DISCRETIZATION APPROACH USING RAY-TESTING MODEL IN PARTING LINE AND PARTING SURFACE GENERATION

Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in auto-matic cavity design based on the my-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.

Geochemistry of Sulfur and Hazardous Elements in Late Paleozoic Coals and Partings from Taozao Coalfield, Shandong Province, China

The analyses of different sulfur forms, the trace elements in pyrites using electron microprobe and the trace elements in coal using INAA (instrumental neutron activation analysis) of the Late Paleozoic coals from the Taozao coalfield in Shandong Province, China, conclude that most sulfur (>75 %) in high-sulfur coal of Taiyuan Formation occurred as pyrite, in which many hazardous elements co-existed and their concentrations varied with their geological origin. The concentrations of hazardous elements in high-sulfur coals from Taiyuan Formation, composing mainly of Cu, As, U, Pb, Mo and Co, are much higher than those in the low-sulfur coals from Shanxi Formation and Shihezi Formation, because the influence of seawater during and after coal accumulation in Taiyuan Formation is stronger than those in Shanxi and Shihezi formations. Moreover, the element As is related to Fe, and both elements exist mainly in the form of pyrite. The element U is richer in the coal influenced by seawater. In addition, the coal affected by the magmatism contains more U, too. When high-sulfur coals are processed with heavy media washing to remove sulfur and minerals, the majority of hazardous elements will also be removed from the coals.

DESIGN TECHNOLOGY FOR INJECTION MOLD PARTING SURFACE BASED ON CASES AND KNOWLEDGE

On the basis of the comprehensive analysis about the automatic generation of the injection mold parting surface, the parting surface design method which introduces knowledge and case-based reasoning （CBR） into the computer-aided design is described by combining with the actual characteristic in injection mold design, and the design process of case-based reasoning method is also given. A case library including the information of parting surface is built with the index of main shape features, The automatic design of the mold parting surface is realized combined with the forward-reasoning method and the similarity solution procedure. The rule knowledge library is also founded including the knowledge, principles and experiences for parting surface design. An example is used to show the validity of the method, and the quality and the efficiency of the mold design are improved.

A Ray-Testing Approach to Automatically Identify Surface Visibility in Parting Line Generation

It is critical to identify core/cavity and undercut surfaces of molds in parting line generation. A new Ray-Testing approach is presented to detect these surfaces by identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. Case studies show that the approach is practical and valuable in automated parting line generation.

CAD APPROACH FOR PLASTIC MOULD PARTING DIRECTIONS OPTIMIZATION

A CAD approach which can optimize and automate the parting direction determination is presented. The approach is based on the geometrical and topological information of the solid modelling of the plastic moulded part in order to select a pair of optimal parting directions of a two plate mould which minimizes the number of side cores. The shell of a part is divided into inter influential regions and non influential faces in the mould design point of view. Through analyzing and computing the accessibility direction cones of the inter influential regions, the optimal parting directions can be determined automatically.

Optimization of Fixture Number in Large Thin-Walled Parts Assembly Based on IPSO

There are lots of researches on fixture layout optimization for large thin-walled parts.Current researches focus on the positioning problem,i.e.,optimizing the positions of a constant number of fixtures.However,how to determine the number of fixtures is ignored.In most cases,the number of fixtures located on large thin-walled parts is determined based on engineering experience,which leads to huge fixture number and extra waste.Therefore,this paper constructs an optimization model to minimize the number of fixtures.The constraints are set in the optimization model to ensure that the part deformation is within the surface profile tolerance.In addition,the assembly gap between two parts is also controlled.To conduct the optimization,this paper develops an improved particle swarm optimization(IPSO)algorithm by integrating the shrinkage factor and adaptive inertia weight.In the algorithm,particles are encoded according to the fixture position.Each dimension of the particle is assigned to a sub-region by constraining the optional position range of each fixture to improve the optimization efficiency.Finally,a case study on ship curved panel assembly is provided to prove that our method can optimize the number of fixtures while meeting the assembly quality requirements.This research proposes a method to optimize the number of fixtures,which can reduce the number of fixtures and achieve deformation control at the same time.

Development of Fixture Layout Optimization for Thin-Walled Parts:A Review

An increasing number of researchers have researched fixture layout optimization for thin-walled part assembly during the past decades.However,few papers systematically review these researches.By analyzing existing literature,this paper summarizes the process of fixture layout optimization and the methods applied.The process of optimization is made up of optimization objective setting,assembly variation/deformation modeling,and fixture layout optimization.This paper makes a review of the fixture layout for thin-walled parts according to these three steps.First,two different kinds of optimization objectives are introduced.Researchers usually consider in-plane variations or out-of-plane deformations when designing objectives.Then,modeling methods for assembly variation and deformation are divided into two categories:Mechanism-based and data-based methods.Several common methods are discussed respectively.After that,optimization algorithms are reviewed systematically.There are two kinds of optimization algorithms:Traditional nonlinear programming and heuristic algorithms.Finally,discussions on the current situation are provided.The research direction of fixture layout optimization in the future is discussed from three aspects:Objective setting,improving modeling accuracy and optimization algorithms.Also,a new research point for fixture layout optimization is discussed.This paper systematically reviews the research on fixture layout optimization for thin-walled parts,and provides a reference for future research in this field.

A Systematic Review of Computer Vision Techniques for Quality Control in End-of-Line Visual Inspection of Antenna Parts

The rapid evolution of wireless communication technologies has underscored the critical role of antennas in ensuring seamless connectivity.Antenna defects,ranging from manufacturing imperfections to environmental wear,pose significant challenges to the reliability and performance of communication systems.This review paper navigates the landscape of antenna defect detection,emphasizing the need for a nuanced understanding of various defect types and the associated challenges in visual detection.This review paper serves as a valuable resource for researchers,engineers,and practitioners engaged in the design and maintenance of communication systems.The insights presented here pave the way for enhanced reliability in antenna systems through targeted defect detection measures.In this study,a comprehensive literature analysis on computer vision algorithms that are employed in end-of-line visual inspection of antenna parts is presented.The PRISMA principles will be followed throughout the review,and its goals are to provide a summary of recent research,identify relevant computer vision techniques,and evaluate how effective these techniques are in discovering defects during inspections.It contains articles from scholarly journals as well as papers presented at conferences up until June 2023.This research utilized search phrases that were relevant,and papers were chosen based on whether or not they met certain inclusion and exclusion criteria.In this study,several different computer vision approaches,such as feature extraction and defect classification,are broken down and analyzed.Additionally,their applicability and performance are discussed.The review highlights the significance of utilizing a wide variety of datasets and measurement criteria.The findings of this study add to the existing body of knowledge and point researchers in the direction of promising new areas of investigation,such as real-time inspection systems and multispectral imaging.This review,on its whole,offers a complete study of computer vision approaches for quality control in antenna parts.It does so by providing helpful insights and drawing attention to areas that require additional exploration.

“三美论”视角下对比赏析When We Two Parted的汉译本——以查良铮和陈锡麟的译本为例

“三美论”是许渊冲先生提出的翻译理论,所谓的“三美”指的是意美、音美和形美。本文以许渊冲先生的“三美论”为理论指导,对比赏析查良铮和陈锡麟对乔治•戈登•拜伦诗歌When We Two Parted的两个中译本。从意美、音美和形美三个层面,对比赏析两个中译本对原文意境、诗歌节奏和尾韵以及诗歌形式上的再现。在诗歌汉译中,三美难以兼顾,译者在进行翻译时要分清主次,原则是意美大于音美,音美大于形美。

农业拖拉机尾灯多色注塑模具设计

以农业拖拉机尾灯为研究对象,分析了尾灯的内部结构和工艺性,并针对双色模具的特殊性,分析了模具成型方案和设计流程,基于AutoCAD和CAE软件完成了尾灯双色塑件模具的设计。开模试验表明:该产品符合设计需求,整个产品结构稳定,透明度好,设计的模具结构合理、工艺流程可靠,能够满足实际的生产应用,工程应用价值较高。

Essex-Lopresti损伤的诊治分析

目的:总结Essex-Lopresti损伤的治疗经验,对比修复前臂骨间膜对近远期前臂功能的影响。方法:2005年1月至2013年12月收治24例Essex-Lopresti损伤患者,其中16例(A组)伴有尺骨干、桡骨干或尺桡骨干双骨折,先行尺骨或桡骨切开复位内固定,同时修复前臂骨间膜,然后再行桡骨小头复位固定和下尺桡关节固定或腕三角纤维复合体修复。8例(B组)不合并尺骨或桡骨骨折仅行桡骨小头复位固定和下尺桡关节固定或腕三角纤维复合体修复。分别于术后2周和2年按Cooney腕关节功能评分表(即改良Green和O’Brien腕关节评分)对腕关节功能进行评定,按Mayo肘关节功能评分表对肘关节功能进行评定。结果:术后2周时,腕关节功能评分A组可4例,差12例;B组可2例,差6例。肘关节评分A组良2例,可8例,差6例;B组良1例,可5例,差2例。术后2年时,A组腕关节功能评分良8例,可6例,差2例;B组良5例,可2例,差1例。肘关节评分A组良8例,可6例,差2例;B组良4例,可3例,差1例。两组术后2周和术后2年的疗效差异无统计学意义。结论:Essex-Lopresti损伤的治疗关键在于恢复尺桡骨的长度和腕、肘关节的动态稳定性,是否修复前臂骨间膜对前臂近远期功能影响无明显区别。

Essex-Lopresti损伤合并同侧前臂骨折的手术治疗

目的 Essex-Lopresti损伤是涉及到下尺桡关节脱位,骨间膜损伤和桡骨头骨折的一种复杂损伤,是一种很难诊断和治疗的损伤,合并前臂骨折更加少见。文中探讨Essex-Lopresti损伤合并同侧前臂骨折的治疗方法和疗效。方法2003年至2010年确诊的20例患者均手术治疗,先解剖复位前臂骨折,后恢复桡骨长度,复位并稳定下尺桡关节,术后对20例患者进行随访。结果 20例患者随访时间12～24个月,平均随访时间18个月,根据Broberg-Morrey肘关节评分系统,肘关节功能平均分74(60～95)分,结果优2例,良11例,差7例,优良率65%。腕关节功能根据改良的Mcbride腕关节临床评分:腕关节功能平均分88.5分(75～98)分,优6例,良10例,可4例,优良率83%。结论 Essex-Lopresti损伤合并同侧前臂骨折,先解剖复位尺骨骨折利于桡骨长度重建或恢复,伴有前臂骨折的Essex-Lopresti损伤,桡骨头骨折和骨间膜的损伤程度较轻。

Rapid Manufacturing of Metal Parts

As a key technology of rapid prototyping and manufacturing (RP&M), rapid manufacturing of metal parts is a target of RP&M. Introducing selective laser sintering (SLS), an important branch of RP&M, this paper gives a new method oriented on low power SLS system to fabricate metal parts. With this kind of technology, the mixture of metal and polymer powder is sintered first to get green part, then, after debinding and metal infiltration, dense parts are gotten. In the end, influencing factors of this technology are analyzed. At the same time, some applications are given.

金属人工桡骨头置换术治疗Essex-Lopresti损伤

目的随访并报告金属人工桡骨头置换治疗Essex-Lopresti损伤的临床疗效。方法 2009年1月至2011年11月间共有11例Essex-Lopresti损伤患者(Edwards-Jupiter分型Ⅰ型2例,Ⅱ型9例)在伤后3～7 d(平均4.5 d)接受金属人工桡骨头置换治疗,术后随访内容包括影像学检查、Mayo肘关节功能评分、改良Mayo腕关节功能评分,并记录并发症发生情况。结果 11例患者均获随访,平均19个月(12～37个月)。Mayo肘关节功能评分为平均82分(55～100分),其中优4例(36.4%),良5例(45.5%),可1例(9.1%),差1例(9.1%),优良率为81.8%;改良Mayo腕关节功能评分为平均92分(65～100分),其中优6例(54.5%),良4例(36.4%),可1例(9.1%),没有差的病例,优良率为91.0%。本组未见神经损伤、假体排异、切口感染等并发症。结论金属人工桡骨头假体置换治疗Essex-Lopresti损伤的临床效果满意,但手术设计和操作要精确。

基于PARTS战略的应用型本科旅游管理专业实践教学改革探索

文章在旅游应用型人才培养现状与培养定位严重错位的背景下,以提高学生综合职业能力为目标,创新性地将源自战略管理竞合理论中的PARTS战略引入旅游管理专业实践教学改革中,从教学主体、合作利益、合作机制、教学方式、教学内容五个方面对实践教学体系改革进行了探索,以期提高旅游实践教学效果,强化旅游应用人才培养质量。

锁阳PartⅢ对环磷酰胺致免疫抑制小鼠免疫功能的影响

目的:研究锁阳PartⅢ对环磷酰胺致免疫抑制小鼠免疫功能的影响。方法:用环磷酰胺(CTX,100 mg/kg)腹腔注射制备小鼠免疫低下模型,给药组和阳性对照人参皂苷(TSPG)组剂量均为300 mg/kg.d,空白对照组和缺氧模型组给予同体积的蒸馏水,灌胃给药,共7 d。分别从外周血象、免疫器官指数、巨噬细胞吞噬功能和血清溶血素水平等方面进行评价。结果:锁阳水提物PartⅢ可使CTX免疫抑制小鼠的免疫器官指数、巨噬细胞吞噬功能和血清溶血素水平不同程度的升高。结论:锁阳水提物PartⅢ能够增强CTX免疫抑制小鼠的非特异性和特异性免疫功能,对免疫失衡机体具有一定的保护作用。

Purchasing policy model based on components/parts unification

This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different prices and quality characteristics. Because of the buyer's quality preference and suppliers' discount rates for bulky purchases, the model assists the procurement manager to determine how best to purchase the components/parts to meet its demand while minimizing the total acquisition costs.

Essex-Lopresti损伤的原因分析及诊疗现状

Essex-Lopresti损伤（Essex-Lopresti Injury,ELI）常因高能量暴力作用于前臂导致桡骨头骨折合并前臂骨间膜破坏及下尺桡关节脱位,是肘、前臂、腕同时受累的三联损伤,也可称之为前臂纵向分离。因Essex-Lopresti在1951年较详细报道而得名,其发生率约占桡骨头骨折的1%[1]。由于临床上对该损伤认识不足,就诊时约有75%的患者因忽视三角纤维软骨复合体与骨间膜损伤而漏诊，而在延迟治疗的患者中仅20％能取得相对满意的疗效圆。因此，早期的诊断是提高该病疗效的关键。

Essex-Lopresti损伤的手术治疗

目的总结切开复位内固定或人工桡骨头置换治疗Essex-Lopresti损伤及其疗效。方法2005年8月至2011年9月收治8例Essex-Lopresti损伤患者。男6例,女2例;年龄20～58岁,平均36岁。新鲜闭合骨折6例,受伤至手术时间2 h～1.5 d;桡骨头骨折按改良的Mason分型:Ⅱ型5例,Ⅲ型1例。余2例于外院行单纯桡骨头切除,因术后出现腕关节疼痛、前臂纵向不稳分别于伤后2个月和4个月入院。X线片示均有下尺桡关节脱位。桡骨头骨折采用切开复位微型钢板或可吸收螺钉内固定(5例)或人工桡骨头置换(3例)治疗,同时复位并固定下尺桡关节。结果患者术后切口均Ⅰ期愈合。8例均获随访,随访时间6～24个月,平均13.6个月。X线片示术后9～20周骨折均达临床愈合,平均15.2周;无桡骨近端移位,下尺桡关节稳定。术后6个月肘关节功能根据Morrey-Broberg功能评分系统评价获优5例,良3例;腕关节临床功能根据改良的腕关节临床评分系统评价获优7例,良1例。患者均无肘关节不稳,关节活动无严重受限;均恢复正常工作生活。结论对Essex-Lopresti损伤的治疗做到早诊断。