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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    

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features of new particle formation events at background sites in China and their influence on cloud condensation

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    

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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    

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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    

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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    

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Condensation of phenol and acetone on a modified macroreticular ion exchange resin catalyst

Baohe WANG, Lili WANG, Jing ZHU, Shuang CHEN, Hao SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 218-225 doi: 10.1007/s11705-013-1330-9

摘要： Macroreticular ion exchange resin catalysts were prepared by suspension polymerization, and then modified by alkylmercaptoamines. The modified catalysts were characterized by N adsorption/desorption measurements, scanning electron microscopy and differential scanning calorimetry. Key factors such as the mercaptan content, the degree of crosslinking and the structures of the promoters were investigated for the synthesis of Bisphenol A (BPA). At optimal conditions, the macroreticular ion exchange resin catalysts modified by alkylmercaptoamines showed high catalytic activity and selectivity for BPA synthesis.

关键词： macroreticular ion exchange resin     catalysts     suspension polymerization     Bisphenol A    

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Synthesis of p -substituted tetraphenylporphyrins and corresponding ferric complexes with mixed-solvents method

Zhicheng SUN, Yuanbin SHE, Rugang ZHONG,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 457-461 doi: 10.1007/s11705-009-0169-6

摘要： By using mixed-solvents method, five kinds of -substituted tetraphenylporphyrin compounds [T(-R)PPH, R=NO, Cl, CH, OCH, OH] were synthesized by the condensation of -substituted benzaldehyde with pyrrole in mixed solvents (propionic acid, acetic acid and nitrobenzene), and corresponding ferric complexes [T(-R)PPFeCl] were synthesized in dimethylformamide. The above free base porphyrins were obtained in 30%–50% yields, metalation yields were up to 90% and total yields of ferric complexes were 27%–50%. Effects of reactive conditions, solvents and oxidants on yields of free base porphyrins were investigated and the relevant mechanism was discussed. Structures of the above porphyrin complexes were characterized by ultraviolet-visible (UV-Vis), infrared (IR) and far infrared (FIR) spectroscopy.

关键词： -substituted tetraphenylporphyrin     condensation     -substituted benzaldehyde     dimethylformamide     metalation    

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Numerical study and control method of interaction of nucleation and boundary layer separation in condensing flow

Liansuo AN , Zhi WANG , Zhonghe HAN ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 254-261 doi: 10.1007/s11708-009-0047-4

摘要： The spontaneous nucleation flow in turbine cascade was numerically studied. The model was implemented within a full Navier–Stokes viscous flow solution procedure and the process of condensation was calculated by the quadrature method of moments that shows good accuracy with very broad size distributions. Results were presented for viscous and inviscous flow, showing the influence of boundary layer separation and wake vortices on spontaneous nucleation. The results show that the degree of flow separation in wet steam flow is greater than that in superheated steam flow due to condensation shock and that the loss cannot be neglected. Furthermore, the impact of boundary layer separation and wake vortices on velocity profiles and its implications for profile loss were considered. The calculations showed that layer separation and wake vortices influence nucleation rate, leading to different droplet distributions. A method for controlling homogeneous nucleation and for reducing degree of flow separation in high-speed transonic wet steam flow was presented. The liquid phase parameter distribution is sensitive to the suction side profile of turbine cascade, which impacts the nucleation rate distribution leading to different droplet distributions and affects the degree of flow separation. The numerical study provides a practical design method for turbine blade to reduce wetness losses.

关键词： wet steam     two-phase flow     spontaneous condensation     numerical simulation     flow separation     profile loss    

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Topology optimization based on reduction methods with applications to multiscale design and additive manufacturing

Emmanuel TROMME, Atsushi KAWAMOTO, James K. GUEST

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 151-165 doi: 10.1007/s11465-019-0564-8

摘要： Advanced manufacturing processes such as additive manufacturing offer now the capability to control material placement at unprecedented length scales and thereby dramatically open up the design space. This includes the considerations of new component topologies as well as the architecture of material within a topology offering new paths to creating lighter and more efficient structures. Topology optimization is an ideal tool for navigating this multiscale design problem and leveraging the capabilities of advanced manufacturing technologies. However, the resulting design problem is computationally challenging as very fine discretizations are needed to capture all micro-structural details. In this paper, a method based on reduction techniques is proposed to perform efficiently topology optimization at multiple scales. This method solves the design problem without length scale separation, i.e., without iterating between the two scales. Ergo, connectivity between space-varying micro-structures is naturally ensured. Several design problems for various types of micro-structural periodicity are performed to illustrate the method, including applications to infill patterns in additive manufacturing.

关键词： multiscale topology optimization     micro-structure     additive manufacturing     reduction techniques     substructuring     static condensation     super-element    

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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    

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On secondary new particle formation in China

Markku Kulmala,Tuukka Petäjä,Veli-Matti Kerminen,Joni Kujansuu,Taina Ruuskanen,Aijun Ding,Wei Nie,Min Hu,Zhibin Wang,Zhijun Wu,Lin Wang,Douglas R. Worsnop

《环境科学与工程前沿（英文）》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0850-1

摘要： Formation of new atmospheric aerosol particles is a global phenomenon that has been observed to take place in even heavily-polluted environments. In China, new particle production has been observed at very high pollution levels (condensation sink about 0.1s ) in several megacities. A holistic scientific understanding on the atmospheric phenomena associated with air quality as a whole, as well as on the connection between air quality and climate, is lacking at the moment.With a network of observation stations, we will be able to understand the interactions and feedbacks associated with the urban pollution mixture, and ultimately, are ready to make targeted strategies for the pollution control. This paper summaries the recent advances in studying secondary new aerosol formation in China and shows how increased process-level understanding will help us to understand air quality-climate-weather interactions and how the feedbacks and interactions affect the air quality in highly-polluted environments such as those frequently encountered in Chinese megacities. Formation of new atmospheric aerosol particles is a global phenomenon that has been observed to take place in even heavily-polluted environments. However, in all environments there appears to be a threshold value of the condensation sink (due to pre-existing aerosol particles) after which the formation rate of 3 nm particles is no longer detected. In China, new particle production has been observed at very high pollution levels (condensation sink about 0.1 s ) in several megacities, including Beijing, Shanghai and Nanjing as well as in Pearl River Delta (PRD). Here we summarize the recent findings obtained from these studies and discuss the various implications these findings will have on future research and policy.

关键词： Aerosol particles     Heavily-polluted environments     Condensation sink     New particle production     Megacities    

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一种促进低温快速沉积Cu(In,Ga)Se2薄膜生长的单加热克努森蒸发源的改良设计 Article

张运祥, 林舒平, 程世清, 何志超, 胡朝静, 周志强, 刘玮, 孙云

《工程（英文）》 2021年 第7卷 第4期   页码 534-541 doi: 10.1016/j.eng.2020.01.016

摘要：

在共蒸发工艺中，克努森蒸发源经常被用来生长高质量Cu(In,Ga)Se2（CIGS）薄膜。然而，在整个薄膜沉积过程中（尤其在低温工艺下），传统单加热克努森蒸发源不能使金属完全硒化，这可能是由蒸发源坩埚喷嘴处的冷凝和液滴喷射现象造成的。本文将通过热力学分析解释这一现象，同时提出了一种新型单加热克努森蒸发源来解决这一问题。与传统低温快速沉积工艺相比，新型单加热蒸发源提高了薄膜质量，并在230 nm·min–1的生长速率下，将器件相对效率提高了29%。

关键词： Cu(In     Ga)Se2     克努森蒸发源     凝结     液滴喷射     低温    

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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

features of new particle formation events at background sites in China and their influence on cloud condensation

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

期刊论文

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

期刊论文

Influence of infiltration on energy consumption of a winery building

Hejiang SUN, Qingxia YANG

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

Condensation of phenol and acetone on a modified macroreticular ion exchange resin catalyst

Baohe WANG, Lili WANG, Jing ZHU, Shuang CHEN, Hao SUN

期刊论文

Synthesis of p -substituted tetraphenylporphyrins and corresponding ferric complexes with mixed-solvents method

Zhicheng SUN, Yuanbin SHE, Rugang ZHONG,

期刊论文

Numerical study and control method of interaction of nucleation and boundary layer separation in condensing flow

Liansuo AN , Zhi WANG , Zhonghe HAN ,

期刊论文

Topology optimization based on reduction methods with applications to multiscale design and additive manufacturing

Emmanuel TROMME, Atsushi KAWAMOTO, James K. GUEST

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

On secondary new particle formation in China

Markku Kulmala,Tuukka Petäjä,Veli-Matti Kerminen,Joni Kujansuu,Taina Ruuskanen,Aijun Ding,Wei Nie,Min Hu,Zhibin Wang,Zhijun Wu,Lin Wang,Douglas R. Worsnop

期刊论文

一种促进低温快速沉积Cu(In,Ga)Se2薄膜生长的单加热克努森蒸发源的改良设计

张运祥, 林舒平, 程世清, 何志超, 胡朝静, 周志强, 刘玮, 孙云

期刊论文