Sulfonated polyimides bearing benzimidazole groups for proton exchange membranes

A series of sulfonated polymides containing benzimidazole groups were synthesized using 4,4'-binaphthyl-1,1',8,8'-tetracarboxylic dianhydride (BTDA), 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid (ODADS) as the sulfonated diamine, and 2-(3',5-diaminophenyl)benzimidazole (a) or 6,4'-diamino-2-phenylbenzimidazole (b) as the nonsulfortated diamine. The electrolyte properties of the synthesized polyimides Ia-x, Ib-x, x refers to molar percentage of the sulfonated diamine) were investigated and compared with those of polyimides (Ic-x) from BTDA, ODADS, and m-phenylenediamine (c). All synthesized polyimides possessed high molecular weights revealed by their high viscosity, and formation of tough and flexible membranes. Polyintides with benzimidazole groups exhibited much better swelling capacity than those without benzimiclazole groups. This was attributed to the strong interchain interaction through basic benzimidazole functions and sulfonic acid groups. The sulfortated polyimides that are incorporated with 1, 1',8,8'-binaphthalimide exhibited better hydrolytic stability than that with 1,4,5,8-naphthalimide. Polyimide membranes with good water stability as well as high proton conductivity were developed. Polyimide membrane (Ia - 90), for example, did not lose mechanical properties after being soaked in boiling water for tOOO h, while its proton conductivity was still at a high level (compared to that of Nafion 117).

High gain in hybrid transistors with vanadium oxide/tris(8-hydroxyquinoline) aluminum emitter

We report the electrical characterization of hybrid permeable-base transistors with tris(8-hydroxyquinoline) aluminum as emitter layer. These transistors were constructed presenting an Al/n-Si/Au/Alq(3)/V2O5/Al structure. We investigate the influence of the V2O5 layer thickness and demonstrate that these devices present high common-base and common-emitter current gain, and can be operated at very low driving voltages, lower than 1 V, in both, common-base and common-emitter modes.

Modeling of organic light-emitting diodes with graded concentration in the emissive multilayer

We model the electrical behavior of organic light-emitting diodes whose emissive multilayer is formed by blends of an electron transporting material, tris-(8-hydroxyquinoline) aluminum (Alq(3)) and a hole transporting material, N,N-'-diphenyl-N,N-'-bis(1,1(')-biphenyl)-4,4-diamine. The multilayer is composed of layers of different concentration. The Alq(3) concentration gradually decreases from the cathode to the anode. We demonstrate that these graded devices have higher efficiency and operate at lower applied voltages than devices whose emissive layer is made of nominally homogeneous blends. Our results show an important advantage of graded devices, namely, the low values of the recombination rate distribution near the cathode and the anode, so that electrode quenching is expected to be significantly suppressed in these devices.

Copper phthalocyanine based hybrid p-type permeable-base transistor in vertical architecture

We demonstrate the production of copper phthalocyanine (CuPc) based p-type hybrid permeable-base transistors, which operate at low voltages having high common-base current gains. These transistors are prepared by evaporating a thin metal layer (Ag or Al) that acts as base on top of a Si substrate that acts as collector. In the sequence CuPc and Au are thermally sublimated to produce the emitter, constituting a quite simple device production procedure with the additional advantage of allowing higher integration due to its vertical architecture.

CE coupling with end-column electrochemiluminescence detection for chiral separation of disopyramide

CE with electrochemiluminescence, (ECL) detection technique was successfully applied for the chiral separation of a kind of class IA antiarrhythmic racemic drug. To the best of our knowledge, this is the first report of ECL detection used in chiral CE. To get better detection sensitivity and good enantioresolution at the same time, the conditions of capillary inlet and outlet buffer were systematically optimized. Unlike the traditional chiral separation method, the buffers we used in the capillary inlet and outlet differed from each other in terms of buffer pH, ionic strength, type of BGE as well as buffer composition. Under the optimum conditions, baseline enantioseparation and highly sensitive detection of the enantiomers were achieved. Wide linear relationship of each enantiomer was achieved in the range of 5 x 10(-7) to 2 x 10(-5) mol/L with relative coefficients of 0.996 and 0.997, respectively. The detection limits were estimated to be 8 x 10(-8) and 1.0 X 10(-7) mol/L (S/N = 3) for the enantiomers, respectively. In addition, a successful application of this new method to the chiral separation of the racemic drug in spiked plasma samples confirmed the validity and applicability of the chiral CE-ECL method.

Synthesis and properties of soluble polyimides based on isomeric ditrifluoromethyl substituted 1,4-bis(4-aminophenoxy)benzene

A new fluorinated diamine monomer, [1,4-bis(4-amino-3-trifluoromethylphenoxy)benzene (2)], and a known isomeric analog 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (3) were synthesized. A series of organosoluble polyimides Ia-d and IIa were prepared from the diamines (2, 3) and dianhydrides (a-d) by a high-temperature one-step method. The effects of the trifluoromethyl substituents on the properties of polyimides were evaluated through the study of their soluble, thermal, optical, and gas permeability properties. Polyimides (Ia-d) had glass transition temperatures between 229 and 279 degrees C, and the temperatures at 5% weight loss ranged from 510 to 533 degrees C under nitrogen. These polyimides could be cast into flexible and tough membranes from DMAc solutions. The membranes had tensile strengths in the range of 137-169 MPa, tensile modulus in the range of 1.6-2.2 GPa and elongations at break from 11% to 14%. The polyimide la with trifluoromethyl groups ortho to the imide nitrogen exhibited enhanced gas permeability, solubility, transparency, and thermal stability compared with the isomeric polyimide IIa with the CF3 group meta to the imide nitrogen.

High current density tris(8-hydroxyquinoline) aluminum-based hybrid transistor in vertical architecture

We report the construction of hybrid permeable-base transistors, in vertical architecture, using tris(8-hydroxyquinoline) aluminum as emitter, a thin gold layer as base, and n-type silicon as collector. These transistors present high common-base current gain, can be operated at low driving voltages, and allow high current density.

超声提取-分光光度法测定刺五加叶中总皂苷含量

刺五加系人参同科属植物，具有类似人参的功效。近年来研究表明：刺五加叶也具有较好的药理活性，对心血管系统疾病疗效显著。总皂苷为其主要药理活性成分，已发现有近20种。由于分离刺五加皂苷标准品的困难，刺五加总皂芽含量测定目前尚无药典方法，文献报道的也仅有薄层扫描等方法。但薄层扫描法操作较繁琐且线性范围窄。本文用分光光度法测定了不同提取方法提取的刺五加叶总皂苷，得到较好的结果，并观察到用超声法提取刺五加叶总皂苷并与常规提取方法相比，总皂苷提取率有显著提高。2 实验部分二．１ 仪胃与材料S8r'tod。BP ZLLD精密电子天平（北京塞多利斯天平有限公司）；bolo紫外－可见分光光度计（安捷伦上海分析仪器有限公司）；CSF-IA超声波发生器（上海超声波仪器厂）。刺五加叶（白山正茂药业有限公司提供）；齐墩果酸标准品（中国药品生物制品检定所）；香兰素、浓硫酸、甲醇、乙醇均为分析纯。水为去离子水。二．2 实骏方法 标准溶泣及试剂的配制 精密称取齐墩果酸14.7lug置于10InL容量瓶中，加甲醇定容，则标准溶液浓度为 1.47IL；香兰素配成8％乙醇溶液；硫酸配成 72％（VIV）溶液。

Charge carrier mobility and electroluminescence in a green-emitting alternating block copolymer with a methoxy Bi-substituted chromophore

We determine the mobility of positive and negative charge carriers in a soluble green-emitting alternating block copolymer with, a methoxy bi-subsbituted conjugated segment. The negative charge carrier mobility of 6 x 10(-11) cm(2)/V.s is directly determined using space-charge-limited current analytical expressions. Positive charge carrier transport is also space-charge-limited, with a mobility of I x 10(-8) cm(2)/V.s. The electron trap distribution is exponential, with a characteristic energy of similar to 0.12 eV. A hole trap with energy similar to 0.4 eV was observed. This copolymer is used as emissive material in organic light-emitting diodes that present brightness of similar to 900 cd/m(2) at 12.5 V.

Charge transport in a blue-emitting alternating block copolymer with a small spacer to conjugated segment length ratio

We analyze current versus voltage data obtained using single carrier injection in several metal/polymer/metal sandwich structures. The polymer used in each case is a soluble blue-emitting alternating block copolymer. Our experimental results demonstrate that the electron transport is space-charge limited by the high density of traps having an exponential energy distribution (temperature dependent characteristic energy) in the copolymer. The electron mobility of 8x10(-10) cm(2)/V s is directly determined using space-charge-limited current analytical expressions. Hole transport is also space-charge limited, with a mobility of 2x10(-6) cm(2)/V s. A hole trap with energy 0.17 eV is observed. We compare these results with those obtained for related block copolymers with different spacer and conjugated segment lengths and discuss the influence of spacer length and conjugated segment length on the charge transport properties. (C) 2000 American Institute of Physics. [S0021-8979(00)04501-1].

Determination of electron mobility in a blue-emitting alternating block copolymer by space-charge-limited current measurements

In this communication we analyse current versus voltage data obtained using one carrier injection at metal/polymer/metal structures, The used polymer is a soluble blue-emitting alternating block copolymer, Our experimental results demonstrate that the electron current is limited by a large amount of traps with exponential energy distribution in the copolymer. The electron ;mobility of 5.1 x 10(-10) cm(2)/V s is directly determined by space-charge-limited current measurements. The electron mobility is at least three orders of magnitude smaller than that for holes in the copolymer. (C) 1999 Elsevier Science Ltd. All rights reserved.

VD-1A型X射线衍射仪信号检测系统故障检修一例

本文以故障实例详细介绍了岛津VD－IA型x社线1行射议信号检测系统一种典型故障的分析及排除方法。

The variability of eddy kinetic energy in the South China Sea deduced from satellite altimeter data

We used fifteen years (1993-2007) of altimetric data, combined from different missions (ERS-1/2, TOPEX/Poseidon, Jason-1, and Envisat), to analyze the variability of the eddy kinetic energy (EKE) in the South China Sea (SCS). We found that the EKE ranged from 64 cm(2)/s(2) to 1 390 cm(2)/s(2) with a mean value of 314 cm(2)/s(2). The highest EKE center was observed to the east of Vietnam (with a mean value of 509 cm(2)/s(2)) and the second highest EKE region was located to the southwest of Taiwan Island (with a mean value of 319 cm(2)/s(2)). We also found that the EKE structure is the consequence of the superposition of different variability components. First, interannual variability is important in the SCS. Spectral analysis of the EKE interannual signal (IA-EKE) shows that the main periodicities of the IA-EKE to the east of Vietnam, to the southwest of Taiwan Island, and in the SCS are 3.75, 1.87, and 3.75 years, respectively. It is to the south of Taiwan Island that the IA-EKE signal has the most obvious impact on EKE variability. In addition, the IA-EKE exhibit different trends in different regions. An obvious positive trend is observed along the east coast of Vietnam, while a negative trend is found to the southwest of Taiwan Island and in the east basin of Vietnam. Correlation analysis shows that the IA-EKE has an obvious negative correlation with the SSTA in Nio3 (5A degrees S-5A degrees N, 90A degrees W-150A degrees W). El Nio-Southern Oscillation (ENSO) affects the IA-EKE variability in the SCS through an atmospheric bridge-wind stress curl over the SCS. Second, the seasonal cycle is the most obvious timescale affecting EKE variability. The locations of the most remarkable EKE seasonal variabilities in the SCS are to the east of Vietnam, to the southwest of Taiwan, and to the west of Philippines. To the east of Vietnam, the seasonal cycle is the dominant mechanism controlling EKE variability, which is attributed primarily to the annual cycle there of wind stress curl. In this area, the maximum EKE is observed in autumn. To the southwest of Taiwan Island, the EKE is enlarged by the stronger SCS circulation, which is caused by the intrusion branch from the Kuroshio in winter. Finally, intra-annual and mesoscale variability, although less important than the former, cannot be neglected. The most obvious intra-annual and mesoscale variability, which may be the result of baroclinic instability of the background flow, are observed to the southwest of Taiwan Island. Sporadic events can have an important effect on EKE variability.

南沙珊瑚礁生态系的营养动力学过程

本论文首次报道了在珊瑚礁向海坡上投放沉积物捕捉器的结果和若干非生源要素如Mo、W、Re、Os、Ni、Ir等在泻湖内外的垂直通量，并在国内首次报道了珊瑚活体培养的结果。将海水、沉降颗粒物、生物和泻湖表层沉积物统一进行系统的研究，重点讨论了珊瑚礁营养动力学过程和维持高生产力的机制等问题。主要的研究内容和结果包括：1. 物理动力过程对营养物质的循环有重要影响物理因素尤其是海水的动力过程更可能是珊瑚礁生长的限制性因素。南沙珊瑚礁的形态及其相关的沉积环境明显受本海区物理过程（海洋和大气）的控制。与此相适应，珊瑚礁生态系统造就了有效保持和快速吸收营养盐的特性。泻湖海水中营养盐分布明显受到泻湖水运动方式的影响，尤其是PO_4-P。2. 营养物质的循环具有快速高效和不均衡的特点 对渚碧礁生源要素的生物地球化学循环研究表明，快速分解、高效再利用是珊瑚礁总生产力很高，净生产力却较低的主要原因。渚碧礁泻湖内两个站的POC分别有93.55%和95.83%在进入沉积物前被消耗，能真正进入沉积物中的却很少。其中99%左右的生物碎屑POC通过生物捕食或腐解作用转变为无机碳重新进入循环。珊瑚礁生态系的高生产力主要是依靠其系统内部快速而高效的再生循环过程维持的。营养盐的原位再生是珊瑚礁营养盐的主要来源，泻湖内PTN和PON释放率分别超过90%和86%；PTP释放率为58.7%～85.2%，多数站位POP的释放率在90%以上。泻湖水中N:P摩尔比平均值仅为8.1，可能存在着氮限制。而在礁坪区，N:P摩尔比的日平均值为26.7，磷的限制作用非常明显。整体来看，氮在泻湖内进入再循环的速度和效率要高于磷2.5～12.8 倍，由于磷缺乏类似于生物固氮作用的持续的供氮机制，磷在珊瑚礁生态系中的限制作用更为明显，至少在礁坪区是如此。珊瑚活体培养的实验表明，珊瑚也存在着短时间里大量消耗营养盐的“奢侈消费”现象。珊瑚对营养盐的吸收速度与营养盐的浓度和珊瑚的种类均有关系。添加营养盐起始浓度高的组营养盐消耗的速度快，与之相适应，其它的各种溶解性营养盐浓度也产生复杂的变化，对迅速稳定水体营养盐浓度产生协同作用，这一过程有助于珊瑚充分吸收突然输入的营养盐。在此实验条件下，珊瑚对含氮盐类的浓度变化要比对磷酸盐更为敏感，可以认为NH_4-N是珊瑚生长的限制性营养盐。在自然界中，这种情况常发生在有大量营养盐输入之后。实验中还发现，对营养盐的吸收速度比营养盐水平更为重要。吸收速度快于某种形态限制性营养盐的输入速度也会导致珊瑚的死亡。反过来讲，珊瑚礁系统可以通过降低对营养盐的消费速度而摆脱营养盐的限制。3. 非生源要素的循环也与生物过种密切相关 非生源要素在海洋颗粒物、生物和沉积物中的分布主要受两种作用的影响，一是颗粒物在生产、沉降和分解过程中的吸附释放作用，另一种是生物的直接利用。颗粒物对IIA族、过渡族的大部分和La系元素都是分布的制约性因素。而IA族、过渡族的一部分和部分非金属元素分布上属于营养盐型，主要受浮游生物直接吸收溶解的盐类（浮游植物）和捕食作用（浮游动物）的影响。轻元素、第四周期的过渡族元素在含量和性质上往往有别于重元素和其它周期的同族过渡元素，更多的参与生物过程。元素分析进一步显示珊瑚礁泻湖内沉降颗粒物主要是自生碎屑，而礁外沉降颗粒物包含了一部分再悬浮的碎屑矿物，但元素在泻湖内外的转移机制是类似的，造成颗粒物来源差别的主要原因是动力学因素。水动力始终是颗粒物中元素垂直转移的主要的、关键性的因素。对于营养盐型的元素，生物的捕食富集是另一个主要控制因素。4. 多种机制的协同作用维持了珊瑚礁生态系的高生产力 考虑到珊瑚礁营养盐的收支并非总是平衡的，珊瑚礁的高生产力的维持可能是通过以珊瑚礁发育位置的选择为基础，“流网”策略、快速吸收营养盐、营养盐的快速循环和高效利用以及“休渔”策略等的协同作用实现的。“休渔”策略是指捕食因素决定的食物链上游生物迁出和初级生产力的恢复过程，当捕食作用高于生产者的生产速度或营养盐供应严重不足时，许多处于食物链上游的游泳动物将迁徙到生产力更高的珊瑚礁中去。大量的生物碎屑和代谢产物中的营养成分重新释放利用。一段时间后又能够重新繁荣起来。由于生物对磷和金属元素等的富集作用，食物链上游生物及其代谢产物作为营养物质输入的一个经常性来源的作用不可忽视。

自治水下机器人在深海采矿系统湖试中的应用

以大洋采矿前期的湖试为例,介绍了AUV在矿产资源调查和深海采矿中的应用。在深海采矿系统作业前期,利用AUV调查湖底的地形地貌、结核的分布与覆盖率,确定集矿机作业地点的大地坐标。在深海采矿系统作业后期,利用AUV调查集矿机在湖底的行走轨迹和压陷深度,估算回采率。