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Search Results: 1 - 10 of 117605 matches for " Mei-Yan Chen "
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5α-Pregna-1,20-dien-3-one
Guang-ying Chen,Mei-Yan Wei,Ni Tan,Zhen Liu
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810000863
Abstract: The title compound, C21H30O, was isolated from the soft coral Sinularia sp. The molecule contains four alicyclic rings, all trans-fused, among which three six-membered rings are in different distorted chair conformations while a five-membered ring assumes an envelope form.
Sparse Planar Array Synthesis Using Matrix Enhancement and Matrix Pencil
Mei-yan Zheng,Ke-song Chen,Hong-gang Wu,Xian-pan Liu
International Journal of Antennas and Propagation , 2013, DOI: 10.1155/2013/147097
Abstract:
Deuterium Fractionation as an Evolutionary Probe in Massive Proto-stellar/cluster Cores
Huei-Ru Chen,Sheng-Yuan Liu,Yu-Nung Su,Mei-Yan Wang
Physics , 2011, DOI: 10.1088/0004-637X/743/2/196
Abstract: Clouds of high infrared extinction are promising sites of massive star/cluster formation. A large number of cloud cores discovered in recent years allows investigation of possible evolutionary sequence among cores in early phases. We have conducted a survey of deuterium fractionation toward 15 dense cores in various evolutionary stages, from high-mass starless cores to ultracompact Hii regions, in the massive star-forming clouds of high extinction, G34.43+0.24, IRAS 18151-1208, and IRAS 18223-1243, with the Submillimeter Telescope (SMT). Spectra of N2H+ (3 - 2), N2D+ (3 - 2), and C18O (2 - 1) were observed to derive the deuterium fractionation of N2H+, Dfrac \equiv N(N2D+)/N(N2H+), as well as the CO depletion factor for every selected core. Our results show a decreasing trend in Dfrac with both gas temperature and linewidth. Since colder and quiescent gas is likely to be associated with less evolved cores, larger Dfrac appears to correlate with early phases of core evolution. Such decreasing trend resembles the behavior of Dfrac in the low-mass protostellar cores and is consistent with several earlier studies in high-mass protostellar cores. We also find a moderate increasing trend of Dfrac with the CO depletion factor, suggesting that sublimation of ice mantles alters the competition in the chemical reactions and reduces Dfrac. Our findings suggest a general chemical behavior of deuterated species in both low- and high-mass proto-stellar candidates at early stages. In addition, upper limits to the ionization degree are estimated to be within 2 \times 10^-7 and 5 \times 10^-6. The four quiescent cores have marginal field-neutral coupling and perhaps favor turbulent cooling flows.
Effects of Incorporation of Nano-carbon into Slow-released Fertilizer on Rice Yield and Nitrogen Loss in Surface Water of Paddy Soil
Mei-yan Wu
Advance Journal of Food Science and Technology , 2013,
Abstract: The use of slow-released fertilizer has become a new trend to save fertilizer consumption and to minimize environmental pollution. Duo to its high surface energy and chemical activity, the application domain of nano-materials has significantly expanded with the development of nanotechnology in conjunction with biotechnology in various fields, such as water purification, wastewater treatment, environmental remediation and food processing and packaging, industrial and household purposes, medicine and in smart sensor development. However, use in agriculture, especially for plant production, is an under-explored area in the research community. In this study, nano-carbon was incorporated into slow-released fertilizer and the influence on rice yield and nitrogen loss in surface water of paddy soil was conducted by field experiment. The experiment was a randomized block design with five treatments and three replications, the Control (CK), Jingzhengda Slow-released fertilizer (JSCU, N 42%), Jingzhengda Slow-released fertilizer and nano-Carbon (JSCU+C), Stanley slow-released compound fertilizer (SSRF, N-P2O5-K2O = 20:9:11), Stanley Slow-Released compound Fertilizer and nano-carbon (SSRF+C), respectively. The results indicated that the total nitrogen concentration in surface water of paddy soil increased rapidly at the 2nd day after fertilization and decreased gradually after that in all treatments. Compare to JSCU, sampling at different times after fertilization, the total nitrogen concentration in surface water of paddy soil under JSCU+C treatment was declined in the range of 19.1-46.8%, the average was 31.0% and the time of nitrogen runoff loss due to rainfall was shorten 2.2 day. For SSCU+C treatment, the average total nitrogen concentration was decreased by 29.8% and the time of nitrogen runoff loss was shortening 1.8 day. The rice grain yield and nitrogen use efficiency were increased significantly after applying slow-released fertilizer added nano-carbon. The rice grain yield and nitrogen use efficiency under JSRU+C and SSRF+C treatments were 11650.5 kg/hm2, 21.4 kg/kg N and 11201.0 kg/hm2, 18.4 kg/kg N, respectively, increased by 11.3%, 7.9 kg/kg N compared with JSRU and 5.6% and 4.4 kg/kg N compared with SSRF. The rate of saving nitrogen was 10.1 and 5.1% for JSCU+C and SSRF+C, respectively. These results suggest that it is possible that the nano-carbon is used as coating material for slow-released fertilizer and incorporation of nano-carbon into slow-released fertilizer is benefit for reducing water pollution, especially JSCU+C.
Optical and structural properties of Ge-ion-implanted fused silica after annealing in different ambient conditions

Xiang Xi,Chen Meng,Chen Mei-Yan,Zu Xiao-Tao,Zhu Sha,Wang Lu-Min,

中国物理 B , 2010,
Abstract: Ge^ + ions are implanted into fused silica glass at room temperature and a fluence of 1× 10^17~cm^ - 2. The as-implanted samples are annealed in O2, N2 and Ar atmospheres separately. Ge^0, GeO and GeO2 coexist in the as-implanted and annealed samples. Annealing in different atmospheres at 600~\du\ leads each composite to change its content. After annealing at 1000~\du, there remains some amount of Ge^0 in the substrates. However, the content of Ge decreases due to out-diffusion. After annealing in N2, Si--N composite is formed. The absorption peak of GeO appears at 240~nm after annealing in O2 atmosphere, and a new absorption peak occurs at 418~nm after annealing in N2 atmosphere, which is attributed to the Si--N composite. There is no absorption peak appearing after annealing in Ar atmosphere. Transmission electron microscopic images confirm the formation of Ge nanoparticles in the as-implanted sample and GeO2 nanoparticles in the annealed sample. In the present study, the GeO content and the GeO2 content depend on annealing temperature and atmosphere. Three photoluminescence emission band peaks at 290, 385 and 415~nm appear after ion implantation and they become strong with the increase of annealing temperature below 700~\du, and their photoluminescences recover to the values of as-grown samples after annealing at 700~\du. Optical absorption and photoluminescence depend on the annealing temperature and atmosphere.
STUDY ON THE ELASTIC RECOVERY OF POLYESTER-POLYETHER ELASTOMERIC FIBER AT LOWER TEMPERATURE
聚酯-聚醚弹体纤维低温弹性回复的研究

Chen Chuan-fu,Liu Pang,Wu Mei-yan,
陈传福
,刘凡,吴美琰

高分子学报 , 1981,
Abstract: The elastic recovery of polyester-polyether fiber at lower temperature was studied. It was found that due to the stress-induced crystallization of soft segments the fiber has a relative low elastic recovery at lower temperature but higher extention ratio. The probable routes of improvements have also been discussed.
Distribution of a specific SCAR marker among Lentinula edodes protoplast monokaryons for strain 135
香菇135菌株特异SCAR标记在其原生质体单核中的分布

ZHANG Mei-Yan,TAN Qi,CHEN Ming-Jie,PAN Ying-Jie,
张美彦
,谭琦,陈明杰,潘迎捷

微生物学报 , 2008,
Abstract: Refrigerated mycelium and fresh fruitbody tissue-isolated mycelium of Lentinula edodes strain 135 were used to prepare protoplast monokaryons. Fifty-eight and 83 monokaryons were isolated respectively and their mating types were determined. PCR amplification employing specific primers was used to establish the distribution among the protoplast monokaryons of a SCAR marker specific for strain 135. Protoplast monokaryons segregated into either A1B1 or A2B2 mating type, and the SCAR marker was detected only in the latter. The outcome is a regular distribution pattern that demonstrates the stable inheritance of the SCAR marker and is fundamental to identification of offspring arising from crosses between protoplast monokaryons of this particular mating type and other karyons.
THE EFFECT OF SEGMENT COMPATIBILITY ON THE COMPOSITIONAL HOMOGENEITY OF POLYESTER-POLYETHER MULTI-BLOCK COPOLYMERS
链段相容性对聚酯-聚醚多嵌段共聚物组成均一性的影响

Wu Mei-yan,Zhang Dong,Chen Chun-fu,Qian Chun-qin,
吴美琰
,张栋,陈传福,钱春琴

高分子学报 , 1981,
Abstract: This paper presents a study on the effect of segment compatibility on the compositional homogeneity of polyester-polyether block copolymers. A series of such block co-polymers with various segment structures were synthesized. A transparency point determination was developed as a relative semi-quantitative comparison of segment compatibility in the melt copolyeondensation.
Distribution of a specific SCAR marker among Lentinula edodes protoplast monokaryons for strain 135
香菇135菌株特异SCAR标记在其原生质体单核中的分布

ZHANG Mei-Yan,TAN Qi,CHEN Ming-Jie,PAN Ying-Jie,
张美彦
,谭琦,陈明杰,潘迎捷

菌物学报 , 2008,
Abstract: Refrigerated mycelium and fresh fruitbody tissue-isolated mycelium of Lentinula edodes strain 135 were used to prepare protoplast monokaryons. Fifty-eight and 83 monokaryons were isolated respectively and their mating types were determined. PCR amplification employing specific primers was used to establish the distribution among the protoplast monokaryons of a SCAR marker specific for strain 135. Protoplast monokaryons segregated into either A1B1 or A2B2 mating type, and the SCAR marker was detected only in the latter. The outcome is a regular distribution pattern that demonstrates the stable inheritance of the SCAR marker and is fundamental to identification of offspring arising from crosses between protoplast monokaryons of this particular mating type and other karyons.
Stacking sequence dependence of electronic properties in double-layer graphene heterostructures
Mei-Yan Ni,Katsunori Wakabayashi
Physics , 2014, DOI: 10.7567/JJAP.53.06JD03
Abstract: First-principles calculation has been performed to investigate the stability and electronic properties of double-layer graphene heterostructure (DLGH). In this system, two graphene layers are separated by hexagonal boron-nitride (h-BN) layers which work as a insulating barrier. Our results show that the stability of the system is determined by the atomistic configurations between graphene and its adjacent h-BN layer. Among different stacking sequences, Ab-stacking is most stable. Since the inserted h-BN layers modulate the on-site energies for carbon atoms of graphene layers, the electronic states of the system can be classified into metallic or semiconducting by the stacking sequence. And the stacking sequence dependence of the energy band structures of DLGHs are well described by the orbital interaction model.
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