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1.
The scope of interest of the IEEE Ultrasonics, Ferroelectrics, and Frequency Control (UFFC) Society shall include theory, technology, materials, and applications relating to: (1) the generation, transmission, and detection of mechanical waves and vibrations and their interactions with other phenomena; (2) medical ultrasound, including hyperthermia, bioeffects, tissue characterization and imaging; (3) ferroelectric, piezoelectric, and piezomagnetic materials, including crystals, polycrystalline solids, films, polymers, and composites; (4) frequency control, timing and time distribution, including crystal oscillators and other means of classical frequency control, and atomic, molecular and laser frequency control standards. Areas of interest range from fundamental studies to the design and/or applications of devices and systems.  相似文献   

2.
为了研究RDX和HMX在机械刺激下的临界反应阈值以及丙酮重结晶工艺对它们的影响,采用BAM撞击感度仪和摩擦感度仪测试了不同温度条件下的临界撞击能量和临界摩擦力。结果显示,80、60、40 ℃和25 ℃下,RDX的临界撞击能量分别为5.0、7.5、7.5、7.5 J,HMX的分别为4.0、4.0、5.0、5.0 J;RDX的临界摩擦力分别为120、120、128、144 N,HMX的分别为108、108、108、120 N。丙酮重结晶后,RDX在25 ℃的临界撞击能量和临界摩擦力分别为5.0 J、128 N;HMX在80、60、40 ℃和25 ℃下的临界撞击能量均为7.5 J,临界摩擦力分别为108、108、120、128 N。撞击感度和摩擦感度的结果表明:在25~80 ℃范围内,RDX和HMX的机械感度随着温度的提高呈下降趋势,重结晶工艺对RDX和HMX的机械感度存在着一定的影响。  相似文献   

3.
王文英 《包装工程》2021,42(14):362-364
目的 探索极简主义在平面设计中的表现及应用方向、路径.方法 极简主义简明、简单、独特的特点给了平面设计领域很大的发展空间,基于此,本文尝试从极简主义在平面设计中的应用价值与必要性着手,就极简主义所带来的视觉效果、作品格调与内涵等方面的强化与提升展开探索,得出两者融合与创新的可行性和重要意义,然后结合色彩、形式与内涵等方面的突出特点,对平面设计中极简主义风格的尝试进行深入分析与总结,并结合包装设计、广告设计、网页设计等设计领域详细分析应用方向与路径,总结其在未来发展的有效策略.结论 极简主义简约而不简单的特点让平面设计摆脱了烦琐的境遇,能够将有限的资源与空间合理组合,以高品质的表现形式与深刻的文化内涵为平面设计开拓更宽广的设计路径.  相似文献   

4.
目的为了探究不同贮藏温度对采后上海青叶片衰老及活性成分的影响。方法以上海青为实验材料,分别在0,5,10,15,20,25,30℃下贮藏,对上海青叶片的感官品质、色差、叶绿素含量、丙二醛(MDA)含量、类胡萝卜素含量、叶黄素含量、叶酸含量和亚硝酸盐含量的变化进行分析。结果与20,25,30℃相比,在10℃和15℃下贮藏可减缓上海青叶片L^*值、b^*值、MDA含量和亚硝酸盐含量的增加,以及|a^*|值、叶绿素含量、类胡萝卜素含量、叶黄素含量和叶酸含量的降低;与10℃和15℃贮藏条件相比,在0℃和5℃下贮藏可显著抑制上海青叶片L^*值、b^*值、MDA含量和亚硝酸盐含量的增加,以及|a^*|值、叶绿素含量、类胡萝卜素含量、叶黄素含量和叶酸含量的降低,减缓上海青叶片的黄化衰老进程,从而维持上海青良好的外观品质。在贮藏温度为20,25,30℃时,上海青的最大贮藏期不超过4 d;贮藏温度为10℃和15℃时,最大贮藏期分别不超过9 d和7 d;贮藏温度为0℃和5℃时,最大贮藏期分别不超过40 d和15 d。结论在低温条件下贮藏,尤其是在0℃下贮藏可最大限度地减缓采后上海青叶片的衰老进程,可维持其较高的活性成分,并抑制其组织中亚硝酸盐的积累,显著延长上海青的贮藏期。  相似文献   

5.
Bleeding complications arising from trauma, surgery, and as congenital, disease‐associated, or drug‐induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf‐life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf‐life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state‐of‐art is provided, and challenges and opportunities to help advancement of the field are discussed.  相似文献   

6.
Intersections are hazardous locations and many studies have been conducted to identify the factors contributing to the frequency and severity of intersection crashes. However, little attention has been devoted to investigating the differences between crashes at urban and rural intersections, which have different road, traffic and environmental characteristics. By applying a random parameters probit model to the data from the Canadian Province of Alberta between 2008 and 2012, we find that urban intersection crashes are more likely to be associated with hit and run behaviours, roads with higher traffic volume, wet surfaces, four lanes and skewed intersections, and crashes on weekdays and off-peak hours, whereas rural crashes are likely to be associated with increases in fatalities and injuries, roads with higher speed limits, special road features, exit and entrance terminals, gravel, curvature and two lanes, crashes during weekends, peak hours and night-time, run-off-road crashes, and police visit to crash scene. Hence, road safety professionals in urban and rural areas should consider these differences when designing and implementing counter-measures to improve intersection safety, especially their safety audits and reviews, enforcement activities and education campaigns, to target the more vulnerable times and locations in the different areas.  相似文献   

7.
景影差异论     
陈琳 《影像技术》2008,20(1):24-27
景物美不等于影像美。其原因何在,本文认为是由于双视野与单视野的效果差异、多感官与单感官感受差异、整体与局部及环境与对象之间的影响、人眼与“照相机”感光差异的影响、强度感受与“强度×时间”积累的影响、一瞥与注目的差异、选择性的影响、透视强弱的影响、视及有限与无限的影响、感受性变化的影响、清晰与朦胧的差异、瞬间与长短之影响、真实与转换的差异等单一作用或多重作用的结果。  相似文献   

8.
选取国内外社区管理服务设施标准化具有代表性的典型城市社区纽约、曼哈顿、澳大利亚、北京、上海、重庆等城市社区作为典型案例,通过对国内外典型社区管理服务设施类别和项目标准对比分析,研究发现我国要加强服务性质和功能的设施的标准化类别和项目配建;加强服务老、幼、病、弱、残等群体服务设施类别和项目的配建;加强顶层设计和长远规划,注重文化、教育、体育、休闲、公园绿地等设施类别和项目的配建.  相似文献   

9.
金属合金及碳材料储氢的研究进展   总被引:1,自引:1,他引:0  
论述了金属合金和碳材料的储氢机理、吸放氢量和动力学性能;探讨了活性金属Ni、Pd、Li和K对碳材料储氢的催化性能和金属Mg与多壁纳米碳管、碳纳米纤维、高比表面积活性炭、无烟煤和纳米石墨等碳材料复合储氢的性能及机理;指出了储氢材料应该向Li、Na、Mg、Al、B等轻元素和无烟煤、石墨等储量大、赋存广、成本低的碳材料方向发展.  相似文献   

10.
于德华 《包装工程》2024,45(2):306-317
目的 通过对折叠炕桌案的形成、发展和榫卯结构进行研究,探索折叠家具中承载的熠熠生辉的科技含量和创新成果,为现代设计和创新提供源泉。方法 用文献考证、田野考查、总结归纳等方法,并通过对考古出土、传世家具进行结构复原、测绘扫描、三维展示等方式来对折叠炕桌案进行研究分析。总结出存世折叠炕桌案的折叠结构和固定结构,并对四种不同的榫卯组合进行了深入的分析和研究。 结论 中国折叠家具通过榫卯组合来实现折叠、拆卸、插接和转动等结构,使家具完成造型变化和高度调整,满足礼仪等级、功能转换、存储存放和搬运移动等需求。折叠家具的产生可以溯源至战国两汉墓出土的矮型折叠家具,发展到明清时期后形成了更为丰富复杂的折叠结构,展现中国古代科学严谨的工匠精神和创新精神。  相似文献   

11.
Metal–organic frameworks (MOFs) are an interesting and useful class of coordination polymers, constructed from metal ion/cluster nodes and functional organic ligands through coordination bonds, and have attracted extensive research interest during the past decades. Due to the unique features of diverse compositions, facile synthesis, easy surface functionalization, high surface areas, adjustable porosity, and tunable biocompatibility, MOFs have been widely used in hydrogen/methane storage, catalysis, biological imaging and sensing, drug delivery, desalination, gas separation, magnetic and electronic devices, nonlinear optics, water vapor capture, etc. Notably, with the rapid development of synthetic methods and surface functionalization strategies, smart MOF‐based nanocomposites with advanced bio‐related properties have been designed and fabricated to meet the growing demands of MOF materials for biomedical applications. This work outlines the synthesis and functionalization and the recent advances of MOFs in biomedical fields, including cargo (drugs, nucleic acids, proteins, and dyes) delivery for cancer therapy, bioimaging, antimicrobial, biosensing, and biocatalysis. The prospects and challenges in the field of MOF‐based biomedical materials are also discussed.  相似文献   

12.
Two‐dimensional materials are responsible for changing research in materials science. After graphene and its counterparts, graphane, fluorographene, and others were introduced, waves of renewed interest in 2D binary compounds occurred, such as in metal oxides, transition‐metal dichalcogenides (most often represented by MoS2), metal oxy/hydroxide borides, and MXenes, to name the most prominent. Recently, interest has turned to two‐dimensional monoelemental structures, such as monolayer black phosphorus and, very recently, to monolayer arsenic, antimony, and bismuth. Here, a short overview is provided of the area of exponentially increasing research in arsenene, antimonene, and bismuthene, which belong to the fifth main group of elements, the so‐called pnictogens. A short review of historical work is provided, the properties of bulk allotropes of As, Sb, and Bi discussed, and then theoretical and experimental research on mono‐ and few‐layered arsenene, antimonene, and bismuthene addressed, discussing their structures and properties.  相似文献   

13.
竹质工程材料的制造方法与性能   总被引:4,自引:0,他引:4       下载免费PDF全文
竹质工程材料是利用性能优良、可迅速再生的竹子为原料制造而成。主要的产品有: 竹集成材、竹层积材和分级竹丝复合材料。在竹子生长、采集、加工、制造、使用和产品的废弃过程中, 消耗能源少, 无污染, 是一种高性能的环保材料。与其它工程材料相比较, 其最大的不足在于材料的均齐性。需要采用多种方法提高材料的均齐性, 包括竹材的分级、规则化的加工、浸胶、定向预压、铺层组坯等工艺技术, 以及采用规范的质量控制和检验方法, 才能制造出符合要求的工程材料。其物理和力学性能良好, 可广泛用于风轮叶片、船舶等领域。   相似文献   

14.
通过对国内外石油标准体系现状进行分析,确定了石油天然气勘探开发数据标准体系研究技术路线,建立了石油天然气勘探开发数据标准体系结构,并以石油天然气勘探开发元数据标准和石油天然气勘探开发业务分类与编码规则这两项标准为基础,对数据标准和应用标准所包含的数据元元数据、勘探开发业务分类与编码、业务模型、源点信息采集、图形图符、数据交换、图形交换等系列标准进行了阐述。石油天然气勘探开发数据标准体系的建立,为油田企业数据中心建设奠定了基础,为油田勘探开发生产、科研一体化业务协同提供了重要支撑。  相似文献   

15.
生物机械工程研究进展   总被引:1,自引:0,他引:1  
论述了生物机械工程的重要意义、研究现状、发展趋势、存在问题及对策,旨在推动我国生物机械工程的研究和学术地位的确立,推动生物医学工程学的进步,提高人民的健康水平。  相似文献   

16.
综述了纳米科技的基本概念、产生、发展及其战略意义,讨论了国内外近几年纳米材料和纳米技术的研究成果及应用发展,并对纳米材料在高强度和高韧性纳米陶瓷材料、新型纳米结构的玻璃、塑料和橡胶制品、粘合剂、密封胶和润滑剂、特殊的光学性能材料、催化剂、水泥添加剂、新型防护材料、静电屏蔽材料、耐热、隔热、阻燃材料、涂料等建材领域的直接应用以及其潜在价值进行了讨论。  相似文献   

17.
经过20多年的发展,中国已可以利用遥感、地理信息系统、全球定位系统等空间技术对洪涝、干旱、森林/草原火灾、地下煤火、雪灾、赤潮、台风、滑坡/泥石流、沙尘暴等自然灾害进行监测、评估与预警研究,也可以对空气质量、水环境及生态环境进行监测与评价。为了能够实现大范围、全天候、快速、动态的环境和灾害监测,进一步提高环境监测和综合减灾能力,中国将分阶段发射由4颗光学小卫星和4颗合成孔径雷达小卫星组成的环境与灾害监测预报小卫星星座,通过卫星系统、地面系统、应用系统的建设,最终实现天地一体化的灾害及环境监测、应急、决策支  相似文献   

18.
简要概括了真空电子束焊接技术在不同材料连接方面的应用现状及研究发展动态,包括铝及其合金、钢铁材料、铜及铜合金、钛及钛合金、难熔金属钨/钽/铌/钼及其合金、金属间化合物及复合材料电子束焊接的发展现状。针对电子束焊接技术,简述了国内外学者已取得的部分研究成果,包括工艺试验、组织分析、数值模拟和力学性能等;分析了目前电子束焊接技术在材料连接方面还存在的问题,并展望了电子束焊接技术应向高温新型结构材料、异种材料、功能复合材料等方向发展,丰富了连接过程中的理论基础,揭示了工艺与组织及性能的对应关系,扩展了电子束焊接技术的应用领域。  相似文献   

19.
A fast, sensitive, and simple method using magnetic nanoparticles (MNPs) coated by 3-(trimethoxysilyl)-1-propantiol and modified with 2-amino-5-mercapto-1,3,4-thiadiazole, as an adsorbent has been successfully developed for extraction, preconcentration, and determination of trace amounts of Ag, Cd, Cu, and Zn from environmental samples. The prepared nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). These magnetic nanoparticles can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a piece of permanent magnet. The main factors affecting the extraction efficiency such as pH value, sample volume, eluent concentration and volume, ultrasonication time, and coexisting ions have been investigated and established. Under the optimal conditions, high concentration factors (194, 190, 170, and 182) were achieved for Ag, Cd, Cu, and Zn with relative standard deviations of 5.31%, 4.03%, 3.62%, and 4.20%, respectively. The limits of detection for Ag, Cd, Cu, and Zn were as low as 0.12, 0.12, 0.13 and 0.11 ng mL(-1). The prepared sorbent was applied for preconcentration of trace amounts of Ag, Cd, Cu, and Zn in the various water samples with satisfactory results.  相似文献   

20.
目的 从数据、方法,以及应用三方面梳理情感化智能艺术的研究现状,并总结该领域的发展历程、局限性及未来研究趋势。方法 基于当前的文献、研究成果与应用产品,回顾了情感标注方式的变化及其对情感艺术数据库的影响。解释了情感识别、可控生成、跨媒体等智能技术的实现原理,以及多种情感驱动的智能艺术方法。总结了三种情感与智能艺术的交互机制,以及代表性产品对医疗健康、文化教育、商业营销等领域的影响。结论 情感化方法提升了智能作品的感染力,支持了艺术创作中的人机协同。随着艺术与技术的进一步融合,艺术领域将迎来新的生产、体验与消费模式。  相似文献   

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