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Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD

Mikyung PARK, Jinkwan OH, Kihong PARK

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 313-319 doi: 10.1007/s11783-011-0346-y

摘要: A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.

关键词: aerosol     cloud condensation nuclei (CCN) counter     ultrafine particle    

Key features of new particle formation events at background sites in China and their influence on cloudcondensation nuclei

Xiaojing SHEN,Junying SUN,Xiaoye ZHANG,Yangmei ZHANG,Lu ZHANG,Ruxia FAN

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0833-2

摘要: New particle formation (NPF) event at multi rural sites in China Identifying the characteristics of NPF event Comparing NPF event between clean and polluted conditions Quantifying contribution to the cloud condensation nuclei Implication of climate and air quality Long-term continuous measurements of particle number size distributions with mobility diameter sizes ranging from 3 to 800 nm were performed to study new particle formation (NPF) events at Shangdianzi (SDZ), Mt. Tai (TS), and Lin’an (LAN) stations representing the background atmospheric conditions in the North China Plain (NCP), Central East China (CEC), and Yangtze River Delta (YRD) regions, respectively. The mean formation rate of 3-nm particles was 6.3, 3.7, and 5.8 cm ·s , and the mean particle growth rate was 3.6, 6.0, and 6.2 nm·h at SDZ, TS, and LAN, respectively. The NPF event characteristics at the three sites indicate that there may be a stronger source of low volatile vapors and higher condensational sink of pre-existing particles in the YRD region. The formation rate of NPF events at these sites, as well as the condensation sink, is approximately 10 times higher than some results reported at rural/urban sites in western countries. However, the growth rates appear to be 1–2 times higher. Approximately 12%–17% of all NPF events with nucleated particles grow to a climate-relevant size (>50 nm). These kinds of NPF events were normally observed with higher growth rate than the other NPF cases. Generally, the cloud condensation nuclei (CCN) number concentration can be enhanced by approximately a factor of 2–6 on these event days. The mean value of the enhancement factor is lowest at LAN (2–3) and highest at SDZ (~4). NPF events have also been found to have greater impact on CCN production in China at the regional scale than in the other background sites worldwide.

关键词: New particle formation     Regional background     Cloud condensation nuclei     Growth rate     Formation rate    

Global sources, emissions, transport and deposition of dust and sand and their effects on the climate and environment: a review

Feng Wang, Xueqiu Zhao, Cynthia Gerlein-Safdi, Yue Mu, Dongfang Wang, Qi Lu

《环境科学与工程前沿(英文)》 2017年 第11卷 第1期 doi: 10.1007/s11783-017-0904-z

摘要: Dust and Sand Storms (DSS) originating in deserts in arid and semi-arid regions are events raising global public concern. An important component of atmospheric aerosols, dust aerosols play a key role in climatic and environmental changes at the regional and the global scale. Deserts and semi-deserts are the main source of dust and sand, but regions that undergo vegetation deterioration and desertification due to climate change and human activities also contribute significantly to DSS. Dust aerosols are mainly composed of dust particles with an average diameter of 2 m, which can be transported over thousands of kilometers. Dust aerosols influence the radiation budget of the earth-atmosphere system by scattering solar short-wave radiation and absorbing surface long-wave radiation. They can also change albedo and rainfall patterns because they can act as cloud condensation nuclei (CCN) or ice nuclei (IN). Dust deposition is an important source of both marine nutrients and contaminants. Dust aerosols that enter marine ecosystems after long-distance transport influence phytoplankton biomass in the oceans, and thus global climate by altering the amount of CO absorbed by phytoplankton. In addition, the carbonates carried by dust aerosols are an important source of carbon for the alkaline carbon pool, which can buffer atmospheric acidity and increase the alkalinity of seawater. DSS have both positive and negative impacts on human society: they can exert adverse impacts on human’s living environment, but can also contribute to the mitigation of global warming and the reduction of atmospheric acidity.

关键词: Dust and sand storm     Climate effects     Radiative forcing     Cloud condensation nuclei     Precipitation     Iron fertilizer    

IN2CLOUD: A novel concept for collaborative management of big railway data

Jing LIN, Uday KUMAR

《工程管理前沿(英文)》 2017年 第4卷 第4期   页码 428-436 doi: 10.15302/J-FEM-2017048

摘要: In the EU Horizon 2020 Shift2Rail Multi-Annual Action Plan, the challenge of railway maintenance is generating knowledge from data and/or information. Therefore, we promote a novel concept called “IN2CLOUD,” which comprises three sub-concepts, to address this challenge: 1) A hybrid cloud, 2) an intelligent cloud with hybrid cloud learning, and 3) collaborative management using asset-related data acquired from the intelligent hybrid cloud. The concept is developed under the assumption that organizations want/need to learn from each other (including domain knowledge and experience) but do not want to share their raw data or information. IN2CLOUD will help the movement of railway industry systems from “local” to “global” optimization in a collaborative way. The development of cutting-edge intelligent hybrid cloud-based solutions, including information technology (IT) solutions and related methodologies, will enhance business security, economic sustainability, and decision support in the field of intelligent asset management of railway assets.

关键词: railway     intelligent asset management     collaborative learning     big data     hybrid cloud     Bayesian    

Toward autonomous mining: design and development of an unmanned electric shovel via point cloud-based

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0686-2

摘要: With the proposal of intelligent mines, unmanned mining has become a research hotspot in recent years. In the field of autonomous excavation, environmental perception and excavation trajectory planning are two key issues because they have considerable influences on operation performance. In this study, an unmanned electric shovel (UES) is developed, and key robotization processes consisting of environment modeling and optimal excavation trajectory planning are presented. Initially, the point cloud of the material surface is collected and reconstructed by polynomial response surface (PRS) method. Then, by establishing the dynamical model of the UES, a point to point (PTP) excavation trajectory planning method is developed to improve both the mining efficiency and fill factor and to reduce the energy consumption. Based on optimal trajectory command, the UES performs autonomous excavation. The experimental results show that the proposed surface reconstruction method can accurately represent the material surface. On the basis of reconstructed surface, the PTP trajectory planning method rapidly obtains a reasonable mining trajectory with high fill factor and mining efficiency. Compared with the common excavation trajectory planning approaches, the proposed method tends to be more capable in terms of mining time and energy consumption, ensuring high-performance excavation of the UES in practical mining environment.

关键词: autonomous excavation     unmanned electric shovel     point cloud     excavation trajectory planning    

Toward resilient cloud warehousing via a blockchain-enabled auction approach

《工程管理前沿(英文)》   页码 20-38 doi: 10.1007/s42524-022-0224-2

摘要: Cloud warehousing service (CWS) has emerged as a promising third-party logistics service paradigm driven by the widespread use of e-commerce. The current CWS billing method is typically based on a fixed rate in a coarse-grained manner. This method cannot reflect the true service value under the fluctuating e-commerce logistics demand and is not conducive to CWS resilience management. Accordingly, a floating mechanism can be considered to introduce more flexible billing. A CWS provider lacks sufficient credibility to implement floating mechanisms because it has vested interests in terms of fictitious demand. To address this concern, this report proposes a blockchain-enabled floating billing management system as an overall solution for CWS providers to enhance the security, credibility, and transparency of CWS. A one-sided Vickrey–Clarke–Groves (O-VCG) auction mechanism model is designed as the underlying floating billing mechanism to reflect the real-time market value of fine-grained CWS resources. A blockchain-based floating billing prototype system is built as an experimental environment. Our results show that the O-VCG mechanism can effectively reflect the real-time market value of CWSs and increase the revenue of CWS providers. When the supply of CWS providers remains unchanged, allocation efficiency increases when demand increases. By analyzing the performance of the O-VCG auction and comparing it with that of the fixed-rate billing model, the proposed mechanism has more advantages. Moreover, our work provides novel managerial insights for CWS market stakeholders in terms of practical applications.

关键词: resilient cloud warehousing     blockchain technology     floating billing management system     auction mechanism     third-party logistics    

云雷达反演层状云微物理参数及其与飞机观测数据的对比

刘黎平,宗蓉,齐彦斌,刘健

《中国工程科学》 2012年 第14卷 第9期   页码 64-71

摘要:

首先根据滴谱假设分析了层状云降水回波强度、径向速度和速度谱宽与降水微物理参数的关系,检验了云雷达探测数据的可用性;然后在忽略空气上升速度和湍流对雷达观测的速度谱宽影响前提下,利用测云雷达观测的回波强度、粒子下落速度和速度谱宽数据进行了液态水含量和滴谱参数的反演试验,并与飞机观测的滴谱进行了对比分析。结果表明,8 mm雷达观测得到的3个量与雨滴谱分析得到的关系比较接近;层状云粒子尺度、数密度和含水量从云顶到云的回波强中心有明显的变化,粒子尺度的增加是回波强度增加的重要原因。毫米波雷达反演得到的降水微物理参数和飞机观测数据具有可比性。

关键词: 云降水微物理参数     毫米波云雷达和飞机观测     降水粒子下落速度和谱宽    

Review of the LNG intermediate fluid vaporizer and its heat transfer characteristics

《能源前沿(英文)》 2022年 第16卷 第3期   页码 429-444 doi: 10.1007/s11708-021-0747-y

摘要: The intermediate fluid vaporizer (IFV), different from other liquefied natural gas (LNG) vaporizers, has many advantages and has shown a great potential for future applications. In this present paper, studies of IFV and its heat transfer characteristics in the LNG vaporization unit E2 are systematically reviewed. The research methods involved include theoretical analysis, experimental investigation, numerical simulation, and process simulation. First, relevant studies on the overall calculation and system design of IFV are summarized, including the structural innovation design, the thermal calculation model, and the selection of different intermediate fluids. Moreover, studies on the fluid flow and heat transfer behaviors of the supercritical LNG inside the tubes and the condensation heat transfer of the intermediate fluid outside the tubes are summarized. In the thermal calculations of the IFV, the selections of the existing heat transfer correlations about the intermediate fluids are inconsistent in different studies, and there lacks the accuracy evaluation of those correlations or comparison with experimental data. Furthermore, corresponding experiments or numerical simulations on the cryogenic condensation heat transfer outside the tubes in the IFV need to be further improved, compared to those in the refrigeration and air-conditioning temperature range. Therefore, suggestions for further studies of IFV are provided as well.

关键词: intermediate fluid vaporizer     design of structure and intermediate fluid     condensation heat transfer    

基于云模型的信任评估研究

路峰,吴慧中

《中国工程科学》 2008年 第10卷 第10期   页码 84-90

摘要:

讨论了信任关系的随机性和模糊性共存以及相互融合问题。分析云模型描述不确定性概念的方法和实现定性语意与定量数值相互转换的算法,提出了基于云理论的信任评估模型—信任云。该模型提出云特征参数表达的信任传递和合并算法,在精确描述信任期望值的同时,通过熵和超熵刻画了信任的不确定性。相对于传统的信任评估策略,该模型获取的信任值包含更多的语意信息,更适合作为信任决策的依据。

关键词: 信任评估     信任模型     云模型     云发生器    

Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

《能源前沿(英文)》 2014年 第8卷 第1期   页码 110-118 doi: 10.1007/s11708-013-0293-3

摘要: With the wide use of light steel structure in industrial buildings, some problems such as air leakage, water dripping and condensation and so forth occur during the construction and operation phases. Through the onsite testing of a winery building in Huailai County, Hebei Province in China, the influence of infiltration on energy consumption in industrial buildings was studied. The pressurization test method and moisture condensation method were used to test the infiltration rates. The results show that the winery building is twice as leaky as normal Chinese buildings and five times as leaky as Canadian buildings. The energy use simulation demonstrates that the reduction of the infiltration rate of the exterior rooms to 1/3 and the interior rooms to 1/2 could help decrease a total energy consumption of approximately 20% and reduce a total energy cost of approximately $ 225000. Therefore, it has a great potential to reduce the energy consumption in this type of buildings. Enforcement of the appropriate design, construction and installation would play a significant role in improving the overall performance of the building.

关键词: industrial building     air change rate     pressurization test method     moisture condensation method     energy cost    

Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

《信息与电子工程前沿(英文)》 2015年 第16卷 第7期   页码 553-567 doi: 10.1631/FITEE.1400410

摘要: Mobile cloud computing (MCC) has become a promising technique to deal with computation- or data-intensive tasks. It overcomes the limited processing power, poor storage capacity, and short battery life of mobile devices. Providing continuous and on-demand services, MCC argues that the service must be available for users at anytime and anywhere. However, at present, the service availability of MCC is usually measured by some certain metrics of a real-world system, and the results do not have broad representation since different systems have different load levels, different deployments, and many other random factors. Meanwhile, for large-scale and complex types of services in MCC systems, simulation-based methods (such as Monte-Carlo simulation) may be costly and the traditional state-based methods always suffer from the problem of state-space explosion. In this paper, to overcome these shortcomings, fluid-flow approximation, a breakthrough to avoid state-space explosion, is adopted to analyze the service availability of MCC. Four critical metrics, including response time of service, minimum sensing time of devices, minimum number of nodes chosen, and action throughput, are defined to estimate the availability by solving a group of ordinary differential equations even before the MCC system is fully deployed. Experimental results show that our method costs less time in analyzing the service availability of MCC than the Markov- or simulation-based methods.

关键词: Service availability     Mobile cloud computing     Fluid-flow approximation     Ordinary differential equations    

Thermal and hydraulic characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud

Linrui MA, Zhifeng WANG, Ershu XU, Li XU

《能源前沿(英文)》 2020年 第14卷 第2期   页码 283-297 doi: 10.1007/s11708-019-0649-4

摘要: To better understand the characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud passages, a novel method which combines a closed-loop thermal hydraulic model (CLTHM) and cloud vector (CV) is developed. Besides, the CLTHM is established and validated based on a pilot plant. Moreover, some key parameters which are used to characterize a typical PTSF and CV are presented for further simulation. Furthermore, two sets of results simulated by the CLTHM are compared and discussed. One set deals with cloud passages by the CV, while the other by the traditionally distributed weather stations (DWSs). Because of considering the solar irradiance distribution in a more detailed and realistically way, compared with the distributed weather station (DWS) simulation, all essential parameters, such as the total flowrate, flow distribution, outlet temperature, thermal and exergetic efficiency, and exergetic destruction tend to be more precise and smoother in the CV simulation. For example, for the runner outlet temperature, which is the most crucial parameter for a running PTSF, the maximum relative error reaches −15% in the comparison. In addition, the mechanism of thermal and hydraulic unbalance caused by cloud passages are explained based on the simulation.

关键词: parabolic trough solar field (PTSF)     thermal hydraulic model     cloud passages     transients    

A multiscale-contour-based interpolation framework for generating a time-varying quasi-dense point cloud

Chu-hua HUANG,Dong-ming LU,Chang-yu DIAO

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 422-434 doi: 10.1631/FITEE.1500316

摘要: To speed up the reconstruction of 3D dynamic scenes in an ordinary hardware platform, we propose an efficient framework to reconstruct 3D dynamic objects using a multiscale-contour-based interpolation from multi-view videos. Our framework takes full advantage of spatio-temporal-contour consistency. It exploits the property to interpolate single contours, two neighboring contours which belong to the same model, and two contours which belong to the same view at different times, corresponding to point-, contour-, and model-level interpolations, respectively. The framework formulates the interpolation of two models as point cloud transport rather than non-rigid surface deformation. Our framework speeds up the reconstruction of a dynamic scene while improving the accuracy of point-pairing which is used to perform the interpolation. We obtain a higher frame rate, spatio-temporal-coherence, and a quasi-dense point cloud sequence with color information. Experiments with real data were conducted to test the efficiency of the framework.

关键词: Multi-view video     Free-viewpoint video     Point-pair     Multiscale-contour-based interpolation     Spatio-temporal-contour     Consistency     Time-varying point cloud sequence    

Synthesis and properties of polybenzazoles containing flexible methylene in backbone

XU Xiaohui, LIU Xiaoyun, ZHOU Chengjun, ZHUANG Qixin, HAN Zhewen

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 412-416 doi: 10.1007/s11705-008-0073-5

摘要: A novel series of polybenzazoles with rigid-rod benzoxazole cycle and soft methylene segment was designed and synthesized via solution condensation polymerizations from 4,6-diamino-1,3-benzenediol diphosphate, terephthalic acid and aliphatic dicarboxylic acid. The structures of polybenzazoles were characterized by means of FT-IR, H NMR and Wide-angle X-ray diffraction (WAXRD). All the polymers show excellent thermal stability and the s was above 471°C. The intrinsic viscosities [] of the polymers ranged from 0.8 to 0.9. The UV-Vis absorption peaks of the polymers in MSA were blue-shifted from 429 nm for PBO to 291 nm for PBOC7, and the Stokes shifts in PL spectra enlarged.

关键词: condensation     Wide-angle     absorption     excellent     diffraction    

Building a dense surface map incrementally from semi-dense point cloud andRGBimages

Qian-shan LI,Rong XIONG,Shoudong HUANG,Yi-ming HUANG

《信息与电子工程前沿(英文)》 2015年 第16卷 第7期   页码 594-606 doi: 10.1631/FITEE.14a0260

摘要: Building and using maps is a fundamental issue for bionic robots in field applications. A dense surface map, which offers rich visual and geometric information, is an ideal representation of the environment for indoor/outdoor localization, navigation, and recognition tasks of these robots. Since most bionic robots can use only small light-weight laser scanners and cameras to acquire semi-dense point cloud and RGB images, we propose a method to generate a consistent and dense surface map from this kind of semi-dense point cloud and RGB images. The method contains two main steps: (1) generate a dense surface for every single scan of point cloud and its corresponding image(s) and (2) incrementally fuse the dense surface of a new scan into the whole map. In step (1) edge-aware resampling is realized by segmenting the scan of a point cloud in advance and resampling each sub-cloud separately. Noise within the scan is reduced and a dense surface is generated. In step (2) the average surface is estimated probabilistically and the non-coincidence of different scans is eliminated. Experiments demonstrate that our method works well in both indoor and outdoor semi-structured environments where there are regularly shaped objects.

关键词: Bionic robot     Robotic mapping     Surface fusion    

标题 作者 时间 类型 操作

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD

Mikyung PARK, Jinkwan OH, Kihong PARK

期刊论文

Key features of new particle formation events at background sites in China and their influence on cloudcondensation nuclei

Xiaojing SHEN,Junying SUN,Xiaoye ZHANG,Yangmei ZHANG,Lu ZHANG,Ruxia FAN

期刊论文

Global sources, emissions, transport and deposition of dust and sand and their effects on the climate and environment: a review

Feng Wang, Xueqiu Zhao, Cynthia Gerlein-Safdi, Yue Mu, Dongfang Wang, Qi Lu

期刊论文

IN2CLOUD: A novel concept for collaborative management of big railway data

Jing LIN, Uday KUMAR

期刊论文

Toward autonomous mining: design and development of an unmanned electric shovel via point cloud-based

期刊论文

Toward resilient cloud warehousing via a blockchain-enabled auction approach

期刊论文

云雷达反演层状云微物理参数及其与飞机观测数据的对比

刘黎平,宗蓉,齐彦斌,刘健

期刊论文

Review of the LNG intermediate fluid vaporizer and its heat transfer characteristics

期刊论文

基于云模型的信任评估研究

路峰,吴慧中

期刊论文

Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

期刊论文

Analyzing the service availability of mobile cloud computing systems by fluid-flow approximation

Hong-wu LV,Jun-yu LIN,Hui-qiang WANG,Guang-sheng FENG,Mo ZHOU

期刊论文

Thermal and hydraulic characteristics of a large-scaled parabolic trough solar field (PTSF) under cloud

Linrui MA, Zhifeng WANG, Ershu XU, Li XU

期刊论文

A multiscale-contour-based interpolation framework for generating a time-varying quasi-dense point cloud

Chu-hua HUANG,Dong-ming LU,Chang-yu DIAO

期刊论文

Synthesis and properties of polybenzazoles containing flexible methylene in backbone

XU Xiaohui, LIU Xiaoyun, ZHOU Chengjun, ZHUANG Qixin, HAN Zhewen

期刊论文

Building a dense surface map incrementally from semi-dense point cloud andRGBimages

Qian-shan LI,Rong XIONG,Shoudong HUANG,Yi-ming HUANG

期刊论文