摘要:

The nonlinearity of the relationship between the extensive and the intensive variables of an ideal energy‐storing thermodynamic system in equilibrium is expressed in terms of the higher‐order moments of the extensive variable, and is thus shown to have both an upper and a lower bound. The bounds are proportional to the size of the system and for most practical systems the upper bound is more restrictive. As an illustration, the bound is applied to the nonlinearity of varactor diode capacitors, and the lower bound is shown to be far from the presently achieved nonlinearity.

ISSN:0021-8979    

DOI:10.1063/1.326066

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Solid rotor iron‐free asynchronous machines are important for the achievement of high‐speed motors with high power‐to‐weight ratios. This paper presents a theoretical study of these machines, based on Maxwell’s relations, which is carried out using simplified two‐dimensional models. Results are compared to experimental measurements.

ISSN:0021-8979    

DOI:10.1063/1.326067

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Using a sensitive microprofilometer, the onset of yielding in the anvils of a supported opposed anvil device can readily be determined. If the pressure at which yielding occurs is measured, the yield stress of the anvil material can be obtained. This is illustrated for 3% cobalt cemented tungsten carbide. The reverse is also true and can be used as the basis for obtaining the transition pressures of a material that transforms to a conducting phase at a pressure near which yielding of the anvil material commences. This is illustrated for the gallium phosphide transition which is found to be near 18 GPa based on the commencement of yielding in boron carbide anvils. Moreover, the yield stress or Knoop hardness can be used as the basis for obtaining the ultimate attainable pressures in supported opposed anvil devices. Based on the measured yield stress of a maraging steel, and the experimental observation that the bismuth transition is near or at the ultimate attainable pressure of this steel in a supported opposed anvil device, the III–V transition is found to be near 7.7 GPa. Based on the Knoop hardness and the previously mentioned observation, this transition is found to be near 7.5 GPa. Based on the measured yield stress of a 3% cobalt cemented tungsten carbide anvil, the ultimate pressure attainable in a supported opposed anvil device is found to be about 18 GPa and in any case less than 19 GPa. Inasmuch as the gallium phosphide transition occurs near the limit of the ultimate attainable pressure with such tungsten carbide pistons, the transition pressure of gallium phosphide to a conducting phase under the stress state present there is near 18 GPa. Based on the ultimate attainable pressure in boron carbide pistons the completion of the transition of sulfur to a conducting phase is found to be less than 33 GPa. The yielding of supported opposed diamond anvils with dislocation densities of ∼5×104/cm2or more is expected to be in the neighborhood of 50 GPa. The onset of this yielding could be used as the basis for determining approximately the transition pressure of silicon carbide to a conducting phase at an estimated value of 64 GPa.

ISSN:0021-8979    

DOI:10.1063/1.326068

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Separation measurements have been made for neon isotopes penetrating a nitrogen jet over a broad range of flow regimes. The products of the jet‐background interaction were collected by molecular probes which projected through the jet orifice from the plenum into the background chamber. The separation profiles are in excellent agreement with a very simple physical model of the penetration process. This model can be used to predict the performance of any isotopic separation experiment and has been shown to agree with another investigator’s argon and SF6data. The amount of separation is adjustable, does not appear to be limited, and thus can be arbitrarily large. The apparatus required is particularly simple to construct.

ISSN:0021-8979    

DOI:10.1063/1.326069

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The motion of a charged particle in a linear electromagnetic device can often be analyzed by using the transport matrices. For an electron storage ring, this technique has been applied to yield fruitful results such as the trajectory of the particle distribution center and the beam sizes and shapes in phase space. Coupling effects among the horizontal, vertical, and longitudinal motions are included in a straightforward manner.

ISSN:0021-8979    

DOI:10.1063/1.326070

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The width of the inverted Lamb dip in H2CO at 3.51 &mgr;m [51,5(ground state) →60,6(v5=1)] was measured by using a low‐noise He‐Xe laser in an axial magnetic field as the light source. To measure the dip width it was necessary to determine first the range of the magnetic field strength and the maximum frequency deviation of the laser frequency modulation. Based on these results, the power‐broadening characteristics were measured. Finally, the relation between the dip width free from the power broadening and the pressure of H2CO was obtained. The dip width (HWHM) was &Dgr;&ngr;h= (123±24)+(155±31)PF(kHz), wherePFrepresents the H2CO pressure expressed in Pascal.

ISSN:0021-8979    

DOI:10.1063/1.326071

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Electromagnetic transmission in a straight cylindrical tunnel with imperfectly conducting walls is considered when the cross section is in elliptical form. The presence of a thin axial conductor is also allowed for in the boundary‐value formulation. The general matrix solution is simplified by invoking the quasistatic approximation which is shown, at least for circular tunnel geometry, to be valid for frequencies up to 20 MHz. The results of the quasistatic calculations indicated that the attenuation rate of the dominant mode is relatively insensitive to the ellipticity if the cross‐section area and the cable‐to‐wall separation is kept constant.

ISSN:0021-8979    

DOI:10.1063/1.326072

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A continuum mixture theory with microstructure is developed for electromagnetic wave propagation in laminated waveguides. The theory leads to simple governing equations for the actual composite which retain the integrity of the propagation process in each constituent but allow them to coexist under derived interactions. The utility of the resulting equations is demonstrated by studying the response of the composite to harmonic excitations. In this case the dispersion relations are found to correlate well with some derived exact solutions.

ISSN:0021-8979    

DOI:10.1063/1.326073

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A new resonance principle in optical filters has been utilized to simultaneously permit realization of wide field‐of‐view (∼2&pgr; sr) and very narrow acceptance bandwidths, approaching 0.01 A˚. A light signal is transmitted through an outer bandpass filter into a resonantly absorbing atomic vapor, resulting in a fluorescence signal at a different wavelength which is transmitted through an inner bandpass filter. The outer and inner bandpass filters have no common transmission band, resulting in complete blockage of all optical signals (background noise) that are not resonantly shifted in wavelength by the intervening atomic vapor. This ’’resonance filter’’ principle is experimentally verified, and system parameters are discussed for filters utilizing potassium, rubidium, or cesium vapor at nine wavelengths between 420 and 532 nm.

ISSN:0021-8979    

DOI:10.1063/1.326074

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

This paper applies a theoretical process model developed by Dilletal. to the polychromatic exposure systems. Exposure and development of a positive photoresist are treated with computer simulation for both contact printing and projection printing. Optical interference within resist film and the effect of it on the development condition are investigated theoretically. The results for the two printing systems are compared in order to clarify the differences between contact exposure and projection exposure. It was made clear that (1) the optical interference still has a considerable influence on the condition imposed on the photolithographic process even in the polychromatic exposure environment and (2) the projection exposure with two spectral lines is more sensitive to such parameters as the thicknesses of resist film and the underlying oxide layer than the contact exposure with three spectral lines.

ISSN:0021-8979    

DOI:10.1063/1.326075

出版商:AIP    

年代:1979

数据来源: AIP