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Thermal performance assessment of self-rotating twisted tapes and Al_(2)O_(3) nanoparticle in a circular pipe

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Chinese Journal of Chemical Engineering 2021年第4期34卷 77-86页

作者： Chuanshuai Dong Lin Lu Tao Wen shaojie zhang Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education Ministry School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510000China Department of Building Services Engineering The Hong Kong Polytechnic University11 Yuk Choi RoadHung HomKowloonHong KongChina Department of Chemical Engineering Imperial College LondonLondonUnited Kingdom

In view of the practical importance of the heat transfer devices in various thermal engineering fields including chemical and nuclear engineering,this study aims at developing an effective method of heat transfer enhancement by using selfrotating twisted tapes(SRTTs)and Al_(2)O_(3) *** effect of the selfrotating twisted tapes and Al2O3 nanoparticles on the thermal performance was comprehensively investigated in a circular *** experimental results indicated the heat transfer rate was effectively improved by SRTTs in comparison of plain *** addition,the heat transfer multiplier with SRTTs decreased from 1.38 to 1.08 with the Reynolds number increasing from 19,322 to 64,407,while the friction factor multiplier decreased from 1.61 to ***,the results indicated that the employment of Al_(2)O_(3) nanoparticles and SRTTs demonstrated superior thermal performance to the single *** Reynolds number increases from 19,322 to 64,407,the heat transfer multiplier decreased from 2.08 to 1.18 in the mass concentration of 3.0%and from 1.38 to 1.08 in mass concentration of 0.0%.Finally,the new heat transfer and friction factor correlations considering the combined effect of Al2O3 nanoparticle and SRTTs were developed within 10%deviation of experimental values.

关键词： Heat transfer enhancement Nanoparticles Friction factor Self-rotating twist tapes Thermal performance factor

Cross-Layer Framework for Fine-Grained Channel Access in Next Generation High-Density Wi Fi Networks

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China Communications 2016年第2期13卷 55-67页

作者： ZHAO Haitao zhang shaojie Emiliano Garcia-Palacios College of Electronic Science and Engineering National University of Defense Technology ECIT Institute Queen's University Belfast

Densely deployed Wi Fi networks will play a crucial role in providing the capacity for next generation mobile internet. However, due to increasing interference, overlapped channels in Wi Fi networks and throughput efficiency degradation, densely deployed Wi Fi networks is not a guarantee to obtain higher throughput. An emergent challenge is how to effi ciently utilize scarce spectrum resources, by matching physical layer resources to traffi c demand. In this aspect, access control allocation strategies play a pivotal role but remain too coarse-grained. As a solution, this research proposes a flexible framework for fine-grained channel width adaptation and multi-channel access in Wi Fi networks. This approach, named SFCA(Subcarrier Fine-grained Channel Access), adopts DOFDM(Discontinuous Orthogonal Frequency Division Multiplexing) at the PHY layer. It allocates the frequency resource with a subcarrier granularity, which facilitates the channel width adaptation for multi-channel access and thus brings more fl exibility and higher frequency efficiency. The MAC layer uses a frequencytime domain backoff scheme, which combines the popular time-domain BEB scheme with a frequency-domain backoff to decrease access collision, resulting in higher access probability for the contending nodes. SFCA is compared with FICA(an established access scheme)showing significant outperformance. Finally we present results for next generation 802.11 ac Wi Fi networks.

关键词： channel width adaptation channel access high-density WiFi

Dynamic-based model for calculating the boulder impact force in debris flow

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Journal of Mountain Science 2024年第6期21卷 1930-1940页

作者： YANG Chaoping zhang shaojie YIN Yueping YANG Hongjuan WEI Fangqiang State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China University of Chinese Academy of Sciences Beijing 100049China China Institute of Geological Environment Monitoring Beijing 100081China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesChongqing 400714China

The boulder impact force in debris flow is generally calculated by static methods such as the cantilever beam ***,these methods cannot describe the dynamic scenario of boulder collision on structures,so the inertia and damping effects of the structures are not involved causing an overestimation on the boulder impact *** order to address this issue,a dynamic-based model for calculating the boulder impact force of a debris flow was proposed in this study,and the dynamic characteristics of a cantilever beam with multiple degrees of freedom under boulder collision were *** using the drop-weight method to simulate boulders within debris flow,seven experiments of drop-weight impacting the cantilever beam were used to calibrate the error of the dynamicbased *** indicate that the dynamic-based model is able to reconstruct the impact force history on the cantilever beam during impact time and the error of dynamic-based model is 15.3%in calculating boulder impact force,significantly outperforming the cantilever beam model’s error of 285%.Therefore,the dynamic-based model can overcome the drawbacks of the static-based models and provide a more reliable theoretical foundation for the engineering design of debris flow control structures.

关键词： Debris flow Impact force Boulder collision Dynamic-based model Engineering design

Evaluation of rainfall threshold models for debris flow initiation in the Jiangjia Gully,Yunnan Province,China

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Journal of Mountain Science 2024年第6期21卷 1799-1813页

作者： YANG Hongjuan zhang shaojie HU Kaiheng WEI Fangqiang LIU Yanhui State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China Chongqing School University of Chinese Academy of SciencesChongqing 400714China China Institute of Geo-Environment Monitoring Beijing 100081China

Systematically determining the discriminatory power of various rainfall properties and their combinations in identifying debris flow occurrence is crucial for early warning *** this study,we evaluated the discriminatory power of different univariate and multivariate rainfall threshold models in identifying triggering conditions of debris flow in the Jiangjia Gully,Yunnan Province,*** univariate models used single rainfall properties as indicators,including total rainfall(R_(tot)),rainfall duration(D),mean intensity(I_(mean)),absolute energy(Eabs),storm kinetic energy(E_(s)),antecedent rainfall(R_(a)),and maximum rainfall intensity over various durations(I_(max_dur)).The evaluation reveals that the I_(max_dur)and Eabs models have the best performance,followed by the E_(s),R_(tot),and I_(mean)models,while the D and R_(a)models have poor ***,the I_(max_dur)model has the highest performance metrics at a 40-min *** used logistic regression to combine at least two rainfall properties to establish multivariate threshold *** results show that adding D or R_(a)to the models dominated by Eabs,E_(s),R_(tot),or I_(mean)generally improve their performances,specifically when D is combined with I_(mean)or when R_(a)is combined with Eabs or E_(s).Including R_(a)in the I_(max_dur)model,it performs better than the univariate I_(max_dur)model.A power-law relationship between I_(max_dur)and R_(a)or between Eabs and R_(a)has better performance than the traditional I_(mean)–D model,while the performance of the E_(s)–R_(a)model is *** evaluation reemphasizes the important role of the maximum intensity over short durations in debris flow *** also highlights the importance of systematically investigating the role of R_(a)in establishing rainfall thresholds for triggering debris *** the regional variations in rainfall patterns worldwide,it is necessary to evaluate the findings of this study across diverse watersheds.

关键词： Rainfall threshold Logistic regression Maximum rainfall intensity Absolute energy Antecedent rainfall

A one-for-all strategy of polyimide coating layer for resolving the comprehensive issues of phosphorus anode

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Journal of Energy Chemistry 2022年第7期31卷 276-282,I0008页

作者： Muyao Han shaojie zhang Yu Cao Chengyu Han Xu Li Yiming zhang Zhanxu Yang Jie Sun Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin UniversityTianjin 300350China School of Petrochemical Engineering Liaoning Petrochemical UniversityFushun 113001LiaoningChina

Phosphorus is a promising anode with high capacity (2596 mAh g^(-1)and 6075~6924 mAh cm^(-3)),low lithium-ion diffusion barrier (0.08 e V),and appropriate lithiation potential (~0.7 V vs Li+/Li).However,it faces the problems of huge volume expansion (~300%),low electronic conductivity (10^(-14)~10^(2)S cm^(-1)),soluble intermediates (lithium polyphosphides,Li_(x)Ps),degradation in air,and low thermal *** this work,phosphorus/carbon nanotube composites were coated with a polyimide layer,which plays the roles of a buffer layer to relieve the volume expansion of phosphorus,an obstruct layer to confine LixPs,an inert layer to prevent the degradation of phosphorus in air,a heat resistant layer to improve the thermal stability of the *** resulting composites (P/CNT@PI) display high capacity retention of798.1 m Ah g^(-1)after 150 cycles at 1 A g^(-1),achieving 17 times as much as the control sample (P/CNT).

关键词： Phosphorus anode Polyimide Lithium-ion batteries Surface coating

In-situ formation of hierarchical solid-electrolyte interphase for ultra-long cycling of aqueous zinc-ion batteries

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Nano Research 2023年第1期16卷 449-457页

作者： shaojie zhang Jiajia Ye Huaisheng Ao Mingying zhang Xilong Li Zhibin Xu Zhiguo Hou Yitai Qian School of Chemistry and Chemical Engineering Shandong UniversityJinan 250100China School of Chemistry and Material Science University of Science and Technology of ChinaHefei 230026China

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low ***,zinc metal anodes face fatal dendrite growth and detrimental side reactions,which affect the cycle stability and practical application of zinc ion ***,an in-situ formed hierarchical solid-electrolyte interphase composed of InF3,In,and ZnF2 layers with outside-in orientation on the Zn anode(denoted as Zn@InF3)is developed by a sample InF3 *** inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn,is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+***,the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces,good chemical inactivity,and high hydrogen evolution ***,the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100%coulombic efficiency(CE).Furthermore,coupled with the MnO2 cathode,the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity(N/P)ratio of 2.8.

关键词： zinc ion batteries solid-electrolyte interphase in-situ formation hierarchical coating

Study on fracture characteristics in coal and shale for coal-measure gas reservoir based on 3D CT reconstruction and fractal features

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Frontiers of Earth Science 2023年第2期17卷 514-526页

作者： Huijun WANG Shangbin CHEN shaojie zhang Chengxing zhang Yang WANG Gaofeng YI Yixuan PENG School of Resources and Geoscience China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process(the Ministry of Education) China University of Mining and TechnologyXuzhou 221116China School of Earth Sciences and Engineering Sun Yat-sen UniversityGuangzhou 510275China

Pores and fractures are important components of flow channels in coal-measure gas *** considerable studies have been conducted on pore structure evolution,very few studies have investigated the fracture distribution and self-similarity *** reveal the characteristics of fracture distribution in coal and shale reservoirs,computed tomography studies were performed on 15 coal and shale samples from the Shanxi and Taiyuan *** results show that the fracture distribution of samples of the same lithology differs significantly,and the fracture distribution heterogeneity of shale samples is much higher than that of coal *** shale,the heterogeneity of fracture distribution is mainly caused by pores and fractures smaller than 2μm in the z-direction,with relatively little contributions from pores and fractures in the x and y ***,the heterogeneity of fracture distribution in coal is mainly controlled by pores and fractures larger than 2μm in all directions,and the difference between the three directions is *** was shown that a great number of microscopic pores and fractures contribute to the highest fractions of porosity in different lithological *** method is useful for determining the fracture distribution characteristics in shale and coal-measure gas reservoir.

关键词： pore-fracture system fracture distribution directionality heterogeneity CT experiment coalmeasure gas reservoirs

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自体黄韧带干预下兔硬膜外纤维瘢痕的形成

中国组织工程研究 2025年第6期29卷 1168-1175页

作者：张德宝王鹏李琨张少杰李志军李树文吴一民内蒙古医科大学第二附属医院脊柱外科中心内蒙古自治区呼和浩特市010000 内蒙古医科大学解剖学教研室内蒙古自治区呼和浩特市010000

背景:临床已证实,腰椎术后纤维瘢痕与硬膜或神经根粘连是造成术后疼痛及麻木等症状的重要因素。目的:验证自体黄韧带抑制腰椎术后硬膜外纤维瘢痕形成及探究可能的分子生物学机制。方法:选择6-8月龄的日本大白兔48只,利用随机数字表将兔... 详细信息

背景:临床已证实,腰椎术后纤维瘢痕与硬膜或神经根粘连是造成术后疼痛及麻木等症状的重要因素。目的:验证自体黄韧带抑制腰椎术后硬膜外纤维瘢痕形成及探究可能的分子生物学机制。方法:选择6-8月龄的日本大白兔48只,利用随机数字表将兔分为3组:黄韧带保留组、黄韧带不保留组、自体脂肪回置组(脂肪组)。3组兔均建立腰椎椎板切除术模型,于造模后3,6周收集兔硬膜外组织,采用苏木精-伊红染色观察组织变化及成纤维细胞数量密度,VG染色观察胶原纤维面积百分比,免疫组化观察转化生长因子β1、Smad3蛋白的表达。结果与结论:①苏木精-伊红染色结果:黄韧带保留组成纤维细胞较少且排列疏松,黄韧带不保留组和脂肪组成纤维细胞数量较多且排列紧密,术后3,6周黄韧带保留组成纤维细胞数量密度小于黄韧带不保留组和脂肪组(P<0.05),而黄韧带不保留组和脂肪组之间比较并未有明显差异;②VG染色结果:黄韧带保留组胶原纤维稀疏且分布不均,而黄韧带不保留组与脂肪组可见大量红色胶原纤维聚集;术后3,6周黄韧带保留组胶原纤维面积百分比小于黄韧带不保留组和脂肪组(P<0.05),而黄韧带不保留组与脂肪组之间无明显差异;③免疫组化结果:黄韧带保留组蛋白阳性着色程度明显弱于其余两组;术后3,6周黄韧带保留组转化生长因子β1、Smad3吸光度值显著低于其余两组(P<0.05),而黄韧带不保留组和脂肪组之间无显著差异;④结果说明,腰椎手术后均会存在不同程度的硬膜外纤维瘢痕的形成。若在术中保留自体黄韧带,可有利于减少硬膜外成纤维细胞数量以及胶原纤维的形成,从而减轻纤维瘢痕组织与硬膜囊、神经根的粘连,其机制不仅为单纯的机械阻隔作用,同时也可通过干预转化生长因子β1/Smad3信号通路来减少硬膜外纤维瘢痕的形成。

关键词：腰椎黄韧带纤维瘢痕 TGF-β1/Smad3 信号通路成纤维细胞兔

13-18岁青少年颈椎关节突关节发育特征的数字化三维形态分析

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中国组织工程研究 2025年第21期29卷 4486-4491页

作者：李贵花和雨洁史君李琨张少杰刘路李志军王星内蒙古自治区监狱管理局第一医院内蒙古自治区呼和浩特市010000 内蒙古医科大学基础医学院解剖学教研室内蒙古自治区呼和浩特市010110 内蒙古医科大学基础医学院生理学教研室内蒙古自治区呼和浩特市010110 内蒙古医科大学基础医学院数字医学中心内蒙古自治区呼和浩特市010110

背景:颈椎关节突关节作为颈椎后柱的重要解剖结构,在颈部活动、应力传导以及维持颈椎稳定性中发挥重要的作用。近年来通过解剖学和生物力学研究表明,颈椎关节突关节不对称可引起关节突关节的退变,颈椎关节突关节的退变可能是引起青年人... 详细信息

背景:颈椎关节突关节作为颈椎后柱的重要解剖结构,在颈部活动、应力传导以及维持颈椎稳定性中发挥重要的作用。近年来通过解剖学和生物力学研究表明,颈椎关节突关节不对称可引起关节突关节的退变,颈椎关节突关节的退变可能是引起青年人颈椎退变的主要原因。现有研究多集中在成人,国内对于学龄前儿童、学龄期儿童也有报道,而对于青少年颈椎小关节形态相关参数鲜有报道。目的:通过三维重建青少年颈椎关节突关节,测量其相关形态参数,并与儿童和成年人进行比较分析,探讨颈椎小关节形态发育的增龄变化规律,为临床颈椎小关节源性颈椎病的诊治和预防提供理论依据。方法:选择13-18岁青少年62例,行颈椎螺旋CT扫描后三维重建,要求无骨质破坏、肿瘤、畸形、骨折等,椎骨形态结构未发生改变,既往无脊柱相关手术,监护人对试验方案知情同意。按年龄分组,A组年龄为13-14岁,B组年龄为15-16岁,C组年龄为17-18岁。对各组青少年进行C_2-C_7关节突关节相关形态测量及统计分析。结果与结论:(1)3组关节突关节面高和关节面宽在随椎序的变化中,分别呈递减和递增趋势,下关节突关节面的高和宽均大于上关节面的相应指标;(2)关节突关节内高在3组年龄中,最小值均位于C5,且与年龄呈正相关变化;(3)关节突关节面间隙在3组中,A组C_(4-5)、B组C_(3-4)和C组C_(4-5)明显大于各组其余间隙;A、B组除C_(4-5)外,其余无显著性差异;C组除C_(2-3)其余椎序间关节面间隙均明显大于A、B组;(4)提示颈椎关节突关节面的形态随椎序的增加,逐渐由圆形过渡到椭圆形;在组间比较中,关节面高较关节面宽受年龄影响明显;各节段下关节面的面积均大于上关节面的面积,仅在C_(4-5)和C_(5-6)形态和面积有显著性差异;加之关节突关节内高最小值均位于C5,关节突关节面间隙明显增宽处也主要位于C_(3-4)和C(_4-5),因此颈椎失稳多发生于中位节段。

关键词：青少年颈椎关节突关节数字化形态三维重建