Ten radionuclides in the standard reference material SRM 4350B(~(60)Co,~(137)Cs,~(152)Eu,~(154)Eu,~(226)Ra,~(4O)K,~(232)2Th,~(235)U,~(238)U,~(228)Th)weremeasured by intercomparison laboratoris,the measured results areanalysed in the paper.

Compared with the isolation of PGR or PGR+NGR,the measured results show that the isolation degree of this structure is improved by 29.2 and 8.1dB at 1GHz,and by 8.1 and 2.5dB at 2GHz,respectively. With a 1.8V supply,each channel of the front-end amplifier consumes a DC power of 85mW,and the total power consumption of 12 channels is about 1W.

The measured results show that the reflectivity at 632.8 nm is no less than 95.0%, the reflectivity at 1 315 nm is no less than 99.8%, and phase retardance at 1 315 nm is 90.235°～95.586°.

Measured results show that the operating frequency is 3 900 MHz,output power of larger than 10 dBm and phase noise of-102 dBc/Hz@1 kHz,-128 dBc/Hz@10 kHz are achieved.

测试结果表明:该振荡器工作频率3 900 MH z,输出功率大于10 dBm,相位噪声达到-102 dB c/H z@1 kH z; -128 dB c/H z@10 kH z。

The measured results show that, the mm-wave frequency synthesizer can output signal at the frequency range of 34.5~35.5GHz with step of 10MHz, and the phase noise performances in the above frequency range are better than –82.7dBc/Hz@1kHz and –83.8dBc/Hz@10kHz.

The example shows that terminal temperature(293.15 K) and vacuum degree(0.01514 Pa) could be measured by the method as KNO_3 solution consisted of NO~-_3(26.85%),Cl~-(13.35%),NH~+_4(7.79%),and the measured results were almost identical with experimental results.

Chlorhexidine content in solution was measured by high performance liquid chromatography at 253 nm wavelength at which chlorhexidine has characteristic absorption peak and there is minimal interference For the solution containing chlorhexidine ≤0 4222 mg/ml, the deviation of measured results was ≤1 4%

Practical circuits are fabricated, and the measured results agree well with the simulated results.

The measured results show that magnetostriction is related to the thickness of the ribbons, and its maximum value, -2100 ppm, has been obtained in the ribbon with a thickness of 75 μm.

The formulas for calculating visibility with this method and analysing the effect of non-black object on measured results have also been derived.

The calculated pressure coefficient and temperature coefficient of ultrasonic velocity are in good agreement with the measured results.

The measured results of ultra micro centrifugal compressors are shown.

Summary The efficiency of thermistor mount is defined as the ratio of power absorbed by thermistor to the total input power in mount.Because of losses caused by waveguide wall,casing of thermistor and poor contact etc,the efficiency is always less than one hundred percent. Determination of efficiency of thermistor mounts prossessed practical importance for the error analysis and calibration of powermeter.It is also important for the research or improvement of thermistor mounts. After the publication of first...

Summary The efficiency of thermistor mount is defined as the ratio of power absorbed by thermistor to the total input power in mount.Because of losses caused by waveguide wall,casing of thermistor and poor contact etc,the efficiency is always less than one hundred percent. Determination of efficiency of thermistor mounts prossessed practical importance for the error analysis and calibration of powermeter.It is also important for the research or improvement of thermistor mounts. After the publication of first paper concerning the method of measurement due to Kerns in 1949,fine papers have been published successively in foreign periodicals up to 1961.This paper reviews in general the fundamental tocory and methods of measurement,and then derives an expression used to calculate the efficiency in terms of input impedance at voltage minimum.In the formula there is advantage of simplioity in measurement and computation of efficiency.The curves of input impedance at voltage minimum with respect to thermistor impedance are in complete agreement with approximate straight lines given by Ginzton. In this paper measured results have been tabulated for the efficiency of tuned thermistor mount in X-band.The results based on different methods have been compared one another.At the end of the paper the restrictions of application of different methods are discussed and the topics to be considered further are suggested,

Measurements of electrical properties using the Van der Pauw technique have been made on the n-type and p-type silicon carbide single crystals and epitaxial layer having resistivity from 10-3 to 102 ohm-cm. Experiments on the selection of measuring conditions and comparison between the Van der Pauw method and the conventional method have been performed. It is found that the magnitude and stability of contact resistance greatly affect the measuring results. Among the pressure contacts studied, indium...

Measurements of electrical properties using the Van der Pauw technique have been made on the n-type and p-type silicon carbide single crystals and epitaxial layer having resistivity from 10-3 to 102 ohm-cm. Experiments on the selection of measuring conditions and comparison between the Van der Pauw method and the conventional method have been performed. It is found that the magnitude and stability of contact resistance greatly affect the measuring results. Among the pressure contacts studied, indium contact has the lowest contact resistance, while copper, tin, and phosphor-bronze contacts must be electrically formed before use. With different electrode materials and sample currents, the deviation of values obtained is about 2%. It is suggested that the sample current should be chosen in accordance with the resistivity and contact resistance of the specific sample. As compared with the conventional method, the Van der Pauw method can give higher precision and reproducibility. High temperature electrical properties of silicon carbide single crystals have been measured in a temperature range from room temperature to 1000 K, and the ionization energy of nitrogen donors is found to be 0.056 eV. Anomalous phenomena that result in experimental errors and their origins are discussed.

The electromagnetic impulse sound-source is a novel device which is capable of radiating high-power wide-band sound pulse with good repetition. In this paper, the functional principle of this device is first analysed from the viewpoint of circuits, and working formulas are obtained for designing such device. The circuitry and construction of a 1000-joule sound-source system are described. The measured results of the sound-source are given, which are in agreement with the theoretical results.