cell death(anoikis)has been proven to be indispensable in ... Objective:Osteosarcoma is a highly aggressive primary malignant bone tumor commonly seen in children and adolescents,with a poor prognosis.Anchorage-dependent cell death(anoikis)has been proven to be indispensable in tumor metastasis,regulating the migration and adhesion of tumor cells at the primary site.However,as a type of programmed cell death,anoikis is rarely studied in osteosarcoma,especially in the tumor immune microenvironment.This study aims to clarify prognostic value of anoikis and tumor immune microenvironment-related gene in the treatment of osteosarcoma.Methods:Anoikis-related genes(ANRGs)were obtained from GeneCards.Clinical information and ANRGs expression profiles of osteosarcoma patients were sourced from the therapeutically applicable research to generate effective therapies and Gene Expression Omnibus(GEO)databases.ANRGs highly associated with tumor immune microenvironment were identified by the estimate package and the weighted gene coexpression network analysis(WGCNA)algorithm.Machine learning algorithms were performed to construct long-term survival predictive strategy,each sample was divided into high-risk and low-risk subgroups,which was further verified in the GEO cohort.Finally,based on single-cell RNA-seq from the GEO database,analysis was done on the function of signature genes in the osteosarcoma tumor microenvironment.Results:A total of 51 hub ANRGs closely associated with the tumor microenvironment were identified,from which 3 genes(MERTK,BNIP3,S100A8)were selected to construct the prognostic model.Significant differences in immune cell activation and immune-related signaling pathways were observed between the high-risk and low-risk groups based on tumor microenvironment analysis(all P<0.05).Additionally,characteristic genes within the osteosarcoma microenvironment were identified in regulation of intercellular crosstalk through the GAS6-MERTK signaling pathway.Conclusion:The prognostic model based on ANRGs and tumor microenvironment demonstrate good predictive power and provide more personalized treatment options for patients with osteosarcoma. 展开更多
关键词 ANOIKIS tumor immune microenvironment BIOINFORMATICS PROGNOSIS OSTEOSARCOMA
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Characterization of the dissociation pathways of dichloromethane and glutathione in dichloromethane dehalogenase
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作者 Gao Xudan Zhang Huizhu Mei Ye 《南京大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第4期651-660,共10页
Dichloromethane(DCM)dehalogenase stands as a crucial enzyme implicated in the degradation of methylene chloride across diverse environmental and biological contexts.However,the unbinding pathways of ligands from DCM d... Dichloromethane(DCM)dehalogenase stands as a crucial enzyme implicated in the degradation of methylene chloride across diverse environmental and biological contexts.However,the unbinding pathways of ligands from DCM dehalogenase remain unexplored.In order to gain a deeper understanding of the binding sites and dissociation pathways of dichloromethane(DCM)and glutathione(GSH)from the DCM dehalogenase,random accelerated molecular dynamics(RAMD)simulations were performed,in which DCM and GSH were forced to leave the active site.The protein structure was predicted using Alphafold2,and the conformations of GSH and DCM in the binding pocket were predicted by docking.A long equilibrium simulation was conducted to validate the structure of the complex.The results show that GSH is most commonly observed in three main pathways,one of which is more important than the other two.In addition,DCM was observed to escape along a unique pathway.The key residues and protein helices of each pathway were identified.The results can provide a theoretical foundation for the subsequent dissociation mechanism of DCM dehalogenase. 展开更多
关键词 DCM dehalogenase GSH Alphafold2 RAMD unbinding pathways
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Highly Weak-light Sensitive and Dual-band Switchable Photodetector Based on CuI/Si Unilateral Heterojunction
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作者 YANG Jialin WANG Liangjun +2 位作者 RUAN Siyuan JIANG Xiulin YANG Chang 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2024年第9期1063-1069,共7页
In recent years,copper iodide(CuI)is an emerging p-type wide bandgap semiconductor with high intrinsic Hall mobility,high optical absorption and large exciton binding energy.However,the spectral response and the photo... In recent years,copper iodide(CuI)is an emerging p-type wide bandgap semiconductor with high intrinsic Hall mobility,high optical absorption and large exciton binding energy.However,the spectral response and the photoelectric conversion efficiency are limited for CuI-based heterostructure devices,which is related to the difficulty in fabrication of high-quality CuI thin films on other semiconductors.In this study,a p-CuI/n-Si photodiode has been fabricated through a facile solid-phase iodination method.Although the CuI thin film is polycrystalline with obvious structural defects,the CuI/Si diode shows a high weak-light sensitivity and a high rectification ratio of 7.6×10^(4),indicating a good defect tolerance.This is because of the unilateral heterojunction behavior of the formation of the p^(+)n diode.In this work,the mechanism of photocurrent of the p^(+)n diode has been studied comprehensively.Different monochromatic lasers with wavelengths of 400,505,635 and 780 nm have been selected for testing the photoresponse.Under zero-bias voltage,the device is a unilateral heterojunction,and only visible light can be absorbed at the Si side.On the other hand,when a bias voltage of-3 V is applied,the photodiode is switched to a broader“UV-visible”band response mode.Therefore,the detection wavelength range can be switched between the“Visible”and“UV-visible”bands by adjusting the bias voltage.Moreover,the obtained CuI/Si diode was very sensitive to weak light illumination.A very high detectivity of 10^(13)-1014 Jones can be achieved with a power density as low as 0.5μW/cm^(2),which is significantly higher than that of other Cu-based diodes.These findings underscore the high application potential of CuI when integrated with the traditional Si industry. 展开更多
关键词 er iodide HETEROJUNCTION PHOTODETECTOR
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在不同社会密度的活动室中活动的幼儿行为的对比研究 被引量:4
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作者 朱家雄 《心理科学》 CSSCI CSCD 北大核心 1996年第3期183-185,共3页
在不同社会密度的活动室中活动的幼儿行为的对比研究朱家雄(华东师大范大学教育系)1问题的提出McGrew(1970)区别了两种不同的拥挤状态,其一是以社会密度(socialdensZty)的增加为特征的,即在一个不变的... 在不同社会密度的活动室中活动的幼儿行为的对比研究朱家雄(华东师大范大学教育系)1问题的提出McGrew(1970)区别了两种不同的拥挤状态,其一是以社会密度(socialdensZty)的增加为特征的,即在一个不变的空间中增加人数;其二是以空间密度(... 展开更多
关键词 幼儿行为 活动室 空间密度 幼儿参与 儿童 对比研究 进行活动 行为观察 社会文化背景 观察记录
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超高层建筑风荷载计算中的振型函数 被引量:5
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作者 徐永林 朱元清 +4 位作者 周晶矛 范宜瑶 秦浩文 阮镇基 干劲 《地震地磁观测与研究》 2010年第3期111-114,共4页
在我国高层建筑建筑规范中关于风荷载计算中有一振型函数表达式Φ_z=tan(π(Z/H)^(0.7)/4),这一公式在计算风荷载中被广泛采用。作者在对金茂大厦风振位移的观测和研究中,发现该公式与实际观测的结果不符。本研究给出金茂大厦这样的超... 在我国高层建筑建筑规范中关于风荷载计算中有一振型函数表达式Φ_z=tan(π(Z/H)^(0.7)/4),这一公式在计算风荷载中被广泛采用。作者在对金茂大厦风振位移的观测和研究中,发现该公式与实际观测的结果不符。本研究给出金茂大厦这样的超高层建筑物的实测振型函数表达式:给出与建筑规范不同的风荷载振型函数,供建筑界参考;积累超高层建筑风振振型函数样本,以便在规范中给出符合实际振型函数的表达式,提高风荷载计算精度,设计出既经济又抗强风的超高层建筑。 展开更多
关键词 超高层建筑 风荷载 振型函数
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Structured binder‐free MWW‐type titanosilicate with Si‐rich shell for selective and durable propylene epoxidation 被引量:8
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作者 Jinpeng Yin Xin Jin +5 位作者 Hao Xu Yejun Guan Rusi Peng Li Chen Jingang Jiang Peng Wu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第9期1561-1575,共15页
Selective and durable fixed‐bed catalysts are highly desirable for developing eco‐efficient HPPO(hydrogen peroxide propylene oxide)process.The powder titanosilicate catalysts must be shaped before being applied in i... Selective and durable fixed‐bed catalysts are highly desirable for developing eco‐efficient HPPO(hydrogen peroxide propylene oxide)process.The powder titanosilicate catalysts must be shaped before being applied in industrial processes.As the essential additives for preparing formed catalysts,binders are usually the catalytically inert components,but they would cover the surface and pore mouth of zeolite,thereby declining the accessibility of active sites.By recrystallizing the binder(silica)/Ti‐MWW extrudates with the assistance of dual organic structure‐directing agents,the silica binder was converted into MWW zeolite phase to form a structured binder‐free Ti‐MWW zeolite with Si‐rich shell,which enhanced the diffusion efficiency and maintained the mechanical strength.Meanwhile,due to the partial dissolution of Si in the Ti‐MWW matrix,abundant silanol nests formed and part of framework TiO4 species were transferred into open TiO_(6)ones,improving the accumulation and activation ability of H_(2)O_(2)inside the monolith.Successive piperidine treatment and fluoridation of the binder‐free Ti‐MWW further enhanced the H_(2)O_(2)activation and oxygen transfer ability of the active Ti sites,and stabilized the Ti‐OOH intermediate through hydrogen bond formed between the end H in Ti‐OOH and the adjacent Si‐F species,thus achieving a more efficient epoxidation process.Additionally,the side reaction of PO hydrolysis was inhibited because the modification effectively quenched numerous Si‐OH groups.The lifetime of the modified binder‐free Ti‐MWW catalyst was 2400 h with the H_(2)O_(2)conversion and PO selectivity both above 99.5%. 展开更多
关键词 Propylene epoxidation TITANOSILICATE Binder‐free formed catalyst RECRYSTALLIZATION MICROENVIRONMENT
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Ru nanoparticles supported on hydrophilic mesoporous carbon catalyzed low-temperature hydrodeoxygenation of microalgae oil to alkanes at aqueous-phase 被引量:5
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作者 Arif Ali Chen Zhao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第8期1174-1185,共12页
The processing of an energy carrier such as microalgae oil into valuable fuels and chemicals is quite promising.Aqueous-phase processing is suitable for this purpose because the separation of intrinsic water from the ... The processing of an energy carrier such as microalgae oil into valuable fuels and chemicals is quite promising.Aqueous-phase processing is suitable for this purpose because the separation of intrinsic water from the algae cell is difficult.In this study,we synthesized ruthenium(Ru)nanoparticles supported on highly hydrophilic mesoporous carbon to catalyze the quantitative hydrodeoxygenation(HDO)of microalgae oil to alkanes in a one-pot process at a low temperature(140℃)in the aqueous phase.The mesoporous carbon was obtained by single-step calcination of starch and zinc chloride in nitrogen.The as-obtained carbon showed high surface areas and pore volumes,allowing high dispersion of Ru nanoparticles.The surface of the carbon material was rich in hydroxyl groups,as evidenced by X-ray photoelectron spectroscopy(XPS),infrared(IR)spectroscopy,and thermogravimetric analysis(TGA)measurements.As a result,the carbon material contacted preferably with the water phase versus the organic phase,improving the accessibility of substrates.On the other hand,the contact angle test results speculated the superior hydrophilic nature of mesoporous Ru/C(ZnCl2,starch)than commercial Ru/C.Both kinetics modeling and in situ IR monitoring in water revealed the superior performance of the hydrophilic mesoporous and hydrophilic Ru/C compared to a commercial Ru/C for the tandem hydrogenation of stearic acid and decarbonylation of stearyl alcohol.The herein designed hydrothermal carbon material was highly active,environmentally benign,sustainable,and recyclable material,and could be potentially used for other hydrogenation reactions in the aqueous phase. 展开更多
关键词 Algae oil Stearic acid Heptadecane Hydrophillic carbon HYDRODEOXYGENATION Ru/C catalyst
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Production of bio-ethanol by consecutive hydrogenolysis of corn-stalk cellulose 被引量:6
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作者 Dawang Chu Yingying Xin Chen Zhao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第5期844-854,共11页
Current bio-ethanol production entails the enzymatic depolymerization of cellulose,but this process shows low efficiency and poor economy.In this work,we developed a consecutive aqueous hydrogenolysis process for the ... Current bio-ethanol production entails the enzymatic depolymerization of cellulose,but this process shows low efficiency and poor economy.In this work,we developed a consecutive aqueous hydrogenolysis process for the conversion of corn-stalk cellulose to produce a relatively high concentration of bio-ethanol(6.1 wt%)without humin formation.A high yield of cellulose(ca.50 wt%)is extracted from corn stalk using a green solvent(80 wt%1,4-butanediol)without destroying the structure of the lignin.The first hydrothermal hydrogenolysis step uses a Ni–WO_(x)/SiO_(2)catalyst to convert the high cumulative concentration of cellulose(30 wt%)into a polyol mixture with a 56.5 C%yield of ethylene glycol(EG).The original polyol mixture is then subjected to subsequent selective aqueous-phase hydrogenolysis of the C–O bond to produce bioethanol(75%conversion,84 C%selectivity)over the modified hydrothermally stable Cu catalysts.The added Ni component favors the good dispersion of Cu nanoparticles,and the incorporated Au3+helps to stabilize the active Cu^(0)-Cu^(+)species.This multi-functional catalytic process provides an economically competitive route for the production of cellulosic ethanol from raw lignocellulose. 展开更多
关键词 Corn-stalk CELLULOSE Aqueous-phase hydrogenolysis BIO-ETHANOL Ni-WO_(x)catalyst Cu^(0)-Cu^(+)species C-C bond cleavage
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Hydrothermal synthesis and catalytic performance of bulky titanium silicalite-1 aggregates assembled by bridged organosilane 被引量:4
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作者 Li Chen Teng Xue +4 位作者 Jian Ding Hai Hong Wu Kun Zhang Peng Wu Ming‐Yuan He 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第2期275-282,共8页
A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μ... A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μm in size,based on the special sol‐gel chemistry of bridged organosilane.Epoxidation of1‐hexene and cyclohexene was used as a probe reaction to investigate the catalytic performance of the resulting materials.These TS‐1zeolite aggregates possessed both the conventional nanoparticle properties of TS‐1zeolites and variable surface hydrophilic/hydrophobic features,which enhanced the catalytic properties of hydroperoxides for alkene epoxidation.Moreover,the large aggregates effectively simplified the separation procedure during preparation and catalytic reactions. 展开更多
关键词 Bridged organosilane TS‐1 seeds TS‐1 nanocrystallites Zeolite aggregation Alkene epoxidation
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One-step post-synthesis treatment for preparing hydrothermally stable hierarchically porous ZSM-5 被引量:5
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作者 Jian Ding Teng Xue +1 位作者 Haihong Wu Mingyuan He 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第1期48-57,共10页
Hierarchically porous ZSM‐5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one‐step post‐synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZS... Hierarchically porous ZSM‐5 (SiO2/Al2O3 ≈ 120) containing phosphorus was prepared by a one‐step post‐synthesis treatment involving controlled desilication and phosphorous modification. The hierarchically porous ZSM‐5 featured high thermal and hydrothermal stability. The obtained ZSM‐5zeolites were systematically characterized by X‐ray diffraction, scanning electron microscopy,transmission electron microscopy, N2 adsorption‐desorption, NH3 temperature‐programmed desorption,and 27Al and 31P magic‐angle spinning nuclear magnetic resonance spectroscopy. Theprepared ZSM‐5 displayed enhanced activity and prolonged lifetime toward hydrocarbon cracking.The high activity was attributed to improved coke tolerance owing to the presence of the highlystable mesoporous network of ZSM‐5 and acid sites introduced upon phosphorus modification.Additionally a mechanism of the stabilization of the zeolites by phosphorus was proposed and discussed. 展开更多
关键词 DESILICATION Phosphorus stabilization One‐step modification Hydrothermal stability Hydrocarbon cracking
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Honeycomb-structured solid acid catalysts fabricated via the swelling-induced self-assembly of acidic poly(ionic liquid)s for highly efficient hydrolysis reactions 被引量:2
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作者 Bihua Chen Tong Ding +6 位作者 Xi Deng Xin Wang Dawei Zhang Sanguan Ma Yongya Zhang Bing Ni Guohua Gao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第2期297-309,共13页
The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designe... The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designed and synthesized via the free radical copolymerization of ionic liquid monomers,sodium p-styrenesulfonate,and crosslinkers,followed by acidification.The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength.The thermogravimetric analysis results in the temperature range of 300–345°C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H)(245°C).Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional(3D)honeycomb structure in water,which was ascribed to the swelling-induced self-assembly of the molecules.Moreover,we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol,and determined that their catalytic activity was much higher than that of homogeneous acid catalysts.The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures.Depending on the reaction mixture,the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it,which suggested the high enrichment ability of SAPILs for cyclohexyl acetate.The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate,which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts. 展开更多
关键词 Heterogeneous acid catalyst Acidic poly(ionic liquid) SWELLING 3D honeycomb structure Enrichment Hydrolysis HYDRATION
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Selective conversion of methanol to propylene over highly dealuminated mordenite:Al location and crystal morphology effects 被引量:2
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作者 Li Ren Bowen Wang +5 位作者 Kun Lu Rusi Peng Yejun Guan Jin‐gang Jiang Hao Xu Peng Wu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第7期1147-1159,共13页
The growing consumption of light olefins has stimulated intensive researches on methanol to olefin(MTO)process which possesses great advantages for coal conversion to value‐added chemicals in an environmentally benig... The growing consumption of light olefins has stimulated intensive researches on methanol to olefin(MTO)process which possesses great advantages for coal conversion to value‐added chemicals in an environmentally benign way.The catalysts commonly used for MTO process faces several challenges such as poor selectivity control,low hydrothermal stability and short lifetime.In the present study,we prepared a series of mordenite zeolites with variable Al contents(Si/Al molar ratios of 51−436)by a sequential dealumination treatment of air‐calcination and acid leaching.The textural properties,acidity and Al location before and after the dealumination treatment have been systematically studied and their effect on MTO especially the methanol to propylene(MTP)performance was thoroughly investigated.The mordenite zeolites with the Si/Al ratios over 150 selectively catalyzed methanol conversion in the MTP pathway,providing a high propylene selectivity of 63%and propylene/ethylene ratio of>10.Compared to the low‐silica MOR catalysts,highly dealuminated MOR showed much higher stability and longer lifetime,which can be further enhanced via harsh hydrothermal pretreatment.Furthermore,the lifetime was highly related to the crystal size along c‐axis.The excellent performance of highly dealuminated MOR is likely ascribed to the mesopores formed upon dealumination and the scarce Al sites located in the T sites shared by the 8‐member ring(MR)side pockets and 12‐MR pore channels. 展开更多
关键词 MORDENITE Methanol to propylene DEALUMINATION Al location Crystal size
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Crossed intergrowth triggered TS-2 microsphere:Formation mechanism,modification and catalytic performance 被引量:2
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作者 Hao Xu Wenwen Tian +5 位作者 Liping Xu Xin Jin Teng Xue Li Chen Mingyuan He Peng Wu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1109-1117,共9页
TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,t... TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes. 展开更多
关键词 TITANOSILICATE TS-2 microsphere Crossed intergrowth Ammoximation reaction POST-TREATMENT
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Efficient electrocatalytic reduction of carbon dioxide to ethylene on copper–antimony bimetallic alloy catalyst 被引量:6
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作者 Shuaiqiang Jia Qinggong Zhu +6 位作者 Haihong Wu Meng’en Chu Shitao Han Ruting Feng Jinghui Tu Jianxin Zhai Buxing Han 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1091-1098,共8页
The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 red... The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate. 展开更多
关键词 Carbon dioxide reduction Ethyene ELECTROCATALYST Copper-antimony bimetallic alloy Synergistic effect
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Oxidative coupling of methane:MO_x-modified (M=Ti,Mg,Ga,Zr) Mn_2O_3-Na_2WO_4/SiO_2 catalysts and effect of MO_x modification 被引量:1
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作者 Pengwei Wang Xin Zhang +2 位作者 Guofeng Zhao Ye Liu Yong Lu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第8期1395-1402,共8页
Mn_2O_3-Na_2WO_4/SiO_2 is considered as the most promising catalyst for the oxidative coupling of methane(OCM) process; however, it only has a better catalytic performance over 800 °C. To improve its low-temper... Mn_2O_3-Na_2WO_4/SiO_2 is considered as the most promising catalyst for the oxidative coupling of methane(OCM) process; however, it only has a better catalytic performance over 800 °C. To improve its low-temperature performance, an attempt has been made to modify the Mn_2O_3-Na_2WO_4/SiO_2 catalyst using TiO_2, MgO, Ga_2O_3, and ZrO_2. Among the synthesized catalysts, the TiO_2-modified Mn_2O_3-Na_2WO_4/SiO_2 catalyst shows markedly improved low-temperature OCM performance,achieving a high CH_4 conversion of ~23% and a good C_2-C_3 selectivity of ~73% at 700 °C(the catalyst bed temperature), along with promising stability for at least 300 h without signs of deactivation.In comparison with the unmodified Mn_2O_3-Na_2WO_4/SiO_2 catalyst, the TiO_2 modification results in significant improvement in the low-temperature activity/selectivity, whereas the MgO modification has almost no impact and the Ga_2O_3 and ZrO_2 modifications have a negative effect. The X-ray diffraction(XRD) and Raman results reveal that the formation of a MnTiO_3 phase and a MnTiO_3-dominated catalyst surface is crucial for the improvement of the low-temperature activity/selectivity in the OCM process. 展开更多
关键词 Oxidative coupling of methane Light olefins ETHYLENE Oxide modification MnTiO3
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Eight new species of the genus Episymploce Bey-Bienko(Blattodea: Blattellinae) from China 被引量:1
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作者 Sainan ZHANG Xianwei LIU Kai LI 《Entomotaxonomia》 CSCD 2019年第3期198-213,共16页
The genus Episymploce Bey-Bienko,1950 from China is reviewed.Eight new species are illustrated.The habitus and male genitalia of these new species are described.
关键词 Blaberoidea BLATTELLIDAE TAXONOMY
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Cooperative structure-directing effect of choline cation and *BEA zeolite in the synthesis of aluminogermanosilicate IWR zeolite 被引量:1
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作者 Wenhua Fu Zhiqing Yuan +6 位作者 Shaoqing Jin Wei Liu Zhendong Wang Chuanming Wang Yangdong Wang Weimin Yang Ming-Yuan He 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第6期856-866,共11页
In this contribution,we report the cooperative structure-directing effect of choline hydroxide and aluminosilicate*BEA zeolite in the synthesis of aluminogermanosilicate IWR zeolites for the first time.*BEA zeolites,a... In this contribution,we report the cooperative structure-directing effect of choline hydroxide and aluminosilicate*BEA zeolite in the synthesis of aluminogermanosilicate IWR zeolites for the first time.*BEA zeolites,at variance with any other aluminosilicate zeolites,can serve as heterogeneous seeds for the growth of IWR zeolites and play a cooperative structure-directing role.The crystallization process was investigated using multiple techniques to characterize a series of solid products obtained with various crystallization times.The experiments clearly showed the dissolution of the*BEA zeolite and of an intermediate CDO-type structure.A plausible mechanism for the novel cooperative synthesis has been proposed.The crystallization of the IWR zeolite involves several steps,among which the crucial one is believed to be the reassembly of the building units produced from the decomposition of*BEA zeolite seeds,induced by choline molecules.Having similar structure and common building units(four-,five-,and six-membered rings)with the IWR zeolite,the*BEA zeolite is capable of promoting the reassembly of the building units and can thus play a cooperative structure-directing role.By highlighting the cooperative structure-directing effect of organic molecules and heterogeneous seeds,this study opens up new perspectives for the synthesis of target zeolites that are difficult to prepare by traditional methods.This new synthetic route is also expected to shed light on the discovery of novel zeolites. 展开更多
关键词 IWR zeolite Cooperative structure-directing effect Organic structure-directing agent Choline cation Heterogeneous seeds *BEA zeolite
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The effects of TiO_(2)crystal-plane-dependent Ir-TiO_(x)interactions on the selective hydrogenation of crotonaldehyde over Ir/TiO_(2)catalysts 被引量:2
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作者 Aiping Jia Yunshang Zhang +5 位作者 Tongyang Song Yiming Hu Wanbin Zheng Mengfei Luo Jiqing Lu Weixin Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第10期1742-1754,共13页
Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)... Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites. 展开更多
关键词 HYDROGENATION α β-unsaturated aldehyde Ir/TiO_(2) Metal-support interactions Surface acidity
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Population Change of OH and H2O in Water Vapor Glow Discharge Measured Using Concentration Modulation Spectroscopy 被引量:1
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作者 Bao Li Li Wang +3 位作者 Bo Fang Wei-xiong Zhao Lun-hua Deng Huai-liang Xu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2020年第4期411-416,I0001,共7页
A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed usin... A distributed feedback laser with a wavelength of 2.8μm was used to measure the species produced by water vapor glow discharge.Only the absorption spectra of OH radicals and transient H2O molecules were observed using concentration modulation(CM)spectroscopy.The intensities and orientations of the absorption peaks change with the demodulation phase,but the direction of one absorption peak of H2O is always opposite to the other peaks.The different spectral orientations of OH and H2O reflect the increase or the decrease of the number of particles in the energy levels.If more transient species can be detected in the discharge process,the dynamics of excitation,ionization,and decomposition of H2O can be better studied.This study shows that the demodulation phase relationship of CM spectrum can be used to study the population change of molecular energy levels. 展开更多
关键词 Glow discharge OH radical Concentration modulation spectroscopy Population change
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高中英语课堂中教师语码转换的情感因素分析
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作者 李辉 王海娉 《中小学英语教学与研究》 北大核心 2012年第5期2-5,25,共5页
一、引言语码转换(code-switching)是一个比较复杂的社会语言现象,语言学家通过社会语言学、心理语言学、语用学等不同的角度对语码转换进行了研究,并取得了丰硕的成果。自从20世纪80年代以来很多学者对于外语课堂语码转换的研究越... 一、引言语码转换(code-switching)是一个比较复杂的社会语言现象,语言学家通过社会语言学、心理语言学、语用学等不同的角度对语码转换进行了研究,并取得了丰硕的成果。自从20世纪80年代以来很多学者对于外语课堂语码转换的研究越来越重视,其中绝大多数研究主要集中在对两种语码的教学功能上的诠释(Rolin—Ianziti&Brownlie,2002;Krashen,1981;Ellis,1984;Eldridge,1996)。然而, 展开更多
关键词 语码转换 情感因素 英语课堂 20世纪80年代以来 KRASHEN 教师 高中 社会语言现象
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