检索结果-南通市图书馆

Distribution of Soil Organic Carbon Fractions Along the Altitudinal Gradient in Changbai Mountain,china

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2011年第5期21卷 615-620页

作者： ZHANG Min ZHANG Xiao-Ke LIANG Wen-Ju JIANG Yong DAI Guan-Hua WANG Xu-Gao HAN Shi-Jie state key {2. of Forest and Soil Ecology Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110164 (China) Vegetable Research Institute Liaoning Academy of Agricultural Sciences Shenyang 110161 (China) Graduate university of Chinese Academy of Sciences Beijing 100049 (China)

Understanding the responses of soil organic carbon(SOC) fractions to altitudinal gradient variation is important for understanding changes in the carbon balance of forest *** our study the SOC and its fractions of readily oxidizable carbon(ROC),water-soluble carbon(WSC) and microbial biomass carbon(MBC) in the soil organic and mineral horizons were investigated for four typical forest types,including mixed coniferous broad-leaved forest(MCB),dark coniferous spruce-fir forest(DCSF),dark coniferous spruce forest(DCS),and Ermans birch forest(EB),along an altitudinal gradient in the Changbai Mountain Nature Reserve in Northeast *** results showed that there was no obvious altitudinal pattern in the *** variation trends of SOC with altitude were observed between the organic and mineral *** differences in the contents of SOC,WSC,MBC and ROC were found among the four forest types and between *** contents of ROC in the mineral horizon,WSC in the organic horizon and MBC in both horizons in the MCB and EB forests were significantly greater than those in either DCSF or DCS *** proportion of soil WSC to SOC was the lowest among the three main *** contents of WSC,MBC and ROC were significantly correlated(P < 0.05) with SOC *** can be concluded that vegetation types and climate were crucial factors in regulating the distribution of soil organic carbon fractions in Changbai Mountain.

关键词： active carbon fractions altitude forest ecosystem Northeast china vegetation type

Synthesis and Luminous Characteristics of Ba2.iO3Cl2.Eu2.,Mn2. Phosphor for White LED

在线全文

学校读者我要写书评

暂无评论

Synthesis and Luminous Characteristics of Ba2SiO3Cl2:Eu2+,Mn...

2.07亚洲光电子会议LED材料与器件分会场

作者： Shen Changyu a,b Yang Yi a,Jin Shangzhong a a Optical engineering, china Jiliang {2., Hangzhou, 310018 b state key laboratory of Modern Optical Instrumentation, Zhejiang {2., Hangzhou, 31002.

Ba2.iO3Cl2.Eu2., Mn2. phosphor was synthesized by high-temperature solid state reaction at 9002.0°C in a slightly reducing atmosphere for 2.0.0 hours. The raw materials were the mixture of BaCO3, SiO2. MnCO3, NH4Cl, and Eu2.3 in the mol ratio of 3, 2. 0.004, 2.and 0.02. Ba2.iO3Cl2.Eu2., Mn2. phosphor’s absorption and luminescence spectra were studied. The results indicated that the emission band consists of three peaks located at 42. nm, 492.m and 608nm, respectively. The emission peaks at 42. and 492.m originate from the transition 5d →4f of Eu2. ions that occupy the two Ba2. sites in the crystal of Ba2.iO3Cl2. while the 608nm emission is attributed to the energy transfer from Eu2. ions to Mn2. ions. The white light can be obtained by mixing the three emission colors of blue (42. nm), green (492.nm) and red-orange (608 nm) in the single host. When the concentrations of the Eu2. ions and Mn2. ions were 0.02.ol and 0.004mol respectively, the sample presented intense white emitting. The excitation spectra of the three emissions extending from 300 nm to 460 nm indicated that Ba2.iO3Cl2.Eu2. phosphor can be excitated by InGaN chip UV emission effectively, and it is a single-phase white phosphor with low-cost and high brightness for white LEDs.

关键词： High-temperature solid-state reaction Phosphor Ba2.iO3Cl2.Eu2., Mn2.

在线全文

cnki会议

学校读者我要写书评

暂无评论

温控电弧放电法大量制备单壁碳纳米管

物理学报 2004年第11期53卷 3961-3965页

作者：赵廷凯柳永宁西安交通大学金属材料强度国家重点实验室西安710049

采用可以控制真空室温度的改进型直流电弧炉 ,在氮气和氦气 (1∶1)混合气氛下 ,使用Co Ni(1∶1wt% )合金催化剂 ,通过控制温度等工艺条件 ,在容器内壁生成了大量单壁碳纳米管 ,尤其在阴极与阳极之间有大量的宏观网状薄膜 .通过两步纯化... 详细信息

采用可以控制真空室温度的改进型直流电弧炉 ,在氮气和氦气 (1∶1)混合气氛下 ,使用Co Ni(1∶1wt% )合金催化剂 ,通过控制温度等工艺条件 ,在容器内壁生成了大量单壁碳纳米管 ,尤其在阴极与阳极之间有大量的宏观网状薄膜 .通过两步纯化方法 :在 5 0 0℃空气中烘烧 30min ;再用 37%盐酸浸泡 72. ,用去离子水过滤至中性烘干 .经SEM ,HRTEM ,XRD ,Raman观察分析 ,纯化后其纯度高 (>95 % )、管径均匀 (1 2.4— 1 38nm) .实验结果表明 :温度强烈影响单壁碳纳米管的产量 ,不同温度下管子的纯度、产量都有差异 ,在温度为 6 0 0℃时 ,其纯度达到 70 % ,产量为12.

关键词：纯度去离子水控制温度制备工艺条件纯化方法合金催化剂单壁碳纳米管电弧放电法网状

Effects of different proportions Of dietary structural and nonstructural carbohydrates on ruminal fermentation and microbial growth efficiency in sheep

在线全文

学校读者我要写书评

暂无评论

Effects of different proportions Of dietary structural and n...

The Ⅶ International Symposium on the Nutrition of Herbivores(ISNH-7)

作者： Z.G.Xia~1 Q.X.Meng~(2.3) ~1china Green Food Development Center Beijing 100081 P.R.china ~2.2. key laboratory of Animal Nutrition College of Animal Sciences and Technology china Agricultural university Beijing 100094 P.R.china

＜正＞Four sheep were used in a 4×4 Latin square design to study the effect of different dietary proportions of structural carbohydrate（SC）and nonstructural carbohydrate（NSC）（SC:NSC ratio: 0.55,1.12.2.2. and 5.2.）on rumen fermentation and microbial growth *** the dietary SC:NSC ratio increased,ruminal pH and ammonia concentration increased（P＜0.001）,but total rumen VFA concentration decreased（P＜0.001）.When dietary SC:NSC ratio increased from 0.55 to 1.12.the molar percentage of acetate increased（P＜0.001）and the molar proportion of propionate decreased（P＜0.001）.However,when the ratio increased from 1.12.to 5.2.,there were no changed molar percentages of acetate and of *** daily microbial nitrogen production and microbial efficiency decreased with increasing dietary SC:NSC ratio.

关键词： sheep SC:NSC rumen fermentation microbial growth efficiency

STUDIES ON THE PRENYLFLAVONOIDS PARTⅡ.SYNTHESIS OF EUCHRENONE A_7

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1992年第1期3卷 3-4页

作者： Yu Lin LI Fang Jie ZHANG Hua Wu ShAO Shao Bai LI state key {2. of Applied Organic Chemistry,Lanzhou university,Lanzhou 730000

Euchrcnonc a_7 has been prcparcd by condensation of 2.hydroxy-4- mcthoxy-3-prcnylacctophcnone with 2.4-dimethoxymethoxybenzaldehyde followed by cyclization and demethoxymethylation.

关键词： ppm OCH STUDIES ON THE PRENYLFLAVONOIDS PART SYNTHESIS OF EUCHRENONE A7

Global strength assessment for semi-submersible column after supply vessel collision accident

在线全文

学校读者我要写书评

暂无评论

Global strength assessment for semi-submersible column after...

第十四届中国海洋（岸）工程学术讨论会

作者： HU Zhi-qiang (state key Lab of Ocean {2., Shanghai Jiao Tong university, Shanghai 2.0030, china)

The researches of the anti-collision characters of a semi-submersible column and its capability of surviving in severe sea state after collision accident are completed. Three collision cases are designed. A 5000-ton vessel hits the semi-submersible column in transversal, longitudinal and oblique directions. Numerical simulation technique is used to finish the analysis, and anti-collision characters of the semi-submersible column are summarized through the summary of the results, including curve of collision force vs. penetration, curve of energy absorption proportion and the structural damages. It is pointed out that the column show a distinctive character when the contact area is large at the beginning of the collision. Although the column structures suffer obvious distortion, there is no rupture of outer shell, which means the column can sustain such kind of collision. Taking advantage of the direct calculation method with finite element technique, the global strength of the semi-submersible is verified to assess the influence of structure damage by the collision on the semi’s survival capability in severe sea state. The structure damage caused by the collision is taken into consideration in the FE models. The code SESAM is used to do the calculation through the design wave method. Several assumptions are made to realize the comparison between collision cases. It is found that the collision influence is restricted within the bound of structural components around the collision zone. The collision damage caused by the striking of the 5000-ton vessel will not bring a serious threat to the global strength capability of the semi-submersible.

关键词： Semi-submersible collision global strength numerical simulation

Genome-wide identification of recombination rates of male versus female gametes in interspecific populations of cotton

在线全文

cnki会议

学校读者我要写书评

暂无评论

Genome-wide identification of recombination rates of male ve...

第十三届全国植物基因组学大会

作者： Yu Yu~(1,2.,Xianlong Zhang~1,Zhongxu Lin~(1*) 1 state key {2. of crop genetic improvement,Huazhong Agricultural university, Wuhan 430070,china 2.Cotton Research Institute,Academy of Sciences of Xinjiang farming cultivate,Xinjiang Shihezi 832.00,china

Based on the established SSR-based BC1 genetic linkage map,2.genetic maps covered with 313 markers have been developed for 2.more backcross populations which was aimed to study the difference of recombination rates be...

关键词：

Retinoid X receptor activities of source waters in china and their removal efficiencies during drinking water treatment processes

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第6期57卷 595-600页

作者： JIANG WeiWei YAN Ye LI Na MA Mei WANG DongHong RAO KaiFeng WANG ZiJian SATYANARAYANAN Senthi Kumaran state key {2. of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Unit of Toxicology Bharathiar UniversityCoimbatore 641046India

There is increasing evidence of estrogenic activities of source waters and drinking waters in china based on estrogen receptors(ERs) ***,relating such activities to retinoid X receptors(RXRs) in both drinking and source waters are *** rectify this situation,we assessed 2. source water samples from six major river systems in *** also collected samples at various stages of water processing from three drinking water treatment plants(DWTPs) using a two-hybrid RXR yeast assay with and without *** RXR agonistic activity was observed,but significant antagonistic activity was detected in all sample *** RXR antagonistic activities of source water sample extracts ranged from 15.2. to 57.8% without metabolism and 11.5% to 68.3% with metabolism,*** the drinking water treatment processes,RXR antagonistic activities without metabolism and with metabolism of up to 31.4% and 37.5% were removed,***,the remaining RXR antagonists in treated drinking water from these source waters could still be harmful to human *** the best of our knowledge,the occurrence of in vitro RXR disruption activities in source and drinking water has not been previously reported in ***,an attempt was made to conduct detailed studies investigating RXR disrupting activities and their possible risks in source and drinking water.

关键词：雌激素受体水处理过程饮用水维甲酸中国水域去除率新陈代谢

Improve methionine adenosyltransferase activity by DNA shuffling to increase SAM production in Pichia pastoris

在线全文

学校读者我要写书评

暂无评论

Improve methionine adenosyltransferase activity by DNA shuff...

2.08年中国微生物学会学术年会

作者： Ju Chu~*,Yingping Zhuang,Siliang Zhang,Hui Hu,Jiangchao Qian~* state key {2. of Bioreactor engineering,East china university of Science & Technology, Shanghai,2.02.7

S-Adenosyl-Lmethionine(SAM) is an important molecule in normal cell function and *** enhance methionine adenosyltransferase(MAT,also known as SAM synthetase) activity and thus SAM production in recombinant Pichia pastoris,MAT genes from Escherichia coli,Saccharmyces cerevisiae,and Streptomyces spectabilis were recombined by DNA *** the shuffled genes were transformed into

关键词： SAM MAT DNA shuffling Pichia pastoris