摘要:

A retardation lens has been placed between the resolving slit and the ion detector in a mass spectrometer. It has been used to reject ions that have lost significant energy by collision with residual gas atoms in the system. Several types of lens have been investigated. A considerable increase in the abundance sensitivity on both the high and low mass side of a peak results from the use of this device.

ISSN:0034-6748    

DOI:10.1063/1.1720931

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A complete profile of automatic acceleration for an analytic ultracentrifuge is established with an electronic speed control system. Motor current is controlled by a Sola (resonant transformer) resonant current source during acceleration and when the rotor reaches full speed the Sola saturates, forming a constant voltage regulator. As full speed is approached, a closed loop system is introduced which compares the frequency of a magnetic‐geartooth counter to a reference circuit and then applies the error as voltage increments to the drive motor. To evaluate performance, a computer program was developed to compare manual control with the automated system. Results indicate greater accuracy in the automated system for the integrated &ohgr;2dtduring the acceleration phase of ultracentrifuge operation, and extremely stable and accurate control of final speed (to within 10 ppm or less).

ISSN:0034-6748    

DOI:10.1063/1.1720932

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A torsion pendulum has been developed which obtains automatically a permanent record of the longitudinal and torsional resonant frequencies of polycrystalline bulk samples. Shear moduli of pure metals and alloys have been measured with this apparatus at room temperature to a reproducibility of approximately 0.1%. The maximum sensitivity was obtained when the piezoelectric pickup crystal was not attached directly to the apparatus, but was fastened to the mounting bracket.

ISSN:0034-6748    

DOI:10.1063/1.1720933

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A quadrupole lens pair is described utilizing permanent ceramic magnets. The field gradient is 470 Oe/cm, across a 7.94‐cm aperture. Variation in lens strength is achieved by driving the lenses over a mild steel magnetic shunt welded to the inside of the beam tube. The lenses are of relatively low cost, light weight, and simple construction. Of the two units described, when used at full strength, the smallest lens pair brings a 10‐MeV proton beam to a focus in a distance of 4 m from it.

ISSN:0034-6748    

DOI:10.1063/1.1720934

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A sample is enclosed in a liquid‐containing steel capsule 3.81 cm in length and 1.27 cm in diameter, which in turn is placed in the pyrophyllite cube normally used as the sample chamber of a 2000‐ton hexahedral press. When pressure is applied in the normal manner, it is transmitted to the enclosed sample by a 1:1 mixture of isopentane and pentane. Successful measurements utilizing six electrical leads into the sample region have been made. A manganin gauge to 60 kbar is demonstrated and used to study previously unobserved time‐dependent pressure variations attributed to the pyrophyllite flow in the solid‐media apparatus.

ISSN:0034-6748    

DOI:10.1063/1.1720935

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

Heat transfer rates across various types of soft solder joints are investigated between 0.06 and 0.5°K using a3He−4He dilution refrigerator. For Cd‐Bi junctions and thin (10 &mgr;) Sn‐Pb junctions, the heat flux per unit area and unit temperature difference is 4.7×106T2.74erg/sec. This rate is about twice that predicted by the theory of Little. Junctions of Sn‐Pb and Sn‐In about 40 &mgr; thick have a much lower conductance. The thermal conductivity of bulk Sn‐Pb solder is found to be 9900T2.31erg/sec‐cm‐°K.

ISSN:0034-6748    

DOI:10.1063/1.1720936

出版商:AIP    

年代:1967

数据来源: AIP

摘要:

A micropenetrometer was constructed using a linear variable differential transformer mounted on a balance arm. Surface contours obtained with this instrument indicate the size of surface irregularities and deviations from planarity. The sizes of colloidal particles in the micron range were determined for a thermosetting epoxy polymer.

ISSN:0034-6748    

DOI:10.1063/1.1720937

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1720938

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1720939

出版商:AIP    

年代:1967

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1720940

出版商:AIP    

年代:1967

数据来源: AIP