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31.
Gary N. Kirby D. L. Sponseller L. H. van Vlack 《Metallurgical and Materials Transactions B》1974,5(6):1477-1494
The relative effects of chromium, molybdenum, and tungsten on the occurrence of σ phase have been studied in Ni-Co-Cr alloys.
These alloys were designed to simulate the γ matrix in commercial nickel-base superalloys that are strengthened primarily
by precipitation of the γ phase, based on Ni3Al. Three alloy series were studied. The first series comprised four alloys varying in chromium content from 34.63 to 43.65
at. pct. The other two series contained separate molybdenum and tungsten additions of 1, 2, 3, and 4 at. pct at constant chromium
contents of 37.5 at. pct. In each of the 12 alloys, the atomic percentages of nickel and cobalt were equal. The alloys were
aged in both the annealed and cold-rolled conditions at 1400°F (760°C), 1550°F (845°C), and 1700°F (925°C) for times up to
3000 h. The contributions of the chromium-group elements to σ formation were evaluated both by measuring the volume percentage
of σ phase and by determining the final composition of the y matrix after σ precipitation. By these two techniques, critical
values of the average electron vacancy number, •N
v
, for σ formation at 1550°F (845°C) were found to be 2.518 and 2.512, respectively; σ precipitation was most rapid at 1550°F
(845°C). Both techniques in-dicated that under conditions approaching equilibrium, molybdenum and tungsten are equiv-alent
in inducing σ formation and about 1.5 to 2 times as potent as chromium. The approxi-mate electron vacancy coefficients(N
v
) for molybdenum and tungsten, as derived from volume-fraction measurements of σ phase, are as follows: 7.35 at 1400°F (760°C)
and 1550°F (845°C), and 8.7 at 1700°F (925°C). The values derived from final compositions of the γ matrix after σ precipitation
are 7.9 at 1550°F (845°C) and 8.6 at 1700°F (925°C). The bulk diffusion of aluminum into alloys that were otherwise not σ-prone
at 1700°F (925°C) caused extensive σ precipitation during aging. This was due to copious precipitation of γ-Ni3Al and β-NiAl, resulting in enrichment of the matrix in elements of the chromium group.
This paper is based on a dissertation submitted by GARY N. KIRBY in partial fulfillment of the requirements for the degree
of Doctor of Philosophy, Metallurgical Engineering, The University of Michigan, 1971. The study was conducted in the Ann Arbor
Research Labora-tory of the Climax Molybdenum Company of Michigan, a subsidiary of American Metal Climax, Inc. 相似文献
32.
A high-pressure (> 3 MPa) on-chip injector has been developed for microchip applications including HPLC. The mechanical injector is implemented using in situ photopolymerization of fluorinated acrylates inside wet-etched silica microchips. The injector allows reproducible injections as small as 180 pL with < 250 ms duration. The injector operated robustly over 60 days and over 1000 injections. The injector is unique among polymer-based valves as it functions in aqueous, acetonitrile, and mixed buffers at high pressures without detectable leakage. 相似文献
33.
We present new vibrational (infrared) planar laser-induced fluorescence (PLIF) imaging techniques for CO(2) that use a simple, inexpensive, high-pulse-energy transversely excited atmospheric CO(2) laser to saturate a CO(2) absorption transition at 10.6 mum. Strong excitation by use of a CO(2) laser provides increased signal levels at flame temperatures and simplifies image interpretation. Because rotational energy transfer and intramodal vibrational energy transfer are fast, vibrational distributions can be approximated by use of a simple three-temperature model. Imaging results from a 425 K unsteady transverse CO(2) jet and a laminar coflowing CO/H(2) diffusion flame with temperatures near 1500 K are presented. If needed, temperature-insensitive signal levels can be generated with a two-laser technique. These results illustrate the potential for saturated infrared PLIF in a variety of flows. 相似文献
34.
Enric Menéndez Hiwa Modarresi Claire Petermann Josep Nogués Neus Domingo Haoliang Liu Brian J. Kirby Amir Syed Mohd Zahir Salhi Earl Babcock Stefan Mattauch Chris Van Haesendonck André Vantomme Kristiaan Temst 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(11)
The combination of lithography and ion implantation is demonstrated to be a suitable method to prepare lateral multilayers. A laterally, compositionally, and magnetically modulated microscale pattern consisting of alternating Co (1.6 µm wide) and Co‐CoO (2.4 µm wide) lines has been obtained by oxygen ion implantation into a lithographically masked Au‐sandwiched Co thin film. Magnetoresistance along the lines (i.e., current and applied magnetic field are parallel to the lines) reveals an effective positive giant magnetoresistance (GMR) behavior at room temperature. Conversely, anisotropic magnetoresistance and GMR contributions are distinguished at low temperature (i.e., 10 K) since the O‐implanted areas become exchange coupled. This planar GMR is principally ascribed to the spatial modulation of coercivity in a spring‐magnet‐type configuration, which results in 180° Néel extrinsic domain walls at the Co/Co‐CoO interfaces. The versatility, in terms of pattern size, morphology, and composition adjustment, of this method offers a unique route to fabricate planar systems for, among others, spintronic research and applications. 相似文献
35.
Kirby G.A. Lucas J. Ostojic R. Mackay R. Nobes S.C. Treadgold J.R. 《Applied Superconductivity, IEEE Transactions on》2000,10(1):61-64
For reasons of geometrical acceptance, 70 mm bore twin aperture quadrupoles are required in the LHC insertions. For an operating gradient of 160 T/m at 4.5 K, a design based on a four layer coil wound from two graded 8.2 mm NbTi conductors has been developed. Three 1 m single aperture quadrupoles of this design have been built and successfully tested. Thereafter, the magnets have been disassembled and the coils re-collared using self-supporting collars. In this paper, we describe the design features of the twin aperture quadrupole, and report on the initial collaring tests and procedures for collaring and final assembly of the 1 m magnet 相似文献
36.
The purpose of this study was to evaluate two types of industrial vacuum cleaners, in terms of cleaning rates, energy expenditure, and perceived exertion. Twelve industrial cleaners (six males and six females, age 28-39 yr) performed two 1-h vacuuming tasks with an upright vacuum cleaner (UVC) and a backpack vacuum cleaner (BPVC). Measures for oxygen uptake (VO2) and ratings of perceived exertion (RPE) were collected continuously during the 1-h vacuuming tasks. Cleaning rates for the UVC and BPVC were 7.23 and 14.98 m2min(-1), respectively. On a separate day subjects performed a maximal treadmill exercise test to determine their maximal aerobic capacity (peak VO2). Average absolute energy costs (in Metabolic equivalents), relative energy costs of the vacuum task compared to the subjects' maximal aerobic capacity (% peak VO2), and RPE responses for the 1-h vacuuming tasks were similar between vacuum cleaners, but % peak VO2 and RPE values differed between genders. These results indicate that the BPVC was more efficient than the UVC. With the BPVC, experienced workers vacuumed at a cleaning rate 2.07 times greater than the UVC and had similar levels of energy expenditure and perceived effort, compared to the slower cleaning rate with the UVC. 相似文献
37.
Jon Brunvoll Björg N. Cyvin Sven J. Cyvin Edward C. Kirby Ivan Gutman 《Polycyclic Aromatic Compounds》2013,33(4):219-229
Abstract A fully-naphthalenoid system (or simply fully-naphthalenoid) is a benzenoid where all vertices can be covered by disjoint naphthalene units. Invariants of these systems are studied with special emphasis on the CnHs formulae. An extensive enumeration of fully-naphthalenoids by means of a computer program is reported. A detailed classification of the numbers includes the symmetry distribution and an enumeration of the CnHs isomers. The forms of the smallest fully-naphthalenoids are displayed together with their Kekulé structure counts. 相似文献
38.
Calhoun Patrick S.; Sampson William S.; Bosworth Hayden B.; Feldman Michelle E.; Kirby Angela C.; Hertzberg Michael A.; Wampler Timothy P.; Tate-Williams Faye; Moore Scott D.; Beckham Jean C. 《Canadian Metallurgical Quarterly》2000,68(5):923
The present study assessed drug use and the validity of self–reports of substance use among help–seeking veterans referred to a specialty clinic for the assessment of posttraumatic stress disorder (PTSD). Patients (n?=?341) were asked to provide a urine sample for use in drug screening as part of an evaluation of PTSD. Self–reports of substance use were compared with same–day supervised urine samples for 317 patients who volunteered to participate in a drug screening. Results suggested that self–reports were generally quite valid. Only 8% of the cases involved patients not reporting substance use detected by urine screens. A total of 42% of the participants were identified as using drugs of abuse (excluding alcohol) through self–report and urine drug screens. Among participants using drugs, PTSD diagnosis was significantly associated with greater marijuana and depressant use as compared with stimulant (cocaine and amphetamines) use. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
Marlowe Douglas B.; Merikle Elizabeth P.; Kirby Kimberly C.; Festinger David S.; McLellan A. Thomas 《Canadian Metallurgical Quarterly》2001,15(2):97
Motivational assessment instruments typically measure clients' attributions about their readiness to change problem behaviors. They do not indicate why a client may be motivated to change, or provide guidance on how to retain an unmotivated client in treatment. The authors interviewed 415 substance abuse clients about their reasons for entering treatment and scored their responses along the dimensions of (a) negative versus positive treatment-entry pressures, (b) internal versus external sources of those pressures, and (c) the life domain from which the pressures emanated. Exploratory cluster analysis yielded 5 types of clients characterized by different profiles of perceived treatment-entry pressures. Cluster membership was predictive of treatment outcomes, and the clusters differed by demographic variables. These data support the discriminative and predictive utility of performing a multidimensional assessment of pressures to enter treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
DJ Adelstein TW Rice M Becker MA Larto TJ Kirby A Koka M Tefft G Zuccaro 《Canadian Metallurgical Quarterly》1997,80(6):1011-1020
BACKGROUND: The results of a Phase II study of concurrent chemotherapy and accelerated fractionation radiation therapy followed by surgical resection for patients with both adenocarcinoma and squamous cell carcinoma of the esophagus are presented. Pretreatment and postinduction staging were correlated with pathologic findings at surgery to assess the role of surgical resection and the predictive value of noninvasive staging techniques. METHODS: Patients received 2 induction courses with 4-day continuous intravenous infusions of cisplatin (20 mg/m2/day) and 5-fluorouracil (1000 mg/m2/day) beginning on Day 1 and Day 21, concurrent with a split course of accelerated fractionation radiation (1.5 grays [Gy] twice daily, to a total dose of 45 Gy). All patients were subsequently referred for surgical resection. A single, identical postoperative course of chemotherapy and 24 Gy accelerated fractionation radiation was planned for patients with residual tumor at surgery. RESULTS: Seventy-four patients were entered on this study; 72 patients were considered eligible and evaluable. Induction toxicity included nausea (85%), increased dysphagia (90%), neutropenia (<1000/mm3) (43%), thrombocytopenia (<20,000/mm3) (10%), and reversible nephrotoxicity (8%). Sixty-seven patients (93%) underwent surgery, and 65 (90%) were found to have resectable tumors. Twelve of these patients (18%) died perioperatively, and 18 (27%) had no residual pathologic evidence of disease. Resolution of symptoms and normalization of radiographic studies, endoscopy, or esophageal ultrasound did not identify pathologic complete responders accurately. No patient completing induction therapy and surgery experienced a locoregional recurrence. The Kaplan-Meier 4-year projected recurrence free and overall survival rates were 49% and 44%, respectively. CONCLUSIONS: Although this regimen is feasible, there was significant preoperative toxicity and perioperative mortality. Nonetheless, the recurrence free and overall survival rates were encouraging. However, no staging tool can predict a pathologic complete response after induction therapy accurately, suggesting a continued need for surgical resection. 相似文献