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91.
H. O. Menlove M. M. Fowler E. Garcia M. C. Miller M. A. Paciotti R. R. Ryan S. E. Jones 《Journal of Fusion Energy》1990,9(4):495-506
Experiments using high-efficiency neutron detectors have detected neutron emission from various forms of Pd and Ti metal in pressurized D2 gas cells and D2O electrolysis cells. Four independent neutron detectors based on3He gas tubes were used. Both random neutrons (0.05–0.2 n/s) and time-correlated neutron bursts (10–280 n) of 100-s duration were measured using time-correlation counting techniques. The majority of the neutron burst events occurred at –30°C as the samples were warming up from the liquid nitrogen temperature. 相似文献
92.
Babbs C.F. Fearnot N.E. Marchosky J.A. Moran C.J. Jones J.T. Plantenga T.D. 《IEEE transactions on bio-medical engineering》1990,37(7):662-672
This paper describes simulation of steady-state intratumoral temperatures achieved by a simple modality of local heat therapy: interstitial treatment with parallel arrays of warmed, conductive heating elements. During "conductive heating" power is directly deposited only in the interstitial probes. Adjacent tissue is warmed by heat conduction. Simulations of interstitial conductive heating involved solution of the bioheat transfer equation on a digital computer using a finite difference model of the treated tissue. The simulations suggest that when the complete temperature distributions for conductive interstitial hyperthermia are examined in detail, substantial uniformity of the temperature distributions is evident. Except for a thin sleeve of tissue surrounding each heating element, a broad, flat central valley of temperature elevation is achieved, with a well defined minimum temperature, very close to modal and median tissue temperatures. Because probes are inserted directly in tumor tissue, the thin sleeve of overheated tissue would not be expected to cause normal tissue complications. The temperature of the heated probes must be continuously controlled and increased in the face of increased blood flow in order to maintain minimum tumor temperature. However, correction for changes in blood flow is possible by adjusting probe temperature according to a feedback control scheme, in which power dissipation from each probe is the sensed input variable. Conductive interstitial heating with continually controlled probe temperature deserves investigation as a technique for local hyperthermia therapy. 相似文献
93.
The effect of rapid solidification on the corrosion behaviour in aerated 0.001 M NaCl solution of Mg-Al alloys containing 9.6 to 23.4wt% AI has been investigated in comparison with chill-cast material. Polarization studies show that rapid solidification decreases corrosion current by up to two orders of magnitude corresponding to a corrosion rate of 6 to 11 mil y–1. Increasing the aluminium content in solid solution by rapid solidification gave rise to a steep increase in pitting potential between 10 and 23 wt% Al and resulted in development of an anodic plateau at 30Acm–2 attributable to magnesium depletion for the alloy surface and formation of a protective film. Chemical analysis of the electrolyte as a function of dissolution time for the rapidly solidified material indicated that initially only magnesium dissolved and that this dissolution of magnesium ceased within 2 to 5 min. The results indicate the formation of an aluminium-enriched interdiffusion zone at the surface underlying a more stable surface oxide than for ingot-processed Mg-Al-based alloys. 相似文献
94.
Time-of-flight secondary ion mass spectrometry has been used to study the interaction of -amino propyl triethoxysilane with an E-glass surface. The fragmentation pattern has been interpreted by assigning a series of mass peaks to the structural unit of the poly(aminosiloxane). The composition of the coating is complicated by the presence of polydimethylsiloxane and its copolymers. The highest mass fragment was obtained from the coating exposed by extraction with warm water (697 AMU). The largest molecular fragments would appear to have degrees of polymerization of 6 with differing numbers of silanol groups. On re-extraction with hot water the fragment size decreased. It is postulated that the network chain length of the three-dimensional polymer decreased as the interface was approached. At the glass surface a chemically bound molecular layer could be identified. The full chemical nature of the deposit is complicated by the incorporation of aluminium from the substrate into the coating. It was also possible to confirm that a layer of warm-water soluble oligomers existed at the air interface. 相似文献
95.
Jones AD Homan AC Favell DJ Hitchcock CH Berryman PM Griffiths NM Billington MJ 《Meat science》1985,15(3):137-147
Protein-bound N(τ)-methylhistidine (N-MeHis) has been suggested as an index for the estimation of muscle (meat) protein in meat and meat products. This paper examines the levels of N-MeHis in a range of six prime beef cuts together with beef flank, cheek, mechanically recovered meat (MRM) and offals. The study was undertaken by two separate laboratories using a previously reported HPLC procedure involving the conversion of N-MeHis to a fluorescent derivative. It is shown that, whilst similar N-MeHis levels are present in the prime cuts, there is considerable variation in those found in the other cuts and offals. The average N-MeHis level in six prime cuts observed at both laboratories is 122 μg/g fat-free connective tissue-free (FFCF) meat; however, flank exhibits apparently high N-MeHis levels, whilst cheek and MRM contain only approximately 70% of the level found in the prime cuts. The offals contain between 0 and 65% of the N-MeHis level found in prime cuts. The greater variability and the often lower value of the N-MeHis content of these legitimate meat materials preclude the establishment of a single realistic index for FFCF beef, and present fundamental problems for the assessment of the lean meat content of manufactured beef products by N-MeHis determination. 相似文献
96.
Jones Robert M. Webster John G. Keesey Ulker Tulunay 《IEEE transactions on bio-medical engineering》1972,(1):29-33
In normal vision, eye movements cause the image to move on the retina. Special apparatus can stabilize the image on the retina so it cannot move, and vision fades away. Previous methods for stabilizing the image were either optical systems or complex computer-controlled feedback systems. A simpler feedback system is presented which detects eye motion and rotates a mirror through which the target is viewed, to exactly compensate for eye motion. Unlike previous optical systems, this new system has no lenses in either the viewing or the image-forming path to limit the spatial resolution. 相似文献
97.
57Fe Mössbauer spectroscopy has been used to characterize the iron-bearing minerals present in some British Columbia coals. The minerals observed in a range of samples include pyrite/marcasite, siderite, jarosite, rozenite or melanterite, and Fe2+ -bearing clay minerals such as illite. The presence of jarosite is confirmed through the magnetic hyperfine interaction observed at 4.2 K. The absence of magnetic ordering at 4.2 K for the ferrous sulphate component indicates the presence of rozenite, FeS04 · 4H20, or melanterite, FeS04 · 7H20, rather than szomolnokite, FeS04 · H20 or FeS04. The effects of ashing on two of the coals is also studied. 相似文献
98.
G. T. Jones L. A. Glasgow L. E. Erickson S. A. Patel C. H. Lee 《Chemical Engineering Communications》1990,97(1):181-196
Understanding the dynamic phenomena of viability loss of shear sensitive cells and bubble breakage and coalescence within airlift reactors requires knowledge of local, liquid-phase hydrodynamics. The laser-Doppler velocimeter (LDV) is a non-invasive instrument which may be used to obtain this information. Experimental procedures and software were developed to detect and measure Doppler bursts in two-phase flow in a split-cylinder airlift reactor. Off-line analysis of the data indicated a detection rate approximately one order of magnitude greater than that observed using an available commercial frequency tracker. Approximately 400 to 500 observations are needed for the ensemble mean to characterize the local mean velocity to within ±5% for a superficial gas velocity of 10.4 cm/s, the highest superficial gas velocity used in these studies. The limitations, prospects, and signal-processing options for LDV in this application are also discussed 相似文献
99.
Analysis of the carbon disulphide extracts of nine samples of UK coal-maceral concentrates by 1H highresolution n.m.r. spectroscopy, gas-liquid chromatography and field-desorption mass spectrometry indicates the presence of components with a wide molecular weight range extending up to 1200 amu; these are attributed to n-alkanes up to ≈C50 and highly condensed polynuclear aromatic compounds. 相似文献
100.
A method of analysing solids downflow through standpipe and slide valve in the moving bed mode is presented. The method is based on combining Yoon and Kunii equations for moving-bed flow with a proposed modified orifice equation for gas—solid flow. The analysis correctly predicts the observed trend of the effects of gas injection into the standpipe. It also provides quantitative prediction of the conditions for transition from moving-bed flow to dense phase fluidized solids flow and to lean phase “streaming flow”. The latter flow pattern refers to solids streaming down a tube at high voidage typified by the discharge of solid down a tube with no constriction at the lower end of the tube. Further work is required to test the general applicability of the present analysis and to extend the analysis to yield a generalized quantitative flow regime diagram for downflow of solids in a pipe. 相似文献