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排序方式: 共有640条查询结果,搜索用时 31 毫秒
41.
Puchkova LV Zhiguleva EA Mokshina SV Sasina LK Tsymbalenko NV Platonova NA Giulikhandanova NE Sviridova TA Mishchenko BS Gaĭtskhoki VS 《Voprosy pitaniia》2000,69(1-2):15-18
The oxidase activity of ceruloplasmin (Cp, EC 1.16.3.1), the content of immunoreactive Cp and copper ion concentration were measured in the serum of eight day-old rats receiving either breast feeding (control group) or commercial nutritive mixture which has been recommended for the newborn children beginning from zero age (experimental group). It was shown that the artificial feeding caused almost 3-fold increase of Cp oxidase activity and copper content in the serum when compared to age-matched controls. No changes in the copper content per Cp molecule were observed. Dot-hybridization of the total liver polyribosomal RNA with Cp [32P]cDNA showed that the increased Cp level in the blood of the rats of experimental group correlated well with the level of expression of Cp gene. The copper content in the liver of experimental rats was two times lower that in control animals while no differences was found in the brain copper content between two groups of rats. The role of the regulation of Cp gene expression in the lactating mammary gland and of milk Cp in the copper homeostasis in the newborn body is discussed. 相似文献
42.
Sébald G Lebrun L Guyomar D 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(11):1491-1498
Electromechanical properties of (1-x)Pb (Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) single crystals with x = 0.35 were investigated as a function of different external disturbances. The polarization dependence on the electromechanical properties was first studied in order to determine the best polarization path. The correlation with X-ray measured phase ratio is presented and shows that the maximum of electromechanical properties may be correlated with a minimum rhombohedral/tetragonal phase ratio. Temperature, stress, electric field, and time (aging) stability was studied in order to determine performance-limiting factors of these materials. The rhombohedral/tetragonal phase transition is observed on temperature (80 degrees C), inducing a decrease of the electromechanical coupling factor (from 85% to 50%); but the whole properties are recovered while returning to room temperature. Stress measurement shows a large depoling of sample for stresses above 30 MPa. The PMN-PT single crystals were found to be surprisingly stable during aging, except for mechanical and dielectric losses. The same tendency was found on alternating current (AC) electric field dependence. 相似文献
43.
Wirelesslan have spread very quickly over the past few years. Demand for wireless access tolans has raised due to new mobile computing devices, such as laptops and personal digital assistants, and a desire for seamless and permanent connections to networks. Nevertheless a lot of security issues remain and stop its deployment in corporations. One of the most important issues is the authentication of a terminal to an Access Point. We propose an interface to integrate the Extensible Authentication Protocol into smart cards and will show that smart cards could constitute the de-facto device for authentication in Wirelesslan as they are forgsm and will be forumts (Universal Mobile Telecommunication System). 相似文献
44.
The use of optimization techniques in production control is discussed. Two optimization problems in relation to typical process industry complexes are formulated. A modified version of Tamura's algorithm is reviewed. The promising performance of the computerised algorithms is illustrated by numerical results. DISPATCHER, a practical operative decision support system, is described. 相似文献
45.
Druon F Sanner N Lucas-Leclin G Georges P Hansen KP Petersson A 《Applied optics》2003,42(33):6768-6770
We present the use of a photonic crystal fiber to straightforwardly compress ultrashort pulses from a diode-pumped ytterbium laser emitting around 1 microm. 75-fs pulse generation and a large 1-1.3-microm tunability for sub-100-fs pulses is reported. 相似文献
46.
Ga?lle?Poulenat Sabine?Sentenac Zéphirin?Mouloungui'ephirin.mouloungui@ensiacet.fr" title="z 'ephirin.mouloungui@ensiacet.fr" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author 《Journal of surfactants and detergents》2003,6(4):305-310
Sodium, lithium, and calcium soaps obtained by saponification of high-oleic sunflower oil were studied by Fourier-transform
infrared spectroscopy. Spectra of crude mixtures containing soap, glycerin, residual alkali, and triacylglycerols were compared
to those of pure soaps obtained from fatty acids. The infrared spectra of crude soaps showed the same characteristic bands
as pure ones. The absorption bands of asymmetric (ω2) and symmetric (ω1) stretching vibrations of the carboxylate group indicated that the metal-oxygen bonds of these soaps had an ionic character
whose strength differed from one cationic counterion to another. Once the characteristic absorption bands of the soaps were
assigned, a kinetics study of saponification was performed. Saponification by sodium, anhydrous lithium, and calcium hydroxides
was an autocatalytic reaction, characterized by an S-shaped kinetics curve, whereas saponification by aqueous lithium hydroxide
was stoichiometric. The structure of the metal-oxygen bond played a role in the kinetic mechanisms. 相似文献
47.
48.
Ga F. Umeda K. Nakajima K. Watanabe T. Takahashi M. 《Display Technology, Journal of》2007,3(4):392-397
A simple method of verifying electromagnetic interference (EMI) reduction effects for liquid crystal display (LCD) driver integrated circuits (ICs) is proposed. In this paper, we discuss correlations between radiated emissions and high-frequency currents of power system at three different levels: print circuit board (PCB) level, chip level, and functional circuit level. The EMI design points for LCD driver ICs are presented too. Simulated and measured results prove that our EMI design effectively reduces LCD EMI noise. 相似文献
49.
Guilian Ga Kenneth Honer 《集成电路应用》2007,(1):48-51
MRAM是一种很有希望的通用存储器候选技术。因为它具有非易失性、高速度、与常规CMOS的兼容性。以及抗辐射的潜力。PoP堆叠技术能够提高封装存储密度并有效地解决磁屏蔽问题。 相似文献
50.
Iman Shahosseini Elie Lefeuvre Johan Moulin Marion Woytasik Emile Martincic Gaël Pillonnet Guy Lemarquand 《Microsystem Technologies》2013,19(6):879-886
This work presents the conception, the microfabrication, and the electroacoustic characterization of a new electromagnetic microspeaker based on silicon. The objectives are to get improved sound quality compared to that of conventional microspeakers, while keeping the electroacoustic efficiency as high as possible. An optimized stiffening silicon microstructure let the sound radiator be extremely light and rigid. The mobile part is suspended to the fixed part by silicon suspension springs, which enable large out-of-plane displacement. The acoustic radiator is actuated by an electromagnetic motor, composed of a fixed permanent magnet and a planar coil located on top of the silicon radiator. The piston-like motion of the radiator favored by this structure is very beneficial for the sound quality. Electro–mechano–acoustic characterization of the microfabricated microspeaker showed that the radiator surface could run out-of-plane with displacements higher than ±400 μm, with no mechanical and electrical failure. For an electrical power of 0.5 W, the microspeaker was capable to generate a sound pressure level of 80 dB at 10 cm, from 330 Hz up to 20 kHz frequency. The efficiency reaches 3 × 10?5, that is to say three times more than typical efficiency of conventional microspeakers. Moreover, as characterization results showed, the existence of very few structural modes and the low electroacoustic distortions evidence the high sound quality of the microspeaker. 相似文献