A 500 N model engine filled with LO2/GCH4 was designed and manufactured.A series of ignition attempts were performed in it by both head spark plug and body spark plug.Results show that the engine can be ignited but th...A 500 N model engine filled with LO2/GCH4 was designed and manufactured.A series of ignition attempts were performed in it by both head spark plug and body spark plug.Results show that the engine can be ignited but the combustion cannot be sustained when head spark plug applied as the plug tip was set in the gaseous low-velocity zone with thin spray.This is mainly because flame from this zone cannot supply enough ignition energy for the whole chamber.However,reliable ignition and stable combustion can be achieved by body spark plug.As the O/F ratio increases from 2.61 to 3.49,chamber pressure increases from 0.474 to 0.925 MPa and combustion efficiency increases from 57.8%to 95.1%.This is determined by the injector configuration,which cannot produce the sufficiently breakup of the liquid oxygen on the low flow rate case.展开更多
This paper provides a detailed introduction to and analysis of the course of China's technological innovation in liquid hydrogen/liquid oxygen(LH2/LOX)rocket engines from a historical point of view.It starts with ...This paper provides a detailed introduction to and analysis of the course of China's technological innovation in liquid hydrogen/liquid oxygen(LH2/LOX)rocket engines from a historical point of view.It starts with the investigation of LH2/LOX rocket engines by relevant departments of the Chinese Academy of Sciences in the 1960s and their preliminary achievements.Then,the policy decision concerning LH2/LOX engine development,the project approval of the Long March-3(Chang Zheng-3,CZ-3)rocket,and the process of developing LH2/LOX engines are analyzed in detail,followed by an introduction to and summary of the development situation and technical innovation characteristics of China's LH2/LOX engines as they grew from 4 tons to 8 tons,and finally to 50 tons.Finally,the paper briefly analyzes the innovation experience connected with China's LH2/LOX engines.展开更多
Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of di...Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of different phases on the EMW absorbing performance,such as 1T and 2H phase,is still not studied.In this work,micro-1T/2H MoS_(2) is achieved via a facile one-step hydrother-mal route,in which the 1T phase is induced by the intercalation of vip molecules and ions.The EMW absorption mechanism of single MoS_(2) is revealed by presenting a comparative study between 1T/2H MoS_(2) and 2H MoS_(2).As a result,1T/2H MoS_(2) with the matrix loading of 15%exhibits excellent microwave absorption property than 2H MoS_(2).Furthermore,taking the advantage of 1T/2H MoS_(2),a flexible EMW absorbers that ultrathin 1T/2H MoS_(2)grown on the carbon fiber also performs outstanding performance only with the matrix loading of 5%.This work offers necessary reference to improve microwave absorption performance by phase engineering and design a new type of flexible electromagnetic wave absorption material to apply for the portable microwave absorption electronic devices.展开更多
Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-T...Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.展开更多
CuCeZrO_x and KCuCeZrO_x catalysts were synthesized and coated on the blank diesel particulate filter(DPF)substrate and a particulate matter(PM)loading apparatus was used for soot loading.The catalytic performances of...CuCeZrO_x and KCuCeZrO_x catalysts were synthesized and coated on the blank diesel particulate filter(DPF)substrate and a particulate matter(PM)loading apparatus was used for soot loading.The catalytic performances of soot oxidation were evaluated by temperature programmed combustion(TPC)test and characterization tests were conducted to investigate the physicochemical properties of the catalysts.The reaction mechanism in the oxidation process was analyzed with diffuse reflectance infrared Fourier transform spectroscopy.The results demonstrated that CuCeZrO_x catalyst exhibited high activities of soot oxidation at low temperature and the best results have been attained with Cu_(0.9)Ce_(0.05)Zr_(0.05)O_x over which the maximum soot oxidation rate decreased to 410~?C.Characterization tests have shown that catalysts containing 90%Cu have uniformly distributed grains and small particle sizes,which provide excellent oxidation activity by providing more active sites and forming a good bond between the catalyst and the soot.The low-temperature oxidation activity of soot could be further optimized due to the excellent elevated NO’s conversion rate by partially substituting Cu with K.The maximum particle oxidation rate can be easily realized at such a low temperature as 347~?C.展开更多
The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.展开更多
Since the first discovery of gold deposits on the northeastern margin of the Jiaolai Basin in Shandong Province at the end of the 20^(th) century,seven medium-sized to large/super-large gold deposits have been identif...Since the first discovery of gold deposits on the northeastern margin of the Jiaolai Basin in Shandong Province at the end of the 20^(th) century,seven medium-sized to large/super-large gold deposits have been identified in this region,with cumulative proven gold resources of 223 t.This study reviewed the metallogenic and geochemical characteristics of various gold deposits in this region,examined the sources of their ore-forming fluids and materials,as well as their gold metallogenic epochs and processes,and developed a gold metallogenic model.The gold deposits in this region are governed by both dense fractures and detachment structural systems along basin margins,primarily categorized into the altered rock type and the pyrite-bearing carbonate vein type.The latter type,a recently discovered mineralization type in the Jiaodong Peninsula,enjoys high gold grade,a large scale,and high gold mineral fineness,suggesting considerable prospecting potential.Both types of gold deposits show metallogenic epochs ranging from 116 Ma to 119 Ma.Their ore-forming fluids are identified as a CO_(2)-NaCl-H_(2)O fluid system characterized by moderate to low temperatures,moderate to low salinity,and low density,with the pyrite-bearing carbonate vein-type gold deposits manifesting slightly higher salinity.The C-H-O,S,and Pb isotopes of hydrothermal minerals reveal that the ore-forming fluids and materials are characteristic of crust-mantle mixing.Specifically,they were derived from mantle fluids in the early stages,mixed with stratum water and meteoric water in the later stages for mineralization.The gold metallogenic process is identified as follows:During the Early Cretaceous,the subduction of the Pacific Plate and the destruction of the North China Craton led to asthenospheric upwelling.The resulting fluids,after metasomatizing the enriched mantle,differentiated and evolved into C-H-O ore-bearing fluids,which were then mixed with crustal fluids.The mixed fluids migrated to the shallow crust,where they mingled with stratum water and meteoric water.Then,the fluids underwent unloading and final mineralization in detachment fault tectonic systems on basin margins.Due to differences in mixed crustal materials or the surrounding rocks involved in water-rock interactions,altered rock-and pyrite-bearing carbonate vein-type gold deposits were formed in acidic and alkaline fluid environments,respectively.展开更多
基金Project(613239)supported by the National Basic Research Program of China
文摘A 500 N model engine filled with LO2/GCH4 was designed and manufactured.A series of ignition attempts were performed in it by both head spark plug and body spark plug.Results show that the engine can be ignited but the combustion cannot be sustained when head spark plug applied as the plug tip was set in the gaseous low-velocity zone with thin spray.This is mainly because flame from this zone cannot supply enough ignition energy for the whole chamber.However,reliable ignition and stable combustion can be achieved by body spark plug.As the O/F ratio increases from 2.61 to 3.49,chamber pressure increases from 0.474 to 0.925 MPa and combustion efficiency increases from 57.8%to 95.1%.This is determined by the injector configuration,which cannot produce the sufficiently breakup of the liquid oxygen on the low flow rate case.
基金Projects funded by the National Social Science Fund (19BDJ064)
文摘This paper provides a detailed introduction to and analysis of the course of China's technological innovation in liquid hydrogen/liquid oxygen(LH2/LOX)rocket engines from a historical point of view.It starts with the investigation of LH2/LOX rocket engines by relevant departments of the Chinese Academy of Sciences in the 1960s and their preliminary achievements.Then,the policy decision concerning LH2/LOX engine development,the project approval of the Long March-3(Chang Zheng-3,CZ-3)rocket,and the process of developing LH2/LOX engines are analyzed in detail,followed by an introduction to and summary of the development situation and technical innovation characteristics of China's LH2/LOX engines as they grew from 4 tons to 8 tons,and finally to 50 tons.Finally,the paper briefly analyzes the innovation experience connected with China's LH2/LOX engines.
基金the National Natural Science Foundation of China(No.51672222)Joint Fund Project-Enterprise-Shaanxi Coal Joint Fund Project(2019JLM-32)+2 种基金Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX202054)the Graduate innovation team of Northwestern Polytechnical Universitythe Analysis and Testing Center of Northwestern Polytechnical University for their technical assistance in SEM(Verios G4).
文摘Phase engineering is an important strategy to modulate the electronic structure of molybdenum disulfide(MoS_(2)).MoS_(2)-based composites are usually used for the electromagnetic wave(EMW)absorber,but the effect of different phases on the EMW absorbing performance,such as 1T and 2H phase,is still not studied.In this work,micro-1T/2H MoS_(2) is achieved via a facile one-step hydrother-mal route,in which the 1T phase is induced by the intercalation of vip molecules and ions.The EMW absorption mechanism of single MoS_(2) is revealed by presenting a comparative study between 1T/2H MoS_(2) and 2H MoS_(2).As a result,1T/2H MoS_(2) with the matrix loading of 15%exhibits excellent microwave absorption property than 2H MoS_(2).Furthermore,taking the advantage of 1T/2H MoS_(2),a flexible EMW absorbers that ultrathin 1T/2H MoS_(2)grown on the carbon fiber also performs outstanding performance only with the matrix loading of 5%.This work offers necessary reference to improve microwave absorption performance by phase engineering and design a new type of flexible electromagnetic wave absorption material to apply for the portable microwave absorption electronic devices.
基金supported by the National Natural Science Foundation of China(21878143,21476106,21838004)Joint Re-search Fund for Overseas Chinese Scholars and Scholars in Hong Kong and Macao Young Scholars(21729601)+1 种基金the fund of State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201702)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)~~
文摘Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.
基金the National Key R&D Program of China(Nos.2016YFC0205200 and 2016YFC0208000)the National Natural Science Foundation of China(No.51676127)
文摘CuCeZrO_x and KCuCeZrO_x catalysts were synthesized and coated on the blank diesel particulate filter(DPF)substrate and a particulate matter(PM)loading apparatus was used for soot loading.The catalytic performances of soot oxidation were evaluated by temperature programmed combustion(TPC)test and characterization tests were conducted to investigate the physicochemical properties of the catalysts.The reaction mechanism in the oxidation process was analyzed with diffuse reflectance infrared Fourier transform spectroscopy.The results demonstrated that CuCeZrO_x catalyst exhibited high activities of soot oxidation at low temperature and the best results have been attained with Cu_(0.9)Ce_(0.05)Zr_(0.05)O_x over which the maximum soot oxidation rate decreased to 410~?C.Characterization tests have shown that catalysts containing 90%Cu have uniformly distributed grains and small particle sizes,which provide excellent oxidation activity by providing more active sites and forming a good bond between the catalyst and the soot.The low-temperature oxidation activity of soot could be further optimized due to the excellent elevated NO’s conversion rate by partially substituting Cu with K.The maximum particle oxidation rate can be easily realized at such a low temperature as 347~?C.
文摘The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.
基金supported by the Program of the National Natural Science Foundation of China(Nos.41973048,U2006201)the Open Project of State Key Laboratory of Geological Processes and Mineral Resources(No.GPMR202203)+1 种基金the Key R&D Program of Shandong Province(No.2023CXGC011001),the Taishan Scholars.Program(tstp20240847)the Open Project of Shandong Engineering Research Center of Application and Development of Big Data for Deep Gold Exploration(No.SDK202207)。
文摘Since the first discovery of gold deposits on the northeastern margin of the Jiaolai Basin in Shandong Province at the end of the 20^(th) century,seven medium-sized to large/super-large gold deposits have been identified in this region,with cumulative proven gold resources of 223 t.This study reviewed the metallogenic and geochemical characteristics of various gold deposits in this region,examined the sources of their ore-forming fluids and materials,as well as their gold metallogenic epochs and processes,and developed a gold metallogenic model.The gold deposits in this region are governed by both dense fractures and detachment structural systems along basin margins,primarily categorized into the altered rock type and the pyrite-bearing carbonate vein type.The latter type,a recently discovered mineralization type in the Jiaodong Peninsula,enjoys high gold grade,a large scale,and high gold mineral fineness,suggesting considerable prospecting potential.Both types of gold deposits show metallogenic epochs ranging from 116 Ma to 119 Ma.Their ore-forming fluids are identified as a CO_(2)-NaCl-H_(2)O fluid system characterized by moderate to low temperatures,moderate to low salinity,and low density,with the pyrite-bearing carbonate vein-type gold deposits manifesting slightly higher salinity.The C-H-O,S,and Pb isotopes of hydrothermal minerals reveal that the ore-forming fluids and materials are characteristic of crust-mantle mixing.Specifically,they were derived from mantle fluids in the early stages,mixed with stratum water and meteoric water in the later stages for mineralization.The gold metallogenic process is identified as follows:During the Early Cretaceous,the subduction of the Pacific Plate and the destruction of the North China Craton led to asthenospheric upwelling.The resulting fluids,after metasomatizing the enriched mantle,differentiated and evolved into C-H-O ore-bearing fluids,which were then mixed with crustal fluids.The mixed fluids migrated to the shallow crust,where they mingled with stratum water and meteoric water.Then,the fluids underwent unloading and final mineralization in detachment fault tectonic systems on basin margins.Due to differences in mixed crustal materials or the surrounding rocks involved in water-rock interactions,altered rock-and pyrite-bearing carbonate vein-type gold deposits were formed in acidic and alkaline fluid environments,respectively.
