Advanced superconducting electron cyclotron resonance ion source SECRAL: Design, construction, and the first test result

Superconducting electron cyclotron resonance (ECR) ion source with advanced design in Lanzhou (SECRAL) is a next generation ECR ion source and aims for developing a very compact superconducting ECR ion source with a structure and high performances for highly charged ion-beam production. The ion source was designed to be operated at 18 GHz at initial operation and finally will be extended to 28 GHz. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. At full excitation, this magnet assembly can produce peak mirror fields on the axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. What is different from the traditional design, such as LBNL VENUS and LNS SERSE, is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. SECRAL may open the way for building a compact and high-performance 18-28 GHz superconducting ECR ion source. Very preliminary commissioning results are promising. Detailed design, construction issues and very preliminary test results of the ion source at 18 GHz are presented.

A low noise charge sensitive preamplifier with switch control feedback resistance

In this paper, the design and analysis of a new low noise charge sensitive preamplifier for silicon strip, Si(Li), CdZnTe and CsI detectors etc. with switch control feedback resistance were described, the entire system to be built using the CMOS transistors. The circuit configuration of the CSP proposed in this paper can be adopted to develop CMOS-based Application Specific Integrated Circuit further for Front End Electronics of read-out system of nuclear physics, particle physics and astrophysics research, etc. This work is an implemented design that we succeed after a simulation to obtain a rise time less than 3ns, the output resistance less than 94 Omega and the linearity almost good.

(Z)-2-(2-chloro-3,3,3-trifluoroprop-1enyl)-6-methoxyphenyl acetate

The crystal structure of the title compound, C12H10ClF3O3, was determined in order to establish the configuration of the C double bond. The compound was found to be the Z isomer. The crystal structure is dominated by Cl center dot center dot center dot O halogen bonds [Cl center dot center dot center dot O = 3.111 (3) angstrom], as well as C-H center dot center dot center dot O and C-H center dot center dot center dot F hydrogen-bonding interactions, that connect neighboring molecules into a three-dimensional supramolecular network.

Luminescent Boron-Contained Ladder-Type pi-Conjugated Compounds

Four diboron-contained ladder-type pi-conjugated compounds 1-4 were designed and synthesized. Their thermal, photophysical, electrochemical properties, as well as density functional theory calculations, were fully investigated. The single crystals of compounds 1 and 3 were grown, and their crystal structures were determined by X-ray diffraction analysis. Both compounds have a ladder-type g-conjugated framework. Compounds I and 2 possess high thermal stabilities, moderate solid-state fluorescence quantum yields, as well as stable redox properties, indicating that they are possible candidates for emitters and charge-transporting materials in electroluminescent (EL) devices. The double-layer device with the configuration of [ITO/NPB (40 nm)/1 or 2 (70 nm)/LiF (0.5 nm)/Al (200 nm)] exhibited good EL performance with the maximum brightness exceeding 8000 cd/m(2).

Progress in polymer solar cell

This review outlines current progresses in polymer solar cell. Compared to traditional silicon-based photovoltaic (PV) technology, the completely different principle of optoelectric response in the polymer cell results in a novel configuration of the device and more complicated photovoltaic generation process. The conception of bulk-heterojunction (BHJ) is introduced and its advantage in terms of morphology is addressed. The main aspects including the morphology of photoactive layer, which limit the efficiency and stability of polymer solar cell, are discussed in detail. The solutions to boosting up both the efficiency and stability (lifetime) of the polymer solar cell are highlighted at the end of this review.

Electrochemical detector based on sol-gel-derived carbon composite material for capillary electrophoresis microchips

An on-chip disk electrode based on sol-gel-derived carbon composite material could be easily and reproducibly fabricated. Unlike other carbon-based electrodes reported previously, this detector is rigid, convenient to fabricate, and amenable to chemical modifications. Based on the stable and reproducible characters of this detector, a copper particle-modified detector was developed for the detection of carbohydrates which extends the application of the carbon-based electrode. In our experiments, the performance of the new integrated detector for rapid on-chip measurement of epinephrine and glucose was illustrated. Experimental procedures including the fabrication of this detector, the configuration of separation channel outlet and electrode verge, and the performance characteristics of this new electrochemical detector were investigated.

Highly efficient pure-white-light-emitting diodes from a single polymer: Polyfluorene with naphthalimide moieties

Light-emitting diodes exhibiting efficient pure-white-light electroluminescence have been successfully developed by using a single polymer: polyfluorene derivatives with 1,8-naphthalimide chromophores chemically doped onto the polyfluorene backbones. By adjusting the emission wavelength of the 1,8-naphthalimide components and optimizing the relative content of 1,8-naphthalimide derivatives in the resulting polymers, white-light electroluminescence from a single polymer, as opposed to a polymer blend, has been obtained in a device with a configuration of indium tin oxide/poly(3,4-ethyleiledioxythiophene)(50 nm)/polymer(80 nm)/Ca(10 nm)/Al(100 nm). The device exhibits Commission Internationale de I'Eclairage coordinates of (0.32,0.36), a maximum brightness of 11900 cd m(-2), a current efficiency of 3.8 cd A(-1), a power efficiency of 2.0 lm W-1. an external quantum efficiency of 1.50 %, and quite stable color coordinates at different driving voltages, even at high luminances of over 5000 cd m(-2).

Phenylene vinylene-based electroluminescent polymers with electron transport block in the main chain

We report a new route for the design of soluble phenylene vinylene (PV) based electroluminescent polymers bearing electron-deficient oxadizole (OXD) and triazole (TZ) moieties in the main chains with the aryloxy linkage. Both series of the PV-based polymers were prepared by Wittig reaction. By properly adjusting the OXD and/or TZ content through copolymerization, we can achieve an enhanced balance of hole- and electron injections, such that the device efficiency is significantly improved. Light-emitting diodes fabricated from P1, P2, P3, P4, P5, P6, and P7 with the configuration of Indium-Tin Oxide (ITO)/Poly (styrene sulfonic acid) doped poly (ethylenedioxythiophene) (PEDOT)/polymer/Ca/Al, emit bright green light with the maximum peak around 500 nm. For the device using the optimal polymer (P4) as emitting layer, a maximum brightness of 1300 cd/m(2) at 20 V and a maximum luminance efficiency of 0.325 cd/A can be obtained.

Fe(2-EHA)(3)/Al(i-Bu)(3)/hydrogen phosphite catalyst for preparing syndiotactic 1,2-polybutadiene

Polymerizing 1,3-butadiene into syndiotactic 1,2-polybutadiene with art iron(III) catalyst system has been investigated. Activity of the catalyst was affected by the type of cocatalyst alkylaluminum and the phosphorus compound as an electron donor, molar ratio of catalyst components, and their aging sequence and aging time of the catalyst. The microstructure and configuration of the polymer was decided by the catalyst components, the higher [Al]/[Fe] molar ratio tending to yield syndiotactic 1,2-polybutadiene, while the higher [P]/[Fe] molar ratio favors the formation of amorphous 1,2-polybutadiene.

White organic electroluminescence based on a new boron complex

A bright blue boron complex BPh2(pybm) containing 2-(2-pyridyl)benzimidazole ligand was designed and synthesized by using N, N-bidentate ligand instead of N, O-bidentate one such as 8-quinolinol. For three-layer LED devices with the configuration of ITO/NPB/BPh2(pybm)/Alq(3)/LiF/Al, the white light emission covering the whole visible region from 400 to 750 nm with the maximum brightness of 110 cd/m(2) and the luminous efficiency of 0.8 cd/A was observed.

A hydroxyphenyloxadiazole lithium complex as a highly efficient blue emitter and interface material in organic light-emitting diodes

We synthesized a hydroxyphenyloxadiazole lithium complex (LiOXD) as a blue light-emitting and electron injection/transport material to be used in double-layer organic electroluminescent devices. Devices with the concise configuration of ITO/TPD/LiOXD/Al showed bright blue EL emission centered at 468 nm with a maximum luminance of 2900 cd m(-2). A current efficiency of 3.9 cd A(-1) and power efficiency of 1.1 lm W-1 were obtained. LiOXD was also examined as an interface material. The efficiency of an ITO/NPB/Alq(3)/Al device increased considerably when LiOXD was inserted between Alq(3) and aluminium. The improvement of the device characteristics with LiOXD approached that observed with the dielectric LiF salt.

Oxadiazole-containing material with intense blue phosphorescence emission for organic light-emitting diodes

2-(2-hydroxyphenyl)-5-phenyl-1, 3, 4-oxadiazole (HOXD), characteristic of excited state intramolecular proton-transfer (ESIPT), was synthesized and found to emit strong blue phosphorescence in the solid state at room temperature and at low temperature (77 K). The photoluminescent spectrum measurement in solution showed that there are two kinds of emission: fluorescence originated from the singlet state and phosphorescence derived from the triplet state in HOXD formed by ESIPT. For the photoluminescent spectrum in the solid state, only phosphorescence emission with the lifetime of 66 mus was observed. Multiple-layer light-emitting diodes with the configuration of ITO/NPB/HOXD/BCP/Alq(3)/Mg:Ag were fabricated using HOXD as emitter and the maximum brightness of 656 cd/m(2) and the luminous efficiency of 0.14 lm/W was obtained.

Bienzymatic amperometric biosensor for glucose based on polypyrrole/ceramic carbon as electrode material

A novel amperometric biosensor utilizing two enzymes, glucose oxidase (GOD) and horseradish peroxidase (HRP), was developed for the cathodic detection of glucose. The glucose biosensor was constructed by electrochemical formation of a polypyrrole (PPy) membrane in the presence of GOD on the surface of a HRP-modified sol-gel derived-mediated ceramic carbon electrode. Ferrocenecarboxylic acid (FCA) was used as mediator to transfer electron between enzyme and electrode. In the hetero-bilayer configuration of electrode, all enzymes were well immobilized in electrode matrices and showed favorable enzymatic activities. The amperometric detection of glucose was carried out at +0.16 V (versus saturated calomel reference electrode (SCE)) in 0.1 M phosphate buffer solution (pH 6.9) with a linear response range between 8.0 x 10(-5) and 1.3 x 10(-3) M glucose. The biosensor showed a good suppression of interference in the amperometric detection.

BETA-RELAXATION IN POLYIMIDES

A series of polyimides with different structures have been synthesized and studied by dynamic mechanical analysis. The results obtained indicate that the beta relaxation in polyimides is related to the rotation of rigid segment(s) of p-phenylene and imide groups around 'hinges' such as -O-, -CH2- and so on in diamines. It is noticed that two kinds of polyimides both with [GRAPHICS] imide groups have verv weak beta relaxation below the glass transition temperature. This phenomenon is due to the fact that the configuration of chains with the above imide groups hinders the rotation of the rigid segments in the chains.

Benzodiazepine Alkaloids from Marine-Derived Endophytic Fungus Aspergillus ochraceus

A new fungus-derived benzodiazepine analogue, 2-hydroxycircumdatin C (1), and a compound which has been isolated from a natural resource for the first time, but has been previously synthesized, namely (11aS)-2,3-dihydro-7-methoxy-1H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H,11aH)-dione (2), along with five structurally related known alkaloids (3-7), were isolated from Aspergillus ochraceus, an endophytic fungus derived from the marine brown alga Sargassum kjellmanianum. Their structures were established on the basis of spectroscopic methods. The absolute configuration of I was determined through CD evidence. Compound 1 displayed significant DPPH radical-scavenging activity with an IC50 value of 9.9 mu M, which is 8.9-fold more potent than that of butylated hydroxytoluene (BHT), a well-known synthetic positive control.