钕铁硼在高温超导磁悬浮技术实验中的应用

将新材料钕铁硼作为磁导轨引入到高温超导磁悬浮技术实验中,介绍了高温超导悬浮技术实验的基本原理、仪器及钕铁硼对实验的改进.     

蒙药心舒安中锗的差分脉冲极谱研究

在pH=1.30的H2SO4和3,4-二羟基苯甲醛(DHB)底液中,采用差分脉冲极谱法,测得无机锗的脉冲极谱波.其峰电位为Ep=-0.53V.Ge(Ⅳ)浓度在1.03×10-3-1.04×10-4mol·L-1范围内与峰电流呈线性关系,样品中总锗和无机锗的回收率分别是95.72%和96.43%.     

Mg、B配比对MgB2材料的影响

我们通过固态反应法制备了MgxB2(x=0.2,0.6,0.8,1.0,1.2,1.4,1.8,2.2,2.6)系列超导样品.用四引线法测量了每一个样品在制备烧结过程中的高温R～T曲线.由这些曲线的升温阶段数据得知MgxB2系列样品的起始成相温度Tonset随着x值的增加而降低.由它们的X光衍射图可知,x≤1.0时,没有Mg和MgO的杂相峰;到x＞1.0后,随x值的增大,杂相Mg和MgO的衍射峰强度逐渐增强.它们的低温R～T曲线表明随x值的增加,正常态电阻减小,起始超导转变温度在39.3 K到39.9 K之间.综合Tc(onset)和△Tc,Mg1.4B2样品呈现出最好的超导状态.这些样品的单位质量M～T测量数据表明起起转变温度处于37.4～38.6 K之间,且Mg1.4B2样品呈现出最高的磁测Tc(onset)=38.60 K.在Mg含量x大于或低于1.4时,磁测Tc(onset)均小于此值.综合R～T和M～T这两种测量,为得到高Tc的MgB2超导块材,胚体MgB2的配比应取x=1.4为好.     

LaMgAl11O19:Co2+被动调Q铒玻璃激光器研究

综述了被动调Q铒玻璃激光器的发展概况,推导了被动调Q铒玻璃激光器输出脉冲能量、脉宽的解析表达式,数值模拟了腔内损耗与输出脉冲能量、脉宽及峰值功率的关系以及输出脉冲能量与输入抽运能量的关系.设计了一台LaMgAl11O19:Co2 被动调Q铒玻璃激光器,实验验证了数值模拟分析结果.结果表明,腔内损耗增加将导致输出脉冲能量下降,脉宽变大,从而峰值功率降低.输入能量低于12 J时,输出只有单脉冲,当输入能量大于12 J时,输出会出现双脉冲.在8 J的电输入下,获得了峰值功率50 kW,2.7 mJ的1.535 tm激光输出.最后讨论了提高单脉冲能量的方法.     

Peptide dendrimer-crosslinked inorganic-organic hybrid supramolecular hydrogel for efficient anti-biofouling

A novel kind of inorganic-organic hybrid supramolecular hydrogel with excellent anti-biofouling capability was developed. The hydrogel was formed via ionic interaction between the negative-charged sodium polyacrylate (SPA) entwined clay nanosheets (CNS) and positive-charged polyhedral oligomeric silsesquioxane (POSS) core-based generation one (L-Arginine) dendrimer (POSS-R).     

Ostrowski type inequalities on H-type groups

The main aim of this paper is to establish an Ostrowski type inequality on H-type groups using the L^∞ norm of the horizontal gradient. The work has been motivated by the work of Anastassiou and Goldstein in [G.A. Anastassiou, J.A. Goldstein, Higher order Ostrowski type inequalities over Euclidean domains, J. Math. Anal. Appl. 337 (2008) 962-968].     

Asymmetric bioreduction of substituted acenaphthenequinones using plant enzymatic systems： A novel strategy for the preparation of （＋）- and （-）-mono hydroxyacenaphthenones

Regio- and enantioselective reduction of substituted acenaphthenequinones were conducted under mild reaction conditions using plant enzymatic systems. A screening of 15 plants allowed the selection of two suitable plants fulfilling enantiocomple- mentarity. The （＋）- and （-）-mono hydroxyacenaphthenones were achieved with high conversion and good enantiomeric purity using peach （Prunus persica （L.） Batsch., conversion 98%, 71% ee） and carrot （Daucus carota L., conversion 95%, 81% ee）, respectively.     

ISOVALEROYL OXOKADSURANE,A NOVEL DIBENZOCYCLOOCTADIENE LIGNAN POSSESSING A SPIROBENZOPURANOID SKELETON

Isovaleroyl oxokadsurane, a novel dibenzocyclooctadiene lignan pos-sessing a spirobenzofuranoid skeleton was isolated from the stems of Kadsura coccinea.Its structure and relative configuration were determined by X-ray diffraction analysis.     

Identification of metabolites of Danggui Buxue Tang in rat urine by liquid chromatography coupled with electrospray ionization time‐of‐flight mass spectrometry

A method coupling liquid chromatography with electrospray ionization time‐of‐flight mass spectrometry (LC/ESI‐TOF/MS) has been developed for rapid and sensitive analysis of rat urinary metabolite profile of Danggui Buxue Tang (DBT), a well‐known Chinese herbal formula. After oral administration of DBT, urine samples were collected during 0–24 h, and then pretreated by solid‐phase extraction. A total of 68 compounds including 13 parent compounds and 55 metabolites were detected in the drug‐containing urines compared with blank urines. The total analytical time was less than 20 min. Metabolites of DBT were identified using dynamic adjustment of the fragmentor voltage to produce structure‐relevant fragment ions. By using this approach, the mass accuracy of precursor and fragment ions was typically within ±5 ppm of the theoretical values, and enabled the identification of 43 metabolites including 27 isoflavanoid and 16 phthalide metabolites. Our results indicated that glucuronidation and sulfation were the major metabolic pathways of isoflavonoids, while glutathione conjugation, glucuronidation and sulfation were the main metabolic pathways of phthalides. No saponin‐related metabolites were detected. The results of the present study provided important structural information relating to the metabolism of DBT. Furthermore, this work demonstrated the potential of the LC/ESI‐TOF/MS approach for identification of metabolites from Chinese herbal medicines in urine. Copyright © 2009 John Wiley & Sons, Ltd.