Coexistence of Rutile and Trirutile Phases in a Natural Tapiolite Sample

We report X-ray powder diffraction (XRD), electron probe microanalysis (EPMA), and Mössbauer spectroscopy (MS) measurements performed on a natural tapiolite with composition Fe_0.57Mn_0.37Ti_0.10Ta_1.27Nb_0.67O₆. XRD and MS suggest that besides being partially ordered the as-collected sample is a mixture of trirutile (P4₂/mnm, a=4.7532(9) Å, c=9.228(7) Å) and Nb-rich rutile (P4₂/mnm, a=4.856(2) Å, c=3.098(1) Å) structures. The Mössbauer spectra of the rutile (Fe, Mn, Ta, Nb)O₂ were fitted to Δ=1.72±0.05 mm/s and δ=1.10±0.03 mm/s at 300 K and to Δ=2.10±0.06 mm/s and δ=1.18±0.03 mm/s at 80 K. The present results suggest that cation ordering in compounds of the tapiolite series can be easily assessed by Mössbauer spectroscopy in a way similar to that as previously demonstrated for the columbite series.     

2-[4-(Dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one: A H-bond-sensitive fluorescent probe for investigating binary mixtures of organic solvents

Molecules of electronically excited 2-[4-(dimethylamino)phenyl]-3-hydroxy-4H-chromene-4-one (a fluorescent probe) co-exist in the normal (N^*) and tautomeric (T^*) forms and emit radiation in different spectral regions. The positions (expressed in wave numbers, ν) and intensities (I) of the emission bands are strongly affected by the ability of the medium's molecules to participate in hydrogen bonding with the probe. In such cases, I_N*, I_N*/I_T*, ν_N*, ν_N* + ν_T* or ν_N* − ν_T*, depend on the concentration (over a certain range) or its base-10 logarithm (log) of the component interacting with the probe. These relationships form the basis for a quantitative assay of such compounds in binary mixtures. On the other hand, the log(I_N*/I_T*) versus ν_N* + ν_T* or ν_N* − ν_T* relationships demonstrate unique features that can be used to distinguish components (alcohols) interacting with the probe and to quantify their contents. The prospects for the analytical application of these findings are outlined briefly.     

一种新型Zn2＋近红外荧光探针的研究

Zn^2＋是多种酶和转录因子的必要成分, 在生物体内起着重要的作用, 检测Zn²⁺具有十分重要的生物学意义. 我们合成了一种新型近红外荧光探针TAEA-IR-780, 该探针通过配位作用与Zn^2＋结合后, 荧光显著增强. 通过质谱和氢谱对该探针进行了表征, 并探讨了pH值、其它金属离子对Zn^2＋检测的影响. 该探针的激发波长为683 nm, 发射波长为750 nm, 可避免对生物活体的损伤, 同时生物体内常见的金属离子对其干扰较小. 该探针对Zn^2＋的检测下限达1.0× 10^－9 mol•L^－1, 具有较高的检测灵敏度.     

Estimation of polarity and fluidity of colloidal interfaces and biosurfaces using rhamnolipid B pyrenacylester as surface-active fluorescent probe

Fluorescent probes are useful to monitor the polarity and fluidity of microenvironments. Therefore, a new amphiphilic fluorescent probe, the pyrenacylester of Rhamnolipid B, was prepared from biosurfactant (Rhamnolipid B) and pyrene. As a result of its surface activity, this probe was expected to be able to penetrate into various kinds of microdomains such as the environments of organic solvents, emulsions, dispersions, surfaces of biomembranes and polymers.     

Selective etching of (Ba,Sr)TiO3 thin films over silicon in an inductively coupled plasma

In this work, we investigated etching characteristics of BST thin films and higher selectivity of BST over Si using inductive coupled O₂/Cl₂/Ar plasma (ICP) system. The maximum etch rate of BST thin films and selectivity of BST over Si were 61.5 nm/min at a O₂ addition of 1 sccm, 9.52 at a O₂ addition of 4 sccm into the Cl₂(30%)/Ar(70%) plasma, respectively. Plasma diagnostics was performed by Langmuir probe (LP), optical emission spectroscopy (OES) and quadrupole mass spectrometry (QMS). These results confirm that the increased etch rates at O₂ addition of 1 sccm is the result of the enhanced chemical reaction between BST and Cl radicals and an ion bombardment effect.     

激光诱导现场探测月壤成分的可行性分析

为了验证激光诱导离解光谱技术在月球环境条件下月壤成分现场探测的可行性，设计了一套实验模拟装置，以合成月壤样品为检测目标，Nd:YAG激光器为光源，线列CCD光栅光谱仪为光谱的采集系统，真空罐模拟月球气压环境。用高纯度Fe2O3,Al2O3作为标准参考光谱样品提高识别精度。实验结果说明在模拟环境下利用激光诱导探测手段能够采集到样品的原子发射光谱，并完全可以定性识别物质中含有的成分。     

90nm硅栅过刻蚀工艺中功率对等离子体性质的影响

通过实验对适用于90nm多晶硅栅刻蚀工艺中过刻蚀阶段等离子体的性质进行了研究分析.实验采用满足200mm硅晶片刻蚀的电感耦合多晶硅刻蚀设备,借助等离子体分析仪器(朗缪尔探针)进行实验数据测定,得到了等离子体性质与功率、气体流量等外部参数的关系.实验表明在射频功率增加的过程中,能量耦合系数处于一个相对稳定的常值;当等离子体处于局部加热状态时,绝大部分的电子处于附着状态,维持等离子体的电子数目相对减少.等离子体中的射频能量耦合空间随着射频功率的增加,分布状态会变得更加一致化.     

多芯片组件基板单探针测试路径的二次优化

基于模拟退火算法给出了一种可用于MCM互连基板单探针测试的二次优化方法,即采用模拟退火算法对启发式算法获得的MCM互连基板单探针测试路径进行二次优化改进.模拟结果显示,所提方法与已有的启发式优化算法相比较,对单探针路径的优化最高可达90.2%,可以有效地降低多芯片组件互连基板单探针测试的成本.     

扫描探针显微镜在激光纳米加工技术上的应用和进展

综述了扫描探针显微镜在激光纳米加工技术上应用的最新进展,介绍了纳米结构的形成机理。     

一种脉冲高电压测量探头的地电位隔离方法

 为了消除脉冲功率装置放电时地电位抬升对测试系统造成的影响,在测量探头和测量设备之间使用了共模电感。对等效电路进行了仿真分析,结果表明：对于探头输出的信号,该共模电感等效为传输线;对于共模信号等效为一个较大的电感,可以实现探头地电位隔离。共模电感使用绕制在磁芯上的同轴电缆制作,并进行了快脉冲信号传输和地电位隔离效果实验。实验结果与理论分析一致。该共模电感的响应时间为5.4 ns,隔离了约10 kV的脉冲高压,确保了示波器的安全运行。