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Comparison of pore characteristics in the coal and shale reservoirs of Taiyuan Formation, Qinshui Basin, China 被引量:30
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作者 yu liu Yanming Zhu 《International Journal of Coal Science & Technology》 EI 2016年第3期330-338,共9页
Coal and shale are both unconventional gas reservoirs. Comparison of pore characteristics in shale and coal would help understand organic pore structure in shale and investigate co-exploration of shale gas and coalbed... Coal and shale are both unconventional gas reservoirs. Comparison of pore characteristics in shale and coal would help understand organic pore structure in shale and investigate co-exploration of shale gas and coalbed methane in coal bearing strata. In this study, five shale samples and three coal samples of Taiyuan Formation were collected from Qinshui Basin, China. High pressure mercury injection, scanning electronic microscopy, and fractal theory have been used to compare pore characteristics in shale and coal. The results show that pore volumes in coal are much larger than that in shale, especially pores 3-100 nm. In coal, there are many semi-closed pores in micro pores (〈10 nm) and transition pores (10-100 nm). On the contrary, micro pores and transition pores are mainly with open pores in shale. The fractal curves show that pores larger than 65 nm in coal and shale reservoir both have obvious self-similarity and the fractal dimension values in shale and coal are similar. But the fractal characteristics of pores smaller than 65 nm in shale reservoir are quite different from that in coal. 展开更多
关键词 COMPARISON COAL SHALE Organic pores FRACTAL
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Comments to “Mechanism of hamstring muscle strain injury in sprinting”by Yu et al. 被引量:5
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作者 yu liu yuliang Sun +1 位作者 Wenfei Zhu Jiabin yu 《Journal of Sport and Health Science》 SCIE 2017年第2期139-140,共2页
We have carefully read Dr.Yu and his colleagues'~1review on the mechanism of hamstring muscle strain injury in sprinting.There is no doubt that they have done a lot work in this field.Their views are based on 3 pi... We have carefully read Dr.Yu and his colleagues'~1review on the mechanism of hamstring muscle strain injury in sprinting.There is no doubt that they have done a lot work in this field.Their views are based on 3 pieces of evidence.First,observations from in situ animal models suggest that muscle strain injuries are highly associated with eccentric contractions.Second,the magnitude of muscle strain,rather than the force。 展开更多
关键词 肌肉 拉伤 机制 评论 危险因素 动物模型 生物力学 最大长度
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Characteristics of canopy interception and its simulation with a revised Gash model for a larch plantation in the Liupan Mountains, China 被引量:2
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作者 Zebin liu Yanhui Wang +7 位作者 Ao Tian yu liu Ashley A.Webb Yarui Wang Haijun Zuo Pengtao yu Wei Xiong Lihong Xu 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第1期187-198,共12页
Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological im... Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.(larch) plantation in the Liupan Mountains of northwestern China during the growing season(May–October) of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was 499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and 0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss(79%) mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model’s ability in simulating the interception of individual rainfall events were suggested. 展开更多
关键词 Canopy interception Larch plantation Revised Gash model STEMFLOW THROUGHFALL
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Interannual Variation of the Onset of Yunnan’s Rainy Season and Its Relationships with the Arctic Oscillation of the Preceding Winter 被引量:1
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作者 Yan Chen Shichang Guo +2 位作者 yu liu Jianhua Ju Juzhang Ren 《Atmospheric and Climate Sciences》 2017年第2期210-222,共13页
Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timi... Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timing of the rainy sea-son by using the NCEP/NCAR reanalysis and observational precipitation data for 1961-2010. The results indicated that, on an interannual time scale, intense Asian summer monsoon and an active EU-pattern wave train circulation in its positive phase, associated with a cold cyclonic cell covering the western part of the East Asian subtropical westerly jet (EASWJ), jointly contributed to the onset of the rainy season in May. Otherwise, the onset might be suppressed. The cold cyclonic cell over East Asia likely led to the southward shift and enhancement of EASWJ as well as its secondary circulation around the jet entrance, which could provide a favorable dynamic and thermal condition for rainfalls in Yunnan as was revealed in previous studies on 10 - 30-day time scale. Further examination showed that the preceding wintertime AO played a significant role in the timing of the onset of the rainy season before the mid-1980s’ by mostly modulating the wave-train-like circulation over East Asia in May. During that time period, when the AO index of the previous winter was positive (negative), Yunnan’s rainy season tended to begin earlier (later) than normal. Correspond-ingly, the precipitation in May was also closely linked to wintertime AO. 展开更多
关键词 ONSET of Yunnan’s RAINY SEASON East Asian SUBTROPICAL WESTERLY Jet (EASWJ) Arctic Oscillation (AO) INTERANNUAL Variation
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Improved Arithmetic Optimization Algorithm with Multi-Strategy Fusion Mechanism and Its Application in Engineering Design
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作者 yu liu Minge Chen +3 位作者 Ran Yin Jianwei Li Yafei Zhao Xiaohua Zhang 《Journal of Applied Mathematics and Physics》 2024年第6期2212-2253,共42页
This article addresses the issues of falling into local optima and insufficient exploration capability in the Arithmetic Optimization Algorithm (AOA), proposing an improved Arithmetic Optimization Algorithm with a mul... This article addresses the issues of falling into local optima and insufficient exploration capability in the Arithmetic Optimization Algorithm (AOA), proposing an improved Arithmetic Optimization Algorithm with a multi-strategy mechanism (BSFAOA). This algorithm introduces three strategies within the standard AOA framework: an adaptive balance factor SMOA based on sine functions, a search strategy combining Spiral Search and Brownian Motion, and a hybrid perturbation strategy based on Whale Fall Mechanism and Polynomial Differential Learning. The BSFAOA algorithm is analyzed in depth on the well-known 23 benchmark functions, CEC2019 test functions, and four real optimization problems. The experimental results demonstrate that the BSFAOA algorithm can better balance the exploration and exploitation capabilities, significantly enhancing the stability, convergence mode, and search efficiency of the AOA algorithm. 展开更多
关键词 Arithmetic Optimization Algorithm Adaptive Balance Factor Spiral Search Brownian Motion Whale Fall Mechanism
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Pseudo-Semi-Overlap Functions-Based Fuzzy Rough Sets Applied to Image Edge Extraction
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作者 Ran Yin Minge Chen +2 位作者 yu liu Yafei Zhao Jianwei Li 《Journal of Applied Mathematics and Physics》 2024年第7期2347-2366,共20页
As an extension of overlap functions, pseudo-semi-overlap functions are a crucial class of aggregation functions. Therefore, (I, PSO)-fuzzy rough sets are introduced, utilizing pseudo-semi-overlap functions, and furth... As an extension of overlap functions, pseudo-semi-overlap functions are a crucial class of aggregation functions. Therefore, (I, PSO)-fuzzy rough sets are introduced, utilizing pseudo-semi-overlap functions, and further extended for applications in image edge extraction. Firstly, a new clustering function, the pseudo-semi-overlap function, is introduced by eliminating the symmetry and right continuity present in the overlap function. The relaxed nature of this function enhances its applicability in image edge extraction. Secondly, the definitions of (I, PSO)-fuzzy rough sets are provided, using (I, PSO)-fuzzy rough sets, a pair of new fuzzy mathematical morphological operators (IPSOFMM operators) is proposed. Finally, by combining the fuzzy C-means algorithm and IPSOFMM operators, a novel image edge extraction algorithm (FCM-IPSO algorithm) is proposed and implemented. Compared to existing algorithms, the FCM-IPSO algorithm exhibits more image edges and a 73.81% decrease in the noise introduction rate. The outstanding performance of (I, PSO)-fuzzy rough sets in image edge extraction demonstrates their practical application value. 展开更多
关键词 Pseudo-Semi-Overlap Functions Fuzzy Rough Set Fuzzy Mathematical Morphology Image Edge Extraction
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基于Hilbert包络谱熵和GA-SVM的水轮发电机轴承故障诊断 被引量:2
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作者 陈培演 孙晓 +2 位作者 欧立涛 于柳 陈元健 《机电工程技术》 2024年第3期199-204,共6页
水轮发电机轴承在运行时承受着整体机组的轴向负荷与复杂水推力,针对其产生的非稳态、非线性特征的振动信号,提出一种基于Hilbert包络谱分析与遗传算法支持向量机(GA-SVM)相结合的诊断方法,用于轴承故障状态的识别。首先对推力轴承运行... 水轮发电机轴承在运行时承受着整体机组的轴向负荷与复杂水推力,针对其产生的非稳态、非线性特征的振动信号,提出一种基于Hilbert包络谱分析与遗传算法支持向量机(GA-SVM)相结合的诊断方法,用于轴承故障状态的识别。首先对推力轴承运行时产生的振动信号进行集合经验模态分解(Ensemble Empirical Mode Decomposition,EEMD),分解成若干个固有模态函数(Intrinsic Mode Function,IMF),依据峭度准则选取主要IMF分量并通过Hilbert包络谱分析,计算包络谱熵,将归一化后的包络谱熵作为特征向量输入GA-SVM进行训练与故障识别。仿真实验结果表明,基于EEMD包络谱熵分析法相比于时频域图像处理能更好地提取出复杂工况下的故障信号特征,遗传算法支持向量机识别准确率达96.87%,该算法模型可进一步应用于水轮发电机轴承故障诊断。 展开更多
关键词 水轮发电机 轴承故障诊断 集合经验模态分解 Hilbert包络谱熵 遗传算法支持向量机
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化学研究与训练课程教学探索与实践
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作者 闫敬 王海媛 +7 位作者 常静 邢福保 张振 陈明月 李晓枫 刘宇 李轶 冯霞 《大学化学》 CAS 2024年第10期236-241,共6页
“化学研究训练II”课程是天津大学化学系高年级学生的一门专业必修课。该课程创新教学模式,采用“自助式”学习探索,课程由学生根据自己的兴趣和特长自由组队、自选方向、自行设计研究方案,在教师的指导下完成探索性研究,并通过集体展... “化学研究训练II”课程是天津大学化学系高年级学生的一门专业必修课。该课程创新教学模式,采用“自助式”学习探索,课程由学生根据自己的兴趣和特长自由组队、自选方向、自行设计研究方案,在教师的指导下完成探索性研究,并通过集体展示、同伴互评等新型评价方式来进行成绩评定。课程因内容丰富、教学方式新颖而广受学生好评。本课程探索了新的教学模式,提高了学生的科研实践能力,对培养拔尖创新人才进行了有益探索。 展开更多
关键词 教学改革 创新人才培养 化学实验课 课程考核
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旋转测量状态下光斑中心定位方法
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作者 解玉成 孙晓 +2 位作者 于柳 文比强 汤迎红 《机电工程技术》 2024年第3期45-49,62,共6页
目前,对管道内腔为自由曲面的截面轮廓进行高精度测量是行业难题。拟将多个不同测量范围的激光位移传感器放置于管道内腔中,采用旋转的方式对内腔进行测量,将得到的测量数据进行归一化处理后获得被测管道内腔截面轮廓形状。分析测量过... 目前,对管道内腔为自由曲面的截面轮廓进行高精度测量是行业难题。拟将多个不同测量范围的激光位移传感器放置于管道内腔中,采用旋转的方式对内腔进行测量,将得到的测量数据进行归一化处理后获得被测管道内腔截面轮廓形状。分析测量过程中激光光斑的变化情况,针对光斑图像的多峰、散斑、平顶与形状变化等现象,提出了一种基于传统灰度重心法进行粗定位的距离倒数加权多项式插值亚像素光斑中心定位方法。采用中值滤波对光斑图像进行预处理,通过自适应阈值分割法从环境背景光强中分离出光斑中心定位区域。通过MATLAB仿真与灰度重心法、加权灰度重心法与高斯拟合法传统光斑中心定位方法相比,结果表明,光斑中心定位精度达到0.01 pixel,在激光光斑中心定位精度和稳定性方面有一定的改善,明显优于传统的光斑中心定位算法。 展开更多
关键词 自由曲面 亚像素光斑中心定位 自适应阈值分割 多项式插值 灰度重心
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Combining stochastic density functional theory with deep potential molecular dynamics to study warm dense matter 被引量:2
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作者 Tao Chen Qianrui liu +2 位作者 yu liu Liang Sun Mohan Chen 《Matter and Radiation at Extremes》 SCIE EI CSCD 2024年第1期44-57,共14页
In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at ... In traditional finite-temperature Kohn–Sham density functional theory(KSDFT),the partial occupation of a large number of high-energy KS eigenstates restricts the use of first-principles molecular dynamics methods at extremely high temperatures.However,stochastic density functional theory(SDFT)can overcome this limitation.Recently,SDFT and the related mixed stochastic–deterministic density functional theory,based on a plane-wave basis set,have been implemented in the first-principles electronic structure software ABACUS[Q.Liu and M.Chen,Phys.Rev.B 106,125132(2022)].In this study,we combine SDFT with the Born–Oppenheimer molecular dynamics method to investigate systems with temperatures ranging from a few tens of eV to 1000 eV.Importantly,we train machine-learning-based interatomic models using the SDFT data and employ these deep potential models to simulate large-scale systems with long trajectories.Subsequently,we compute and analyze the structural properties,dynamic properties,and transport coefficients of warm dense matter. 展开更多
关键词 STOCHASTIC theory FUNCTIONAL
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Chloride ion battery:A new emerged electrochemical system for next-generation energy storage 被引量:1
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作者 Shulin Chen Lu Wu +3 位作者 yu liu Peng Zhou Qinyou An Liqiang Mai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第1期154-168,I0004,共16页
In the scope of developing new electrochemical concepts to build batteries with high energy density,chloride ion batteries(CIBs)have emerged as a candidate for the next generation of novel electrochemical energy stora... In the scope of developing new electrochemical concepts to build batteries with high energy density,chloride ion batteries(CIBs)have emerged as a candidate for the next generation of novel electrochemical energy storage technologies,which show the potential in matching or even surpassing the current lithium metal batteries in terms of energy density,dendrite-free safety,and elimination of the dependence on the strained lithium and cobalt resources.However,the development of CIBs is still at the initial stage with unsatisfactory performance and several challenges have hindered them from reaching commercialization.In this review,we examine the current advances of CIBs by considering the electrode material design to the electrolyte,thus outlining the new opportunities of aqueous CIBs especially combined with desalination,chloride redox battery,etc.With respect to the developing road of lithium ion and fluoride ion batteries,the possibility of using solid-state chloride ion conductors to replace liquid electrolytes is tentatively discussed.Going beyond,perspectives and clear suggestions are concluded by highlighting the major obstacles and by prescribing specific research topics to inspire more efforts for CIBs in large-scale energy storage applications. 展开更多
关键词 Chloride ion battery Anion shuttling Conversion reaction Chloride redox
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Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques 被引量:1
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作者 Xian-Lin Yang Chang-Lin Lan +6 位作者 yu-Ting Wei Yi Zhang Gong Jiang Bo Xie yu liu Hong-Tao Shen Xiao-Jun Sun 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第6期78-89,共12页
Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al re... Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc. 展开更多
关键词 14-MeV neutron ^(27)Al(n 2n)^(26)Al Cross section AMS
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Fully automatic AI segmentation of oral surgery-related tissues based on cone beam computed tomography images 被引量:1
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作者 yu liu Rui Xie +5 位作者 Lifeng Wang Hongpeng liu Chen liu Yimin Zhao Shizhu Bai Wenyong liu 《International Journal of Oral Science》 SCIE CAS CSCD 2024年第3期413-424,共12页
Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully autom... Accurate segmentation of oral surgery-related tissues from cone beam computed tomography(CBCT)images can significantly accelerate treatment planning and improve surgical accuracy.In this paper,we propose a fully automated tissue segmentation system for dental implant surgery.Specifically,we propose an image preprocessing method based on data distribution histograms,which can adaptively process CBCT images with different parameters.Based on this,we use the bone segmentation network to obtain the segmentation results of alveolar bone,teeth,and maxillary sinus.We use the tooth and mandibular regions as the ROI regions of tooth segmentation and mandibular nerve tube segmentation to achieve the corresponding tasks.The tooth segmentation results can obtain the order information of the dentition.The corresponding experimental results show that our method can achieve higher segmentation accuracy and efficiency compared to existing methods.Its average Dice scores on the tooth,alveolar bone,maxillary sinus,and mandibular canal segmentation tasks were 96.5%,95.4%,93.6%,and 94.8%,respectively.These results demonstrate that it can accelerate the development of digital dentistry. 展开更多
关键词 SURGERY CBCT BEAM
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基于BWO优化VMD联合小波阈值的管道泄漏次声波去噪方法
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作者 陈元健 黄靖 +3 位作者 孙晓 于柳 罗剑宾 陈培演 《机电工程技术》 2024年第3期54-59,共6页
管道泄漏次声波信号中的干扰噪声影响管道泄漏定位的精准度。提出了一种基于白鲸优化算法(BWO)优化变分模态分解(VMD)联合小波阈值(WT)的管道泄漏次声波去噪方法。针对VMD算法中分解层数K和惩罚因子α的取值对信号分解结果影响较大,利... 管道泄漏次声波信号中的干扰噪声影响管道泄漏定位的精准度。提出了一种基于白鲸优化算法(BWO)优化变分模态分解(VMD)联合小波阈值(WT)的管道泄漏次声波去噪方法。针对VMD算法中分解层数K和惩罚因子α的取值对信号分解结果影响较大,利用白鲸优化算法(BWO)对VMD分解的两关键参数进行寻优,获得最优参数组合[K、α],并利用优化后的参数对次声波信号进行VMD分解,获得一系列本征模函数(IMF)分量。通过计算各IMF分量的相关系数来区分噪声IMF分量和有效IMF分量,引入一种改进的小波阈值函数对有效的IMF分量进行去噪处理,再重构去噪后各有效IMF分量,得到去噪后的管道泄漏次声波信号。通过仿真实验,将所提方法与灰狼优化算法(GWO)优化VMD联合小波阈值和麻雀搜索算法(SSA)优化VMD联合小波阈值两种方法对比,所提方法去噪后信号的信噪比分别提高了1.27%、2.01%,表明所提方法的去噪效果具有一定的优越性,为后续管道泄漏计算定位奠定了良好的基础。 展开更多
关键词 管道泄漏次声波 信号去噪 变分模态分解 白鲸优化算法 小波阈值
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Corrigendum to“Migration pattern of a population of Barn Swallows(Hirundo rustica)breeding in East Asian tropical region”[Avian Res.15(2024)100192] 被引量:1
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作者 Li Tian yu liu +3 位作者 Yang Wu Zimei Feng Dan Hu Zhengwang Zhang 《Avian Research》 SCIE CSCD 2024年第3期402-402,共1页
The authors regret that the caption of Fig.4 should be replaced as below.
关键词 BREEDING pattern TROPICAL
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Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China
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作者 Limei YANG Jun GE +4 位作者 Yipeng CAO yu liu Xing LUO Shiyao WANG Weidong GUO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第11期2259-2275,共17页
Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter d... Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter days.These results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming. 展开更多
关键词 urban trees cooling efficiency China's cities EVAPOTRANSPIRATION SUMMER hot days
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Crystallization management of CsPbI_(2)Br perovskites by PbAc_(2)-incorporated twice spin-coating process for efficient and stable CsPbI_(2)Br perovskite solar cells
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作者 yu liu Kun Lang +6 位作者 Huifang Han Huijing liu Yao Fu Pengchen Zou Yinhui Lyu Jia Xu Jianxi Yao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第10期419-428,I0008,共11页
CsPbI_(2)Br perovskite solar cell has been extensively studied due to its exceptional thermal stability and relatively stable perovskite phase structure.However,the presence of bromine leads to a rapid crystallization... CsPbI_(2)Br perovskite solar cell has been extensively studied due to its exceptional thermal stability and relatively stable perovskite phase structure.However,the presence of bromine leads to a rapid crystallization rate of CsPbI_(2)Br films,resulting in small grain size and high defect density.Additionally,CsPbI_(2)Br demonstrates poor light absorption due to its wide bandgap.Therefore,it is crucial to control the crystallization rate and increase the film thickness to reduce defect density,enhance light absorption,and improve photovoltaic performance.In this study,we utilized a PbAc_(2)-incorporated twice spincoating(PTS) process to address these issues.Initially,PbAc_(2) was added to the CsPbI_(2)Br precursor solution to form a CsPbI_(2)Br film,which was then coated with the CsPbI_(2)Br precursor solution to produce the PTS film,Ac^(-)can delay the perovskite crystallization,leading to the formation of thicker and denser CsPbI_(2)Br films.Moreover,lone-pair electrons of the oxygen atom provided by Ac^(-)formed coordination bonds with under-coordinated Pb~(2+) ions to fill halogen ion vacancies,thereby reducing the defect density.Ultimately,the PTS CsPbI_(2)Br device achieved a peak power conversion efficiency(PCE) of 16.19% and maintained 96.7% of its initial PCE over 1500 h at room temperature under 25% relative humidity without any encapsulation. 展开更多
关键词 CsPbI_(2)Br Twice spin-coating process PbAc_(2) Crystallization management Perovskite solar cells
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地理大数据揭示中国主要城市建成环境物质存量的空间格局
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作者 Zhou Huang Yi Bao +13 位作者 Ruichang Mao Han Wang Ganmin Yin Lin Wan Houji Qi Qiaoxuan Li Hongzhao Tang Qiance liu Linna Li Bailang yu Qinghua Guo yu liu Huadong Guo Gang liu 《Engineering》 SCIE EI CAS CSCD 2024年第3期143-153,共11页
The patterns of material accumulation in buildings and infrastructure accompanied by rapid urbanization offer an important,yet hitherto largely missing stock perspective for facilitating urban system engineering and i... The patterns of material accumulation in buildings and infrastructure accompanied by rapid urbanization offer an important,yet hitherto largely missing stock perspective for facilitating urban system engineering and informing urban resources,waste,and climate strategies.However,our existing knowledge on the patterns of built environment stocks across and particularly within cities is limited,largely owing to the lack of sufficient high spatial resolution data.This study leveraged multi-source big geodata,machine learning,and bottom-up stock accounting to characterize the built environment stocks of 50 cities in China at 500 m fine-grained levels.The per capita built environment stock of many cities(261 tonnes per capita on average)is close to that in western cities,despite considerable disparities across cities owing to their varying socioeconomic,geomorphology,and urban form characteristics.This is mainly owing to the construction boom and the building and infrastructure-driven economy of China in the past decades.China’s urban expansion tends to be more“vertical”(with high-rise buildings)than“horizontal”(with expanded road networks).It trades skylines for space,and reflects a concentration-dispersion-concentration pathway for spatialized built environment stocks development within cities in China.These results shed light on future urbanization in developing cities,inform spatial planning,and support circular and low-carbon transitions in cities. 展开更多
关键词 Urban system engineering Built environment stock Spatial pattern Urban sustainability Big geodata
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Investigation into the Methodology and Implementation of Life Cycle Engineering under China’s Carbon Reduction Target in the Process Industry
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作者 Mingyang Li Feng Gao +3 位作者 Zuoren Nie Boxue Sun yu liu Xianzheng Gong 《Engineering》 SCIE EI CAS CSCD 2024年第9期87-99,共13页
The industrial sector is the primary source of carbon emissions in China.In pursuit of meeting its carbon reduction targets,China aims to promote resource consumption sustainability,reduce energy consumption,and achie... The industrial sector is the primary source of carbon emissions in China.In pursuit of meeting its carbon reduction targets,China aims to promote resource consumption sustainability,reduce energy consumption,and achieve carbon neutrality within its processing industries.An effective strategy to promote energy savings and carbon reduction throughout the life cycle of materials is by applying life cycle engineering technology.This strategy aims to attain an optimal solution for material performance,resource consumption,and environmental impact.In this study,five types of technologies were considered:raw material replacement,process reengineering,fuel replacement,energy recycling and reutilization,and material recycling and reutilization.The meaning,methodology,and development status of life cycle engineering technology abroad and domestically are discussed in detail.A multidimensional analysis of ecological design was conducted from the perspectives of resource and energy consumption,carbon emissions,product performance,and recycling of secondary resources in a manufacturing process.This coupled with an integrated method to analyze carbon emissions in the entire life cycle of a material process industry was applied to the nonferrous industry,as an example.The results provide effective ideas and solutions for achieving low or zero carbon emission production in the Chinese industry as recycled aluminum and primary aluminum based on advanced technologies had reduced resource consumption and emissions as compared to primary aluminum production. 展开更多
关键词 Carbon neutrality Life cycle engineering Process Industry Carbon reduction technology ECO-DESIGN
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A data and physical model dual-driven based trajectory estimator for long-term navigation
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作者 Tao Feng yu liu +2 位作者 yue yu Liang Chen Ruizhi Chen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第10期78-90,共13页
Long-term navigation ability based on consumer-level wearable inertial sensors plays an essential role towards various emerging fields, for instance, smart healthcare, emergency rescue, soldier positioning et al. The ... Long-term navigation ability based on consumer-level wearable inertial sensors plays an essential role towards various emerging fields, for instance, smart healthcare, emergency rescue, soldier positioning et al. The performance of existing long-term navigation algorithm is limited by the cumulative error of inertial sensors, disturbed local magnetic field, and complex motion modes of the pedestrian. This paper develops a robust data and physical model dual-driven based trajectory estimation(DPDD-TE) framework, which can be applied for long-term navigation tasks. A Bi-directional Long Short-Term Memory(Bi-LSTM) based quasi-static magnetic field(QSMF) detection algorithm is developed for extracting useful magnetic observation for heading calibration, and another Bi-LSTM is adopted for walking speed estimation by considering hybrid human motion information under a specific time period. In addition, a data and physical model dual-driven based multi-source fusion model is proposed to integrate basic INS mechanization and multi-level constraint and observations for maintaining accuracy under long-term navigation tasks, and enhanced by the magnetic and trajectory features assisted loop detection algorithm. Real-world experiments indicate that the proposed DPDD-TE outperforms than existing algorithms, and final estimated heading and positioning accuracy indexes reaches 5° and less than 2 m under the time period of 30 min, respectively. 展开更多
关键词 Long-term navigation Wearable inertial sensors Bi-LSTM QSMF Data and physical model dual-driven
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