Tl系超导薄膜金属涂层的生长与特性研究

我们研究了Tl-2212超导薄膜在带有YSZ/CeO2缓冲层和带有CeO2/YSZ/CeO2缓冲层的Ni金属RABiTS基带上的生长情况.基带上的缓冲层是采用PLD方法制备的,Tl-2212薄膜的制备采用了磁控溅射和后热处理两步方法.XRD 实验结果表明,Tl-2212薄膜都具有很好的C轴垂直于膜面的织构,并具有双向外延生长特性.在CeO2/YSZ/CeO2/Ni基带上制作的Tl-2212薄膜的Tc达到102.8 K,Jc(77 K,0 T)达到2.6 MA/cm2;在YSZ/CeO2/Ni基带上薄膜Tc可达97.7 K,Jc(77 K,0 T)也可以达到0.45 MA/cm2.     

基于FPGA的DDS设计方法

介绍了一种基于FPGA的DDS设计方法,结合DDS的原理,给出了具体设计程序以及仿真波形。基于FPGA的DDS与传统的专业DDS芯片相比具有电路简单、输出波形调整灵活以及性价比高等特点。     

Ameliorating the interfacial issues of all-solid-state lithium metal batteries by constructing polymer/inorganic composite electrolyte

Lithium metal is one of the most promising anodes for next-generation batteries due to its high capacity and low reduction potential.However,the notorious Li de...     

一种超混沌映射的单双参量自适应同步

利用参量自适应法实现了超混沌系统Kawakami映射的同步.通过严密的数学推导,给出了Kawakami映射在单参量自适应下实现同步的充分条件,并在双参量自适应控制下系统同样实现了同步.数值模拟结果显示,该映射输出具有类似于白噪声的宽谱特性,因此比较适合用于保密通信.     

基于硅基硼掺金刚石电极的电化学-原位核磁共振波谱电解池的设计、制备与可行性研究

电化学与核磁共振波谱联用技术(EC-NMR)可以实时监测电化学反应过程,从分子水平阐释反应机理,是一种非常有前景的无损在线检测技术.本文首次报道以硅基硼掺金刚石(Si/BDD)作为工作电极的原位EC-NMR三电极单室电解池的设计和制作.研究表明,由于尺寸12.5 mm×1.2 mm×0.5 mm的Si/BDD电极在核磁...     

Anthraquinones from the Aerial Parts of Rubia cordifolia with Their NO Inhibitory and Antibacterial Activities

The present study aimed to identify the composition of the aerial parts of Rubia cordifolia L. A chemical investigation on the EtOAc extracts from the aerial parts of Rubia cordifolia resulted in the isolation of four new anthraquinones, namely Cordifoquinone A–D (1–4), along with 16 known anthraquinones. Their structures were elucidated on the basis of NMR and HR-ESIMS data. All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds 1, 3 and 10 exhibited significant inhibitory activities with IC₅₀ values of 14.05, 23.48 and 29.23 μmol·L⁻¹, respectively. Their antibacterial activities of four bacteria, Escherichia coli (ATCC 25922), Staphylococcus aureus subsp. aureus (ATCC 29213), Salmonella enterica subsp. enterica (ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853), were also evaluated. Our results indicated that the antibacterial activity of these compounds is inactive.     

Inhibitory Effect and Mechanism of Chitosan–Ag Complex Hydrogel on Fungal Disease in Grape

Hydrogel antibacterial agent is an ideal antibacterial material because of its ability to diffuse antibacterial molecules into the decayed area by providing a suitable microenvironment and acting as a protective barrier on the decay interface. The biocompatibility and biodegradation make the removal process easy and it is already widely used in medical fields. However, there have been few reports on its application for controlling postharvest diseases in fruit. In this study, the Chitosan–silver (CS–Ag) complex hydrogels were prepared using the physical crosslinking method, which is used for controlling postharvest diseases in grape. The prepared hydrogels were stable for a long period at room temperature. The structure and surface morphology of CS–Ag composite hydrogels were characterized by UV-Vis, FTIR, SEM, and XRD. The inhibitory effects of CS–Ag hydrogel on disease in grape caused by P. expansum, A. niger, and B. cinerea were investigated both in vivo and in vitro. The remarkable antibacterial activity of CS–Ag hydrogels was mainly due to the combined antibacterial and antioxidant effects of CS and Ag. Preservation tests showed that the CS–Ag hydrogel had positive fresh-keeping effect. This revealed that CS–Ag hydrogels can play a critical role in controlling fungal disease in grapes.     

气相色谱-质谱法测定电子电气产品中多溴二苯醚及多溴联苯

建立了利用气相色谱-质谱测定电子、电气产品中多溴二苯醚及多溴苯的方法。对样品的粉碎、提取方法、色谱柱的选择、测定条件进行研究,并自建标准质谱图库;采用保留时间、Br同位素规则、质谱特征离子、谱库检索等4种方式相结合进行定性,避免了假阳性及漏检的情况,结果更加准确可靠。本法检出限为5mg/kg,PBDEs的回收率为91.3%,PBBs的回收率为92.5%,相对标准偏差(RSD)为4.3%。与现有方法相比,本法分离时间最短(6min),具有简便快速、实用性强、灵敏度高、准确可靠等特点,适用于电子电气产品、塑料、橡胶、汽车内饰材料等的溴系阻燃剂分析,满足欧盟RoHS指令检测的要求。     

NO在稀有金属钇表面的吸附行为

以往的理论在预测六方结构(HCP)金属的表面能时,计算值与实验值存在较大误差.鉴于此,本文首先用一种较为合理的方法精准地预测了稀有金属钇(Y)(0001)面的表面能,计算值(1.141 J/M²)与实验值(1.125 J/M²)吻合的很好.随后,系统研究了NO小分子在Y(0001)面不同位置(空位、桥位和端位)的吸附行为.结果表明:空位(H1)表现出了良好的吸附能力,吸附能超过了5eV,同时N-O键长伸长量超过了24%,此时,NO分子几乎平行地吸附于Y(0001)表面.所有的吸附位置的N-O分子伸长量范围为0.2?-0.42?.这种伸长量明显超过了NO在其它金属表面时的计算结果.     

2.45GHz ECR 强流等离子体源核心部件设计与实验研究

电子回旋共振(Electron Cyclotron Resonance,ECR)等离子体源能产生高电荷态离子、高流强的单电荷态离子,提供稳定的束流和良好的重复性.核心部件的设计对ECR等离子体源是至关重要的,磁场对等离子体的生成和分布有直接影响,良好的磁场可以提高等离子体的性能和效率.采用有限元分析方法对ECR等离子体源磁场进行分析与设计,得到了满足设计需求与目标的磁场位形,通过高斯计对设计的永磁环轴向磁场精确测量,发现磁场仿真结果与实验结果吻合比较好,只是轴向磁场最大值及对应位置上有点偏差.通过集成实验,研究核心部件对离子源引出束流强度的影响,引出束流稳定且强度达到7 m A.