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.

Study on extraction of agaropectin from Gelidium amansii and its anticoagulant activity

Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg.d in rats for 15 days, TT (thrombin time), CT (coagulation time), PT (prothrombin time), and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.

The Liquefaction and Displacement of Highly Saturated Sand under Water Pressure Oscillation

In order to investigate the characteristics of water wave induced liquefaction in highly saturated sand in vertical direction, a one-dimensional model of highly saturated sand to water pressure oscillation is presented based oil the two-phase continuous media theory. The development of the effective stresses and the liquefaction thickness are analyzed. It is shown that water pressure oscillating loading affects liquefaction severely and the developing rate of liquefaction increases with the decreasing of the sand strength or the increasing of the loading strength. It is shown also that there is obvious phase lag in the sand Column. If the sand permeability is non-uniform, the pore pressure and the strain rise sharply at which the smallest permeability occurs. This solution may explain Why the fracture occurs in the sand column in some conditions.

Rapidly Infrared-Assisted Cooperatively Self-Assembled Highly Ordered Multiscale Porous Materials

In this paper, cooperative self-assembly (CSA) of colloidal spheres with different sizes was studied. It was found that a complicated jamming effect makes it difficult to achieve an optimal self-assembling condition for construction of a well-ordered stacking of colloidal spheres in a relatively short growth time by CSA. Through the use of a characteristic infrared (IR) technique to significantly accelerate local evaporation on the growing interface without changing the bulk growing environment, a concise three-parameter (temperature, pressure, and IR intensity) CSA method to effectively overcome the jamming effect has been developed. Mono- and multiscale inverse opals in a large range of lattice scales can be prepared within a growth time (15-30 min) that is remarkably shorter than the growth times of several hours for previous methods. Scanning electron microscopy images and transmittance spectra demonstrated the superior crystalline and optical qualities of the resulting materials. More importantly, the new method enables optimal conditions for CSA without limitations on sizes and materials of multiple colloids. This strategy not only makes a meaningful advance in the applicability and universality of colloidal crystals and ordered porous materials but also can be an inspiration to the self-assembly systems widely used in many other fields, such as nanotechnology and molecular bioengineering.

Directly synthesized strong, highly conducting, transparent single-walled carbon nanotube films

We report the direct synthesis of strong, highly conducting, and transparent single-walled carbon nanotube (SWNT) films. Systematically, tests reveal that the directly synthesized films have superior electrical and mechanical properties compared with the films made from a solution-based filtration process: the electrical conductivity is over 2000 S/cm and the strength can reach 360 MPa. These values are both enhanced by more than 1 order. We attribute these intriguing properties to the good and long interbundle connections. Moreover, by the help of an extrapolated Weibull theory, we verify the feasibility of reducing the interbundle slip by utilizing the long-range intertube friction and estimate the ultimate strength of macroscale SWNTs without binding agent.

Pure Coulomb explosions of highly charged methane clusters investigated by a simple electrostatic model

The pure Coulomb explosions of the methane clusters (CA(4))(n), (light atom A = H or D) have been investigated by a simplified electrostatic model for both a single cluster and an ensemble of clusters with a given cluster size distribution. The dependence of the energy of ions produced from the explosions on cluster size and the charge state of the carbon ions has been analysed. It is found that, unlike the average proton energy which increases with the charge q of the carbon ions, the average deuteron energy tends to saturate as q becomes larger than 4. This implies that when the laser intensity is sufficiently high for the (CD4)(n) to be ionized to a charge state of (C4+D4+)(n), the neutron yield from a table-top laser-driven Coulomb explosion of deuterated methane clusters (CD4)(n) could be increased significantly by increasing the interaction volume rather than by increasing the laser intensity to produce the higher charge state (C6+D4+)(n). The flight-time spectra of the carbon ions and the light ions have also been studied.

Highly sensitive wave-front sensor with a non-zero-order phase plate

We propose a novel highly sensitive wave front detection method for a quick check of a flat wave front by taking advantage of a non-zero-order pi phase plate that yields a non-zero-order diffraction pattern. When a light beam with a flat wave front illuminates a phase plate, the zero-order intensity is zero. When there is a slight distortion of the wave front, the zero-order intensity increases. The ratio of first-order intensity to that of zero-order intensity is used as the criterion with which to judge whether the wave front under test is flat, eliminating the influence of background light. Experimental results demonstrate that this method is efficient, robust, and cost-effective and should be highly interesting for a quick check of a flat wave front of a large-aperture laser beam and adaptive optical systems. (c) 2005 Optical Society of America.

Design of a highly stable, high-conversion-efficiency pumping source for optical parametric amplifier by extending efficient crystal length

The objective of this study is to improve the stability of pumping source of optical parametric amplifier. Analysis by simulation leads to the conclusion that the stability of the second harmonic can be improved by using properly the intensity of fundamental light and corresponding length of the crystal. By the method of the noncollinear two-pass second harmonic or the tandem second harmonic, the efficient crystal length is extended to a proper value, and the stability of the second harmonic output has been improved two times more than that for the fundamental light, and the conversion-efficiency is about 70% in experiment. When the variation of the fundamental light is about 10%, the variation of the second harmonic intensity has been controlled within 5%. (c) 2006 Elsevier Ltd. All rights reserved.

Highly stable, diode-pumped Nd : YLF regenerative amplifier

We present the design and experimental results for a diode pumped Nd:YLF regenerative amplifier applied to amplify a nanosecond laser pulse. Numerical simulation shows that the maximum output energy and the best stability can be obtained when the regenerative amplifier operates in a saturated mode for all pulse duration and temporal profiles. Using extra post-pulse is a good method to decrease the square-pulse distortion caused by gain saturation effect. The amplifier shows output energy of 4.2mJ with a total energy gain of more than 107 and output energy stability of better than 1% rms. When extra post-pulse is added, square-pulse distortion is decreased from 1.33 to 1.17 for the amplifier that is seeded with an optical pulse of 3 ns.

A humidity-resistant highly sensitive holographic photopolymerizable dry film

A new humidity-resistant highly sensitive acrylamide-based photopolymeric holographic recording material has been developed. The photopolymer is resistant to the humidity of environment. Diffraction efficiencies near 50% are obtained with exposure energy of 60 mJ/cm(2) in materials of 150 mu m. thickness. Diphenyl iodonium chloride is added to the material and can increase the exposure sensitivity by a factor of more than 4 (to about 28 mJ/cm(2)). An image has been successfully stored in the material with a small distortion. (C) 2005 Elsevier B.V. All rights reserved.

Highly efficient Nd:YAG ceramic CW laser with 59.8% slope-efficiency

In this paper, a highly efficient Ti:sapphire end-pumped 1 at.-% Nd:YAG ceramic laser that is comparable in efficiency with Nd:YAG single crystal lasers has been developed. Optical absorption and emission spectra for Nd:YAG ceramics have been measured. With 673-mW pumping, 295-mW laser output at 1064 nm has been obtained. The laser threshold is only 13 mW. Deducted the transmitted light, the corresponding optical-to-optical conversion efficiency is 58.4%. The lasing characteristics of Nd:YAG ceramic are nearly equal to those of Nd:YAG single crystal.

Highly efficient diode side-pumped Nd : YAG ceramic laser with 210W output power

We developed a highly efficient diode side-pumped Nd:YAG ceramic laser with a diffusive reflector as an optical pump cavity. A maximum output power of 211.6W was obtained with an optical -to- optical conversion efficiency of 48.7%. This corresponds to the highest conversion efficiency in the side-pumped ceramic rod. Thermal effects of the Nd:YAG ceramic rod were analyzed in detail through the measurements of laser output powers and beam profiles near the critically unstable region. A M-2 beam quality factor of 18.7 was obtained at the maximum laser output power. (c) 2006 Elsevier Ltd. All rights reserved.

The growth of gamma-LiAlO2 layer with a highly-preferred orientation on (0001) sapphire

Using vapor transport equilibration (VTE) technique we succeeded in the fabrication of single-phase gamma-LiAlO2 layer on (0001) sapphire substrate. X-ray diffraction indicated that the as-fabricated layer was highly textured with [100] orientation at proper VTE treatment temperature range from 1050 degrees C to 1100 degrees C. The main factors affecting the quality of the gamma-LiAlO2 layer were investigated by SEM and transmission spectra. These results reveal the possibility of fabricating gamma-LiAlO2 (100)//sapphire (0001) composite substrate for GaN-based epitaxial film by VTE.

Edge-defined, film-fed growth (EFG) technique for the preparation of alpha-Al2O3 : C crystal with highly sensitive thermoluminescence response

In this work, alpha-Al2O3:C, a highly sensitive thermoluminescence dosimetry crystal, was grown by the EFG method in which a graphite heating unit and shield acted as the carbon source during the growth process. The optical, luminescent properties and dosimetric characteristics of the crystal were investigated. The as-grown crystal shows a single glow peak at 536 K, which is associated with Cr3+ ions. After annealing in H-2 at 1673 K for 80 h, the crystal shows a single glow peak at 460 K and a blue emission band at 415 nm. The thermoluminescent response of the annealed crystal shows linear-sublinear-saturation characteristics in the dose range from 5 x 10(-6) to 100 Gy.