Yb：FAP晶体生长

采用中频感应提拉法生长了Yb：FAP晶体。对晶体生长中影响晶体质量的因素特别是原料的处理、CaF2的挥发等进行了研究和讨论。运用ICP-AES测定Yb^3＋离子在Yb：FAP晶体中的分凝系数。对Yb：FAP晶体进行了高分辨X射线的四圆衍射实验，结果表明晶体具有比较高的晶格完整性。

Growth and spectral properties of Yb : FAP single crystal

In this paper, single crystal of ytterbium (Yb) doped Ca-5(PO4)(3)F (FAP) has been grown along the c-axis by using the Czochralski method. The segregation coefficients of Yb3+ in the Yb:FAP crystal has been determined by ICP-AES method. The absorption spectrum, fluorescence spectrum and fluorescence lifetime of the Yb:FAP crystal has been also measured at room temperature. In the absorption spectra, there are two absorption bands at 904 and 982 nm, respectively, which are suitable for InGaAs diode laser pumping. The absorption cross-section (sigma(abs)) is 5.117 x 10(-20) cm(2) with an FWHM of 4 nm at 982 nm. The emission cross-section is (sigma(em)) 3.678 x 10(-20) cm(2) at 1042 nm. Favorable values of the absorption cross-section at about 982 nm are promising candidates for laser diode (LD) pumping. (c) 2005 Elsevier B.V. All rights reserved.

稀土元素镧在植物细胞中超微结构定位及与钙、铝关系研究

本文主要利用等离子体发射光谱元素含量分析( ICP)、亚细胞定位观察技术、以及电镜与能谱分析相结合技术，研究镧在绿豆(Phmeatus radiatus L.)幼苗不同部位组织细胞中的进入、运转、分配、含量和超微结构定位及与钙、铝关系。在全营养液加镧和缺钙营养液加镧处理的幼苗中，细胞超微结构受到不同程度影响，但其内未检测到镧。无离子水加镧处理幼苗，在低浓度、短时间条件下，镧进入、分布在质膜以外质外体系统中。高浓度镧处理时，镧沉淀能进入细胞内，并常看到堵塞胞间连丝，在质膜以外发现解体物质穿壁转移，并在壁中形成明暗相间的染色带。镧在植株中运输层层受阻，由根向叶其含量逐渐减少，而钙含量变化呈负相关，表明镧钙之间存在拮抗作用。 用焦锑酸钙的电镜细胞化学方法与能谱分析技术相结合，研究镧对细胞内Ca2+定位分布的影响，发现镧、钙沉淀颗粒的差异。在镧胁迫下，细胞质和核中Ca2+增多，液泡中Ca2+趋向于沿被膜分布，细胞结构受到破坏，说明镧胁迫下Ca2+水平增加与膜透性变化和Ca2+_CaM相关的许多生理生化过程有关。 初步探讨铝的毒害机理，发现铝也能进行超微结构定位观察，铝通过拮抗钙起作用，其作用机制与镧相似。

药用牡丹资源与重金属污染问题的研究

我国牡丹资源丰富、药用历史悠久、药材出口量大。近年来国际上对进口植物药的重金属限量标准不断提高，已成为影响丹皮出口的最大贸易壁垒之一，严重阻碍了丹皮产业化进程。为了提高我国丹皮药材整体质量水平和国际竞争力，本试验探讨了不同产地、不同种质资源的丹皮与Cu、Cd、Pb、As四种重金属的关系，重点研究了两个代表性品种对重金属Cu的富集规律，分析了重金属Cu对牡丹生长、生理和药材品质的影响。实验中采用火焰原子吸收分光光度法（FAAS ）和电感耦合等离子体质谱法（ICP-MS）为基本检测手段来分析样品中重金属元素的含量，从植物与重金属相互关系的角度对牡丹药用、花药兼用以及生态修复可行性等方面进行了系统研究。结果如下： 1. 丹皮重金属含量与牡丹种质资源和栽培环境关系密切。野生种中滇牡丹丹皮中Cu、Cd含量相对较高，多数野生种丹皮中Pb、As含量较栽培种偏高；铜陵产区的丹皮重金属含量明显高于其它产区，铜尾矿上栽培出产的丹皮重金属Cu含量明显超标，建议其改变种植模式，可以考虑丰富牡丹品种，开发生态旅游、观赏栽培。 2. 综合比较同一地块的7个常用药用品种发现，‘JPH’和‘CKL’品种对重金属富集能力相对较弱。‘JPH’是传统的优良观赏品种，适宜花药兼用；结合前期研究的结果‘CKL’药效成分含量相对较高，药用价值较高，适宜药用栽培。 3. 对药用牡丹品种‘凤丹’和‘建始粉’外施不同浓度CuSO4溶液处理后发现，丹皮中重金属富集量与外施重金属浓度成显著正相关。当外施Cu 浓度超过150mg/kg 时，两个品种的丹皮中Cu含量均已超标。 4. 重金属Cu对牡丹生长的影响效应与重金属浓度和植物体自身部位有关。当外施Cu浓度小于600mg/kg 时，对牡丹生长有一定的促进作用，主要表现在地上部分；超过600mg/kg 时，对牡丹生长有抑制作用，随着浓度增大，毒害症状愈加明显。地下部主要表现出受抑制作用，抑制效应随外施浓度增大而加重。 5. 牡丹通过自身的生理生化调节机制抵抗Cu胁迫对细胞造成的氧化伤害：低浓度Cu可以刺激抗氧化酶系统SOD和POD 活性升高，高浓度下SOD和 POD活性则显著降低。相同处理条件下‘凤丹’品种的抗铜性要高于‘建始粉’。 6. 本试验未发现外施Cu处理对丹皮中药效成分丹皮酚、芍药苷产生影响。 7. ‘凤丹’及‘建始粉’根系铜富集质量分数均达到超富集植物的要求，因此牡丹可能在重金属Cu污染的环境修复方面存在巨大潜力。

化学修饰铋膜电极检测重金属镉

随着我国工业的快速发展，环境污染日益严重，其中重金属已经成为最主要的污染物 之一。重金属具有分布广泛、半衰期长等特点，因而对人们的生产生活危害巨大。镉作为 一种常见的重金属污染物，它能够引发废用性萎缩、肾功能衰竭和感染等疾病，因此对环 境中存在的痕量镉的进行检测显得极为重要。传统的痕量分析方法包括光谱分析法和色谱 分析法，但这两方法所使用的仪器比较笨重，操作过程复杂，因而不适于在线分析。电化 学分析方法因其快速、便携、价格低廉、灵敏度高等特点而受到了人们的广泛关注，其中 较为常用的阳极溶出伏安法已经在镉离子等重金属离子的现场快速高灵敏检测中发挥了 重要作用。然而传统阳极溶出法中使用的汞电极因具有毒性而被许多国家禁止使用，所以 寻找汞电极的替代电极成为近年来的阳极溶出技术的研究热点。铋膜电极因具有类似汞电 极的分析性能且环境友好而受到了广泛重视，特别是各种化学修饰方法使得铋膜电极的性 能得到了显著提高。但是目前铋膜电极仍存在稳定性低、抗干扰能力差等问题，这些不足 严重制约了该类电极在重金属的阳极溶出分析中的应用。本文旨在通过新的化学修饰方法 解决铋膜电极应用中的瓶颈问题，发展具有优异分析性能的化学修饰铋膜电极应用于镉离 子等重金属离子的阳极溶出分析。本文的主要研究内容包括： l）以阳极溶出法测定镉离子为例，研究了化学修饰铋膜电极的响应特性，考察了富 集时间、富集电位、铋离子浓度、离子载体浓度和Nafion 浓度等实验条件对检测灵敏度的 影响。 2）将离子载体引入铋膜电极与Nafion 结合使用，研究了镉离子在该电极上的阳极溶 出响应，并探讨了铜、铅、铟三种金属离子对镉离子检测选择性的影响。将这种改良后的 化学修饰铋膜电极用于实际海水样品的检测，所得结果与ICP-MS 的测量结果基本一致。 3）将四氟硼酸钠引入铋膜电极与离子载体、碳纳米管结合使用，研究了镉离子在该 电极上的阳极溶出响应，考察了铜、铅、铟离子对镉离子测定的影响。 4）考察了电解富集和开路电位富集两种富集方式对电极灵敏度和选择性的影响。 实验表明：通过预富集，在未除氧的溶液中即可得到显著的镉离子溶出电流峰，且背 景噪音低；加入离子载体后，电极对目标金属有良好的选择性，可以在复杂基体条件下测 定重金属离子镉；电解富集条件下电极的的灵敏度较高，而开路电位富集条件下电极的选 择性较好。这种环保的无汞化学修饰电极为海水中重金属污染物的检测提供了新的手段。

聚合物膜离子选择性电极的制备与性能研究

聚合物膜离子选择性电极具有选择性高、使用简便、价格低廉等优点，在环境监测中日益受到人们的关注。这类电极的响应特性主要取决于聚合物膜相中起分子识别作用的离子载体的选择性。本文设计合成了一系列对重金属离子具有高选择性的有机配体，并将其作为电中性离子载体应用于银、汞、锌、铬等离子选择性电极中，实现了对重金属离子的高选择性测定。此外，我们对海水中有机物质的紫外线消解进行了研究，优化了消解条件，采用离子选择性电极技术实现了对海水中重金属污染物的快速检测。具体内容如下： 1、以硫氮杂冠醚为离子载体的银离子选择性电极制备及性能研究。 合成了一系列硫氮杂冠醚配体，通过优化反应条件，提高了反应产率，简化了产物处理过程。将此类冠醚作为离子载体用于银离子选择性电极的制备，并讨论了冠醚环大小、冠醚环的韧性以及硫原子个数对电极选择性的影响。在此研究基础上，利用沉淀-溶解平衡法调节内充液主离子浓度，采用冠醚9，10，12，13，24，25-六氢-5H，15H，23H-二苯[b，q][1，7，10，13，19，4，16]五硫二氮二十三环-6，16 (7H，17H)-二酮环作为低检出限银离子选择性电极载体，通过优化电极的内充液和聚合物膜组份，测得最低检出限为2.2×10-10 M，电极电位响应斜率为54.5 mV/dec.，线性范围为1.0×10-9-1.0×10-5 M，电极使用寿命为一个月。采用标准加入法，成功实现了自来水中银离子浓度的测试，并以该电极作为指示电极，以硝酸银溶液为滴定剂，成功滴定了I-、Br-和Cl-离子的混合液。 2、以1，2，4-三唑衍生物为离子载体的汞离子选择性电极的制备及性能表征。 设计合成了一种基于1，2，4-三唑的希夫碱结构化合物，3，5-二(二硫代甲酸苄酯肼基-2-亚甲胺基苯氧甲基)-1-(四氢-2H-吡喃)-1H-1，2，4-三唑，并成功用作中性载体实现对汞离子的测定。在最佳膜组分条件下，以该化合物作为载体的汞离子选择性电极的检出限为2.6×10-7 M Hg2+，电极电位响应斜率为29.3±0.3 mV/dec.，线性范围为1.0×10-6-3.0×10-4 M。该电极使用寿命为2个月，在pH 2.6-5.2范围内测试不受酸度影响。以该电极为指示电极，以EDTA为滴定剂，可准确滴定溶液中汞离子的浓度。 3、以希夫碱结构化合物为离子载体的锌离子选择性电极的制备及性能研究。 本文设计了一种含吡啶杂环的希夫碱结构化合物(E)-N'-(吡啶-2-亚甲胺基)-2-((E)-吡啶-2-亚甲胺基)苯甲酰肼，并成功用作离子载体实现对锌离子的测定。在最佳膜组分条件下，以该化合物为载体的锌离子选择性电极的检出限为7.4×10-7M Zn2+，电极电位响应斜率为25.9 mV/dec.，线性范围为1.0×10-6-1.0×10-3 M。该电极使用寿命为3个月，在pH 3.4-5.8范围内测试不受酸度影响。以该电极为指示电极，以EDTA为滴定剂，可准确滴定溶液中锌离子的浓度。 4、紫外光在线消解技术用于离子选择性电极测试海水中重金属离子的研究。 海水中重金属离子大多以络合物形式存在，而离子选择性电极只对游离态金属离子响应，因此要实现离子选择性电极测试海水中的重金属，首先必须使金属离子从络合物中游离出来。紫外光消解方法相对于其它海水预处理手段是一种清洁的样品预处理方法。我们以模拟海水为考察对象，考察了盐度、酸度、有机物浓度对消解效率的影响，并在优化消解条件的基础上对实际海水进行消解，利用离子选择性电极成功实现了海水中铜离子浓度的测试，测试值与ICP-MS数值一致。 5、合成希夫碱结构罗丹明B衍生物作为载体和分子探针用于Cr3+离子的检测。 设计合成了希夫碱结构罗丹明B衍生物2-亚甲胺基-8-乙酯基喹啉-罗丹明。荧光法显示，在化合物对铬离子(III)有较好的选择性，进而我们将该化合物作为分子探针进行了详细的研究。结果表明，分子探针与铬离子配位比为1:1，铬离子响应的线性范围是8.0×10-7-8.0×10-5 M，检测下限为1.9×10-7 M。电化学测试结果显示，基于该化合物为载体的离子选择性电极对铬离子(III)的选择性较差。

ARL—3520AES电感耦合等离子体发射光谱仪疑难故障的分析与排除

介绍了在瑞士ＡＲＬ公司生产的ＩＣＰ—３５２０ＡＥＳ型电感耦合等离子体原子发射光谱仪上存在的一种疑难故障的分析与排除过程，对同类型仪器的故障分析有借鉴作用．

一种用来可同时测定氮及其它金属元素的新型延长炬管的设计

本文介绍了一种新型延长炬管的设计。该炬管使在电感耦合等离子体原子发射光谱仪（ＩＣＰ－ＡＥＳ）上同时测定氮及其它金属元素成为可能，并且在不同程度上改善了一些金属元素的检测限。本文利用该炬管，在ＡＲＬ３５２０光谱仪上同时测定了生物标准样品中的氮及Ｆｅ、Ｍｎ、ＣｕＺｎ等四种金属元素。结果与定值吻合，相对标准偏差均小于５％。

Total and subcellular distribution of trace elements in the liver of a mother-fetus pair of Dall's porpoises (Phocoenoides dalli)

Total and subcellular hepatic Zn, Cu, Se, Mn, V, Hg, Cd, and Ag were determined in a mother-fetus pair of Dall's porpoises (Phocoenoides dalli). Except for higher fetal Cu concentration, all maternal elements were higher. Elements existed mostly in the cytosol of both animals except in the case of maternal Ag in the microsome and fetal Cu and Ag in the nuclei and mitochondria. In the maternal cytosol, Zn, Mn, Hg, and Ag were present in the high-molecular-weight substances (HMW); Se and V were present in the low-molecular-weight substances (LMW); Cu and Cd were mostly sequestered by metallothionein (MT). In the fetal cytosol, Zn, Se, Mn, Hg, Cd, and Ag were present in the HMW and V in the LMW, while Cu and Ag were mostly associated with MT. MT isoforms were characterized using the HPLC/ICP-MS. Two and four obvious peaks appeared in the maternal and fetal MT fractions, respectively. The highest elemental ion intensities were at a retention time of 7.8 min for the mother, and for the fetus the peak elemental ion intensities occurred at a retention time of 4.3 min, suggesting that different MT isoforms may be involved in elemental accumulation in maternal and fetal hepatocytosols. (C) 2003 Elsevier Ltd. All rights reserved.

Fabrication and characterization of GaN-based LEDs grown on nanopatterned sapphire substrates

Sapphire substrates were nanopatterned by dry (inductively coupled plasma, ICP) etching to improve the performance of GaN-based light-emitting diodes (LEDs). GaN-based LEDs on nanopatterned sapphire substrates (NPSS) were fabricated by metal organic chemical vapor deposition (MOCVD). The characteristics of LEDs fabricated on NPSS prepared by dry etching were studied. The light output power and wall-plug efficiency of the LEDs fabricated on NPSS were greater than those of the conventional LEDs fabricated on common planar sapphire substrates when the injection currents were the same. The LEDs on NPSS and common planar sapphire substrates have similar I-V characteristics.

A photonic wire-based directional coupler based on SOI

A photonic wire-based directional coupler based on SOI was fabricated by e-beam lithography (EBL) and the inductively coupled plasma (ICP) etching method. The size of the sub-micron waveguide is 0.34 mu m x 0.34 mu m, and the length in the coupling region and the separation between the two parallel waveguides are 410 and 0.8 mu m, respectively. The measurement results are in good agreement with the results simulated by 3D finite-difference time-domain method. The transmission power from two output ports changed reciprocally with about 23 nm wavelength spacing between the coupled and direct ports. The extinction ratio of the device was between 5 and 10 dB, and the insertion loss of the device in the wavelength range 1520-1610 nm was between 22 and 24 dB, which included an about 18.4 +/- 0.4 dB coupling loss between the taper fibers and the polished sides of the device. (c) 2008 Elsevier B.V. All rights reserved.

Multi-channel micro neural probe fabricated with SOI

Silicon-on-insulator (SOI) substrate is widely used in micro-electro-mechanical systems (MEMS). With the buried oxide layer of SOI acting as an etching stop, silicon based micro neural probe can be fabricated with improved uniformity and manufacturability. A seven-record-site neural probe was formed by inductive-coupled plasma (ICP) dry etching of an SOI substrate. The thickness of the probe is 15 mu m. The shaft of the probe has dimensions of 3 mmx100 mu mx15 mu m with typical area of the record site of 78.5 mu m(2). The impedance of the record site was measured in-vitro. The typical impedance characteristics of the record sites are around 2 M Omega at 1 kHz. The performance of the neural probe in-vivo was tested on anesthetic rat. The recorded neural spike was typically around 140 mu V. Spike from individual site could exceed 700 mu V. The average signal noise ratio was 7 or more.

Design and Fabrication of a Photonic Crystal Channel Drop Filter Based on an Asymmetric Silicon-on-Insulator Slab

We report on the design and fabrication of a photonic crystal (PC) channel drop filter based on an asymmetric silicon-on-insulator (SOI) slab. The filter is composed of two symmetric stick-shape micro-cavities between two single-line-defect (W1) waveguides in a triangular lattice, and the phase matching condition for the filter to improve the drop efficiency is satisfied by modifying the positions and radii of the air holes around the micro-cavities. A sample is then fabricated by using electron beam lithography (EBL) and inductively coupled plasma (ICP) etching processes. The measured 0 factor of the filter is about 1140, and the drop efficiency is estimated to be 73% +/- 5% by fitting the transmission spectrum.

Light extraction of GaN LEDs with 2-D photonic crystal structure

Ultraviolet photo-lithography is employed to introduce two-dimensional (2D) photonic crystal (PC) structure on the top surface of GaN-based light emitting diode (LED). PC patterns are transferred to 460-nm-thick transparent indium tin oxide (ITO) electrode by inductively coupled plasma (ICP) etching. Light intensity of PC-LED can be enhanced by 38% comparing with the one without PC structure. Rigorous coupled wave analysis method is performed to calculate the light transmission spectrum of PC slab. Simulation results indicate that total internal reflect angle which modulated by PC structure has been increased by 7 degrees, which means that the light extraction efficiency is enhanced outstandingly.

Mode characteristics of semiconductor equilateral triangle microcavities with side length of 5-20 mu m

Semiconductor equilateral triangle microresonators (ETRs) with side length of 5, 10, and 20 mum are fabricated by the two-step inductively coupled plasma (ICP) etching technique. The mode properties of fabricated InGaAsP ETRs are investigated experimentally by photoluminescence (PL) with the pumping source of a 980-nm semiconductor laser and distinct peaks are observed in the measured PL spectra. The wavelength spacings of the distinct peaks agree very well with the theoretical longitudinal mode intervals of the fundamental transverse modes in the ETRs, which verifies that the distinct peaks are corresponding to the enhancement of resonant modes. The mode quality factors are calculated from the width of the resonant peaks of the PL spectra, which are about 100 for the ETR with side length of 20 mum.