机械合金化过程中的金属相变

简述了机械合金化的工艺特点和应用,总结了机械合金化过程中的相变规律,着重分析了过饱和固溶体的形成机制及其在合金化过程中的相变过程。     

热轧带钢FeO共析转变动力学行为分析与预测

热轧后的带钢表面会形成氧化铁皮，其中的FeO在卷取之后的冷却过程中会发生共析相变，形成由Fe与Fe₃O₄共同组成的共析组织。传统对FeO共析相变的研究，多集中在诸如化学成分、相变环境等因素对共析反应的定性分析上，但针对相变的具体进程却少有模型化的分析和计算。同时，由于实际生产中FeO的相变过程多是在连续冷却过程中发生，相变过程受到了不同时刻温度变化的叠加影响，这也加大了研究的困难程度。为此，以常见的普碳钢为例，首先使用同步热分析仪进行了不同温度及时间下氧化铁皮的等温结构转变试验，统计了30个试验节点下的共析组织在FeO中的体积分数，之后基于Johnson-Mehl-Avrami-Kolmogorov(JMAK)方程建立了FeO在等温过程下共析相变的动力学模型，通过试验数据求解其中的关键参数，得到了等温转变条件下FeO中共析组织体积分数与时间的关系，可直接绘制描述FeO共析转变的Time-Temperature-Transformation(TTT)曲线。在此基础上，结合Scheil可加性法则，建立了连续冷却过程中FeO的共析相变模型，通过计算...     

连铸数学模型研究新进展

迄今文献研究连铸含铸锭）的数学模型均基于单元系相变过程；事实上，钢铁生产中熔化与凝固乃是多元系相变过程。由此出发，建立了连铸的新数学模型，并且构造了相应的算法以进行数字仿真与生产过程自动控制应用。     

相变储热系统在工业加热过程的应用

阐述了相变储能技术在工业加热过程中应用的可行性和节能意义，对几种类型的相变储热系统的工作原理及应用进行了描述，并对相变储热系统用于锻造加热过程的系统技术性能进行了分析，结果表明，相变储热系统的节能效果要优于传统的余热回收系统。     

Fe—Mn—Si合金的形状记忆效应及工程应用

评述了近年来Ｆｅ－Ｍｎ－Ｓｉ合金形状记忆效应（ＳＭＥ）的研究及工程应用，并对Ｍｎ，Ｓｉ元素，应力诱发相变，母相强化及热－机械处理（训练）等对ＳＭＥ的影响进行讨论。     

机械力作用下锐钛矿型TiO2的相变

采用振动磨样机和行星球磨机研磨锐钛矿型TiO2粉体,利用XRD技术对比分析锐钛矿相在2种研磨设备中的相变特点,利用SEM观察振动磨样机中粉体的形貌变化,并对振动磨样机中生成金红石相的机械化学相变宏观动力学及相变过程物质的微观结构变化进行研究。结果表明:锐钛矿相在振动磨样机和行星球磨机中的相变现象不同,在行星球磨机中表现为锐钛矿相→TiO2-Ⅱ相→金红石相的分步相变;而在振动磨样机中除了发生分步相变外,推测还可能发生了锐钛矿相→金红石相的直接相变,并进一步推测剪切力是促进这一直接相变的重要因素。在振动磨样机中形成金红石相的机械化学相变宏观动力学满足Avrami-Erofe’ev模型。     

冷却模式对NM400相变塑性及残余应力的影响

轧后快速冷却已成为制备耐磨钢NM400的重要手段，但快速冷却过程会在带钢内引入高幅值残余应力，导致带钢出现板形缺陷，并在后续加工以及使用过程中出现畸变。因此，弄清NM400在连续冷却过程的相变行为以及冷却速度对其相变行为的影响规律，是干预带钢相变行为、改善连续冷却过程带钢内残余应力水平及分布的关键。针对某厂热轧连续冷却过程采取的两种冷却模式造成的板形差异问题，通过热模拟试验、基于断裂力学原理的裂纹柔度法以及建立ABAQUS有限元仿真模型，计算了连续冷却过程的温度场、应力应变场，揭示了冷却模式对NM400相变塑性及残余应力的影响规律。研究结果表明，连续冷却过程残余应力的形成分为3个阶段，即热应力主导阶段、表面相变主导阶段和心部相变主导阶段；相变塑性应变的大小及方向与加载在相变瞬间的应力直接相关；加大冷速会提高带钢心部相变开始时带钢表面相变的体积分数，该体积分数越大，心部开始相变时所受到的拉应力水平越高，所产生的相变塑性应变越大，与相变应变两者叠加后在材料内会引入高幅值残余应力。研究成果可为耐磨钢NM400连续冷却过程残余应力调控提供数据基础和理论依据。     

热轧带钢在冷却过程中的内应力解析

针对热轧带钢的冷却过程,开发了温度、相变的内应力的耦合解析模型,该模型采用有限元法,同时考虑了相变的温度依存性、相变潜热、相变膨胀。通过该数值解析模型,能够模拟热轧带钢在冷却过程中温度一组织内应力的演变过程,计算结果与实测值符合良好。     

钛合金固态相变的归纳与讨论（Ⅰ）——同素异构转变

分别从冷却和时效两个过程对钛合金的固态相变作一系统论述，指出，在冷却过程中，根据冷却速度的不同发生的主要相变有：β→α＇＇,β→α＇,β→ω（althermal）＇β→α;时效过程中主要相变有．β→β＋ω（althermal）→β-α,β→β＋β→β＋α,β→α,α＇→β＋α,α＇＇→（β＋α＇）→β＋α.并分析了这些相变的形成特点；最后就目前钛合金固态相变中易混淆的过渡相的关系进行了讨论。     

浅析NiTi形状记忆合金的疲劳机理

由于NiTi形状记忆合金具有可逆的热弹性马氏体相变效应等不同与一般金属的特性，使得其疲劳机理也不同于一般的工程材料。为此，本文侧重分析了温度变化对NiTi形状记忆合金疲劳机理的影响和应力诱发马氏体相变等特征相变过程，以及相关的研究方法与主要结果，将为进一步研究其疲劳过程及增韧工艺提供理论参考依据．     

钢铁组织中MA岛含量的定量分析方法

MA岛是某些钢组织中的重要组成部分，钢中MA岛的含量对钢的韧性、强度等力学性能有一定影响。本试验针对MA岛定量方法的内容进行了分析，定量时首先对试样进行精细抛光和着色侵蚀，使MA岛侵成白亮色；然后用共聚焦显微镜采集图片，MA岛和基体组织对比黑白分明。接着利用中科仪的Sisc- Ias8金相分析软件根据二值分割进行定量，得出MA岛定量结果；最后描述了定量方法在双相钢中的应用。结果表明，MA岛定量技术弥补了以前定量分析方法的不足，能够快速、准确地分析出钢材组织中MA岛的百分含量。     

Preliminary results of treatment of solid tumors in children with non-standard radiotherapy]

Urinary excretion of mefenamic acid (MA) and its two oxidative metabolites, M-I (3'-hydroxymethyl derivative) and M-II (3'-carboxyl derivative), and their glucuronides was investigated in preterm infants undergoing MA therapy. MA was given orally at a dose of 2 mg/kg and the dose was repeated every 24 h a maximum of three times. Urine was collected for up to 5 d after the last dose, and MA and the metabolites were determined by a newly developed HPLC. The cumulative amounts of MA and the metabolites excreted in the urine varied from 7 to 46% of the total dose administered, and were less than those reported in adults and children. Significant correlation was observed between the plasma half-life of MA and the cumulative amount of MA and the metabolites excreted in the urine. These results suggest that long plasma half-lives of MA observed in preterm infants are due mainly to low activity of drug metabolizing enzyme(s). In an infant who received the two regimens of MA therapy about 2 weeks apart, the plasma half-life of MA was shortened and the urinary excretion of the MA metabolites including their glucuronides was greatly increased during this period. It is suggested that the activities of both cytochrome P-450(s) and glucuronyltransferase(s) related to MA metabolism rapidly increased during the first month of the infant's life.     

Do Psychotherapists Have Better Marriages Than Nonpsychotherapists? Do Therapeutic Skills and Experience Relate to Marriage Adjustment?

Couples in which 1 or both members were psychotherapists were compared with nontherapist couples for marriage adjustment (MA). The authors predicted higher MA scores for the therapists and a positive correlation between the MA of therapists and years of therapy training, years of practice, rating of therapeutic ability, length of marital therapy training, number of marital therapy clients, experience as a marital therapist, and self-rating as a marital therapist. Therapist and nontherapist couples did not differ on MA. Only self-rated ability as a marital therapist correlated positively with MA. For men, ability as a therapist, as a marital therapist, and marital therapist experience correlated significantly with MA. For female therapists only self-rated ability as a marital therapist correlated significantly with MA. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Upper and lower motor neuron lesions in the upper extremity muscles of tetraplegics

The Rorschach was given to 60 school children in two designs: CA and MA orthogonal (9 and 12 years) and CA =MA (for 6, 9 and 12 years). Responses were scored for Form Accuracy, Complexity, Movement, and Friedman's Developmental Level (DL) Scoring System. There were significant MA effects independent of CA on Form Accuracy, Complexity and DL, and significant CA effects on Complexity and Movement. Form Accuracy was highly correlated with the DL score and correlated with MA at a slightly higher level than DL with MA. The Complexity score provided some additional information about development. Movement decreased with age but was higher in intelligent subjects. The results suggested that the DL system does assess MA independently of CA, but this is accounted for primarily by Form Accuracy.     

Further studies on the potentiating effect of lithium chloride on methamphetamine-induced stereotypy in mice

To study the mechanism of the potentiating effect of lithium chloride (LiCl) on methamphetamine (MA)-induced stereotypy in mice, effects of various drugs on the action of LiCl on the stereotypy and pharmacokinetics of MA in different brain regions and liver were examined. The potentiating effect of LiCl disappeared in mice pretreated with atropine or scopolamine whereas LiCl potentiated the stereotypy in mice pretreated with p-chlorophenylalanine, alpha-methyl-p-tyrosine, nialamide, physostigmine or butylscopolamine. The concentrations of MA in the striatum, brainstem and liver were increased and the half-life of MA in these tissues was prolonged by LiCl. The effect of LiCl on the kinetics of MA in the brain, but not that in the liver, was blocked by scopolamine. LiCl prolonged the half-life of MA in the brain and liver in mice treated with physostigmine or butylscopolamine. The inhibition of MA elimination from the brain and its blockade by scopolamine seem to explain the potentiating action of LiCl on the stereotypy and the antagonism by scopolamine of the behavioural action of LiCl, respectively.     

Formation of malonaldehyde in the presence of probucol, an anti-atherosclerosis drug

Formation and inhibition of malonaldehyde (MA) from blood plasma lipids oxidized by Fenton's reagent in the absence or presence of probucol [4,4'-(isopropylidenedithio)bis(2,6-di-tert-butylphenol)] and L-ascorbic acid were investigated. The amount of MA formed was quantitatively analysed by gas chromatography. L-Ascorbic acid inhibited MA formation by about 30% at the level of 4.0/micromol, but the amount of MA formed was increased by the presence of probucol. When 3.0 micromol oxidized probucol was hydrolysed at pH 1. 3 and 5, 2616.5 nmol, 287.5 nmol and 103.9 nmol MA were recovered, respectively. This is the first report of quantitative analysis of MA formed from probucol on oxidation.     

Familial occurrence of migraine without aura and migraine with aura

We report a study of 121 probands (patients) with migraine without aura (MO) and 72 probands with migraine with aura (MA), diagnosed according to the operational diagnostic criteria of the International Headache Society and selected from 35 general practices in Denmark. The probands were interviewed about the presence of MO and MA among their first-degree relatives. Compared with the general population, the first-degree relatives of probands with MO had a threefold increase of MO, and only one first-degree relative of one proband with MO had MA. First-degree relatives of probands with MA had a twofold increase of both MA and MO. Compared with the general population, few spouses had MO and MA. This threefold and twofold increase in family risk of MO and MA, combined with the lack of increased risk in spouses, strongly suggests that MO and MA are genetically determined.     

Membrane binding of human immunodeficiency virus type 1 matrix protein in vivo supports a conformational myristyl switch mechanism

The interaction of the human immunodeficiency virus (HIV) Gag protein with the plasma membrane of a cell is a critical event in the assembly of HIV particles. The matrix protein region (MA) of HIV type 1 (HIV-1) Pr55Gag has previously been demonstrated to confer membrane-binding properties on the precursor polyprotein. Both the myristic acid moiety and additional determinants within MA are essential for plasma membrane binding and subsequent particle formation. In this study, we demonstrated the myristylation-dependent membrane interaction of MA in an in vivo membrane-binding assay. When expressed within mammalian cells, MA was found both in association with cellular membranes and in a membrane-free form. In contrast, the intact precursor Pr55Gag molecule analyzed in an identical manner was found almost exclusively bound to membranes. Both membrane-bound and membrane-free forms of MA were myristylated and phosphorylated. Differential membrane binding was not due to the formation of multimers, as dimeric and trimeric forms of MA were also found in both membrane-bound and membrane-free fractions. To define the requirements for membrane binding of MA, we analyzed the membrane binding of a series of MA deletion mutants. Surprisingly, deletions within alpha-helical regions forming the globular head of MA led to a dramatic increase in overall membrane binding. The stability of the MA-membrane interaction was not affected by these deletions, and no deletion eliminated membrane binding of the molecule. These results establish that myristic acid is a primary determinant of the stability of the Gag protein-membrane interaction and provide support for the hypothesis that a significant proportion of HIV-1 MA molecules may adopt a conformation in which myristic acid is hidden and unavailable for membrane interaction.     

Relationship of ego disjunction and manifest anxiety to conflict resolution.

The purpose of this study was to discover the influence of 2 determinants, ego disjunction (ED) and manifest anxiety (MA), on conflict resolution. ED, defined as antagonistic response tendencies within an individual, was measured by the Edwards Personal Preference Schedule, and MA by the Taylor MA scale. From a sample of 56 college Ss, it was found that Ss high in both ED and MA required significantly more time to resolve approach-approach and avoidance-avoidance conflicts than Ss high in only one determinant but low in the other and Ss low in both determinants. No significant differences in conflict scores were found when Ss low in both determinants were compared with Ss high in only one determinant but low in the other. The results were interpreted as indicating that ED and MA interact, producing interfering responses which hinder efficient resolution of conflicts when ED and MA are both high within an individual High MA and high ED scores, when taken alone, did not yield any conclusive results. It is only when both determinants are taken into consideration that greater confidence can be invested in those measures to predict conflict performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mathematics anxiety: Some basic issues.

Investigated 4 considerations about mathematics anxiety (MA): (a) the degree of MA experienced by men and women, (b) the internal consistency and test–retest reliabilities of 3 MA measures, (c) the relationship of MA instruments to each other, and (d) the relationship of MA to test anxiety and its worry and emotionality components. 769 college students' MA was measured by the Mathematics Anxiety Scale (MAS), the Anxiety Toward Mathematics Scale (ATMS), and the Mathematics Anxiety Rating Scale (MARS). Ss also completed the Test Anxiety Inventory. Results indicate nonequivalent internal consistency and test–retest reliability coefficients for the 3 MA measures, with the ATMS having the lowest coefficients. Small but significant gender differences were found on the MARS and MAS. The MA measures were moderately related to each other, and almost invariably, they were more closely related to each other than to test anxiety and its components. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)