Recrystallization in a low-density low-alloy Fe–Mn–Al–C duplex-phase alloy

The recrystallization behaviour of a cold-rolled, low-density, low-alloy duplex-phase alloy (Fe–6.57Al–3.34Mn–0.18C, wt.%) has been studied. Temperature-resolved X-ray diffraction and dilatometry showed that the alloy recrystallizes at 850?°C during continuous heating. However, electron back-scattered diffraction investigations using Kernel average misorientation revealed that during annealing ferrite recrystallizes at lower temperatures while austenite remains strained up to 1200?°C. This study underlines the complexity of recrystallization of a microstructure comprising of constituents with high and low stacking fault energy.     

Partners' internal stress and well-being: The role of dyadic coping and problem resolution

Couples' experiences of daily stress can be detrimental for partners' individual and relational well-being, specifically their identity as a couple, their relational satisfaction, and their life satisfaction. Grounded in the Systemic Transactional Model, this study aimed at analyzing factors that may safeguard partners and their relationship from detrimental effects of internal stress (i.e., stress that originates inside the relationship). We examined the buffering effect of partners' positive dyadic coping and internal problem resolution. Daily diary data were collected across 7 days from 82 heterosexual couples. Multilevel dyadic analyses showed that internal stress was negatively associated with partners' individual and relational well-being. Positive dyadic coping moderated the association between partners' internal stress and couple satisfaction for both partners, but not life satisfaction and couple identity. Moreover, for partners who reported a resolution to the internal problem, the negative associations of internal stress with life satisfaction, couple satisfaction, and couple identity were significantly lower than for those who did not resolve the internal problem. This study confirms the negative role of internal stress on well-being, shows the associations between internal stress and couple identity, and highlights the protective role of dyadic coping and internal problem resolution in couples' daily lives.     

Equivalent strain-hardening work theorem

A new physical concept, termed ‘equivalent strain-hardening work’, is proposed. The physical concept can be used to redefine the commonly used effective stress and effective strain theory as applied in constructing the constitutive relations of stress and strain, especially when related to an anisotropic strain-hardening material. The concept concerns that part of plastic work which emphasizes the action due to the strain-hardening behaviour of a material. Based on this concept, any one of the strain-hardening stress–strain curves obtained through common experiments on anisotropic materials can be selected as a nominally effective stress and an associated effective strain, and the rest of the strain-hardening relations can all be then transformed to be functions of variables of the nominally effective strain. Thus, any kind of loading path can be characterized by a single relation between effective stress and effective strain. When applied to the isotropic materials, the equivalent strain-hardening work concept is identical with the work-equivalent deformation concept but is more general.     

The interactive effects of locus of control and situational stress upon performance accuracy and time

The present paper sought to clarify the conceptual relationship between expectancy for personal control, stress, and behavioral reactions to stress. Expectancy for control was assessed as a personality characteristic of internal control; stress was experienced as strong environmental interruptions, disturbances, and unpredictable obstacles encountered during the performance of assigned tasks. Subjects were junior high school aged students who attempted to complete three academic type tasks during one of two levels of stress or a base line, no stress, condition. Analyses of the data included: (a) internal subjects were capable of sustaining task performance under high stress, but external students experienced performance decrements as stress increased; (b) time to complete the mathematics task reflected a facilitating effect of stress for internals but a debilitating effect for externals; (c) performance differences between internal and external students, in the absence of differences in reported anxiety, could be attributed to the stronger reward expectancies possessed by the internal individual. Interpretation of the data suggested an interactive relationship between type of stress (threat to ego vs. threat to instrumental performance) and expectancy for control in the influencing of behavior reactions to stress.     

Microstructures and tensile properties of 304 steel with dual nanocrystalline and microcrystalline austenite content prepared by aluminothermic reaction casting

The microstructures of 304 stainless steels with different amounts of nanocrystalline and microcrystalline austenite prepared by an aluminothermic reaction casting, without and with annealing at 1073?K for 8?h, have been investigated by X-ray diffraction, an electron probe micro-analyser, a transmission electron microscope and a scanning electron microscope. The steels, both without and with annealing, consisted of different dual nanocrystalline and microcrystalline austenite combinations and a little nanocrystalline δ ferrite, while the average grain size of the nanocrystalline austenite increased from 19 to 26?nm and volume fraction of the microcrystalline austenite increased from 17 to 30% after annealing. The tensile strength of the steel was dramatically increased from 500 to 1000?MPa and the tensile elongation ratio increased from 8 to 12% after annealing. However, the tensile strength was decreased to 600?MPa and the tensile elongation ratio increased from 12 to 22% after an annealing at 1273?K. The combination of dual nanocrystalline and microcrystalline austenite obtained after the annealing at 1073?K results in the best tensile properties.     

Octapod-shaped,nanosized, amorphous precipitates in a crystalline ferrite matrix

The development of uniquely octapod-shaped nanosized amorphous silicon–nitride precipitates in a ferrite matrix was observed upon nitriding of Fe–4.5at.%Si alloy. The legs of the amorphous precipitate are oriented along ?1?1?1?-directions of the ferrite. The occurrence of such peculiarly shaped amorphous silicon–nitride precipitates, which experience a volume misfit of more than 100% with the surrounding ferrite, was attributed to precipitate growth influenced by long-range diffusion within the evolving highly anisotropic stress field around the developing precipitates after nucleation.     

Current and Military‐Specific Gender Minority Stress Factors and Their Relationship with Suicide Ideation in Transgender Veterans

Research suggests the prevalence of suicide ideation and suicide attempts in the transgender veteran community may be upwards of 20 times higher than nontransgender veterans, who are known to be at increased risk than the general US population. This study aimed to understand the potential influence of external and internal minority stress experienced during and after military service on past‐year and recent suicide ideation in a sample of 201 transgender veterans. Nonparametric bootstrapping analyses indicated past‐year transgender‐specific discrimination and rejection (external minority stress) indirectly predicted frequency of both past‐year and past 2‐week suicide ideation through past‐year shame related to gender identity (internal minority stress). This result was significant when controlling for symptoms of depression and demographics. Similar patterns emerged when examining relationships among military external and internal minority stress on suicide outcomes. These results suggest that attempts to reduce both the experience and impact of minority stressors related to gender identity during and after military service may be an important avenue for suicide prevention.     

教师集体效能和自我效能对工作压力影响作用的调节--多水平分析研究

通过对28所小学1299名教师的调查结果,作者主要对教师集体效能和自我效能对工作压力与教师工作满意度、内在动机及离职倾向之间关系的调节作用进行了分析。多层分析结果表明：(1)教师工作压力与教师工作满意度和内在动机的关系受教师自我效能高低的调节,教师自我效能高的教师．工作压力所带来的负面影响较小;在考虑了教师自我效能的调节作用后,教师工作压力对教师工作满意度、内在动机和离职倾向的影响存在显著的学校水平的差异。(2)学校水平背景特征一教师集体效能对教师工作压力与内在工作动机和离职倾向之间的关系有显著的调节作用,在集体效能高的学校中的教师,工作压力的负面影响较弱。     

Psychological and Social Factors that Promote Positive Adaptation to Stress and Adversity in the Adult Life Cycle

The phenomenon of resilience reflects positive adaptation despite contexts of risk, significant adversity, or trauma (Masten and Powell 2003; Luthar 2006). The purpose of this investigation was to propose a mediation model to explain the relation between stress and some psychological and social resources that enhance positive adaptation throughout the entire adult life cycle, and to explore the moderator role of age and country of origin. The indicator of positive adaptation was life satisfaction (LS). The sample comprised 171 Mexicans and 154 Spaniards (N?=?325), aged between 18 and 87?years. Mediation was tested by means of various hierarchical regression analyses, which revealed that the positive adaptation process is enhanced by a group of psychological and social resources that mediate the effects of stress on LS. Self-esteem, optimism, internal control, coping aimed at acceptance, and coping aimed at seeking emotional support, as well as social contacts can mediate the negative effects of stress. Finally, it was found that age moderates the internal control but none of the remaining variables whereas the country does not moderate the relation of the variables.     

Stress at encoding,context at retrieval,and children’s narrative content

Research concerning the relations between stress and children’s memory has been primarily correlational and focused on memory volume and accuracy. In the current study, we experimentally manipulated 7- and 8-year-olds’ and 12- to 14-year-olds’ experienced stress during a to-be-remembered event to examine the effects of stress on the content of their memory. We further manipulated the degree of interviewer support at retrieval to determine whether it moderated the effects of stress at encoding on memory. Children’s age, gender, stress at encoding, and interviewer support all influenced the type of information included in their narrative reports. Most notably, across ages, children who experienced a more stressful event but were questioned in a supportive manner provided the largest ratio of terms representing internal states such as those about cognitions and emotions. Results suggest that how children process past events may be influenced by both the nature of the event itself and the context within which it is recalled.     

父亲、母亲抚养压力在母亲抑郁和学龄前儿童内外部问题行为间的链式中介作用

研究旨在探讨父亲和母亲的抚养压力在母亲抑郁与学龄前儿童内、外部问题行为间的作用。以北京市某区75所幼儿园的2222名3~5岁在园幼儿及其父母为被试,采用《流调中心抑郁量表》、《抚养压力量表》、《学龄前儿童问题行为问卷》分别对母亲抑郁、父母抚养压力及儿童问题行为进行测查,结果发现：（1）母亲抑郁可以正向预测儿童的内、外部问题行为;（2）母亲抑郁对儿童内部问题行为的作用被"母亲抚养压力"、"母亲抚养压力-父亲抚养压力"两条路径部分中介;（3）母亲抑郁对儿童外部问题行为的作用被"母亲抚养压力"、"母亲抚养压力-父亲抚养压力"两条路径完全中介。综上,研究揭示了母亲抚养压力、父亲抚养压力在母亲抑郁和学龄前儿童内、外部问题行为间的链式中介作用。     

Tensile behaviour of submicrocrystalline ferritic steel processed by large-strain deformation

Mechanical tests have been carried out on Fe–15%Cr ferritic stainless steel with various microstructures. Ultrafine-grained microstructures with grain sizes of 0.2–0.3 µm were developed by large-strain cold-working and light annealing. The effects of severe deformation on the mechanical behaviour of as-processed and recovered steel were evaluated with reference to the same material having conventional work-hardened and recrystallised microstructures. Despite the low dislocation density in the fine grain interiors in the as-processed state, the samples with strain-induced submicrocrystalline structure were characterised by high internal stresses that resulted in a higher strength than could be expected from simple grain-size strengthening. These internal stresses were associated with a non-equilibrium state of strain-induced grain boundaries after severe deformation.     

Effects of annealing temperature on structural,optical, and electrical properties of antimony-doped tin oxide thin films

Antimony-doped tin oxide (ATO) films, approximately 320 nm in thickness, have been prepared by electron beam evaporation onto glass substrates. The films were annealed at temperatures between 400°C and 550°C in air and their structure and surface morphologies were observed by X-ray diffraction (XRD) and atomic force microscopy (AFM) after the different annealing treatments. XRD patterns of the ATO thin films as-deposited and annealed at 400°C showed that they were amorphous, but annealing beyond 400°C caused the films to become polycrystalline with tetragonal structure and orientated in the (1 1 0) direction. The grain size in the annealed films, obtained from the XRD analysis, was in the range 146–256 Å and this increased with the annealing temperature. The dislocation density, cell volume and strain were found to decrease gradually with increasing annealing temperature. Photoluminescence spectra revealed an intensive blue/violet peak at 420 nm, which increased gradually in height with annealing. It is suggested that an increase in the population of Sb⁺⁵ ions might be the reason for the enhancement of the blue/violet emission. The optical properties of the films were also investigated in the UV-visible-NIR region (300–1000 nm). The optical constants, namely the refractive index n and the extinction coefficient k in the visible region were calculated. The optical energy band gap, as determined by the dependence of the absorption coefficient on the photon energy at short wavelengths, was found to increase from 3.59 to 3.76 eV with annealing temperature.     

Ineffective Schools as Organizational Reactions to Stress

Educational research has identified effective schools in terms of characteristics associated with high student achievement, and conversely, schools lacking these characteristics are often conceived as ineffective schools. In this article, I propose that organizational stress responses create the conditions that make schools effective or ineffective. In other words, low achievement does not make schools ineffective but rather organizational behavior associated with stress creates and perpetuates school ineffectiveness, including low achievement. Drawing on the threat-rigidity thesis and open systems theory, hypotheses regarding how groups and organizations respond to stress were tested using demographic and achievement data for students attending elementary schools, in addition to survey data obtained from students (N= 18,189), principals (N= 75), and parents (N= 13,768). Using cluster analysis, schools were grouped and described in terms of the schools stress level (student populations requiring more resources for learning), school adaptations to stress (emphases on varied school internal processes), and school output (student achievement). To lessen input from the external environment, schools experiencing more stress had less permeable bound- aries, as indicated by parent reports of less school involvement and less positive school climate. Schools experiencing more stress also had more internal disruption, as indicated by less consensus among parents and students regarding school internal processes and by more principal changes. However, in such schools, there was little evidence of more control over school internal processes in terms of principals self-reported behavior and student and parent perceptions of school order and discipline, and teacher support of learning. Results call for a better understanding of school ineffectiveness in terms of organizational adaptations to stress and points at which to intervene for more effective school adaptation and functioning.     

Coarsening behaviour of gamma prime precipitates and concurrent transitions in the interface width in Ni-14 at.% Al-7 at.% Cr

Coupling atom probe tomography and transmission electron microscopy, the temporal evolution of γ′ precipitate morphology and size distribution and compositional width of the γ/γ′ interface, have been tracked in a model Ni-14Al-7Cr (at.%) alloy, during isothermal annealing at 800?°C subsequent to rapid quenching. During the initial annealing period, coalescence-dominated growth and coarsening of γ′ precipitates are accompanied by a gradual decrease in the interface width, eventually leading to classical LSW coarsening with a constant interface width at extended annealing time periods.     

A study of thermal vacancies and dislocation structure in Fe–40 at.% Al

The densities of thermal vacancies and residual dislocations in bulk specimens of Fe–40?at.%?Al have been investigated using differential dilatometry and X-ray diffraction. A large quenched-in vacancy concentration at temperatures above about 873?K was apparent from the decrease in average lattice parameter. This was correlated to a lowering of the effective enthalpy of vacancy formation from about 91 to 42?kJ mol^?1, possibly caused by the presence of different types of point defect in lower- and higher- temperature regimes. The residual dislocations were found to have a major concentration on {100} planes at any given temperature. An increase in the dislocation density and a concurrent fall in the vacancy concentration was observed with a lowering of the quenching temperature from 1223 to 1073?K, indicating the possibility of vacancy annihilation at 1073?K.     

Locus of Control as a Stress Moderator and Mediator in Children of Divorce

This paper examined the stress moderator and mediator effects of four dimensions of perceived control in children of divorce. The dimensions of locus of control included internal control for positive events, internal control for negative events, unknown control for positive events, and unknown control for negative events. The sample consisted of 222 children between the ages of 8 and 12 whose parents had divorced in the previous 2 years. Moderational analyses showed that unknown control for positive events interacted with negative events to predict total symptoms. Plots of the simple slopes indicated a stress buffering effect whereby the slope of negative events on symptoms was higher for high than for low levels of unknown control for positive events. Mediational analysis showed that the relations between negative events and symptoms were mediated by both unknown control for positive events and unknown control for negative events. In contrast, evidence was not found for either a stress mediational or a moderational model for perceived internal control for positive or negative events. These results suggest that unknown control beliefs may be a particularly important dimension of control for children of divorce.     

Affective and attributional features of acculturative stress among ethnic minority college students

Little is known about the affective features of acculturative stress or its relation to attributional styles for negative events. The authors examined associations among acculturative stress, attributional style, and positive and negative affect among 96 ethnic minority college students. They hypothesized that acculturative stress would be characterized by elevated negative affect and global and stable attributions for negative events. Consistent with prediction, acculturative stress was significantly associated with negative affect and global attributions, even when controlling for other relevant predictors. Attributional style did not account for the association between negative affect and acculturative stress. Positive affect and stable and internal attributional styles were not related to acculturative stress. The authors discuss implications for reducing stress associated with acculturation.     

Microplasticity of copper thin films on silicon substrates

Internal friction in polycrystalline copper films 0.2-1.5 w m thick on silicon substrates has been measured as a function of strain amplitude. The internal friction in the films increases with increasing strain amplitude but at a value of the strain amplitude that is at least two orders of magnitude greater than the similar increase in bulk copper. Analysis of the amplitude-dependent internal friction provides the plastic strain of the order of 10 -9 as a function of effective stress on dislocation motion. Since the grain size is larger than the film thickness, the microflow stress at a constant level of plastic strain varies inversely with the film thickness. The film thickness effect in the microplastic range can be explained on the basis of a dislocation-bowing model.     

Development and Validation of the Weekly Stress Inventory-Short Form

The Weekly Stress Inventory (WSI) has been used both in research and in clinical settings to measure minor stress. Although this tool offers a reliable and valid measure to assess minor stress, it lacks brevity that would make it more feasible for rapid assessments of stress needed in many research and clinical settings. The current study assessed the psychometrics of the newly developed Weekly Stress Inventory Short Form (WSI-SF), a 25-item scale to measure minor stress. Adults attending general medicine clinics (n = 171) at a public teaching hospital completed the WSI-SF and the WSI. The WSI-SF was found to have good internal consistency for both the events score (.92) and impact score (.91) and good convergent validity with the WSI. The results of the present study suggest that the WSI-SF is a reliable and valid instrument for use in assessing minor stress.