298 research outputs found
不同品种、盐度及月份菊芋叶中绿原酸的含量测定
建立HPLC 法测定菊芋叶中绿原酸含量的方法,对菊芋植株中不同部位绿原酸的分布规律,以及不同品系、盐度、采摘时间等因素对菊芋叶中绿原酸含量的影响情况进行研究。方法:色谱柱为Hypersil BDS C-18(4.6×250 mm,5 μm),流速为1 mL min-1 ,检测波长为327 nm,进样量为10 μL,柱温为30℃,流动相为0.1%三氟乙酸水(A)-乙腈(B)。结果:菊芋叶中绿原酸的含量(3.40%)显著高于其他部位绿原酸的含量;10 月份菊芋叶中绿原酸的平均含量达最大值(2.74%)。南芋(N)受盐度影响较小,菊芋叶中绿原酸的平均含量(3.15%)明显高于莱芋(L)叶中绿原酸的平均含量(2.32%)。结论:菊芋植株中的绿原酸主要存在于菊芋叶中;不同采摘时间对菊芋叶中绿原酸的积累影响很大,10 月中旬可以作为菊芋叶的最佳采收时间;不同菊芋品种对盐度高低的适应能力不同,其中,南芋可能更适 合在盐碱地土壤类型中生长
Photogenerated Cathodic Protection Properties of a TiO_2 Nanowire Film Prepared by a Hydrothermal Method
Corresponding author.
Email: [email protected]; Tel: +86-592-2189192.[中文文摘]应用水热法在钛箔表面制备TiO2纳米线薄膜,采用场发射扫描电子显微镜、X射线衍射和紫外-可见分光光度法对薄膜进行表征,用电极电位和电化学阻抗谱考察TiO2光生阴极保护性能.结果表明:薄膜由纵横交错的锐钛矿型TiO2纳米线组成,纳米线的直径约10nm.在150℃下反应6h生成的TiO2纳米线薄膜在0.3mol·L-1 Na2SO4溶液和0.3mol·L-1 Na2SO4+0.5mol·L-1 HCOOH混合溶液中对与TiO2薄膜耦连的403不锈钢均有良好的阴极保护效应.TiO2膜所在溶液中含有HCOOH时,可使耦连的403不锈钢在0.5mol·L-1 NaCl溶液中电极电位负移约545mV,界面反应电阻显著变小,表明电解质溶液加入HCOOH可以增强TiO2纳米线薄膜对403不锈钢的光生阴极保护效应.[英文文摘]A TiO2 film was synthesized on the surface of a Ti substrate by a hydrothermal method,followed by acid treatment and calcination.The properties of the TiO2 film were characterized by scanning electron microscopy,X-ray diffraction,and ultraviolet-visible spectrophotometry.The photogenerated cathodic protection properties of the TiO2 film were investigated by electrochemical techniques.The corrosion performance of 403 stainless steel coupled to a TiO2 film photoanode in different solutions was evaluated by photogenerated potential and electrochemical impedance spectroscopy. The results showed that the TiO2 film was composed of many randomly-oriented anatase nanowires of
about 10 nm in diameter. The TiO2 nanowire film prepared by the hydrothermal reaction at 150 ℃ for 6 h was used for
the photogenerated cathodic protection of 403 stainless steel. When we coupled the steel in a 0.5 mol·L -1 NaCl
solution to the TiO2 film photoanode in a mixed solution containing 0.3 mol·L-1 Na2SO4 and 0.5 mol·L-1 HCOOH, its
potential decreased by 545 mV. Additionally, the charge transfer resistance of the electrode reaction process for the
coupled steel decreased considerably. The results also indicated that the HCOOH in the mixed solution improved the
photogenerated cathodic protection of the TiO2 film photoanode.国家高技术研究发展专项(2009AA03Z327); 国家科技支撑计划项目(2007BAB27B04)资
Characteristics of macrobenthic communities in the estuary of Dagujia River and its adjacent water areas in Yantai, Shandong
为了解烟台大沽夹河河口及邻近海域大型底栖动物群落特征及受干扰情况,于2012年9月在上述区域设置12个采样点进行大型底栖动物群落调查和分析。对采集的生物样品进行物种鉴定、计数和称重,利用生物统计软件PRIMER计算优势度指数(Y)、Shannon-Wiener多样性指数(H')、Margalef丰富度指数(D)和Pielou均匀度指数(J),并进行等级聚类(CLUSTER)、非度量多维标度排序(non-metric multi-dimensional scaling,MDS)及丰度/生物量曲线(abundance and biomass curves,ABC)分析。共采集和鉴定大型底栖动物89..
Long-Term Trends of Macrobenthos in Southern Bohai Sea, China, in Relation toEnvironmental Changes
根据50多年来渤海南部海域大型底栖动物群落的历史资料,以及2011~2013年的现场调查数据,从渤海南部包括黄河口邻近海域及莱州湾大型底栖动物群落结构变化特征出发,分析了其长期演变的过程和规律,旨在阐明底栖动物群落的演变趋势,识别其重要的演变时段.并结合50年来渤海南部海域相关底栖环境因子的变化特征,探讨底栖动物群落的演变原因.过去50余年来,渤海南部海域大型底栖动物群落在物种数、生物量、丰度以及群落结构组成等方面都发生了较大的变动,具体表现为寿命长、体积大、具有高竞争力的K对策种的优势地位正逐渐丧失,而被寿命短、适应能力宽、具有高繁殖能力的R对策种所取代.按照50余年来渤海南部海域大型底栖动..
Progress of C_2-Symmetric Biphenyl Bisphosphine LigandsⅡ
手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近十年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法、C2-轴对称联苯类手性双膦配体在不对称催化氢化以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展。A vast number of biphenyl atropisomeric diphosphine ligands have been successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands on the asymmetric catalysis hydrogenation and other asymmetric induced reaction.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109
Progress of C_2-Symmetric Biphenyl Bisphosphine Ligands Ⅲ
手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近10年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法、C2-轴对称联苯类手性双膦配体在不对称催化氢化、以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展,并对今后配体的合成及应用前景进行了展望。A vast number of biphenyl atropisomeric diphosphine ligands are successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands on the asymmetric catalysis hydrogenation and other asymmetric induced reaction,and the future ligand synthesis and application prospect.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109
Progress of the Study on C_2-symmetric Biphenyl Bisphosphine Ligands(一)
手性膦配体的合成及其在手性诱导催化反应中的应用一直是不对称合成与催化研究中非常重要的研究领域之一。近10年来,大量的C2-轴对称手性双膦配体被合成出来并成功地应用于不对称催化研究,本文从C2-轴对称联苯类手性双膦配体的介绍、合成方法,C2-轴对称联苯类手性双膦配体在不对称催化氢化,以及其在其他不对称诱导反应中的应用4个方面综述了相关研究进展,并对今后配体的合成及应用前景进行了展望。A vast number of biphenyl atropisomeric diphosphine ligands are successfully applied in asymmetric catalysis.The synthesis and applications of this type of ligands are a continuous interesting theme in organic chemistry.This review describes recent progress in synthesis and application of C2-Symmetric diphosphine ligands in the asymmetric catalysis hydrogenation and other asymmetric induced reaction.And the future ligand synthesis and application are predicted.国家自然科学基金(20272037); 教育部博士点基金(20080610022); 四川自然科学基金重点项目(07ZA109
Hepatopancreas cell cultures from mud crab, Scylla paramamosain
Hepatopancreas is an important digestive and endocrine organ in crustacean. However, there are few reports on cell cultures from crabs. Here, the cell cultures of hepatopancreas from Scylla paramamosain was studied in vitro. Both the primary cell culture and subculture were grown in Leibovitz' L-15 medium, M199 medium, or a specially designed medium for S. paramamosain (MSP). The results showed that hepatopancreas cells in vitro grew in compact clusters in 2-3 d. Four types of cells could be identified. They were embryo cells, fibrillar cells, resorptive cells, and blister-like cells, respectively. Some of these cells could be subcultured for three generations. The MSP supported the best survival of these hepatopancreas cells, while M199 medium was the least effective of these three media. Fetal bovine serum and crab muscle extracts as supplements stimulated growth, but the crab hemolymph inhibited cell growth. Taken together, MSP is an appropriate medium for hepatopancreas cell cultures from S. paramamosain and can support cultures through several passages.National Natural Science Foundation of China [40776084]; National High Technology Research and Development Program of China [2006AA10A406
两相流多尺度作用模型和能量最小方法
本工作从理论和实验两个方面研究两相流局部动力学和整体动力学。建立了两相流多尺度作用模型;提出两相流能量最小方法,在此基础上,计算分析了两相流中的能量传递和流型过渡,从能量的角度确定流型过渡的判据,得到不同类型的两相流相图。从理论上预测了两相流设备的一些整体特征。通过实验验证了理论分析的正确性。本工作将已有压力扫描系统改进为压差扫描。建立了多点压差自动检测系统,用软件措施实现了零点漂移的自动补偿。改进后的测量精度提高一个数量级以上,并实现了数据处理的自动化。在从最小流化到气力输送的整个两相流动区域中,理论计算结果与前人试验以及本试验结果一致
浅谈21世纪的化学工程
在参考我国化工界已有战略研究的基础上,进一步分析了当前我国社会经济发展需求和世界科技发展的趋势,指出我国化学工程科学正面临难得的发展机遇,同时也面临多方位的挑战。化学工程作为一个共性的工程学科,既要适应其应用领域的扩展,更要充分利用科学技术发展带来的机遇,扩展深化自身的知识基础,为各种物质转化相关领域提供共性的理论、方法和技术。复杂系统理论的发展、计算技术的进步以及测试技术的提升,为化学工程科学的发展提供了新的动力;经济社会的进步,能源、资源与环境问题的突显以及高技术的发展,大大扩展了化学工程服务的领域。我们应当抓住这一机遇,适应这一变化,为解决能源、资源和环境等领域的瓶颈问题,推动高技术的发展做出贡献,开创化学工程新的发展阶段
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