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EFFECT OF NANOCRYSTALLINE CELLULOSE ON THE CURING CHARACTERISTICS AND AGING RESISTANCE PROPERTIES OF CARBON BLACK REINFORCED NATURAL RUBBER

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Chinese Journal of Polymer Science 2013年第10期31卷 1382-1393页

作者： ju gu Wan-juan Chen Lu Lin Yuan-fang Luo De-min Jia College of Materials Science and Engineering South China University of Technology

This work focused on the effect of nanocrystalline cellulose （NCC） on the curing characteristics, aging resistance and thermal stability of natural rubber （NR） reinforced with carbon black （CB）. Sharing the same fillers loading of 45 parts per hundred rubber （phr）, NR/NCC/CB composites with different NCC/CB ratios （i.e. 0/45, 5/40, 10/35, 15/30, 20/25 phr） were prepared and analyzed. Resorcinol and hexamethylene tetramine （RH）, acting as the modifier in NR/NCC interface, was also discussed for its influence. The result showed that an relatively higher ratio of NCC/CB led to a lower torque, a shorter cure time （Tg0）, a slightly longer scorch time （Ti0） and a bigger vulcanization rate constant （K）. This tendency suggested that the existence of NCC accelerated the vulcanization process. Additionally, modified by RH, NR/NCC/CB compounds exhibited a short T10 and a elevated torque. And a moderate RH content would lower the E of vulcanization. A 10 phr substitute of CB by NCC can help to improve aging resistance in terms of mechanical properties. In a high temperature aging condition, composites with 10 phr NCC also performed the highest storage modulus （G＇） among composites tested. A moderate NCC content contributed to the best retention of G＇ after high temperature aging, so did the incorporation of RH. With the partial replacement of CB by NCC, the temperature of 5% weight-lose had a slight drop and the apparent crosslink density showed a decrease. Thanks to the interaction of RH with both NR and NCC, composites showed an improvement in apparent crosslink density after modified by RH.

关键词： Nanocrystalline cellulose Natural rubber Curing characteristics Aging resistance Thermal stability.

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Response of slope surface roughness to wave-induced erosion during water level fluctuating

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Journal of Mountain Science 2020年第4期17卷 871-883页

作者： gu ju LIU Gang ABD ELBASIT Mohamed Ahmed Mohamed SHI Hong-qiang State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China Agricultural Research Council Institute for SoilClimate&WaterPrivate Bag X79Pretoria 0001South Africa

The bank slopes in hydro-fluctuation areas of reservoirs or lakes suffer from severe erosion due to an absence of protection. Waves are one of the important external forces that cause bank erosion and slope failures. However, the processes and quantified impacts of wave-induced erosion on slopes remain unclear under different water level-fluctuation conditions. This paper focuses on the characteristics of wave-induced slope erosion under three conditions: water level dropping(WLD), fixed(WLF) and rising(WLR). A steel tank with glass pane was used to simulate the wave-induced slope erosion in the three treatments. The slope elevation data were collected by using the method of the pin meter for every 15 minutes from the beginning to the end, a total of 5 times during all treatments. These data were processed by using software(SURFER 9.0) to get the slope micro-topography and the erosion volume. Then the temporal and spatial change of slope erosion was analysed according to the erosion amount or erosion rate calculated based on bulk density of slope soil. The results demonstrated that the soil erosion rates for different water level changing treatments are in the following order: WLR>WLD>WLF. For the erosion spatial variation, the middle part of the slope was the major source of sediment in the WLD. The upper part of the slope was the major source of the sediment for the other two treatments. Compared with the standard deviation(SD), the coefficient of variation(CV) based on the SD is more representative of variations in the soil surface roughness(SSR). Furthermore, the good fit between the SSR and soil erosion rate have the potential to be used to predict soil erosion. Above all, the injection angle of the wave determined the rate of erosion to some extent, and the fall-back flow of the wave could also influence the extent of erosion, deposition, and bank morphology. It is vital to choose the appropriate index(SD or CV) in the three water levels to improve the predict

关键词： Bank erosion Erosion rate Micro topography Soil surface roughness Breaking point

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Nonreciprocal two-photon transmission and statistics in a chiral waveguide QED system

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Chinese Physics B 2022年第5期31卷 340-349页

作者： Lei Wang Zhen Yi Li-Hui Sun Wen-ju gu School of Physics and Optoelectronic Engineering Yangtze UniversityJingzhou 434023China

We study the nonreciprocal properties of transmitted photons in a chiral waveguide quantum electrodynamics(QED)system,including single-and two-photon transmissions and second-order *** the single-photon transmission,the nonreciprocity is induced by the effects of chiral coupling and atomic dissipation in the weak coupling *** vanishes in the strong coupling regime when the effect of atomic dissipation becomes *** the case of two-photon transmission,there exist two ways of going through the emitter:independently as plane waves and formation of bound *** the nonreciprocal behavior of plane waves,the bound state that differs in two directions also alters transmission *** addition,the second-order correlation of transmitted photons depends on the interference between plane wave and bound *** destructive interference leads to the strong antibunching in the weak coupling region,while the effective formation of bound state leads to the strong bunching in the intermediate coupling ***,the negligible interactions for left-propagating photons hardly change the statistics of the input coherent state.

关键词： chiral waveguide QED nonreciprocal transmissions nonreciprocal correlations

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Color Medical Image Enhancement Based on Adaptive Equalization of Intensity Numbers Matrix Histogram

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International Journal of Automation and computing 2015年第5期12卷 551-558页

作者： ju-Ping gu Liang Hua Xiao Wu Hui Yang Zhen-Tao Zhou Department of Electrical Engineering Nantong University

The enhancement technique for color medical images is conductive to improve the resolution and accuracy of the original image. A new enhancement method combining the Young-Helmholtz(Y-H) transformation with the adaptive equalization of intensity numbers matrix histogram is proposed in this paper. The adaptive histogram equalization method is applied to strengthen the details,enhance the contrast, and suppress the noise of the original image effectively. The enhanced image can be displayed in the red-greenblue(RGB) color space through inverse Y-H transformation with the same hue and saturation. The experiment results demonstrate that the method has the enhancement effect with low computational complexity, which provides the foundation for the medical diagnosis and further processing of medical images.

关键词： Youag-Helmhotz(Y-H) color space adaptive histogram

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Spatial distribution of supraglacial debris thickness on glaciers of the China-Pakistan Economic Corridor and surroundings

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Research in Cold and Arid Regions 2020年第6期12卷 447-460页

作者： YaJie Zheng Yong Zhang ju gu Xin Wang ZongLi Jiang junFeng Wei School of Resource Environment and Safety Engineering Hunan University of Science and TechnologyXiangtanHuan 411201China

Debris-covered glaciers,characterized by the presence of supraglacial debris mantles in their ablation zones,are widespread in the China-Pakistan Economic Corridor(CPEC)and *** these glaciers,thin debris layers accelerate the melting of underlying ice compared to that of bare ice,while thick debris layers retard ice melting,called debriscover *** about the thickness and thermal properties of debris cover on CPEC glaciers is still unclear,making it difficult to assess the regional debris-cover *** this study,thermal resistance of the debris layer estimated from remotely sensed data reveals that about 54.0%of CPEC glaciers are debris-covered glaciers,on which the total debris-covered area is about 5,072 km2,accounting for 14.0%of the total glacier area of the study *** find that marked difference in the extent and thickness of debris cover is apparent from region to region,as well as the debris-cover effect.53.3%of the total debris-covered area of the study region is concentrated in Karakoram,followed by Pamir with 30.2%of the total debris-covered *** revealed by the thermal resistance,the debris thickness is thick in Hindu Kush on average,with the mean thermal resistance of 7.0×10^-2((m^2∙K)/W),followed by Karakoram,while the thickness in western Himalaya is thin with the mean value of 2.0×10^-2((m^2∙K)/W).Our findings provide a basis for better assessments of changes in debriscovered glaciers and their associated hydrological impacts in the CPEC and surroundings.

关键词： debris thickness debris-cover effect thermal resistance ice melting CPEC

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OPTIMAL ANTENNA SUBSET SELECTION AND BLIND DETECTION APPROACH APPLIED TO ORTHOGONAL SPACE-TIME BLOCK CODING

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Journal of Electronics(China) 2007年第2期24卷 150-156页

作者： Xu Hongji Liu ju gu Bo School of Information Science and Engineering Shandong University Jinan 250100 China State Key Lab of Integrated Services Networks Xidian University Xi＇an 710071 China

An approach combining optimal antenna subset selection with blind detection scheme for Orthogonal Space-Time Block Coding (OSTBC) is proposed in this paper. The optimal antenna sub- set selection is taken into account at transmitter and/or receiver sides, which chooses the optimal an- tennas to increase the diversity order of OSTBC and improve further its performance. In order to en- hance the robustness of the detection used in the conventional OSTBC scheme, a blind detection scheme based on Independent Component Analysis (ICA) is exploited which can directly extract transmitted signals without channel estimation. Performance analysis shows that the proposed ap- proach can achieve the full diversity and the flexibility of system design by using the antenna selec-tion and the ICA based blind detection schemes.

关键词： Orthogonal Space-Time Block Coding (OSTBC) Antenna subset selection IndependentComponent Analysis (ICA) Channel State Information (CSI)

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秸秆纳米纤维素与炭黑补强天然胶的界面作用

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高分子材料科学与工程 2017年第11期33卷 93-100,107页

作者：黄仕文古菊华南理工大学材料科学与工程学院广东广州516040

基于橡胶复合材料的力学性能、交联密度、粘弹行为、热行为、动态性能和形貌结构,利用红外光谱(FT-IR)、X射线光电子能谱(XPS)、差示扫描量热分析、动态力学分析等对酚醛树脂(PF)改性前后秸秆纳米纤维素(SNC)与炭黑(CB)补强的天然橡胶(... 详细信息

基于橡胶复合材料的力学性能、交联密度、粘弹行为、热行为、动态性能和形貌结构,利用红外光谱(FT-IR)、X射线光电子能谱(XPS)、差示扫描量热分析、动态力学分析等对酚醛树脂(PF)改性前后秸秆纳米纤维素(SNC)与炭黑(CB)补强的天然橡胶(NR)的界面影响进行了系统分析,并对SNC,PF与NR的成键形式进行了理论分析。FT-IR分析表明SNC-PF上的羟基(-OH)吸收峰发生了蓝移,XPS谱图中显示改性后SNC中O1s结合能升高,说明SNC与PF之间具有强的氢键作用。与NR/CB/PF体系相比,NR/CB/SNC/PF体系在大形变下具有更高的弹性模量(G′),说明其具有更强的橡胶交联网络,该体系具有更高的受限橡胶层质量分数(χ_(im)),说明该材料存在更厚的受限橡胶分子层,意味着其填料更好地分散和填料-基体间更强的相互作用。而NR/CB/SNC/PF复合材料较低的损耗因子(tanδ)、较高的填料-基体间相互作用参数和大应变下较高的上扬临界值(λ^(-1)),都表明其中的填料与NR之间具有更强的相互作用。扫描电镜(SEM)显示PF的加入使填料包埋在NR基体中,且分散更均匀。说明PF的加入使CB/SNC(填料网络)与NR基体形成互穿聚合物网络,填料与NR基体的相互作用增强,交联密度增加,而使CB补强NR的力学性能得到保持或改善。

关键词：秸秆纳米纤维素补强复合材料界面相互作用分散

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蔗渣纳米纤维素的制备与表征

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高等学校化学学报 2017年第7期38卷 1286-1294页

作者：李彩新梁小容古菊华南理工大学材料科学与工程学院广州510640

以甘蔗渣为原料,通过无废酸的一步法、两步法和三步法制备了蔗渣纳米纤维素(BNC),并与酸解法进行对比.采用傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线衍射(XRD)和热重分析(TGA)等手段表征了纳米纤维素的光谱性质、形貌结构、结... 详细信息

以甘蔗渣为原料,通过无废酸的一步法、两步法和三步法制备了蔗渣纳米纤维素(BNC),并与酸解法进行对比.采用傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)、X射线衍射(XRD)和热重分析(TGA)等手段表征了纳米纤维素的光谱性质、形貌结构、结晶性能及热稳定性能.结果表明,4种方法处理后纤维形貌尺寸均可达到纳米级别且在一定浓度的水溶液中均可形成类果冻状的胶体,其中酸解法和三步法所制备的纳米纤维素长径比较小,形貌多为短棒状,在水溶液中分散稳定性较好,可稳定悬浮超过30 d;一步法和两步法所制备的纳米纤维素长径比较大,为类纤维状结构,分散稳定性相对较差,但也可稳定悬浮至少5 d;一步法所制备的纳米纤维素晶型为纤维素Ⅰ型和纤维素Ⅱ型的混合物,两步法、三步法和酸解法处理后的纤维晶型没有改变,仍然保持纤维素Ⅰ型.与酸解法相比,无废酸法所制备的纳米纤维素热稳定性更优,无废酸法工艺简单,反应条件温和,而酸解法反应步骤繁复,会产生大量废酸增加后续处理成本.

关键词：蔗渣纳米纤维素形貌热稳定性

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Facile Green Synthesis of Magnetic Fe3C@C Nanocomposite using Natural Magnetite

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Chinese Journal of Chemical Physics 2020年第3期33卷 371-375,I0003页

作者： ju-wen gu Yong Bai Song-bai Qiu Qian Zhang Tie-jun Wang School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China

One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe3C@C materials has been facilely developed using a modified sol-gel approach,wherein natural magnetite acted as the iron source.A chelating polycarboxylic acid such as citric acid(CA)was employed as the carbon source,and it dissolved Fe very effectively,Fe3O4 and natural magnetite to composite an iron-citrate complex with the assistance of ammonium *** core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature *** Fe3C@C materials exhibited superparamagnetic properties(38.09 emu/mg),suggesting potential applications in biomedicine,environment,absorption,catalysis,etc.

关键词： Magnetic material Natural magnetite Fe3C@C Citric acid complexation

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基于诊断观测器的最优事件触发故障检测

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控制与决策 2024年第2期39卷 559-567页

作者：吴劲松邱爱兵顾菊平姜旭南通大学电气工程学院江苏南通226019

提出一种基于诊断观测器的最优事件触发故障检测方法.首先,针对自适应混合事件触发下的远程监控系统,发展一种数值代数结合型的低阶诊断观测器参数矩阵计算方法,以满足残差生成中的Luenberger条件;然后,通过评估事件触发传输误差、干扰... 详细信息

提出一种基于诊断观测器的最优事件触发故障检测方法.首先,针对自适应混合事件触发下的远程监控系统,发展一种数值代数结合型的低阶诊断观测器参数矩阵计算方法,以满足残差生成中的Luenberger条件;然后,通过评估事件触发传输误差、干扰和故障对残差信号的影响,构建H∞/H∞型性能指标,并利用互内外分解技术设计最优后置滤波器,以实现对故障灵敏度和对干扰鲁棒性的最优权衡;进一步,为降低传统的预设残差阈值方法的保守性,依据系统初始状态和干扰的有界性,采用基于中心对称多胞体的方法设计残差评价函数及相应的故障决策逻辑来实现故障检测;最后,通过多车跟踪系统的仿真,验证所提方法的有效性.

关键词：诊断观测器事件传输误差故障检测鲁棒性灵敏度权衡

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