Application of a high magnetic field in the carbonization process to increase the strength of carbon fibers

Carbon fibers produced from PAN (polyacrylonitrile) as a precursor are generally subjected to the three heat treatment processes of stabilization and carbonization followed by graphitization. Stabilized fibers were carbonized in a high magnetic field of 5 T imposed parallel to the fiber axis at a temperature of 1445 K and graphitized without a magnetic field at 2273 K. The tensile strength of these treated fibers is increased by 14% in comparison with those of no magnetic treatment. The reason why the imposition of the magnetic field could improve the strength of the fibers has been studied through microscopic observation of the fiber surface as well as a statistical analysis by use of Weibull distributions.     

Bradykinin-induced vasodilation of human coronary arteries in vivo: role of nitric oxide and angiotensin-converting enzyme

Voltage-clamped GABA(A fast) and GABA(A slow) inhibitory postsynaptic currents (IPSCs) were selectively elicited in hippocampal area CA1 pyramidal neurons. Clinically relevant concentrations of halothane (1.2 vol.%) prolonged both GABA(A fast) and GABA(A slow) IPSC decay times approximately 2.5 fold, while having little to no effect on current amplitudes or rise times. Current-voltage analysis revealed that IPSC reversal potentials (-70 to -75 mV) remained constant in the presence of halothane. Under control conditions, GABA(A slow) IPSC decay times increased linearly with membrane depolarization, and this IPSC decay time voltage dependence was not significantly altered by halothane. These results confirm the existence of separable GABA(A fast) and GABA(A slow) IPSCs in hippocampus, and further elucidate the effects of halothane on these currents.     

Gain of chromosome 20 is a frequent aberration in liver metastasis of colorectal cancers

To investigate the characteristics of the numerical chromosome aberrations in liver metastasis of colorectal cancers, fluorescence in situ hybridization (FISH) for chromosomes 8, 18, 14/22, and 20 was performed in 18 specimens of primary regions and 18 of metastatic regions in liver metastasis of colorectal cancers compared with 15 of non-liver metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic regions of liver metastasis groups compared with that of the non-liver metastasis group (P < 0.05). The incidences of gain of chromosome 20 in both regions of the liver metastasis group were higher than that of the non-liver metastasis group (P < 0.05). The gain of chromosome 20 is a frequent aberration in primary and metastatic regions in patients with liver metastatic colorectal cancers and may be available as a genetic marker for the diagnosis or prediction of liver metastasis.     

Partial cloning of the hormone-binding domain of the cortisol receptor in tilapia, Oreochromis mossambicus, and changes in the mRNA level during embryonic development

The success of managing the infectious complications of acute leukemia has permitted oncologists to develop new approaches to induction and high-dose therapy. The single most important risk factor for infection is the duration of absolute neutropenia. Historically, most attention was directed towards gram negative aerobes, especially Pseudomonas aeruginosa, but in recent years gram positive bacteria, generally considered to be less virulent, have become the most frequent isolates in most centers. A recent disturbing trend is the isolation of vancomycin-resistant enterococci. A recent controversy has been whether to use empirical vancomycin; the Centers for Disease Control has issued a formal recommendation discouraging empirical vancomycin in the febrile neutropenic patient. Empirical monotherapy has replaced combination therapy in many institutions except where there has been an increase in resistant isolates. In patients who remain profoundly neutropenic, fungal infections represent a serious source of secondary infection, especially species of Candida and Aspergillus. Recently lipid-based formulations of amphotericin B have offered reduced nephrotoxicity. Less toxic antifungals, the azoles, which include fluconazole and itraconazole, offer an attractive alternative to amphotericin B. New patterns of invasive mycoses have emerged, as for example hepatosplenic candidiasis, presenting new problems in diagnosis and therapy. The successful management of virus infections with herpes simplex, cytomegalovirus, varicella zoster, and Epstein Barr virus is based on early recognition and careful attention to prevention.     

A REACTION-EXTRACTION-REGENERATION SYSTEM FOR HIGHLY SELECTIVE OXIDATION OF BENZENE TO PHENOL

The reaction-extraction-regeneration system for the liquid-phase oxidation of benzene to phenol in the benzene-water-oxygen system was investigated. Phenol was extracted in the extractor to reduce the concentration of phenol in the benzene phase. As vanadium catalyst was oxidized to inactive species after the oxidation reaction, the regenerator was installed in the system to reduce the oxidation state of vanadium catalyst from V⁴⁺ or VO²⁺ to the active V³⁺ under H₂ flow. The effects of various operating parameters including concentration of VCl₃ catalyst, O₂ and H₂ flow rates, benzene bubble size, pH, surface area of Pt regeneration catalyst, the metal species, and amount of ascorbic acid were investigated. Ascorbic acid was employed as a reducing agent for helping reduce the V⁴⁺ form to the active form and therefore improving the activity of vanadium catalyst. VCl₃ catalyst concentration of 10 mol/m³ with pH of 3–4 in the reactor and Pt surface area of 0.05 m² in the regenerator showed optimal conditions for the system.     

WATER MIST FLOW IN A SUPERCONDUCTING MAGNET INCLINED AT VARIOUS ANGLES

Water mist (diamagnetic) flow in a superconducting magnet of 10 T at various angles is studied experimentally and numerically. Water mist is produced by ultrasonic atomizers and fed into a cylindrical Plexiglas pipe (inner diameter, 90 mm) placed in a bore space of an inclined superconducting magnet. The water mist is found to stop at some locations in the magnet at inclined angles ψ ≤ π/6. At ψ ≥ π/4, the amount of mist flowing out of the other opening of the pipe increases with an increase in inclined angle. In the computation of this phenomenon, water mist is simulated with 1000 water droplets of 3 μm diameter. Brownian motion is considered and the Langevin equation is solved. The numerical results show that at ψ ≤ π/6, most of the water droplets accumulate above the magnetic coil. However, at ψ ≥ π/4, with an increase in inclined angle, the number of water droplets passing through the magnetic coil increases.     

Comparison of Macro and Microtribological Property of Molybdenum Disulfide Film Exposed to LEO Space Environment

Macro- and microtribological properties of the MoS₂ film exposed to atomic oxygen, ultraviolet rays and radiation both in low earth orbit (LEO) and in ground-based facility were evaluated relevance to micro/nano satellites. MoS₂ samples are exposed to LEO space environment by the space environment exposure device experiment on international space station. Laser-detonation atomic oxygen beam source was used for atomic oxygen simulation on the ground. X-ray photoelectron spectroscopy and energy dispersive spectroscopy measurements suggested that electron beam and ultraviolet exposure did not affect chemical structure of MoS₂ surfaces. However, atomic oxygen-exposed and flight samples showed surface oxidation. It was found that the macroscopic friction coefficient of the flight sample was similar to that of the control sample. In contrast, remarkable increase in friction coefficient in microscopic properties was observed.     

直线翼垂直轴风力机起动性的实验研究

为探明直线翼垂直轴风力机的叶片个数对其起动性的影响,设计制作了可更换叶片个数(1～5枚)的风力机模型,通过风洞实验获得了起动力矩与转角的关系曲线,并与用单叶片力矩模拟的结果进行了对比。接着又制作了1台3叶片小型风力机模型,进行了烟线法可视化实验,获得了不同转角下的风力机周围流场迹线图。两项实验结果表明:增加叶片个数可使风力机平均起动性提高,但叶片间相互影响也增加,不同角度下各叶片周围流场受影响程度不同,对叶片受力和风力机起动力矩的影响程度和趋势也不同。     

Response compensation of fine‐wire thermocouples and its application to multidimensional measurement of a fluctuating temperature field

A novel sensor technique is proposed to visualize readily the spatiotemporal behavior of a fluctuating temperature field of air flow. Two temperature probes were fabricated: a rod‐type probe consisting of 24 two‐thermocouple sensors set in line, and a plane‐type probe with 64 two‐thermocouple sensors arrayed on a two‐dimensional grid (8 × 8 points). Each two‐thermocouple sensor used in these probes was composed of two fine‐wire thermocouples (type K) of unequal diameters of 25 and 51 μm, respectively. An adaptive response‐compensation scheme was applied to accurately reconstruct rapidly‐changing airflow temperatures. The plane‐type probe enables visualization of fluctuating temperature fields of an artificially disturbed hot‐air jet and of the adequate capture of spatiotemporal behavior of a rapid circular motion of a hot‐air jet blown out from a hair dryer. A time‐constant estimation scheme was proposed to estimate instantaneous time‐constants which serve as a basis for a real‐time response compensation technique for multidimensional temperature measurement. In addition, by scanning a temperature field with the rod‐type probe, the temperature distribution can be reconstructed in one‐dimensional space and time. This quasi two‐dimensional visualization can become a prototype of a “scanner” for fluid temperature fields. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20355