Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam pl...Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.展开更多
Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four...Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four diverse tree species: ashleaf maples ( Acer negundo L.), hankow willow (Salix matsudana Koidz.), Chinese white poplar ( Populus tomentosa Carr.) and poplar opera 8277 (P. simonii x P. pyramibalis cv.), were used as materials. The blends of volatiles collected after damage were detected with GCMS. Most of the induced compounds reach high concentrations in 5 h. They are acyclic monoterpenes, fatty acid derivatives, and aromatic compounds. To authors' knowledge, dimethyl adipate, diisobutyl succinate and benthothiazole have never been reported in previous herbivore insect-plant systems, After being damaged 2 h, green leaf volatiles were released in large amount. The repellents were detected in higher concentration after 24 h. The time of releasing is different within different species, but many kinds of volatiles widely existed in different trees. There were some difference among species. Health ashleaf maple released more terpenoids, but poplars and willow produced more aromatic compounds.展开更多
Zeolitic imidazolate framework-8(ZIF-8) was prepared through a solve-thermal reaction method and then shaped using different additives. The in fluence of the shaping conditions on the microstructure of the shaped samp...Zeolitic imidazolate framework-8(ZIF-8) was prepared through a solve-thermal reaction method and then shaped using different additives. The in fluence of the shaping conditions on the microstructure of the shaped samples was characterized by the XRD, BET, and SEM techniques. The results demonstrate that the compressive strength of the various shaped tablets is greatly increased and capable of meeting the industrial requirements compared to the unshaped ZIF-8 and that the loss rate of speci fic surface areas was maintained at 10% after the addition of 10%(by mass) binder and 10%(by mass) solvent. The adsorption isotherms of CO2, CH4, C3H8, and C3H6 on powdery ZIF-8and the shaped tablets(T-shaped ZIF-8, C-shaped ZIF-8, and N-shaped ZIF-8) were determined through volumetric measurements under different pressures and temperatures(298.2, 323.2, and 348.2 K). The adsorption capacities of the gases on both the ZIF-8 powder and the shaped tablets follow the order C3H6 N C3H8N CO2 N CH4. Furthermore,the results show that the adsorption capacities of the gases on the shaped tablets are lower by approximately 10%–20% than those on the powdery ZIF-8. In fact, the adsorption equilibrium isotherms for CO2, CH4, C3H8, and C3H6 on both powdery and shaped ZIF-8 can be well described by the Langmuir equation.展开更多
A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffr...A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.展开更多
An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while...An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while the analysis of Mrssbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to： （i） rapid nanocrystallization of aluminium and/or （ii） small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.展开更多
文摘Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.
文摘Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four diverse tree species: ashleaf maples ( Acer negundo L.), hankow willow (Salix matsudana Koidz.), Chinese white poplar ( Populus tomentosa Carr.) and poplar opera 8277 (P. simonii x P. pyramibalis cv.), were used as materials. The blends of volatiles collected after damage were detected with GCMS. Most of the induced compounds reach high concentrations in 5 h. They are acyclic monoterpenes, fatty acid derivatives, and aromatic compounds. To authors' knowledge, dimethyl adipate, diisobutyl succinate and benthothiazole have never been reported in previous herbivore insect-plant systems, After being damaged 2 h, green leaf volatiles were released in large amount. The repellents were detected in higher concentration after 24 h. The time of releasing is different within different species, but many kinds of volatiles widely existed in different trees. There were some difference among species. Health ashleaf maple released more terpenoids, but poplars and willow produced more aromatic compounds.
基金Supported by the National Natural Science Foundation of China(21176010,21476009,21406007,and U1462104)
文摘Zeolitic imidazolate framework-8(ZIF-8) was prepared through a solve-thermal reaction method and then shaped using different additives. The in fluence of the shaping conditions on the microstructure of the shaped samples was characterized by the XRD, BET, and SEM techniques. The results demonstrate that the compressive strength of the various shaped tablets is greatly increased and capable of meeting the industrial requirements compared to the unshaped ZIF-8 and that the loss rate of speci fic surface areas was maintained at 10% after the addition of 10%(by mass) binder and 10%(by mass) solvent. The adsorption isotherms of CO2, CH4, C3H8, and C3H6 on powdery ZIF-8and the shaped tablets(T-shaped ZIF-8, C-shaped ZIF-8, and N-shaped ZIF-8) were determined through volumetric measurements under different pressures and temperatures(298.2, 323.2, and 348.2 K). The adsorption capacities of the gases on both the ZIF-8 powder and the shaped tablets follow the order C3H6 N C3H8N CO2 N CH4. Furthermore,the results show that the adsorption capacities of the gases on the shaped tablets are lower by approximately 10%–20% than those on the powdery ZIF-8. In fact, the adsorption equilibrium isotherms for CO2, CH4, C3H8, and C3H6 on both powdery and shaped ZIF-8 can be well described by the Langmuir equation.
基金Project supported by the National Natural Science Foundation of China (No. 50674062)the Key Projects in the National Science & Technology Pillar Program (No. 2006BAC21B03)the Beijing Science and Technology Plan Projects of China (No. D07040300690000)
文摘A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.
文摘An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while the analysis of Mrssbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to： （i） rapid nanocrystallization of aluminium and/or （ii） small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.
