百kV级纳秒脉冲源的设计与实验研究

GW级Tesla型脉冲源在触发开关技术研究中作为触发脉冲源使用,抖动较大,触发开关工作不稳定,需要为其研制一台触发器以解决这一问题。结合其他使用需求,设计了一台百kV级纳秒脉冲源,该脉冲源采用Tesla变压器结合单筒脉冲形成线结构,进行了Tesla变压器结构、Tesla变压器初次级参数、Tesla开路磁芯与初级电路设计,调试结果为：最高输出电压100 kV,峰值功率250 MW,重复频率1~100 Hz,输出脉冲宽度约4 ns,前沿约1 ns。该脉冲源作为触发器使用,可以将GW级Tesla型纳秒脉冲源抖动由500 ns降低至150 ns,满足触发开关研究需求,还可用于产生超宽谱短脉冲进行辐射。     

第4代航天育种白芷的FTIR分析

针对植物航天育种变异大的特点,利用傅里叶变换红外光谱(FTIR)结合二阶导数谱对第4代航天育种白芷与地面组白芷从整体上对主要组分进行测定和对比分析。结果表明:太空白芷主要活性成分香豆素类组分(1 741cm-1)含量增加,蛋白质(1 459,1 419cm-1)和脂肪(930cm-1)组分含量略有增加;而淀粉、膳食纤维(1 152,1 105,1 080,1 050cm-1)的含量大幅度降低。二阶导数谱中峰强差异更明显,1 279cm-1处揭示出太空白芷含有胺类组分。航天育种有利于选育出变异幅度大的特异质白芷新品种。     

Mechanism of nickel extraction from sulfuric acid medium by synthesized α‐aminophosphonate derivative

A new compound, α‐aminophosphonate derivative containing pyridine ring (PPDE), was designed and synthesized as an extractant for the separation of nickel from metal impurities. Over 94.5% of Ni (II) extraction from sulfuric acid solution was achieved by using PPDE with an equilibrium pH of 4.02. Meanwhile, high separation coefficients of 23.8 for Ni to Co, 84.9 for Ni to Mn, 254.1 for Ni to Ca and 696.7 for Ni to Mg, respectively, were obtained. It was noted that PPDE exhibited an excellent regenerability, and the extraction of Ni with the recycled organic phase ranged from 92.5% to 93.9% during six circulations. The extracted nickel complex was determined as [Ni (PPDE)₂(DNNSA^?)₂(H₂O)₄], which was supported by the data obtained from Fourier transform‐infrared, UV–Vis and electrospray ionization‐mass spectrometry spectra.     

Development,validation and application of a UHPLC–MS/MS method for quantification of the adiponectin-derived active peptide ADP355 in rat plasma

A UHPLC–MS/MS method for the quantification of ADP355, an adiponectin-derived active peptide, was developed and validated. The extraction method employed simple protein precipitation using methanol and chromatographic separation was achieved on anAccucore™ RP-MS C₁₈ column (100 × 2.1 mm, 2.6 μm, 80 Å), using 0.1% formic acid in both water and acetonitrile with gradient elution at the flow rate of 400 μl/min within 4.0 min. Detections were performed under positive ion mode with multiple reaction monitoring ion transitions m/z 1109.2 → 309.8 and 871.4 → 310.1 for ADP355 and Jt003 respectively at unit resolution. The linearity range of the calibration curve was 2–1,000 ng/ml with a lower limit detection of 0.5 ng/ml. The selectivity, linearity, precision, accuracy, recovery, matrix effect and stability were validated, and all items met the requirement of US Food and Drug Administration guidance. This method was successfully applied to an intravenous pharmacokinetic study of ADP355 in rats and the in-vitro stability in rat serum, plasma and whole blood was also assessed.     

Preparation of novel antimicrobial-modified starch and its adsorption on cellulose fibers: Part I. Optimization of synthetic conditions and antimicrobial activities

Antimicrobial-modified starch was synthesized by covalently bonding guanidine polymer (PHGH) with potato starch via coupling reaction. Orthogonal tests were applied to optimize the reaction conditions. The coupling efficiency could reach 90.21% at the optimal conditions: temperature, 70 °C; time, 2 h; PHGH/starch, 120 wt.%; GDE/starch, 8 wt.%; pH, 11. PHGH modified starches exhibited high antimicrobial activities against both E. coli and S. aureus. Shaking flask method was more suitable for current non-released modified starches than diffusion method to evaluate the antimicrobial activities. In the presence of 1.0 wt.% PHGH in wood fibers, the growth inhibition reached almost 100%. The AFM results also demonstrated that the antimicrobial mechanism of PHGH was to destroy the membrane of the cells.     

Synthesis and characterization of fluorescent starch using fluorescein as fluorophore: potential polymeric temperature/pH indicators

A convenient method for attaching fluorescein (via its epoxy derivate) to natural starch and its temperature/pH‐sensitive qualities of fluorescence were investigated. 3‐epoxypropoxy fluorescein (EPF) was first synthesized through the reaction between fluorescein and epichlorohydrin, and starch‐bearing fluorescein (ST‐EPF) was prepared via ring‐opening reaction with EPF in dimethyl sulfoxide (DMSO) solution, in the presence of NaH as a catalyst. Both of them were characterized by the methods of ¹H NMR, MS, IR, XRD, UV–Vis, and luminescence spectra, respectively. The chemiluminescent and photophysical behaviors of the dye fluorescein derivative and the polymer‐containing fluorescein were studied. The results indicated that ST‐EPF could still provide temperature and pH sensitivity similar to that of fluorescein and could achieve better long‐term stability and fast equilibrium response. ST‐EPF had an excellent linear response between relative fluorescence intensity and temperature in the range of 0–60°C and a nonlinear relationship between relative fluorescence intensity and pH in the wide range of 0.0–12.0, and so it has promise as an optical transducer for temperature and pH value determinations. Copyright © 2008 John Wiley & Sons, Ltd.     

Structure elucidation and NMR spectral assignments of three new lignan glycosides from Akebia trifoliata

Three new lignan glycosides (1-3) were isolated from the stems of Akebia trifoliata. Their structures were elucidated as (7R,8R,7'R,8'R)3,3',5,5'tetramethoxy-4,4'dihydroxy-7,9':7',9-diepoxylignan-4-O-beta-D-glucopyranoside (1), (7S,8S,8'R)-4,4',9-trihydroxy-3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (2), (7R,8R,8'S)-4,4',9-trihydroxy3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (3) by spectral analyses, primarily NMR, MS and CD. The NMR assignments for the compounds were carried out using 1H, 13C, DEPT, COSY, HSQC, HMBC and ROESY NMR experiments.     

湛江市几种蔬菜的营养成分分析

对湛江产芥菜,芫荽和麦菜的微量元素,氨基酸进行了定量分析。结果表明营养元素如Ｃｕ、Ｚｎ、Ｆｅ、Ｃａ、Ｍｇ、Ｋ、Ｍｎ、Ｎａ等的含量较丰富,也含有多种人体必需的氨基酸,但共同的特征是均缺乏赖氨酸。     

V2O5电致变色薄膜的Raman光谱

近年来,通过向过渡金属氧化物薄膜注入Ｌｉ 制作可调节光透过率的电变色器件已越来越引起广泛的重视[1、2].由于Ｖ2Ｏ5薄膜的稳定性差,限制了它在实际中的应用.因此,为了获得变色效率高、稳定性和可逆性能好的Ｖ2Ｏ5薄膜,使用了多种制备方法,如磁控溅射法[3、6]、电化学沉积法[7、8]、溶胶凝胶法[9、10]、旋涂法[11、12]、真空蒸镀法[13、14]等.但是,无论那种方法都要解决Ｖ2Ｏ5本身在Ｈ2Ｏ或醇等的电解质溶液中电致变色时的溶解问题,通常采用控制薄膜的沉积温度或者退火处理来提高薄膜的电致变色性能[3、4、11].为了探明薄膜结构与电致变色…     

Reversible redox-switchable second-order optical nonlinearity in polyoxometalate: a quantum chemical study of [PW11O39(ReN)]n- (n = 3-7)

In this paper, the relationship between the reversible redox properties and the second-order nonlinear optical (NLO) responses for the title series of complexes has been systematically investigated by using the time-dependent density functional theory (TDDFT) method combined with the sum-over-states (SOS) formalism. The results reveal that the successive reduction processes of five PW11ReN redox states should be PW11ReVII (1) --> PW11ReVI (2) --> PW11ReV (3) --> PW11ReV1e ( 4) --> PW 11ReV2e (5). Furthermore, their electrochemical properties have been reproduced successfully. It is noteworthy that the second-order NLO behaviors can be switched by reversible redox for the present studied complexes. Full oxidation constitutes a convenient way to switch off the second-order polarizability (system 1). The incorporation of extra electrons causes significant enhancement in the second-order NLO activity, especially for the third reduced state (system 4), whose static second-order polarizability (betavec) is about 144 times larger than that of fully oxidized 1. The characteristic of the charge-transfer transition corresponding to the dominant contributions to the betavec values indicates that metal-centered redox processes influence the intramolecular donor or acceptor character. Therefore, these kinds of complexes with the facile and reversible redox states could become excellent switchable NLO materials.