Ir-base refractory superalloys for ultra-high temperatures

The microstructure and compression strengths of Ir-15 at. pct X (X=Ti, Ta, Nb, Hf, Zr, or V) binary alloys at temperatures between room temperature and 1800 °C were investigated to evaluate the potential of these alloys for ultra-high-temperature use. The fcc and L1₂ two-phase structures of these alloys were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The strengths of the Ir-Ta, -Nb, -Hf, and -Zr alloys were above 800 MPa at temperatures up to 1200 °C and about 200 MPa at 1800 °C. The strengths of these alloys under 1000 °C are equivalent to or higher than those of the commercially used Ni-base superalloys, MAR-M247 and CMSX-10. The Nb concentration dependence of strength was investigated using a series of Ir-Nb alloys with Nb concentrations from 0 to 25 at. pct. It was found that the Ir-base alloys were strengthened by L1₂ precipitation hardening. The potential of the Ir-base alloys for ultra-high temperature use is discussed.     

One Method of Determination of the Effective Absorption Coefficient in Pulsed Laser Irradiation of Metals

An experimentaltheoretical method of determination of the absorption coefficients in laser treatment of metals has been proposed based on the solution of the boundaryvalue axisymmetric problem of heat conduction for a halfspace and metallographic measurements of the dimensions of the thermalhardening zone.     

Integrated light collimating system for extended optical-path-length absorbance detection in microchip-based capillary electrophoresis

We have developed an integrated light collimating system with a microlens and a pair of slits for extended optical path length absorbance detection in a capillary electrophoresis (CE) microchip. The collimating system is made of the same material as the chip, poly(dimethylsiloxane) (PDMS), and it is integrated into the chip during the molding of the CE microchannels. In this microchip, the centers of an extended 500-microm detection cell and two optical fibers are self-aligned, and a planoconvex microlens (r = 50 microm) for light collimation is placed in front of a light-delivering fiber. To block stray light, two rectangular apertures, realized by a specially designed three-dimensional microchannel, are made on each end of the detection cell. In comparison to conventional extended detection cell having no collimator, the percentage of stray radiation readout fraction in the collimator integrated detection cell is significantly reduced from 31.6 to 3.8%. The effective optical path length is increased from 324 to 460 microm in the collimator integrated detection cell. The detection sensitivity is increased by 10 times in the newly developed absorbance detection cell as compared to an unextended, 50-microm-long detection cell. The concentration detection limit (S/N = 3) for fluorescein in the collimator integrated detection cell is 1.2 microM at the absorbance detection limit of 0.001 AU.     

Studies on interaction of Nd3+ — Glass laser light with armco-Fe high pressure nitrogen medium

Some effects of the interaction of Nd³⁺-glass laser, working in ordinary generation regime, with Armco-Fe surrounded by nitrogen in the pressure range (1–109) atm. have been investigated. Thephenomenon of capillary waves and the increase of the N₂ content have been observed in the irradiated area. The mechanism of the laser light interaction with the metal is discussed in terms of plasma theory and X-ray analysis.     

Electrospray ionization with a pointed carbon fiber emitter

A new type of electrospray ionization emitter employing a pointed carbon fiber has been developed for interfacing nanoliquid sampling techniques to mass spectrometry. The pointed carbon fiber protruding from an orifice with a surrounding hydrophobic surface confines a small Taylor cone at the tip, which generates a stable electrospray at the tip point. The small Taylor cone improves the electrospray efficiency thereby enhancing the detection limit. This emitter is rugged and able to generate stable electrospray over a wide range of flow rate, ESI voltage, and surface tension variation. Using a solution of angiotensin I, the carbon fiber emitter in 75-microm-i.d. fused-silica tubing was shown to give ion current comparable to that from a commercial 8 microm orifice nanospray emitter. Use of the emitter for ESI-MS/MS analysis of peptides was examined by infusing a mixture of cytochrome c and myoglobin tryptic digest peptides. Protein identification was demonstrated at the level of less than 1 fmol of the peptide consumed. The use of the carbon fiber emitter for interfacing monolithic capillary HPLC to MS was also demonstrated.     

颅脑损伤治疗仪的研究

本项研究是一种高氧低温式颅脑损伤治疗仪.它设有颅脑罩,颅脑罩扣合在底板上,颅脑罩上分别设置有与其内腔相通的进氧口,进冷口及阀门.制氧由电子制氧机制氧充入颅脑罩内,低温由晶体管降温技术降温,使罩内温度降至4℃左右.本仪器是在计算机控制下,使罩内达到高氧低温.在此环境内,能够对伤者头部进行均匀供氧并保持低温状态,使之达到治疗目的.它的特点是操作简单,治疗效果好,治疗费用低.