自发产生相干对探测场的色散和吸收影响

在Y形四能级原子系统中,分析了自发产生相干对探测场的色散和吸收影响. 结果发现,随着自发产生相干的增强,系统呈现的电磁感应透明窗口逐渐变窄,并在共振处出现反常色散,吸收从负值变为正值. 同时,当抽运场和耦合场的相对强度不同时,共振处附近吸收为零或出现增益,而两场强相等或接近时,系统对探测场表现为吸收. 关键词： 非线性光学 电磁感应透明 自发产生相干     

中国环流器二号A(HL-2A)超声分子束注入最新结果

HL-2A装置电子回旋共振加热时,氘脉冲超声分子束穿越分界面,等离子体各项重要参数,包括等离子体储能、极向比压、中平面线平均密度、中心密度和温度上升,中子产额急剧增加. 超声分子束注入有可能较常规脉冲送气在台基顶部提供较强的粒子源,被认为是可供ITER替换脉冲送气的加料方法之一. HL-2A装置氢超声分子束注入的平均速度约为1.7km,与溢流(分子流)注入真空的速度测量作了比较. 关键词： 超声分子束注入 托卡马克 飞行时间法 加料     

空调冷凝热热回收技术研究现状及发展趋势

界定了空调冷凝热热回收系统的分类,总结了国内外空调冷凝热热回收技术的研究现状,提出了空调冷凝热热回收技术的发展趋势。     

基于矢量波像差理论的计算机辅助装调技术研究

在三阶矢量波像差理论的基础上,建立了系统内失调量与系统波像差Zernike系数的关系式,并以共轴三反射光学系统为数学模型进行了仿真分析.结果表明,基于矢量波像差理论的装调技术可行,并可用于大型光学系统的装调.利用该理论对一共轴非球面三反系统进行装调,最终使系统波像差RMS<0.080λ.     

基于高分辨质谱技术的婴幼儿食品中过敏原蛋白质的高灵敏检测

基于高效液相色谱-串联质谱(LC-MS/MS)技术,选择稳定性好、灵敏度高的特征肽段,利用平行反应监测(PRM)技术,实现了多类过敏原蛋白质的高灵敏度同时检测,并成功应用于婴幼儿食品中过敏原成分的分析。对于婴幼儿食品中蛋白质的提取,与传统的丙酮沉淀法比,采用膜上原位样品预处理方法(i-FASP)可实现更高的蛋白质提取效率和抗干扰能力。所检测的过敏原蛋白质的定量限(LOQ)最小可达到0.028 mg/L,其线性范围最宽可跨越4个数量级,且线性关系良好(相关系数R~2≥0.99)。该方法为食品中过敏原蛋白质组学快速分析提供了一种可靠的分析方法。     

Artematrovirenolides A—D and Artematrolides S—Z,Sesquiterpenoid Dimers with Cytotoxicity against Three Hepatoma Cell Lines from Artemisia atrovirens

Inspired by the intriguing structures and remarkable activities of sesquiterpenoid dimers,12 new sesquiterpenoid dimers,artematrovirenolides A—D(1—4)and artematrolides S—Z(8—12),were isolated from the EtOAc fraction of Artemisia atrovirens through a bioactivity-guided approach.Their structures were elucidated by comprehensive spectroscopic data and absolute configuration was assigned based on single crystal X-ray diffraction data and ECD calculations.Structurally,all compounds are presumably formed via[4+2]cycloaddition involving three connecting model.Compounds 1—4 are four novel hetero-dimeric[4+2]Diels-Alder adducts dimerized from a rotundane-type unit and a guaiane-type monomer,and compounds 5—12 are eight new homo-dimeric[4+2]adducts derived from two guaianolide moieties.A putative biosynthetic pathway for compounds 1—4 was also proposed.Compounds 4,6,7,and 10 demonstrated moderate cytotoxicity against HepG2,SMMC-7721,and Huh7 cell lines with IC50 values ranging from 9.3 to 62.3μmol/L.Interestingly,compounds 5 and 11 manifested cytotoxicity with IC50 values of 13.6 and 12.8(HepG2),18.5 and 13.1(SMMC-7721),and 16.5 and 19.4μmol/L(Huh7),respectively,which were equivalent to the positive control,sorafenib.This investigation suggests that compounds 5 and 11 might be considered as potent antihepatoma candidates and deserve further structural modification and mechanism study.     

Nonmetal Doping as a Robust Route for Boosting the Hydrogen Evolution of Metal-Based Electrocatalysts

Recently, nonmetal doping has exhibited its great potential for boosting the hydrogen evolution reaction (HER) of transition-metal (TM)-based electrocatalysts. To this end, this work overviews the recent achievements made on the design and development of the nonmetal-doped TM-based electrocatalysts and their performance for the HER. It is also shown that by rationally doping nonmetal elements, the electronic structures of TM-based electrocatalysts can be effectively tuned and in turn the Gibbs free energy of the TM for adsorption of H* intermediates (ΔG_H*) optimized, consequently enhancing the intrinsic activity of TM-based electrocatalysts. Notably, we highlight that concurrently doping two nonmetal elements can continuously and precisely regulate the electronic structures of the TM, thereby maximizing the activity for HER. Moreover, nonmetal doping also accounts for enhancing the physical properties of the TM (i.e. surface area). Therefore, nonmetal doping is a robust strategy for simultaneous regulation of the chemical and physical features of the TM.     

Pharmacokinetic study of tanshinol and ligustrazine in rat plasma after intravenous administration of tanshinol and Danshen Chuanxiongqin Injection

To investigate the effect of ligustrazine on the pharmacokinetic profile of tanshinol after intravenous administration in rats, a sensitive liquid chromatography tandem mass spectrometry method was developed and validated for quantitative determination of tanshinol and ligustrazine in rat plasma. After prepared by protein precipitation, the analytes were separated on a Waters Acquity HSS T3 column (100 × 2.1 mm, 1.8μm) and eluted by 0.1% formic acid in water and acetonitrile at a flow rate of 0.4 ml/min. The precursor–product ion transitions were m/z 197.0 → 135.0 for tanshinol, m/z 417.1 → 255.1 for liquiritin (internal standard) in negative ion mode and m/z 137.1 → 55.0 for ligustrazine in positive ion mode. To avoid the interference of tanshinol metabolite transformation, the stability of analytes in samples collected after administration was assessed. The validated method was successfully applied to a pharmacokinetic study after intravenous administration of single tanshinol and Danshen Chuanxiongqin Injection. After Danshen Chuanxiongqin injection administration, the values of elimination half-time, area under the concentration–time curve and C_o were 0.36 ± 0.13 h, 1.29 ± 0.37 μg/ml h and 10.51 ± 2.58 μg/ml for male rats, respectively. In the single tanshinol group, the corresponding values were 0.56 ± 0.24 h, 1.85 ± 0.44 μg/ml h and 14.11 ± 2.26 μg/ml for male rats—30–40% higher than those for the Danshen Chuanxiongqin Injection group. There was a significant different between male and female rats. This study provided information on the influence of ligustrazine on the pharmacokinetic characteristics of tanshinol after intravenous administration of Danshen Chuanxiongqin Injection in rats, which will be helpful for its clinical application.     

Zn–Co Sulfide Microflowers Anchored on Three-Dimensional Graphene: A High-Capacitance and Long-Cycle-Life Electrode for Asymmetric Supercapacitors

Zinc–cobalt double-metal sulfides (ZCS) as Faradic electrode materials with high energy density have great potential for supercapacitors, but their poor transfer efficiency for electrons and ions hinders their electrochemical response. Herein, ZnCo₂(CO₃)_1.5(OH)₃@ZCS microflower hybrid arrays consisting of thin nanolayer petals were anchored on three-dimensional graphene (ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG) by a simple hydrothermal method and additional ion-exchange process. A ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG electrode delivered high capacitance (2228 F g⁻¹ at 1 A g⁻¹) and long cycling life (85.7 % retention after 17 000 cycles), which are ascribed to the multicomponent structural design. The 3DG conductive substrate improves the electron-transfer dynamics of the electrode material. Meanwhile, the microflowers consisting of thin nanolayer petals could not only provide many active sites for ions to improve the capacitance, but also alleviate the volume expansion to ensure the structural stability. Furthermore, an all-solid-state asymmetric supercapacitor based on a ZnCo₂(CO₃)_1.5(OH)₃@ZCS/3DG electrode achieved a high energy density of 27 W h kg⁻¹ at 528.3 W kg⁻¹ and exhibits exceptional cyclic stability for 23 000 cycles. Its ability to light a blue LED for 9 min verified the feasibility of its application for energy storage devices.