Visual perception of mean relative phase and phase variability.

Perception of relative phase and phase variability may play a fundamental role in interlimb coordination. This study was designed to investigate the perception of relative phase and of phase variability and the stability of perception in each case. Observers judged the relative phasing of two circles rhythmically moving on a computer display. The circles moved from side to side, simulating movement in the frontoparallel plane, or increased and decreased in size, simulating movement in depth. Under each viewing condition, participants observed the same displays but were to judge either mean relative phase or phase variability. Phase variability interfered with the mean-relative-phase judgments, in particular when the mean relative phase was 0°. Judgments of phase variability varied as a function of mean relative phase. Furthermore, the stability of the judgments followed an asymmetric inverted U-shaped relation with mean relative phase, as predicted by the Haken-Kelso-Bunz model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Co-Cr系相平衡的热力学计算和fcc相的磁性诱导相分离

Two-phase equilibria between the ferromagnetic fcc and the paramagnetic fcc phase from 800 ℃ to 900 ℃ in the Co-rich region have been detected by the diffusion couple technique. Two phase separation region of the fcc has been confirmed along the Curie temperature. The phase equilibria including the present results and the thermodynamic data of the Co-Cr system reported in the literature were analyzed on the basis of the thermodynamic evaluation. A set of thermodynarnic values for the liquid, fcc, hcp, bcc, sigma phases was obtained. The calculated phase equilibria were in good agreement with most of the experimental data.     

Ab initio phase determination and phase extension using non-crystallographic symmetry

Non-crystallographic symmetry (NCS) can be used to improve, extend or find ab initio phases to be associated with a set of observed structure amplitudes, resulting in an interpretable electron-density map. The simplest application is merely to improve the accuracy of the phases by cyclically averaging the electron density, Fourier back-transformation of the modified map, and recomputing a new map with the newly found phases. The first sophistication of this procedure is to phase extend, in successive small steps, the currently available phase information to higher resolution, where only observed amplitudes were previously available. A further sophistication is to initiate the phase extension from very low resolution where a simple geometric model, or an electron microscope image, would be consistent with the chosen resolution. A number of recent examples of virus structure determination exist where such ab initio phasing was successful. The ultimate ab initio phase determination would be to extend phases given only an estimate of the F(000) term.     

Nickel-aluminum-molybdenum phase equilibria

Recent work on alloys based on the Ni-Al-Mo system has brought to light several inconsistencies with published equilibrium phase diagrams for this system. Published diagrams have been based on theoretical computer models and on data gathered ostensibly before equilibrium was achieved, especially at temperatures below 1100 °C. The intent of this effort was to produce an experimentally validated ternary equilibrium phase diagram for the Ni-Al-Mo system. Specimens for this task were produced by both conventional casting and powder metallurgy techniques. The temperatures studied included 1260, 1171, 1093, 1038, and 927 °C (2300, 2140, 2000, 1900, and 1700 °F) for times up to 2500 hours. Phases were identified using an electron probe microanalyzer and X-ray diffraction. The results show significant deviations from the proposed phase diagrams published in the literature in the temperature range investigated. In particular, a class II four-phase equilibrium reaction γ + α cooling // heating γ′+ δ has been shown to occur at 1127 ± 2 °C (2060 ± 4 °F). Formerly NRC Senior Research Associate.     

Acute phase proteins

One hundred eleven patients with burns who were age 60 years or older were treated from January 1984 through December 1992. Twenty-nine patients had pulmonary failure defined as 7 or more days of ventilatory support from the day of burn. The mortality rate for these patients was 41%; only four were discharged to home. The mortality rate for patients without pulmonary failure was 11%. Billing information was analyzed for 102 of the 111 patients. Charges for patients without pulmonary failure were two to three times greater than reimbursement. Charges for patients with pulmonary failure were 4 to 14 times greater than reimbursement. Reimbursement for elderly patients with burns is inadequate. Altering the Diagnosis-Related Group (DRG) definition of extensive burn to reflect the severity of injury in the geriatric population is one step toward reimbursement reform. Patients who require 7 or more days of ventilatory support after burn injury should be reimbursed under a separate DRG category or should have a DRG modifier.     

Second phase dissolution

A detailed theoretical study was made of the dissolution of precipitates. The kinetic analyses of the atomic mechanisms included the concurrent effects of diffusion, interface reaction, and curvature, and considered the more complex problems of precipitate arrays and nondepleted matrices. The general formalism thus obtained was used to interpret the results of an experimental investigation of the technologically important problem of the dissolution of “reluctantly soluble” carbides in the Fe-C-V system. It was found that vanadium carbide (and iron carbide as well) were quite easily dissolved while complex alloy sulfides, silicates and oxides (possibly associated with the presence of vanadium) persisted, with little if any dissolution. Previous views of the reasons for poor hardenability were reevaluated in light of these results. Formerly with the Process Research Department, Scientific Research Staff, Ford Motor Co. This paper is based on an invited talk presented at a symposium on Homogenization of Alloys, sponsored by the IMD Heat Treatment Committee, and held on May 11, 1970, at the spring meeting of The Metallurgical Society of AIME, in Las Vegas, Nev.     

超声波对金属相与陶瓷相间润湿角的影响

金属相与陶瓷相间的润湿性对陶瓷刀具的性能起着重要作用,为了改善固-液界面结构,提高陶瓷材料的综合性能,研究了烧结过程中超声作用产生的能量对金属相与陶瓷相间润湿角的影响.根据粉末液相烧结理论,构建了固?液双球冠润湿模型.依据润湿模型和最小能量原理,建立了润湿角与表面能、超声能、几何参数之间的关系.研究表明:在超声波作用下...     

Effects of shortening the steeplechase phase (phase B) of a 3-day-event

Thirty-four horses competing in the Endurance Test of a 3-day-event were divided into 3 groups: horses in Group 1 (n = 15) competing in a 3.5 min steeplechase phase; horses in Group 2 (n = 13) in a 3 min steeplechase phase (Phase B) and horses in Group 3 (n = 6) in a 2.5 min steeplechase phase. The shortening of Phase B was associated with a lengthening of Phase C so that the total distance of the event for all horses was 14,940 m. Bodyweight (BW) was measured and total body water (TBW) and water loss estimated. Blood samples were collected from the horses prior to the Endurance Test, at the end of Phase B, the 4 km marker on Phase C (C4K), the end of Phase C, and 20 min after the completion of Phase D for measurement of packed cell volume (PCV), total plasma protein [TPP], lactate, ionised calcium, pH, sodium, potassium, chloride, total calcium and glucose concentrations, and aspartate aminotransferase, creatine kinase and lactate dehydrogenase activities. Mean +/- s.d. ambient environmental temperature during the Endurance Test was 25.3 +/- 1 degrees C (range 20.3 degrees C-29.7 degrees C). Mean relative humidity was 43.8 +/- 2.4% (range 39%-48.6%) and the average 'comfort index' (CI) was 121. There were no significant differences between the groups competing in the Endurance Test, despite the shorter Phase B. However, there were significant decreases in BW, TBW, net exchangeable cations, chloride, ionised calcium, and pH. The sodium and total calcium concentrations remained at near pre-event values. The PCV, TPP, lactate, potassium, glucose, aspartate aminotransferase, and lactate dehydrogenase activity increased during the Endurance Test, when compared to pre-event values. Horses competing in this competition experienced significant fluid and electrolyte losses, reduced glomerular filtration, increased glycogenolysis and had significant leakage of enzymes from working muscles during competition. These changes could not be reduced by shortening Phase B and lengthening Phase C.     

Kinetics of the peritectic phase transformation: In-situ measurements and phase field modeling

An experimental study has been conducted into the role of cooling rate on the kinetics of the peritectic phase transformation in a Fe-C alloy. The interfacial growth velocities of the peritectic phase transformation were measured in situ for cooling rates of 100, 50, and 10 K/min. In-situ observations were obtained using high-temperature laser scanning confocal microscopy (HTLSCM) in a concentric solidification configuration. The experimentally measured interface velocities of the liquid/austenite (L/γ) and austenite/delta-ferrite (γ/δ) interphase boundaries were observed to increase with higher cooling rates. A unique finding of this study was that as the cooling rate increased, there was a transition point where the L/γ interface propagated at a higher velocity than the γ/δ interface, contrary to the findings of previous researchers. Phase field modeling was conducted using a commercial multicomponent, multiphase package. Good correlation was obtained between model predictions and experimental observations in absolute values of interface velocities and the effect of cooling rate. Analysis of the simulated microsegregation in front of the L/γ and γ/δ interfaces as a function of cooling rate revealed the importance of solute pileup. This microsegregation plays a pivotal role in the propagation of interfaces; thus, earlier modeling work in which complete diffusion in the liquid phase was assumed cannot fully describe the rate of propagation of the L/γ and δ/γ interfaces during the course of the peritectic transformation.     

液相烧结非晶纳米氮化硅陶瓷粉体结晶与相变行为研究

以Y2 O3 和Al2 O3 纳米陶瓷粉体作为烧结助剂 ,液相烧结非晶纳米Si3 N4陶瓷粉体 ,研究了不同温度下烧结体的结晶与相变行为。 1 5 0 0℃烧结 ,烧结体为非晶与晶体混合态 ,结晶相主要为α Si3 N4和 β Si3 N4,结晶度达到 70 %。温度超过 1 6 0 0℃以后 ,烧结体已经完全结晶 ,为 β Si3 N4和Si2 N2 O双相陶瓷。当温度达到1 6 5 0℃ ,Si2 N2 O的体积分数达到最大值 ,说明烧结体中的O2 与Si3 N4已经反应完全。烧结温度超过 1 70 0℃时 ,Si2 N2 O的体积分数开始减小 ,烧结体中没有SiO2 出现 ,证明反应 2Si3 N4(s) +1 5O2 (g) =3Si2 N2 O(s) +N2(g)为可逆反应。 1 6 0 0℃烧结体的典型结晶形貌分析表明 :粒径尺寸基本分布在两个区域 ,大部分较大晶粒粒径在 1 5 0～ 2 5 0nm之间 ,小部分晶粒粒径 <1 0 0nm ,个别晶粒的长径比达到 1 5。     

局域平衡原理与相图的扩散偶法测定

介绍了局域平衡原理和扩散偶法测定平衡相图的方法要点.扩散偶法是一种高效的、可靠的相图测定方法,它可以大幅度减少实验工作量,减少原材料消耗,加快相图实测进程.此外,这种方法还具有可直接测定相平衡关系、相平衡成分,避免“过冷效应”等优点,特别适合于多组元系统平衡相图的实验测定.