机械设计中形位公差的确定

机械产品设计中,合理确定形位公差,是关系到实现设计的目的和生产经济性的问题。位置公差的公差带包容整个被测要素,位置公差确定后,当作用上已能够控制规定的形状误差且能满足使用要求时,一般不再提形状误差的要求;在具体选择设计的零件公差时,首先,在根据零件的使用要求提出形位公差,在不影响使用的情况下,应考虑加工设备,加工工艺、检测等的经济合理性;对一般零件相对尺寸精度,形位公差精度要求较低,形位公差能被尺寸公差控制,可不再提出形位公差;在选用形位公差时还应随时考虑独立原则和相关原则及最大实体则。     

公差原则中最大实体要求的分析及应用

在机械产品设计中,绝大多数情况下尺寸公差和形状、位置公差间的关系都采用独立原则。相关原则应用极少,但相关原则的意义重大,不容忽视,其中最大实体原则在实际生产中起着重要作用。本文对最大实体要求相关术语概念及应用等方面进行了分析。     

对零件对称度公差的分析

对对称度公差值的计算公式进行了推导；对对称度公差应用最大实体原则时的计算进行了分析，对不能直接测量出对称度公差值的零件面对线的对称度，按最小条件用相似三角形进行计算的方法进行了分析。     

用动态公差图解释相关要求初探

相关要求中机械零件的实际尺寸与形位误差允许值之间的动态变化规律,有时用文字和语言难以表达清楚,用动态公差图分别对相关要求中的包容要求、最大实体要求、最小实体要求及其可逆要求作解释,可使机械零件的实际尺寸与形位误差允许值之间的动态变化规律清晰、直观。     

公差原则与配合件的可装配性分析

三种公差原则在一定条件下都可以满足配合件的可装配性.从制造成本、检验效率、假废品三个方面分析了三种公差原则在满足配合件的可装配性上的差异.当配合件仅要求可装配且无其他功能要求时,若进行尺寸设计,最适宜采用的公差原则是最大实体原则.     

跳动公差是形位公差的综合项目

跳动公差以其检测方便在回转类零件设计中被广泛使用。不少人认为:跳动公差是专为检测方便而设置的一种位置公差项目,国家标准形位公差(GB1182-80)也将跳动公差项目归类为位置公差。其实,跳动公差除了可以综合控制部分形位公差项目外,当跳动与零件的实际工作状态吻合时,就有其特定的功能和作用,所以说,跳动公差不是简单的位置公差,而是形位公差的综合项目。     

关于公差原则的应用

在机械制造业中，零件精度的高低，表面质量的好坏，不但取决于零件的尺寸误差，而且取决于它的形位误差，因此，在设计零件时，既要给出尺寸公差要求，又要给出形位公差要求，因此，我们要研究尺寸公差和形位公差之间的关系，称这种关系为公差原则。公差原则分为独立原则和相关原则，其中相关原则又包含最大实体原则和包容原则。独立原则独立原则主要是指尺寸公差和形位公差彼此无关而独立存在的一种公差原则。尺寸公差主要用于控制零件的局部实际尺寸，形位公差用于控制形位误差，加工后的零件上的实际要素，应同时满足两种公差值要求，检…     

《公差原则与公差要求》教学改革的探索与实践

介绍《互换性与测量技术基础》课程中《公差原则与公差要求》一节在课时少、内容多、难度大的条件下进行的教学改革。通过探索和实践收到了良好的教学效果,为本课程其它章节及类似其它课程的改革提供了借鉴。     

公差课程知识点在机械产品设计中的应用

众所周知,任何机械产品的零件图中都要标注尺寸公差、几何公差及表面粗糙度等技术要求,所以从事机械行业的设计人员都必须掌握公差的相关知识.本文重点介绍,公差课程的几个知识点在机械产品设计中的应用.     

统计公差在装配尺寸链中的应用

针对在装配尺寸链的计算中,装配尺寸精度设计通常所采用的极值公差计算法,计算所得的各组成环的公差过小,导致加工困难．这种计算方法不合理。本文介绍用统计公差法计算各组成环的公差,在保证封闭环的公差要求前提下,计算出的各组成环的公差大些,这样,计算出的尺寸公差,既可保证产品质量,又可降低加工难度,提高经济效益。     

Researching religious tolerance education using discourse analysis: a case study from Indonesia

ABSTRACT

Complementing existing studies on religious tolerance education which have mainly evaluated interventions using pre–post designs, this article argues that discourse analysis can be a viable alternative methodology for generating new knowledge in this field. To illuminate the potentials of discourse analysis, the article also presents a case study of the application of this methodology in analysing a religious tolerance education project in an under-represented Global South country, Indonesia – where religious conservatism and intolerance are on the rise. Following the contact hypothesis, the project involved students from different religions working on a film-making group assignment about religious tolerance. Three key discourses drawn upon by students in giving meaning to religious tolerance within these films are identified, namely, a discourse of nationalism, tolerant theologies, and romantic love; and their implications are discussed with regard to the promotion of religious tolerance in education.     

Low-cost fault tolerance in evolvable multiprocessor systems: a graceful degradation approach

The evolvable multiprocessor （EvoMP）, as a novel multiprocessor system-on-chip （MPSoC） machine with evolvable task decomposition and scheduling, claims a major feature of low-cost and efficient fault tolerance. Non-centralized control and adaptive distribution of the program among the available processors are two major capabilities of this platform, which remarkably help to achieve an efficient fault tolerance scheme. This letter presents the operational as well as architectural details of this fault tolerance scheme. In this method, when a processor becomes faulty, it will be eliminated of contribution in program execution in remaining run-time. This method also utilizes dynamic rescheduling capability of the system to achieve the maximum possible efficiency after processor reduction. The results confirm the efficiency and remarkable advantages of the proposed approach over common redundancy based techniques in similar systems.     

软件坚固性与基于软件的容错技术

坚固性是软件可靠性的主要方面之一，并正在成为衡量软件质量的重要指标。基于软件的容错技术是实现软件系统坚固性的主要途径，包含了操作容错、数据容错、软件容错和硬件容错四个方面内容，其本质都是冗余方法，基本手段的故障检测与故障定位、故障包容与故障屏蔽、系统重构与故障恢复等，软件容错的基本方法是多样性设计，其代表性方法是恢复块RB和多版本编程NVP技术。本文同时简要介绍了容错技术的基本思想、方法及相关研究的发展概况。     

Mathematical model of cylindrical form tolerance

Tolerance is essential for integration of CAD and CAM.Unfortunately,the meaning of tolerances in the national standard is expressed in graphical and language forms and is not adaptable for expression,processing and data transferring with computers.How to interpret its semantics is becoming a focus of relevant studies.This work based on the mathematical definition of form tolerance in ANSI Y 14.5.1 M-1994,established the mathematical model of form tolerance for cylindrical feature.First,each tolerance in the national standard was established by vector equation.Then on the foundation of tolerance's mathematical definition theory,each tolerance zone's mathematical model was established by inequality based on degrees of feature.At last the variance area of each tolerance zone is derived.This model can interpret the semantics of form tolerance exactly and completely.     

多重耐药性细菌性痢疾的治疗

目的:研究痢疾杆菌的耐药性及多重耐药性菌痢的抗生素治疗。方法:对患者进行便培养及药敏检查,应用氨基糖甙类、喹诺酮类、第三代头孢菌素类、利福平等抗菌药物及联合用药。结果:证实本地区急性菌痢的病原体仍以福氏志贺菌为主,该菌对氨苄青霉素、复方新诺明、痢特灵耐药率在80％以上,对头孢曲松钠未见耐药性,急性菌痢136例经不同药物治疗,头孢曲松钠组、氧氟沙星组及丁胺卡那霉素加利福平组均有较高治愈率。头孢哌酮组及庆大霉素加诺氟沙星组治愈率较低,与上述各组比较有显著性差异(P<0.05)。结论:通过对志贺菌属耐药性研究表明应及时选用无耐药性或耐药性较低的抗菌药物,第三代喹诺酮(氧氟沙星)及第三代头孢菌素(头孢曲松钠)类药物为首选药物。     

Fostering uncertainty tolerance in anatomy education: Lessons learned from how humanities,arts and social science (HASS) educators develop learners' uncertainty tolerance

Uncertainty tolerance, individuals' perceptions/responses to uncertain stimuli, is increasingly recognized as critical to effective healthcare practice. While the Covid-19 pandemic generated collective uncertainty, healthcare-related uncertainty is omnipresent. Correspondingly, there is increasing focus on uncertainty tolerance as a health professional graduate “competency,” and a concomitant interest in identifying pedagogy fostering learners' uncertainty tolerance. Despite these calls, practical guidelines for educators are lacking. There is some initial evidence that anatomy education can foster medical students' uncertainty tolerance (e.g., anatomical variation and dissection novelty), however, there remains a knowledge gap regarding robust curriculum-wide uncertainty tolerance teaching strategies. Drawing upon humanities, arts and social sciences (HASS) educators' established uncertainty tolerance pedagogies, this study sought to learn from HASS academics' experiences with, and teaching practices related to, uncertainty pedagogy using a qualitative, exploratory study design. Framework analysis was undertaken using an abductive approach, wherein researchers oscillate between inductive and deductive coding (comparing to the uncertainty tolerance conceptual model). During this analysis, the authors analyzed ~386 min of data from purposively sampled HASS academics' (n = 14) discussions to address the following research questions: (1) What teaching practices do HASS academics' perceive as impacting learners' uncertainty tolerance, and (2) How do HASS academics execute these teaching practices? The results extend current understanding of the moderating effects of education on uncertainty tolerance and supports prior findings that the anatomy learning environment is ripe for supporting learner uncertainty tolerance development. This study adds to growing literature on the powerful moderating effect education has on uncertainty tolerance and proposes translation of HASS uncertainty tolerance teaching practices to enhance anatomy education.     

Science Letters: Low-cost fault tolerance in evolvable multiprocessor systems: a graceful degradation approach

The evolvable multiprocessor (EvoMP), as a novel multiprocessor system-on-chip (MPSoC) machine with evolvable task decomposition and scheduling, claims a major feature of low-cost and efficient fault tolerance. Non-centralized control and adaptive distribution of the program among the available processors are two major capabilities of this platform, which remarkably help to achieve an efficient fault tolerance scheme. This letter presents the operational as well as architectural details of this fault tolerance scheme. In this method, when a processor becomes faulty, it will be eliminated of contribution in program execution in remaining run-time. This method also utilizes dynamic rescheduling capability of the system to achieve the maximum possible efficiency after processor reduction. The results confirm the efficiency and remarkable advantages of the proposed approach over common redundancy based techniques in similar systems.     

Relocating respect and tolerance: A practice approach in empirical philosophy

Respect and tolerance are key values in education. They are also among the aims of education and are brought to the foreground in educational policy. We argue that these values are neither philosophically nor politically given aims for which education is a means. Instead, respect and tolerance are enacted and negotiated through educational practices. We emphasize that respect and tolerance should be empirically and critically studied in educational practices. The discussion is based in two previous research projects and the material includes interviews with teachers and students and classroom observations. Moral philosophy is positioned as a conversation partner with the data material. We conclude that respect and tolerance are performed in different modes in practice. These two values cannot be understood as individual cognitive aspects but as multimodal processes and as aspects of collective, bodily and material practices. This article provides a contribution to the theorizing about educating for respect and tolerance.     

Religious tolerance in Oman: addressing religious prejudice through educational intervention

This paper examines the impact of a school‐based intervention entitled ‘Our Brothers and Sisters in Humanity’ on 10th grade female Omani students' religious tolerance. A questionnaire was administered before and after an intervention to a sample of 241 girls, of whom 116 were in the experimental group and 125 in the control group. A semi‐structured interview was conducted before and after the intervention with 16 participants, of whom 8 were from the experimental group and 8 from the control group. Analysis of the quantitative data in the postintervention round reveals that there are statistically significant differences between the experimental group and the control group in favour of the experimental group in religious tolerance. Similarly the experimental group shows greater tolerance when compared to the control group in post‐intervention interviews. The study suggests that religion is one of the most salient components of Omani pupils' ‘identity’. The participants use religion to define their relations with, and determine their tolerance of, those who hold different religious beliefs. However, we conclude that education that capitalises on the perceived similarities between religions can be a means to suppress intolerance.