摘要:

The properties of an intense neutral beam injector, the modified duoPIGatron ion source, are discussed and compared with other injectors. For this source (a) beam composition for hydrogen is ∼ (85±5) % monatomic, (b) nucleon gas efficiency is 50%, (c) the electrical efficiency of ion generation is 1.1 A/kW, and (d) up to 52% of the input power is delivered in the ion and neutral beam to a target subtending a half angle of 1.8°×1.4°.

ISSN:0034-6748    

DOI:10.1063/1.1135901

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The attenuation of turbulence and mean velocity signals due to the line averaging imposed by hot wires when used in the wake of an isolated circular cylinder has been investigated in a wind tunnel by measurements using several choices of hot‐wire length, cylinder diameter, and freestream mean velocity. The results are presented graphically in order to provide a practical method for determining attenuation of the turbulence and mean velocity signals obtained in a wake. The length scale of the wake can be defined asL=0.6[(x−xo)d]1/2, wherexis the downstream distance from the cylinder,dis the cylinder diameter, andxo=25d. For all the wires tested, the attenuation of the measured turbulence signal is limited to within 5% only if the wire length is smaller than 0.1L. For a wire normal to the cylinder and cross wind, the attenuation of the signal of the mean velocity‐defect factor, expressed as (1−u/u∞), whereuandu∞are local and free‐stream velocities, respectively, is less than 5% only if the wire is less than 0.5Lin length.

ISSN:0034-6748    

DOI:10.1063/1.1135902

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A SQUID magnetometer used in the study of dilute magnetic alloys or other weak magnetic systems can be calibrated by using the nuclear paramagnetism of aluminum metal. This material is useful as a calibration standard since magnetic impurities such as Fe and Mn form no local moment. This calibration is compared to others obtained with CMN powder and indium metal.

ISSN:0034-6748    

DOI:10.1063/1.1135903

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The separated oscillatory field magnetic resonance technique (Ramsey technique) has been employed with flowing water as a volume averaging magnetometer. Polarization and detection were performed in high fields, external to the volume over which the magnetic field was to be averaged. An accuracy of a few parts in 107at a nominal field of 18 G was obtained. The technique is applicable, using standard equipment, for the measurement of fields ranging from kilogauss down to milligauss.

ISSN:0034-6748    

DOI:10.1063/1.1135904

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Pressure gradients in a diamond anvil cell have been measured with a 4:1 methanol:ethanol mixture as a pressure medium up to 350 kilobars. When pressure is applied rapidly, stress gradients are shown to be negligible up to 200 kilobars and probably above. With this procedure it is possible to significantly increase the precision of pressure measurements above 100 kilobars.

ISSN:0034-6748    

DOI:10.1063/1.1135877

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An experimental device consisting of a plane source of charged particles and of a magnetic spectrometer equipped with horizontal and vertical diaphragms is considered. An analysis intended to achieve an exact analytical expression to connect the observed particle flux to the source emission and spectrometer transmission characteristics is developed. An analytical expression for the average value of the source brightness that is actually obtained from corpuscular flux measurements is also given. The effectiveness of the diaphragms in defining the domains of the initial conditions of the particles is also emphasized and general definitions of these domains are introduced. These definitions are stated for exact optical transformations, i.e., accounting for geometric and chromatic aberrations, and for general positions of the diaphragms along the optical axis as well as for symmetrical or asymmetrical apertures of the same. The results obtained and the introduced definitions will be used in Part II of this work. The important case of a thick source is considered in Appendix A.

ISSN:0034-6748    

DOI:10.1063/1.1135878

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

On the basis of the analysis developed in Part I and of the definitions therein introduced, a procedure for the calculation in the Gaussian approximation of the integral quantities characterizing the momentum transmission of a magnetic spectrometer is carried out. Such procedure applies both to symmetrical or asymmetrical diaphragm apertures and for diaphragms located anywhere along the optical axis.

ISSN:0034-6748    

DOI:10.1063/1.1135879

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A microprocessor‐controlled inhalation exposure system (MCIES) has been built to automate aerosol generation and sampling while controlling exposure time for animal toxicity studies. The system has a time resolution of 0.1 s and automatically sequences the exposure events from initiation to temination of the exposure. The operator is required to preset all airflows, read in a paper tape containing the time sequence of events, and initiate the automatic sequence by closing a switch.

ISSN:0034-6748    

DOI:10.1063/1.1135880

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The classical way of preparing thin films under one set of conditions and measurement of their properties under a different set of conditions produces large variations in film properties. A system has been designed which provides for measurements of many thin film parameters without removal from the deposition chamber. These parameters include thickness as well as film structural, electrical, and magnetic properties. Such an automatic film fabrication/measurement equipment is highly desirable for thin film research.

ISSN:0034-6748    

DOI:10.1063/1.1135881

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Conformal mapping is used to obtain an implicit solution for a slightly specialized version of a planar electrostatic mirror for which Bosi claims to have obtained an exact solution by means of a Taylor series in the ratio of two dimensions. It is shown that the intervention of logarithmic terms invalidates Bosi’s series after the first‐order term. Comparison of Bosi’s series for cylindrical and spherical mirrors with the exact expansion for an analogous planar problem suggests that in these cases not even the first‐order terms are valid.

ISSN:0034-6748    

DOI:10.1063/1.1135882

出版商:AIP    

年代:1979

数据来源: AIP