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Energy-saving Technology of Vent in Passive Solar Wall of Rural House of Severe Cold Region

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Journal of Harbin institute of Technology(New Series) 2014年第4期21卷 30-36页

作者： Wei Ling Tian-Yu Zhao Hong Jin Xi-Peng Zhao School of Architecture Harbin Institute of Technology China Construction design international

This paper aims at solving the problems of low thermal collection rate,inconvenient maintenance,hindering indoor using during the application of passive solar technologies in rural houses in severe cold region.All these defects prevent the passive solar houses' further development. This paper chooses trombe wall,which has higher thermal efficiency of the passive solar house,as research object. The traditional vent is improved into a new type of ventilation device. This improvement overcomes the shortcoming,which traditional vent loses huge heat,and simplifies the construction of vent. Comparing with traditional trombe wall,the energy saving rate is 15. 69%.

关键词： severe cold region rural house passive solar wall energy-saving technology of vent

A Statistical Model for Phase Difference Spectrum of Ground-Motion and Its Application in Generating Non-Stationary Seismic Waves

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Computer Modeling in Engineering & Sciences 2020年第7期124卷 265-285页

作者： Dongsheng Du Sheng Shi Weizhi Xu Chen Kong Shuguang Wang Weiwei Li College of Civil Engineering Nanjing University of TechnologyNanjing210009China China Jiangsu international Group Architecture design institute Nanjing211816China

The intensity non-stationarity is one of the most important features of earthquake records.Modeling of this feature is significant to the generation of artificial earthquake waves.Based on the theory of phase difference spectrum,an intensity non-stationary envelope function with log-normal form is proposed.Through a tremendous amount of earthquake records downloaded on Kik-net,a parameter fitting procedure using the genetic algorithm is conducted to obtain the value of model parameters under different magnitudes,epicenter distances and site conditions.A numerical example is presented to describe the procedure of generating fully non-stationary ground motions via spectral representation,and the mean EPSD(evolutionary power spectral density)of simulated waves is proved to agree well with the target EPSD.The results show that the proposed model is capable of describing the intensity non-stationary features of ground motions,and it can be used in structural anti-seismic analysis and ground motion simulation.

关键词： Intensity non-stationarity parameter fitting genetic algorithm phase

An Urban Road Risk Assessment Framework Based on Convolutional Neural Networks

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international Journal of Disaster Risk Science 2023年第3期14卷 475-487页

作者： Juncai Jiang Fei Wang Yizhao Wang Wenyu Jiang Yuming Qiao Wenfeng Bai Xinxin Zheng Department of Engineering Physics Tsinghua UniversityBeijing 100084China institute of Safety Science and Technology Tsinghua Shenzhen International Graduate SchoolShenzhen 518000China Guangzhou Metro design Research institute Co. LtdGuangzhou 510010China

In contemporary cities,road collapse is one of the most common disasters.This study proposed a framework for assessing the risk of urban road collapse.The framework first established a risk indicator system that combined environmental and anthropogenic factors,such as soil type,pipeline,and construction,as well as other indicators.Second,an oversampling technique was used to create the dataset.The framework then constructed and trained a convolutional neural network(CNN)-based model for risk assessment.The experimental results show that the CNN model(accuracy:0.97,average recall:0.91)outperformed other models.The indicator contribution analysis revealed that the distance between the road and the construction site(contribution:0.132)and the size of the construction(contribution:0.144)are the most significant factors contributing to road collapse.According to the natural breaks,a road collapse risk map of Foshan City,Guangdong Province,was created,and the risk level was divided into five categories.Nearly 3%of the roads in the study area are at very high risk,and 6%are at high risk levels,with the high risk roads concentrated in the east and southeast.The risk map produced by this study can be utilized by local authorities and policymakers to help maintain road safety.

关键词： Convolutional neural networks Data augmentation Risk assessment Urban road collapse

Unravelling the Anomalous Coking Resistance over Boron Nitride-Supported Ni Catalysts for Dry Reforming of Methane

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CCS Chemistry 2023年第9期5卷 2111-2124页

作者： Jiang Deng Min Gao Jun-ya Hasegawa Xiaoyu Zhang Aiyong Wang Aling Chen Dengsong Zhang international Joint Laboratory of Catalytic Chemistry College of SciencesShanghai UniversityShanghai 200444 institute for Chemical Reaction design and Discovery(WPI-ICReDD) Hokkaido UniversitySapporo 001-0021 institute for Catalysis Hokkaido UniversitySapporo 001-0021

Metal oxides have been used as the supports for heterogeneous catalysis formany years,but they still suffer from coking in some high-temperature applications.The main reasons for coking are the uncontrollable dissociation of C-H and the overbalance between carbon deposition and removal.Herein,we find a boron nitride(BN)-immobilized Ni catalyst shows unprecedented coking resistance in dry reforming of methane via the incomplete decomposition of methane.Unlike the Ni-based catalysts supported by traditional metal oxides,BN-supported Ni accelerates the first C-H dissociation while inhibiting the breaking of the final C-H bond;hence,the suppression of the complete decomposition of methane thoroughly addresses the coking issue.This work reveals the fundamental reason for the coking resistance over BN-supported Ni catalysts is selective activation of the C-H bond,which can provide an inspiring idea for other applications.

关键词： heterogenous catalysis boron nitrides dry reforming of methane coking resistance methane conversion

A cost-effectiveness assessment of the operational parameters of central HVAC systems during pandemics

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Building Simulation 2023年第5期16卷 667-682页

作者： Yufan Chang Zhengtao Ai Jinjun Ye Guochuan Ma Department of Building Environment and Energy College of Civil EngineeringHunan UniversityChangshaHunanChina National Center for international Research Collaboration in Building Safety and Environment Hunan UniversityChangshaHunanChina China Southwest Architectural design and Research institute ChengduSichuanChina

The present study develops a cost-effectiveness assessment model to analyze the performance of major operational parameters of central HVAC systems in terms of airborne transmission risk,energy consumption,and medical and social cost.A typical multi-zone building model with a central HVAC system is built numerically,and the effect of outdoor air(OA)ratio(from 30%to 100%)and filtration level(MERV 13,MERV 16,and HEPA)are assessed under the conditions of five climate zones in China.Compared with the baseline case with 30%OA and MERV 13 filtration,the airborne transmission risk in zones without infector is negligibly reduced with the increase in OA ratio and the upgrade of filtration level,owing to their slight modification on the equivalent ventilation rate of virus-free air.However,depending on climate zone,a 10%increase in OA ratio results in 12.5%-78.6%and 0.1%-8.6%increase in heating and cooling energy consumption,respectively,while an upgrade of filtration level to MERV 16 and HEPA results in an increase of 0.08%-0.2%and 1.4%-2.6%,respectively.Overall,when compared to the use of 100%OA ratio and HEPA filtration,the application of 30%or 40%OA ratio and MERV 13 filtration would save annually an energy and facility related cost of$29.4 billion in China,though giving an increase of approximately$0.1 billion on medical and social cost from the increased number of confirmed cases.This study provides basic method and information for the formulation of cost-effective operational strategies of HVAC systems coping with the airborne transmission,especially in resource-limited regions.

关键词： outdoor air ratio filtration level airborne transmission risk energy consumption cost-effectiveness

界定土地利用面积值并优化其结构以改善生态系统服务供需平衡状态

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Journal of Geographical Sciences 2024年第5期34卷 891-920页

作者：黄佩赵筱青普军伟顾泽贤冉玉菊徐逸飞吴倍昊董雯雯瞿国寻熊波周龙进 institute of international Rivers&Eco-Security Yunnan UniversityKunming 650500China School of Earth Sciences Yunnan UniversityKunming 650500China Nujiang Forestry and Grassland Administration Lushui 673100YunnanChina Yunnan institute of Land Resources Planning and design Kunming 650200China

Improving the supply-demand balance of ecosystem services(SDBES)from the perspective of land use is essential for managing regional ecosystem and realizing sustainable development.By combining land use with the supply and demand of ecosystem services(SDES),a technical framework for defining land use threshold and optimizing its structure to improve the SDBES state was constructed and applied to a practical case.The spatial pattern of supply and demand of each ES in Lancang county was distinctly heterogeneous,with sig-nificant differences in SDES across different land use types.Strong spatial heterogeneity ex-isted in the ESDR of each ES at the grid scale,and the areas of deficit were ranked as carbon sequestration>water conservation>habitat quality>food production.The structure of dry land,paddy field,tea,evergreen broad-leaved forest,grassland,urban construction land,and indus-trial and mining construction land were the focus of land use optimization.Based on the land use area thresholds under the SDBES,the optimal land use structure for maximizing compre-hensive benefits contributed to a balanced relationship between SDES and promoted sustain-able regional development.The study provides a new perspective and method for improving the SDBES state,alleviating land conflicts,and managing ecological environment.

关键词： ecosystem services supply-demand balance ecological supply-demand ratio land use area threshold landuse structureoptimization

Simulation Analysis of Ammonia Leakage and Dispersion in a Large-Scale Refrigeration System

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Fluid Dynamics & Materials Processing 2022年第4期18卷 1049-1066页

作者： Jianlu Cheng Kaiyong Hu Jiang Shen Lu Jia Rui Niu Zhaoxian Yang Tianjin Key Laboratory of Refrigeration Technology Tianjin University of CommerceTianjin300134China international Trade Engineering design institute Beijing100037China Tianjin Tengsheng Technology Co. Ltd.Tianjin300380China

The use of ammonia in large-scale refrigeration systems(such as those used for a stadium)requires adequate ammonia leakage prevention mechanisms are put in place.In the present study,numerical simulations have been conducted to study the dispersion law in the ammonia machinery room of the refrigeration system for the 2022 Beijing Winter Olympics.The wind speed,and release location have been varied to investigate their effects on the dispersion profile.Different positions of the leakage points in the ammonia storage tank have been found to lead to different areas affected accordingly.In general,the dangerous region area decreases with an increase in the wind speed.However,when the wind is aligned with the leakage direction,this trend is reverted.The study may offer an effective method to predict the impact of ammonia dispersion and implement the safe operation of such large-scale systems.

关键词： Numerical simulation ammonia diffusion leakage location ventilation

Influence of sand content on the flow characteristics of soft soil under cyclic and high-frequency vibration

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 487-496页

作者： Zhuang Zhongxun Yin Deshun Bai Chunyu Zhou Chao College of Mechanics and Material Hohai UniversityNanjing 211100China China Machinery international Engineering design & Research institute Co. Ltd East China Branch Nanjing 214006China

The flow characteristics of foundation soils subjected to train loads can present engineering hazards in highspeed railways. In order to verify the feasibility of blending coarse sand in modifying soft subsoil, undrained pulling sphere tests were carried out and the train loads were simulated through localized and cyclic vibration at various frequencies. Laboratory testing results indicate that the fl ow characteristics of soft soil can be signifi cantly enhanced by high-frequency vibration;meanwhile the continuous increase in fl ow characteristics caused by cyclic vibration may be an important reason for the long-term settlement of soft subsoil. The infl uence of sand content on fl ow characteristics is also studied in detail, and it is shown that the addition of coarse sand can weaken the fl ow characteristics of soft soil induced by sudden vibration at lower than 50 Hz. Under the condition of cyclic vibration, the growth of the fl ow characteristics of sand-clay mixtures is mainly caused by the fi rst-time vibration in the cycle, and the increase in sand content can make the fl ow characteristics present a faster convergent tendency.

关键词： sand content flow characteristics pulling sphere tests soft soil

Integrated Wireless Communication System Using MANET for Remote Pastoral Areas of Tibet

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China Communications 2016年第4期13卷 49-57页

作者： HUANG Cao ZHOU Qing ZHANG Dongchen School of Information Engineering Xizang Minzu University international school Beijing University of Posts and Telecommunications China Mobile Group design institute Co. Ltd.

To reduce the network deployment cost and provide voice, message and low rate data services in remote pastoral areas of Tibet effectively, an integrated wireless communication system utilizing MANET(Mobile Ad hoc Network) is proposed. The sparse mobile devices, assisted with the solar-powered multi-functional standing stations mainly on networking maintenance and routing arrangement, self-organize into a MANET. The topology of the standing stations is designed for networking robust and to simplify the routing method and energy strategy. Then in the OMNe T++(Objective Modular Network Test bed in C++) simulation, the energy consumption is analysis while adjusting routing with the different energy status of the standing stations. The result shows that the standing stations should adjust routing as well as control the mobile devices' activity level according to the energy states of the standing stations and their adjacent mobile devices.

关键词： wireless communication system OMNeT++ MANET Tibet