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自修复与阻燃功能一体化玄武岩纤维增强环氧树脂基复合材料的制备及性能
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作者 陈练辉 董丽楠 +4 位作者 廉婷婷 张圣昌 许启彬 姜猛进 刘鹏清 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2024年第6期115-124,共10页
纤维增强环氧树脂基复合材料(FREPC)在实际应用中常因裂纹失效和燃烧破坏而受到限制。文中将自制的DA加合物(DOPO-FU-BMI)与糠胺(FA)配合,引入到环氧树脂DGEBA中,通过热压成型工艺制备了兼具自修复和阻燃双重功能的玄武岩纤维增强环氧... 纤维增强环氧树脂基复合材料(FREPC)在实际应用中常因裂纹失效和燃烧破坏而受到限制。文中将自制的DA加合物(DOPO-FU-BMI)与糠胺(FA)配合,引入到环氧树脂DGEBA中,通过热压成型工艺制备了兼具自修复和阻燃双重功能的玄武岩纤维增强环氧树脂基复合材料。结果表明,DA加合物在复合材料中实现了均匀分布,提升了材料的热稳定性和玻璃化转变温度;复合材料通过动态可逆化学键的可逆Diels-Alder(DA)反应实现了裂纹的修复,当DA加合物质量分数为20%时,经2次“冲击-修复”循环后复合材料的强度保留率仍高达92.5%;同时,复合材料发挥了玄武岩纤维的阻燃特性优势,引入DA加合物后使其阻燃性能进一步增强,极限氧指数最高可达44.5%,较未改性复合材料提升25.4%。 展开更多
关键词 自修复 阻燃性能 玄武岩纤维 环氧树脂基复合材料 可逆Diels-Alder反应
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中国儿童福利政策发展的逻辑与趋向 被引量:12
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作者 廉婷婷 乔东平 《中国公共政策评论》 2021年第1期1-18,共18页
本文运用文献研究法,通过时代背景、中国特色福利思想、政策理念、儿童权利、政策主体与客体、政策过程和领域的分析,呈现新中国成立以来儿童福利政策演变的脉络、内容、特点和发展逻辑。本文聚焦于儿童福利权、受保护权、健康权、受教... 本文运用文献研究法,通过时代背景、中国特色福利思想、政策理念、儿童权利、政策主体与客体、政策过程和领域的分析,呈现新中国成立以来儿童福利政策演变的脉络、内容、特点和发展逻辑。本文聚焦于儿童福利权、受保护权、健康权、受教育权的政策发展历程分析,发现中国儿童福利政策呈现出四种演变趋向,即理念从"消极被动"到"积极主动",内容从单一化、无序化到体系化、制度化,对象从特殊性、选择性到普遍性、全程性,福利责任从模糊到多元主体共担。基于政策问题、新时代发展要求和儿童需要,本文建议多层立法保护"儿童最大利益",在治理现代化背景下厘清福利责任边界,优化"儿童福祉"取向的政策体系。 展开更多
关键词 儿童福利政策 70年发展逻辑 发展趋向 儿童权利
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Thermal property evaluation of a 2.5D integration method with device level microchannel direct cooling for a high-power GaN HEMT device 被引量:1
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作者 tingting lian Yanming Xia +5 位作者 Zhizheng Wang Xiaofeng Yang Zhiwei Fu Xin Kong Shuxun Lin Shenglin Ma 《Microsystems & Nanoengineering》 SCIE EI CSCD 2022年第6期195-203,共9页
Gallium nitride high electron mobility transistor(GaN HEMT)devices have become critical components in the manufacturing of high-performance radio frequency(RF)or power electronic modules due to their superior characte... Gallium nitride high electron mobility transistor(GaN HEMT)devices have become critical components in the manufacturing of high-performance radio frequency(RF)or power electronic modules due to their superior characteristics,such as high electron saturation speeds and high power densities.However,the high heat characteristics of GaN HEMTs make device level cooling a critical problem to solve since performance degradation or even failure may occur under high temperatures.In this paper,we proposed a 2.5D integration method with devicelevel microchannel direct cooling for a high-power GaN HEMT device.To demonstrate this technological concept,a multigate GaN HEMT device featuring a gate length/width/source drain spacing of 0.5μm/300μm/6μm that underwent in-house backside thinning and metallization was used as the test vehicle.A high-resistivity silicon(HR Si)interposer embedded with four-layer microchannels was designed,having widths/pitches of 30μm/30μm at the top microchannel.The high-power GaN HEMT device was soldered on a Si interposer embedded with open microchannels for heat dissipation.A pair of GSG Pad chips was soldered simultaneously to display the capacity for the heterogeneous integration of other chip types.Thermal property evaluation was conducted with experiments and simulations.The test results showed that the maximum surface temperature of the GaN HEMT device decreased to 93.8°C when it experienced a heat dissipation density of 32 kW/cm^(2) in the gate finger area and an average heat dissipation density of 5 kW/cm^(2) was found in the active area with the DI water coolant at a flow rate of 3 mL/min.To our knowledge,among recently reported works,this finding was the best cooling capacity of heterogeneously integrated microchannels for GaN HEMT devices.In addition,this technology was scalable regarding the numbers of gate fingers or GaN HEMT devices. 展开更多
关键词 power INTEGRATION high
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