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Pullout characteristics and conceptual model of gabion reinforcement

岩石力学与工程学报 2017年第7期36卷 1670-1679页

作者： fang wei School offranc and Transportation Engineering Changsha University of Science and TechnologyChangshaHunan 410004China Co-innovation Centerfor Advanced Construction and Maintenance Technology of Modern Transportation Infrastructural Facility Changsha University of Science and TechnologyChangshaHunan 410004China

The reinforced gabion wall on the west line of Xiangtan to Hengyang highway in Hunan province was studied with the large scale pullout model tests and numerical simulations to obtain the interface friction characteristics between the double twisted hexagonal gabion mesh(2.2 mm and 2.7 mm respectively) and red sandstone. The experimental results showed that the pullout displacement-shear stress curve could be roughly divided into 3 sections:the rapid growth,the steady progression and the yielding sections. The thinner gabion mesh led to the higher peak shear stress,larger cohesion and friction angle under the same normal stress. The pullout displacement-shear stress curve from the numerical simulation had two sections,namely,the rapid growth of shear stress and the yielding of gabion mesh. Under the same conditions,the 2.2 mm meshes resulted in the larger drawing coefficient and pseudo-friction coefficient and thus presented the better interface friction properties. The conceptual model suggested that the proportion of pullout force shared by the horizontal bars and longitudinal bars relied on the magnitude,the length,the coefficient of earth pressure and the friction factor,etc. The pullout bearing resistance on the transversal bars(T_1) comprises the largest proportion of the total resistance(about 62%–72%),on the other hand,the proportions of the annular pullout friction on the longitudinal bars(T_2) and the interface friction acting on the surfaces of all nodes(T_3) both grow against T_1 when the normal stress increases.

关键词： numerical simulation gabion mesh pullout test interface friction characteristics conceptual model

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A generalized dilatancy angle equation of granular soil

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Journal of Mountain Science 2022年第5期19卷 1456-1463页

作者： YU fang-wei Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences CAS-HECIslamabad 45320Pakistan University of Chinese Academy of Sciences Beijing 100049China Department of Civil Engineering The University of TokyoTokyo 113-8656Japan

This paper presents a generalized dilatancy angle equation of granular soil to cover not only the drained tests but also the undrained tests by introducing a generalized structure of soil:soil skeleton formed by soil particles and the fluid in soil voids,under the assumptions of the incompressibility of soil particles and the compressibility of the fluid in soil *** the drained tests,the generalized dilatancy angle equation of granular soil would be degenerated to its current dilatancy angle ***,for the undrained tests,the generalized dilatancy angle equation of granular soil was derived with aλparameter that was related to the stress-strain state of soil and the nature of the fluid in soil ***λparameter was determined by the initial dilatancy angles of granular soil at the onset of shearing on the same initial state of the soil in the drained and undrained *** addition,the generalized dilatancy angle equation of granular soil was verified for application in calculation of the dilatancy angles of sands in the drained and undrained tests.

关键词： Elastoplastic theory Dilatancy Granular soil Sands Soil Skeleton Triaxial tests

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Rapid and robust initialization for monocular visual inertial navigation within multi-state Kalman filter

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Chinese Journal of Aeronautics 2018年第1期31卷 148-160页

作者： wei fang Lianyu ZHENG School of Mechanical Engineering and Automation Beihang University

Sensor-fusion based navigation attracts significant attentions for its robustness and accuracy in various applications. To achieve a versatile and efficient state estimation both indoor and outdoor, this paper presents an improved monocular visual inertial navigation architecture within the Multi-State Constraint Kalman Filter （MSCKF）. In addition, to alleviate the initialization demands by appending enough stable poses in MSCKF, a rapid and robust Initialization MSCKF （I-MSCKF） navigation method is proposed in the paper. Based on the trifocal tensor and sigmapoint filter, the initialization of the integrated navigation can be accomplished within three consecutive visual frames. Thus, the proposed I-MSCKF method can improve the navigation performance when suffered from shocks at the initial stage. Moreover, the sigma-point filter is applied at initial stage to improve the accuracy for state estimation. The state vector generated at initial stage from the proposed method is consistent with MSCKF, and thus a seamless transition can be achieved between the initialization and the subsequent navigation in I-MSCKF. Finally, the experimental results show that the proposed I-MSCKF method can improve the robustness and accuracy for monocular visual inertial navigations.

关键词： Estimator initialization Navigation Kalman filter Pose estimation Visual inertial fusion

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椎体骨皮质强化差异对骨质疏松性椎体压缩性骨折生物力学的影响

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中国组织工程研究 2025年第21期29卷 4430-4438页

作者：方伟黄兴桦屈波杨红胜重庆市云阳县中医院骨伤科重庆市404500 成都医学院附属第一医院骨科四川省成都市610500

背景:骨质疏松性椎体压缩性骨折经皮椎体成形过程中骨水泥在椎体内的骨皮质强化区域对脊柱生物力学及临床疗效有重要影响,但以往研究大多局限于二维层面。目的:采用有限元分析法探讨经皮椎体成形过程中骨水泥在椎体三维层面内骨皮质强... 详细信息

背景:骨质疏松性椎体压缩性骨折经皮椎体成形过程中骨水泥在椎体内的骨皮质强化区域对脊柱生物力学及临床疗效有重要影响,但以往研究大多局限于二维层面。目的:采用有限元分析法探讨经皮椎体成形过程中骨水泥在椎体三维层面内骨皮质强化差异对骨质疏松性椎体压缩性骨折椎体、邻近椎间盘及终板生物力学分布的影响,以评估其效果。方法:建立T12椎体骨质疏松性压缩性骨折行经皮椎体成形治疗的有限元模型,从横断面、矢状面、冠状面对骨水泥有无皮质强化情况进行分组分析,研究不同体位变化下,骨皮质强化对T12椎体松质骨、皮质骨、T11/T12椎间盘、T12/L1椎间盘、T11下终板、L1上终板生物力学的影响。结果与结论:(1)在垂直压缩力作用下,经皮椎体成形过程中有或无骨水泥皮质强化在不同体位变化下除伤椎皮质骨以外结构应力变化均不明显;(2)伤椎皮质骨Von Mises应力值在人体前屈、左/右侧弯和左/右轴向旋转时差异显著,同一平面内骨皮质完全强化组较无骨皮质强化组最大Von Mises应力值明显变小,随着骨皮质强化越广泛Von Mises应力值整体呈下降趋势;(3)提示行经皮椎体成形治疗时,横断面内骨水泥应尽量广泛对称水平分布于椎体骨皮质边缘,矢状面内骨水泥应广泛纵向分布且靠近上下终板及前后壁,冠状面内骨水泥应广泛分布于中线两侧同时对称接触上下终板及侧壁,可有效避免伤椎再骨折风险且不增加邻椎骨折、残留盘源性疼痛风险。

关键词：经皮椎体成形骨皮质强化骨质疏松性椎体压缩性骨折邻近椎间盘终板三维有限元分析生物力学

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Gray codes over certain run-length sequences for local rank modulation

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Science China(Information Sciences) 2018年第10期61卷 98-113页

作者： Xiang WANG fang-wei FU National Computer Network Emergency Response Technical Team The Chern Institute of Mathematics and LPMC Nankai University

In the local rank modulation(LRM) scheme, a sliding window produces a sequence of permutations by moving over a sequence of variables. LRM has been presented as a method of storing data in flash memory, which represents a natural generalization of the classical rank modulation scheme. In this paper, we present a study on Gray codes over certain run-length sequences for the(1, 2, n)-LRM scheme to simulate virtual multilevel flash memory cells while maintaining the advantages of LRM. Unlike previous studies on the LRM scheme, we present Gray codes over certain run-length sequences in the(1, 2, n)-LRM scheme. This class of Gray codes can overcome the drawback of the many distinct charge levels required in the rank modulation scheme and in certain Gray codes for LRM. Furthermore, we demonstrate that the proposed codes have an asymptotically optimal rate.

关键词： flash memory local rank modulation Gray codes rank modulation run-length sequences

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In vitro regeneration of Populus tomentosa from petioles

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Journal of Forestry Research 2017年第3期28卷 465-471页

作者： fang wei fang-fang Zhao Bao-ming Tian School of Life Sciences Zhengzhou University

A reliable in vitro regeneration procedure for Populus tomentosa is a prerequisite for its trait improvement through genetic transformation. We established a systematic protocol for indirect regeneration of P. tomentosa using in vitro petioles of Chinese poplar cultivar ＇fasta-3＇. A high frequency of callus induction （〉97 %） was obtained from isolated petioles cultured on the modified 1/2MS basal medium supplemented with 0.5 mg/L ZT and 1.0 mg/L NAA, and the tested calli were subsequently plated on 1/2MS basal medium supplemented with 0.25 mg/L BA, 0.25 mg/L ZT, 0.25 mg/L NAA, 0.01 mg/L TDZ, and 0.5 mg/L KT for efficient regeneration of shoots after being cultured for 6 weeks. The regenerated shoots were vigorously rooted on the tested media supplemented with 1.0 mg/ L IBA and 0.5 mg/L NAA. These results can facilitate genetic transformation of P. tomentosa for trait improvements in future.

关键词： Callus induction Genetic transformation In vitro regeneration Petiole Populus tomentosa

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Vacancy-defect-dipole amplifies the thermoacoustic conversion efficiency of carbon nanoprobes

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Nano Research 2020年第9期13卷 2413-2419页

作者： wei fang Yujiao Shi Da Xing MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science South China Normal UniversityGuangzhou 510631China College of Biophotonics South China Normal UniversityGuangzhou 510631China

The immense potential of carbon nanoprobes(CNPs)for using as contrast agents has propelled much recent research and development in the field of thermoacoustic(TA)molecular imaging,while the proper engineering and design of such materials with required high TA conversion efficiency is still a highly challenging *** this work,we proposed a controllable strategy to amplify the TA conversion efficiency of the CNPs by constructing vacancy defect(VD)dipoles,and systematically demonstrated the amplification mechanism through theoretical and experimental ***-principles calculation results indicate that,when a carbon atom is removed from the CNPs by chemical approach,owing to local electron density redistribution,the VDs are formed at the positions of the original carbon atoms and act as the structural origin of permanent electric dipoles with the dipole moment several orders higher than that of non-defect *** pulsed microwave irradiation,the VD dipoles are polarized repeatedly and significantly contribute to the conversion efficiency from absorbed electromagnetic waves to ultrasound through enhanced dielectric relaxation *** experimentally synthesized graphene samples with different VD densities and VD types to demonstrate the efficiency of the proposed strategy,and results coincide well with the theoretical *** work offers feasible guidance to the systematic development and rational design of new high-conversion-efficiency TA CNPs via VD engineering.

关键词： thermoacoustic conversion efficiency vacancy-defect carbon nanoprobes

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Automatic Colorization with Improved Spatial Coherence and Boundary Localization

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Journal of Computer Science & Technology 2017年第3期32卷 494-506页

作者： wei Zhang Chao-wei fang Guan-Bin Li Department of Computer Science The University of Hong Kong Hong Kong China School of Data and Computer Science Sun Yat-sen University Guangzhou 510006 China

Grayscale image colorization is an important computer graphics problem with a variety of applications. Recent fully automatic colorization methods have made impressive progress by formulating image colorization as a pixel-wise prediction task and utilizing deep convolutional neural networks. Though tremendous improvements have been made, the result of automatic colorization is still far from perfect. Specifically, there still exist common pitfalls in maintaining color consistency in homogeneous regions as well as precisely distinguishing colors near region boundaries. To tackle these problems, we propose a novel fully automatic colorization pipeline which involves a boundary-guided CRF （conditional random field） and a CNN-based color transform as post-processing steps. In addition, as there usually exist multiple plausible colorization proposals for a single image, automatic evaluation for different colorization methods remains a challenging task. We further introduce two novel automatic evaluation schemes to efficiently assess colorization quality in terms of spatial coherence and localization. Comprehensive experiments demonstrate great quality improvement in results of our proposed colorization method under multiple evaluation metrics.

关键词： automatic colorization deep learning conditional random field (CRF) color transform quality evaluation

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A field experimental study on the impact of Acer platanoides,an urban tree invader,on forest ecosystem processes in North America

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Ecological Processes 2020年第1期9卷 93-107页

作者： wei fang Xianzhong Wang Department of Ecology and Evolution Stony Brook University650 Life Sciences BuildingStony BrookNew York 11794USA School of Earth and Environmental Sciences Queens CollegeCity University of New York65-30 Kissena BoulevardFlushingNew York 11367USA Department of Biology Indiana University-Purdue University Indianapolis723 West Michigan StreetIndianapolisIN 46202-5132USA.

Background:Invasive species affect community dynamics and ecosystem functions,but the mechanisms of their impacts are poorly *** on invasion impact range from Superior Competitor to Novel Function,from Enemy Escape to Microbial *** this study,we examined the effects of an urban tree invader,Acer platanoides(Norway maple,NM),on a mesic deciduous forest in contrast to its native congener Acer rubrum(red maple,RM)with a split-plot design experiment.A total of 720 maple seedlings were transplanted to 72 plots under 24 trees of three canopy *** three experimental treatments were removal of resource competition at above-and belowground and removal of leaf-litter *** moisture and nitrogen-related microbial activities were followed for each ***:We found that partial canopy removal increased canopy openness and light transmission to the forest floor,but to a greater extent under NM than under RM *** seedlings were more shade tolerant than RM seedlings in height *** the reciprocal transplantation in the mixed forest,biomass accumulation of NM seedlings under RM trees were twice as much as under NM,while that of RM seedlings under NM trees was 23.5%less than under *** net nitrification and relative nitrification were significantly higher,but mineralization rate was much lower under NM than under RM trees,which would lead to faster N leaching and lower N availability in the *** with litter removal had significantly higher seedling mortality due to herbivory by the end of 2 years,especially for NM seedlings under NM *** enhanced soil water availability but there was no difference among canopy ***:Our results demonstrated that invasion of NM not only altered forest canopy structure but also changed herbivory rate for seedlings and N dynamics in the *** seedlings were more shade tolerant under NM canopies than RM seedlings and were more protected by NM litter under NM canopie

关键词： Norway maple(Acer platanoides) Urban tree Invasive species Red maple(Acer rubrum) Ecosystem processes Canopy and belowground competition Biomass production Soil N mineralization and nitrification Seedling herbivory Soil microbial communities

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Drug-induced erythroderma in patients with acquired immunodeficiency syndrome

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World Journal of Emergency Medicine 2021年第4期12卷 299-302页

作者： wei-fang Zhu De-ren fang Hong fang Department of Dermatology the First Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310003China

BACKGROUND: To explore the clinical manifestations, diagnosis, and treatment of patients with acquired immunodeficiency syndrome(AIDS) complicated with drug-induced ***: The clinical data of 12 AIDS patients with drug-induced erythroderma in our hospital were retrospectively analyzed. The general information, offending medications, complications, modified severity-of-illness score for toxic epidermal necrolysis(SCORTEN) scores, and disease outcome spectrums were ***: Drug-induced erythroderma was mostly caused by antiviral drugs, antituberculosis drugs, antibiotics, traditional Chinese medicine, and immune checkpoint inhibitors. The spectrum of sensitizing drugs was broad, the clinical situation was complex, and infections were common. The affected areas were greater than 40% body surface area in all patients. The modified SCOTERN score averaged 3.01±0.99. All patients were treated with glucocorticoids, and nine patients were treated with intravenous immunoglobulin(IVIG) pulse therapy at the same time. The average time to effectiveness was 7.08±2.23 days, and the average hospital stay was 17.92±8.46 days. Eleven patients were cured, and one patient died of secondary multiple infections, who had a modified SCORTEN score of 5 points. The mortality rate in this study was 8.3%.CONCLUSIONS: The clinical situation of AIDS patients with drug-induced erythroderma in hospitalized patients is complex and the co-infection rate is high. The use of modified SCORTEN score may objectively and accurately assess the conditions, and the use of glucocorticoid combined with IVIG therapy may improve the prognosis.

关键词： Acquired immunodeficiency syndrome Drug eruption Erythroderma Modified severity-of-illness score for toxic epidermal necrolysis

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