In order to reduce deep level defects, the theory and process design of 4H-SiC homoepitaxial layer implanted by carbon ion are studied. With the Monte Carlo simulator TRIM, the ion implantation range, location of peak...In order to reduce deep level defects, the theory and process design of 4H-SiC homoepitaxial layer implanted by carbon ion are studied. With the Monte Carlo simulator TRIM, the ion implantation range, location of peak concentration and longitudinal straggling of carbon are calculated. The process for improving deep energy level in undoped 4H-SiC homoepitaxial layer by three times carbon ion-implantation is proposed, including implantation energy, dose, the SiO2 resist mask, annealing temperature, annealing time and annealing protection. The deep energy level in 4H-SiC material can be significantly improved by implantation of carbon atoms into a shallow surface layer. The damage of crystal lattice can be repaired well, and the carbon ions are effectively activated after 1 600 ℃ annealing, meanwhile, deep level defects are decreased.展开更多
After a brief review on the progresses in GaN substrates by ammonothermal method and Na-flux method and hydride vapor phase epitaxy （HVPE） technology, our research results of growing GaN thick layer by a gas fow-rno...After a brief review on the progresses in GaN substrates by ammonothermal method and Na-flux method and hydride vapor phase epitaxy （HVPE） technology, our research results of growing GaN thick layer by a gas fow-rnodulated HVPE, removing the GaN layer through an efficient self-separation process from sapphire substrate, and modifying the uniformity of multiple wafer growth are presented. The effects of surface morphology and defect behaviors on the GaN homo-epitaxial growth on free standing substrate are also discussed, and followed by the advances of LEDs on GaN substrates and prospects of their applications in solid state lighting.展开更多
Objective： To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods： In vitro anti-tumor activity was assayed in adenoma cells A549 and hum...Objective： To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods： In vitro anti-tumor activity was assayed in adenoma cells A549 and human liver cancer cells Bel-7402 using MTT method, and half-inhibitory concentration （IC50） were observed. In vivo the pulmonary adenoma LA795 cells was selected and the conventional assay method of anti-tumor activity was employed. 5, 7.5, 10 mg/kg of 17a α-D-homo-ethynylestradiol-3-acetate was administered by i.p., and tumor-inhibitory rate, thymus and spleen indexes, bone marrow cells （BMC） were observed. Results： IC50 of 17a α-D-homo-ethynylestradiol-3-acetate in vitro for A549 and Bel-7402 cells were 12.28 μg/ml and 17.79 μg/ml, respectively. In vivo the highest tumor-inhibitory rates for LA795 was 60.0% （P〈0.01）. The drug had hardly any side-effect in spleen indexes, thymus indexes, and BMC compared with control mice. Nevertheless, compared with the positive control drug cyclophosphamide （CY）, thymus and spleen indexes, BMC showed obvious differences （P〈0.01）. Conclusion： 17a α-D-homo-ethynylestradiol-3-acetate has obvious anti-tumor activities in vitro and in vivo with low side-effect, thus worth further investigation.展开更多
A series of solvents were examined for the ligand free Pd（II）-catalyzed Suzuki reaction of 4-bromotoluene with phenylboronic acid. It was found that the PdCl2/i-PrOH system could efficiently inhibit the homo-couplin...A series of solvents were examined for the ligand free Pd（II）-catalyzed Suzuki reaction of 4-bromotoluene with phenylboronic acid. It was found that the PdCl2/i-PrOH system could efficiently inhibit the homo-coupling of phenylboronic acid and give a cross-coupling product in high yields. The substrates with a wide variety of functional groups were tolerated in the system. A possible mechanism for this system was proposed.展开更多
The methanolic extract from a Chinese endemic Chrysanthemum plant, Dendranthema indicum var. aromaticum, was found to show high antifeeding activity against Pieris brassicae L., and by bioassay-guided separation, the ...The methanolic extract from a Chinese endemic Chrysanthemum plant, Dendranthema indicum var. aromaticum, was found to show high antifeeding activity against Pieris brassicae L., and by bioassay-guided separation, the ac-tive component, B-ring-homo-tonghaosu, 2-(2',4'-hexadiynylidene)-1,6-dioxaspiro-[4,5]-dec-3-ene (2) was isolated. Its structure was elucidated by comparing its spectroscopic data with those of 2 reported in the literatures. Further-more new convenient total synthesis methods of B-ring-homo-tonghaosu were also developed to confirm its struc-ture and make its further application in crop protection available. In addition, extensive comparison of spectroscopic data showed that the structure of compound 21 reported in literature should be revised to 2.展开更多
Protein homo-oligomers play an important role in various vital activities. Successful prediction of protein homo-oligomers directly from primary sequence is very beneficial to understand their protein function. In thi...Protein homo-oligomers play an important role in various vital activities. Successful prediction of protein homo-oligomers directly from primary sequence is very beneficial to understand their protein function. In this paper, a total of 14 238 homo-oligomeric protein sequences are predicted by IB1 algorithm. 10-fold cross-validation test is applied to test the predictive capability of the proposed method. The predictive results show that overall prediction accuracy is 90.46%, which is at least 9% higher than that of previous results; furthermore,the sensitivity and Matthew＇s correlation coefficient for each class of homo-oligomers are also improved significantly. The results show that IB1 algorithm is effective and feasible,and very suitable for predicting protein homo-oligomer types.展开更多
基金Supported by the National Natural Science Foundation of China (No. 61006008)Xi'an Applied Materials Innovation Fund (No. XA-AM-200607)
文摘In order to reduce deep level defects, the theory and process design of 4H-SiC homoepitaxial layer implanted by carbon ion are studied. With the Monte Carlo simulator TRIM, the ion implantation range, location of peak concentration and longitudinal straggling of carbon are calculated. The process for improving deep energy level in undoped 4H-SiC homoepitaxial layer by three times carbon ion-implantation is proposed, including implantation energy, dose, the SiO2 resist mask, annealing temperature, annealing time and annealing protection. The deep energy level in 4H-SiC material can be significantly improved by implantation of carbon atoms into a shallow surface layer. The damage of crystal lattice can be repaired well, and the carbon ions are effectively activated after 1 600 ℃ annealing, meanwhile, deep level defects are decreased.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2014AA032605)the National Key Basic Research and Development Program of China(Grant Nos.2012CB619304 and 2011CB301904)the National Natural Science Foundation of China(Grant Nos.61376012,61474003,and 61327801)
文摘After a brief review on the progresses in GaN substrates by ammonothermal method and Na-flux method and hydride vapor phase epitaxy （HVPE） technology, our research results of growing GaN thick layer by a gas fow-rnodulated HVPE, removing the GaN layer through an efficient self-separation process from sapphire substrate, and modifying the uniformity of multiple wafer growth are presented. The effects of surface morphology and defect behaviors on the GaN homo-epitaxial growth on free standing substrate are also discussed, and followed by the advances of LEDs on GaN substrates and prospects of their applications in solid state lighting.
基金the grant from Tianjin Nature Science Fund Key Item(No.043802411)
文摘Objective： To study the anti-tumor activities of novel estrogen compound 17a α-D-homo-ethynylestradiol-3-acetate in vitro and in vivo. Methods： In vitro anti-tumor activity was assayed in adenoma cells A549 and human liver cancer cells Bel-7402 using MTT method, and half-inhibitory concentration （IC50） were observed. In vivo the pulmonary adenoma LA795 cells was selected and the conventional assay method of anti-tumor activity was employed. 5, 7.5, 10 mg/kg of 17a α-D-homo-ethynylestradiol-3-acetate was administered by i.p., and tumor-inhibitory rate, thymus and spleen indexes, bone marrow cells （BMC） were observed. Results： IC50 of 17a α-D-homo-ethynylestradiol-3-acetate in vitro for A549 and Bel-7402 cells were 12.28 μg/ml and 17.79 μg/ml, respectively. In vivo the highest tumor-inhibitory rates for LA795 was 60.0% （P〈0.01）. The drug had hardly any side-effect in spleen indexes, thymus indexes, and BMC compared with control mice. Nevertheless, compared with the positive control drug cyclophosphamide （CY）, thymus and spleen indexes, BMC showed obvious differences （P〈0.01）. Conclusion： 17a α-D-homo-ethynylestradiol-3-acetate has obvious anti-tumor activities in vitro and in vivo with low side-effect, thus worth further investigation.
文摘A series of solvents were examined for the ligand free Pd（II）-catalyzed Suzuki reaction of 4-bromotoluene with phenylboronic acid. It was found that the PdCl2/i-PrOH system could efficiently inhibit the homo-coupling of phenylboronic acid and give a cross-coupling product in high yields. The substrates with a wide variety of functional groups were tolerated in the system. A possible mechanism for this system was proposed.
基金the National Natural Science Foundation of China (Grant Nos. 29672083, 20072043), Chinese Academy of Sciences, the State Ministry of Science and Technology (No. G2000077502), Shanghai Committee of Science and Technology and the
文摘The methanolic extract from a Chinese endemic Chrysanthemum plant, Dendranthema indicum var. aromaticum, was found to show high antifeeding activity against Pieris brassicae L., and by bioassay-guided separation, the ac-tive component, B-ring-homo-tonghaosu, 2-(2',4'-hexadiynylidene)-1,6-dioxaspiro-[4,5]-dec-3-ene (2) was isolated. Its structure was elucidated by comparing its spectroscopic data with those of 2 reported in the literatures. Further-more new convenient total synthesis methods of B-ring-homo-tonghaosu were also developed to confirm its struc-ture and make its further application in crop protection available. In addition, extensive comparison of spectroscopic data showed that the structure of compound 21 reported in literature should be revised to 2.
基金Supported by the Discipline-Crossing Research Foundation of Huazhong Agricultural University (2008XKJC006)
文摘Protein homo-oligomers play an important role in various vital activities. Successful prediction of protein homo-oligomers directly from primary sequence is very beneficial to understand their protein function. In this paper, a total of 14 238 homo-oligomeric protein sequences are predicted by IB1 algorithm. 10-fold cross-validation test is applied to test the predictive capability of the proposed method. The predictive results show that overall prediction accuracy is 90.46%, which is at least 9% higher than that of previous results; furthermore,the sensitivity and Matthew＇s correlation coefficient for each class of homo-oligomers are also improved significantly. The results show that IB1 algorithm is effective and feasible,and very suitable for predicting protein homo-oligomer types.
