The Components having calcium antagonist effect were isolated from richosanthes with 70% C 2H 5OH.The analytical data showed that the mixture was composed of saturated aliphatic acids,spinasterol and 24 dihydro 10α c...The Components having calcium antagonist effect were isolated from richosanthes with 70% C 2H 5OH.The analytical data showed that the mixture was composed of saturated aliphatic acids,spinasterol and 24 dihydro 10α cucurbitadienol.展开更多
In recent years, great attention has been paid to the exploitation and use of biomass energy.Using bamboo as the raw material to produce energy and other chemicals is significantly important.A primary study was made o...In recent years, great attention has been paid to the exploitation and use of biomass energy.Using bamboo as the raw material to produce energy and other chemicals is significantly important.A primary study was made on the pubescens,one kind of bamboo distributed broadly in China with fast growth rate.The contents of cellulose, hemi-cellulose, and lignin in different parts of pubescens with different growth ages, as major components of the cell wall,were determined.The analysis procedures were as follows:firstly the substances other than the above mentioned three were removed chemically, then the hydrolyzed cellulose liquid was oxidized with excess oxidants,and at last titrated.Pubescens powder was packed into the quartz tube reactor, then was heated from room temperature to 300,350, 400, 450, 500, 550 ℃ and 600 ℃ respectively in flowing N 2.Pyrolysis was held at the final temperature for 10 h.The liquid products were analyzed with GC/MS.The main products in the liquid obtained were: acetic acid, 2,6-dimethoxy phenol, 2,3-dihydrobenzofuran,etc.The pyrolysis temperature exerted great effect on the composition of the liquid products.The distribution of the products could be regulated by controlling pyrolysis temperature.展开更多
Li1.06Co0.05Cr0.1Mn1.85O4 powders were prepared by heating metal-urea nitrate complexes precursors. The influence of synthesis conditions on the structural and electrochemical properties of Li1.06Co0.05Cr0.1Mn1.85O4 w...Li1.06Co0.05Cr0.1Mn1.85O4 powders were prepared by heating metal-urea nitrate complexes precursors. The influence of synthesis conditions on the structural and electrochemical properties of Li1.06Co0.05Cr0.1Mn1.85O4 was investigated by X-ray diffraction, scanning electron microscopy and charge-discharge experiments. The powders were well crystallized and with a narrow particle size distribution and regular morphology about 60 nm. Electrochemical performances indicated that Li1.06Co0.05Cr0.1Mn1.85O4 delivered a high capacity of 191 mAh·g-1 at 14th cycle due to additional 3 V (vs Li) plateau, 145 mAh·g-1 at 22st cycle. The results show that there are two pairs of voltammetric wave (centered at 4 V (vs Li)) and a pairs of voltammetric wave (centered at 3 V (vs Li)), indicating an excellent reversibility.展开更多
A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results...A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results showed that lanthanum ion could suppress alumina transition to α-phase and then inhibit alumina from sintering and the thermal stability of the Al 2O 3 was improved. Different ratios of La/Al had different effects on the specific surface area of Al 2O 3.The Al 2O 3 containing 1.0 mol/% lanthanum has a BET specific surface area of 71.8 m 2/g after calcination for 32 hours at 1*#100℃, whereas the undoped Al 2O 3 only had a BET specific surface area of 10 m 2/g under similar conditions.展开更多
The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanth...The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanthanum can prevent alumina crystal from growing at high temperature and inhibit alumina from transforming to α phase and improve its pore structure.PVA can also make lanthanum less rich at the surface of samples,so alumian can keep high surface area after calcination at high temperature,then its thermal stability was improved.When W(La)∶W(Al)=0.052∶1 and W(PVA)∶W(alumina)=0.4∶1,the alumina can maintain surface area of 102.7m 2g -1 after calcination at 1100℃ for 32h.展开更多
文摘The Components having calcium antagonist effect were isolated from richosanthes with 70% C 2H 5OH.The analytical data showed that the mixture was composed of saturated aliphatic acids,spinasterol and 24 dihydro 10α cucurbitadienol.
文摘In recent years, great attention has been paid to the exploitation and use of biomass energy.Using bamboo as the raw material to produce energy and other chemicals is significantly important.A primary study was made on the pubescens,one kind of bamboo distributed broadly in China with fast growth rate.The contents of cellulose, hemi-cellulose, and lignin in different parts of pubescens with different growth ages, as major components of the cell wall,were determined.The analysis procedures were as follows:firstly the substances other than the above mentioned three were removed chemically, then the hydrolyzed cellulose liquid was oxidized with excess oxidants,and at last titrated.Pubescens powder was packed into the quartz tube reactor, then was heated from room temperature to 300,350, 400, 450, 500, 550 ℃ and 600 ℃ respectively in flowing N 2.Pyrolysis was held at the final temperature for 10 h.The liquid products were analyzed with GC/MS.The main products in the liquid obtained were: acetic acid, 2,6-dimethoxy phenol, 2,3-dihydrobenzofuran,etc.The pyrolysis temperature exerted great effect on the composition of the liquid products.The distribution of the products could be regulated by controlling pyrolysis temperature.
文摘Li1.06Co0.05Cr0.1Mn1.85O4 powders were prepared by heating metal-urea nitrate complexes precursors. The influence of synthesis conditions on the structural and electrochemical properties of Li1.06Co0.05Cr0.1Mn1.85O4 was investigated by X-ray diffraction, scanning electron microscopy and charge-discharge experiments. The powders were well crystallized and with a narrow particle size distribution and regular morphology about 60 nm. Electrochemical performances indicated that Li1.06Co0.05Cr0.1Mn1.85O4 delivered a high capacity of 191 mAh·g-1 at 14th cycle due to additional 3 V (vs Li) plateau, 145 mAh·g-1 at 22st cycle. The results show that there are two pairs of voltammetric wave (centered at 4 V (vs Li)) and a pairs of voltammetric wave (centered at 3 V (vs Li)), indicating an excellent reversibility.
文摘A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results showed that lanthanum ion could suppress alumina transition to α-phase and then inhibit alumina from sintering and the thermal stability of the Al 2O 3 was improved. Different ratios of La/Al had different effects on the specific surface area of Al 2O 3.The Al 2O 3 containing 1.0 mol/% lanthanum has a BET specific surface area of 71.8 m 2/g after calcination for 32 hours at 1*#100℃, whereas the undoped Al 2O 3 only had a BET specific surface area of 10 m 2/g under similar conditions.
文摘The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanthanum can prevent alumina crystal from growing at high temperature and inhibit alumina from transforming to α phase and improve its pore structure.PVA can also make lanthanum less rich at the surface of samples,so alumian can keep high surface area after calcination at high temperature,then its thermal stability was improved.When W(La)∶W(Al)=0.052∶1 and W(PVA)∶W(alumina)=0.4∶1,the alumina can maintain surface area of 102.7m 2g -1 after calcination at 1100℃ for 32h.
