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61.
A simple method which maintains the hydraulic pressure at a constant level during fixation of organs by perfusion is described. This is obtained by means of a glass tube interposed between a peristaltic pump and the organ to be perfused, the specially designed glass tube acting as a safety valve. The efficiency of the system is tested by electromagnetic pressure recording. 相似文献
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In order to solve a power consumption problem of the driver stage in the cathode-follower RF system, a grid-cathode driving scheme is investigated by means of an isolation transformer. A very low output impedance can be realized together with a voltage gain a few tens of times higher than that of a cathode-follower. The model system has been tested under frequency modulation in the 1-3-MHz range at 40-Hz repetition; the output impedance is less than 30 Ω and the driver voltage 62 V to produce a 1.2-kV peak at the cavity gap 相似文献
66.
Observation of atomic steps on single crystal surfaces by a commercial scanning electron microscope.
Atomic steps on (111) and (100) crystal surfaces of Pt were observed using a commercial scanning electron microscope (SEM) in secondary electron mode. By comparing the SEM images and those by reflection electron microscopy (REM), the observed contrast was confirmed to be that from atomic steps on crystal surfaces. The contrast mechanism is briefly discussed. One application of this imaging technique is also shown. 相似文献
67.
Lee SY Kolski J Liu Z Pang X Park C Tam W Wang F 《The Review of scientific instruments》2007,78(7):075107
A low energy electron storage ring is designed to have many desirable properties, such as varying momentum compaction factor, damping partition numbers, favorable betatron tunes for multiturn accumulations, and excellent dynamic aperture. This storage ring can be used for debunching rf linac beams in one turn, for compression of linac pulses, and more importantly for a compact photon source based on inverse Compton scattering of laser beams. 相似文献
68.
Huang TX Ding YK Zheng ZJ Miao WY Cao ZR Jiang SE Liu SY Liu ZL 《The Review of scientific instruments》2008,79(5):053503
A novel inversion technique is proposed to unfold core asymmetries at the source with x-ray emission images, which were obtained from imploded surrogate capsules in symmetry diagnostic experiments. The axisymmetrical core emission can be expanded as a Fourier series, with Legendre polynomials and spherical Bessel functions as bases concerned with polar angle and radius, respectively. A least-squares estimator is employed to obtain the unknown coefficients from its two-dimensional image data. The unfolded Legendre coefficients can be further used to test modeling of drive asymmetries in hohlraums. This technique is also demonstrated with a proof-of-principle experiment performed on the Shenguang II laser facility [L. Zunqi et al., Chin. J. Lasers B10, 6 (2001)]. 相似文献
69.
J.S.Wang ) M.L.Zhou) J.X.Zhang) Z.R.Nie) T.Y.Zuo) G.J.Zhang) ) State Key Laboratory of Materials Chemistry Applications Peking University Beijing China) Schoolof Materials Science Engineering Beijing Polytechnic Univers 《金属学报(英文版)》1999,12(4):602-606
1.IntroductionAsanewkindofrareearthmolybdenumcathodematerial,MoY2O3isexpectedtosubstituteradioactiveWThO2cathodematerialsinthefuture.Mo4wt%Y2O3allows,relativetoMoLa2O3〔12〕(whichhasbeenwidelystudiedsince1970sinordertosubstituteWThO2cathodemater… 相似文献
70.
S. Y. Gerlsma 《Starch - St?rke》1970,22(1):3-9
The effect of polyhydric and monohydric alcohols, of phenols, of carboxylic acids and their anions, of halide anions, of alkalimetalions and of some other compounds on the gelatination temperature of potato starch granules in aqueous solutions were studied. Polyhydric alcohols and methanol raise the gelatination temperature, whereas ethanol, propanol, butanol, p-dioxane, carboxylic acids, phenols, urea and hydrogen peroxide cause a decrease in the gelatination temperature. The effect of polyhydric alcohols may be attributed to the lessened tendency of the medium to rupture hydrogen bonds. Carboxylic acids, phenols, urea and hydrogen peroxide may act in a opposite way. The lowering effect of the monohydric alcohols, dioxane, and other non-polar substances may be due to structural and kinetic alterations of the aqueous medium, induced by the non-polar groups. At higher concentrations of ethanol, propanol, p-dioxane, acetic, propionic and butyric acid the gelatination temperature tends to increase. This is to be attributed to the association of solute molecules. 相似文献