Effect of the Streamwise Component of the Vorticity Formed in a Turbulent Jet Source on the Acoustic Characteristics of the Jet

The results of an experimental study of the effects of different nozzle heads on turbulent jet noise are analyzed. A configuration of four cylindrical heads, tabbed heads, and chevron nozzles are considered and the decreases in the acoustic-mechanical efficiency of the jet (acoustic power reduction) for jets exposed to different modes of action are compared.It is shown that the effects of tabbed and cylindrical heads, as well as of chevrons, share a common property which is associated with the occurrence of vorticity in the jet source and can be described on the basis of a unified criterion characterizing the action on both the jet flow structure and the jet noise.     

Two photon optogalvanic spectrum of theD-X system of HgBr

Two photon laser optogalvanic spectrum of theD-X system of HgBr molecule has been recorded using Nd-YAG laser pumped dye laser for the first time. A large number of new bands involving higher vibrational levels have been observed. Isotopic heads due to the two bromine isotopes have been observed and used in fixing the vibrational assignment. Vibrational constants for theX andD states of the two isotopic molecules have been determined.     

A phenomenological model of percolating magnetic nanostructures

Transport and magnetotransport properties were analysed systematically in percolating magnetic nanostructures such as Ni-rich and films. These granular magnetic films exhibit giant Hall effect. We identified features which are common and unique to these systems. Among the features are the correlation between a -like temperature dependent resistivity and a particle size distribution having a large fraction of small nanometer sized particles, and the power law dependence between the magnetoresistivity and the room temperature resistivity. Assuming the presence of nanometer sized particles in the percolating conduction channels whose contributions are sensitive to temperature and the external magnetic field, we developed a phenomenological model to explain all the common features. Received 4 November 1998     

Stochastic resonance in ferromagnetic domain motion

A model for the motion of a single ferromagnetic domain is studied numerically and analytically. A single strip in two dimensions and pinned at two inhomogeneities is considered. We suppose two stable configurations (positively or negatively curved with pinned ends) due to the action of a bistable potential. Further, it is assumed that the domain is driven externally by periodic and noisy magnetic fields. The noise makes the domain able to flip between the two configurations. The small temporally periodic fields synchronize these flippings and the phenomenon of stochastic resonance is observed. The signal to noise ratio of the output is investigated and shows a maximum for a nonvanishing intensity of the applied noise. Its dependency on the stiffness of the domain is studied. Received 14 May 1999 and Received in final form 14 October 1999     

C_2a~3П_■.d~3П_g 态振动能级和基态离解能的实验研究

测量了 c_2放电管中 d~3Π_(?)→a~3Π_(?)跃迁电振光谱带系.观察到了(2、0),(1、0)(0、0)和(0、1)各带的带头头和若干“尾带”,从而确定了 a~3Π_u、d~3Π_8二个态的较高振动能级.将 d~3Π_g 能级外推得到 c_2基态的离解能 D(?)=5.05eV.     

虾蛄脂肪酸分析

用快速脂肪提取器对雄、雌虾蛄肉及虾蛄头中的脂肪进行了提取和测定。脂肪经KOH CH3OH溶液水解并甲酯化后 ,采用 60m× 0 .3 2mmi.d.交联PEG 2 0M弹性石英毛细管柱 ,FID检测器 ,结合GC MS ,对脂肪酸进行了分析。结果表明 :雄虾蛄肉脂肪含量为 5 .1 4 % ,不饱和脂肪酸占脂肪酸总量的 74 .7% ,其中多不饱和脂肪酸 (PUFA)为 4 9.3 % ,EPA +DHA为 3 0 .2 % ;雌虾蛄肉脂肪含量为 6.0 2 % ,不饱和脂肪酸占脂肪酸总量的 71 .5 % ,其中多不饱和脂肪酸 (PUFA)为 4 2 .1 % ,EPA +DHA为 2 5 .2 % ;虾蛄头脂肪含量为 5 .65 % ,不饱和脂肪酸占脂肪酸总量的 74 .3 % ,其中多不饱和脂肪酸 (PUFA)为 5 1 .5 % ,EPA +DHA为 2 9.7%。     

Review of perpendicular magnetic recording research at Fujitsu

Perpendicular magnetic recording (PMR) research and development (R&D) was carried out at Fujitsu for 32 years from 1978 to 2009, separated into three stages. We developed PMR for use in hard disk drives (HDDs). We sputtered Co-Cr alloy thin film onto a disk substrate and evaluated it using thin-film heads. Some interesting results were obtained at each stage. On the way we fabricated 1.8″ HDDs in 1992 and finally shipped the mass-produced PMR HDDs in 2006. Unfortunately, the HDD business at Fujitsu closed down. I would like to review the exceptional PMR research undertaken at Fujitsu.