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Scaling up of cluster beam deposition technology for catalysis application

《化学科学与工程前沿（英文）》 2021年第15卷第6期页码 1360-1379 doi: 10.1007/s11705-021-2101-7

摘要： Many research works have demonstrated that the combination of atomically precise cluster deposition and theoretical calculations is able to address fundamental aspects of size-effects, cluster-support interactions, and reaction mechanisms of cluster materials. Although the wet chemistry method has been widely used to synthesize nanoparticles, the gas-phase synthesis and size-selected strategy was the only method to prepare supported metal clusters with precise numbers of atoms for a long time. However, the low throughput of the physical synthesis method has severely constrained its wider adoption for catalysis applications. In this review, we introduce the latest progress on three types of cluster source which have the most promising potential for scale-up, including sputtering gas aggregation source, pulsed microplasma cluster source, and matrix assembly cluster source. While the sputtering gas aggregation source is leading ahead with a production rate of ~20 mg·h^–1, the pulsed microplasma source has the smallest physical dimensions which makes it possible to compact multiple such devices into a small volume for multiplied production rate. The matrix assembly source has the shortest development history, but already show an impressive deposition rate of ~10 mg·h^–1. At the end of the review, the possible routes for further throughput scale-up are envisaged.

关键词： nanoparticle cluster cluster beam deposition magnetron sputtering heterogeneous catalysis

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Effect of carbon deposition over carbonaceous catalysts on CH

Yongfa ZHANG, Meng ZHANG, Guojie ZHANG, Huirong ZHANG

《化学科学与工程前沿（英文）》 2010年第4卷第4期页码 481-485 doi: 10.1007/s11705-010-0523-8

摘要： An investigation was made using a continuous fixed bed reactor to understand the influence of carbon deposition obtained under different conditions on CH -CO reforming. Thermogravimetry (TG) and X-ray diffraction (XRD) were employed to study the characteristics of carbon deposition. It was found that the carbonaceous catalyst is an efficient catalyst in methane decomposition and CH -CO reforming. The trend of methane decomposition at lower temperatures is similar to that at higher temperatures. The methane conversion is high during the initial of stage of the reaction, and then decays to a relatively fixed value after about 30 min. With temperature increase, the methane decomposition rate increases quickly. The reaction temperature has significant influence on methane decomposition, whereas the carbon deposition does not affect methane decomposition significantly. Different types of carbon deposition were formed at different methane decomposition reaction temperatures. The carbon deposition Type I generated at 900°C has a minor effect on CH -CO reforming and it easily reacts with carbon dioxide, but the carbon deposition Type II generated at 1000°C and 1100°C clearly inhibits CH -CO reforming and it is difficult to react with carbon dioxide. The results of XRD showed that some graphite structures were found in carbon deposition Type II.

关键词： carbon deposition carbonaceous catalyst CH₄-CO₂ reforming

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Influence mechanism of dynamic and static liquid bridge forces on particle deposition behaviors in solar

Xueqing LIU, Xiaodong ZHAO, Luyi LU, Jianlan LI

《能源前沿（英文）》 2021年第15卷第2期页码 499-512 doi: 10.1007/s11708-021-0742-3

摘要： Solar energy is one of the most promising forms of renewable energy for solving the energy crisis and environmental problems. Dust deposition on photovoltaic mirrors has a serious negative impact on the photoelectric conversion efficiency of solar power stations. In this paper, the influence mechanism of the dynamic and static liquid bridge forces on particle deposition behaviors on solar photovoltaic mirrors is investigated. In addition, the expression and physical meaning of the particle critical separation velocity are proposed. The research results show that the static liquid bridge force can be the primary deposition force causing dust particles to adhere to photovoltaic mirrors. However, the dynamic liquid bridge force can act as a resistance force for the particle motion process and even make dust particles roll along and finally stay on the mirror. The contact force is the primary separation force that causes dust particles to flow away from the mirror. Whether dust particles adhere to the mirror depends on the relative size of the deposition and separating forces. The particle critical separation velocity describes the relative size of the collision-rebound effect and mirror adhesion effect and is expressed in Eq. (16). These research findings can provide theoretical guidance for mirror cleaning methods in the operation process of photovoltaic mirrors.

关键词： dust deposition discrete element method (DEM) photovoltaic mirrors solar energy

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ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION ON URBAN FORESTS: AN OVERVIEW

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 445-456 doi: 10.15302/J-FASE-2021429

摘要：

● Patterns and effects of N deposition on urban forests are reviewed.

关键词： biodiversity carbon sequestration nitrogen deposition nutrient imbalance soil acidification urban forest

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Fault simulation of boiler heating surface ash deposition in a power plant system

Weiwei ZHANG, Huisheng ZHANG, Ming SU

《能源前沿（英文）》 2011年第5卷第4期页码 435-443 doi: 10.1007/s11708-011-0162-x

摘要： The simulation model of a power generation system was developed based on EASY5 simulation platform. The performances of the power plant under the conditions of the furnace slagging and ash deposition of the heating surfaces in the boiler were simulated. The results show that the simulation model can reasonably reflect the characteristics of the power plant when each component is under fault conditions. Through fault simulation, the change of the performance parameters can be obtained, which can be used in fault diagnosis system as the diagnosis criterion for expert system.

关键词： boiler slagging ash deposition fault simulation

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Influence of phosphate on deposition and detachment of TiO

Zhan Wang, Chongyang Shen, Yichun Du, Yulong Zhang, Baoguo Li

《环境科学与工程前沿（英文）》 2019年第13卷第5期 doi: 10.1007/s11783-019-1163-y

摘要： We examined influence of phosphate on transport of TiO2 NPs in soil. Deposition was reduced at higher pH and by adsorption of phosphate in soil. Release was more for NPs initially deposited at higher pH. Release was more for NPs initially deposited in the presence of phosphate. Surface roughness and charge heterogeneity play a role in the deposition/ release. The widespread use of TiO2 nanoparticles (NPs) makes inevitable their release into the soil. Phosphate is also widespread within soil, and is likely copresent with TiO2 NPs. However, the influence of phosphate on deposition/release— and thereby on transport— of TiO2 NPs in soil is yet to be elucidated. In this study we conducted saturated column experiments to systematically examine the transport of TiO2 NPs in soil amended with phosphate at different ionic strengths (ISs) (1, 10, 100 mmol/L NaCl) and pHs (4 and 9). Results show that the deposition of TiO2 NPs decreased with decreasing IS, increasing pH, and when soil absorbed phosphate. These observations are qualitatively in agreement with Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy calculations, because the repulsive energy barrier is larger and secondary minimum depth is smaller at a lower IS, higher pH, and in the presence of phosphate. Accordingly, both primary- and secondary-minimum deposition were inhibited. Interestingly, although the deposition was less at higher pH and in the presence of phosphate, the subsequent spontaneous detachment and detachment by reduction of solution IS in these cases were greater. In addition, the presence of phosphate in the solution can cause a small quantity of attached TiO2 NPs to detach, even without perturbations of physical and chemical conditions. Our study was the first to investigate the influence of phosphate on detachment of TiO2 NPs and the results have important implication for accurate prediction of fate and transport of TiO2 NPs in subsurface environments.

关键词： Phosphate TiO₂ nanoparticles Transport Soil Deposition Detachment

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RESEARCH PROGRESS ON THE IMPACT OF NITROGEN DEPOSITION ON GLOBAL GRASSLANDS

《农业科学与工程前沿（英文）》 2022年第9卷第3期页码 425-444 doi: 10.15302/J-FASE-2022457

摘要：

● Grasslands in many regions of the world have been impacted by atmospheric nitrogen deposition.

关键词： Acidification biomass production critical load eutrophication species composition species richness

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Lagrangian simulation of deposition of CO gas-solid sudden expansion flow

HUANG Dongping, DING Guoliang, QUACK Hans

《能源前沿（英文）》 2008年第2卷第2期页码 216-221 doi: 10.1007/s11708-008-0032-3

摘要： Freezing and blockage resulting from the deposition of solid CO formed because of sudden expansion of the downstream pipe during the release of CO through safety valves, will endanger the protected equipment. To overcome this problem, the characteristics of the CO gas-solid sudden expansion flow are studied by using the disperse Lagrangian model. A comparison of the calculated deposition of the solid CO with the experimental results shows that they are in reasonable agreement. The simulation results show that the size of the solid CO formed should not be in the range of 0.04–0.07 mm ( number 3.2–9.8). This can be achieved by using an appropriate flow cross section of the safety valve.

关键词： comparison gas-solid downstream blockage Lagrangian

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Effect of soil crust on evaporation and dew deposition in Mu Us sandy land, China

SUN Yongliang, LI Xiaoyan, XU Heye, YANG Zhipeng, TANG Jia, ZHANG Xiaoying

《环境科学与工程前沿（英文）》 2008年第2卷第4期页码 480-486 doi: 10.1007/s11783-008-0034-8

摘要： The development of soil crust on sandy land may affect the surface hydrological process. This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were dominated by sand, primitive biotic crust, and advanced biotic crust, respectively, in the south fringe of Mu Us sandy land in Northwest China from July to September of 2006. The experimental results indicate that the advanced biotic crust could increase evaporation and dew deposition compared to the primitive biotic crust and bare sand although the differences between them were not significant. The average evaporation from advanced biotic crust, primitive biotic crust and sand was 6.8, 6.6, and 6.5 mm/d, respectively, and water content is around 16.2 % in the condition of initially identical soil. The average dew amount on advanced biotic crust was 0.116 mm/d with extreme 0.05 and 0.24 mm/d. The average values on primitive biotic crust and sand were 0.105 and 0.101 mm/d, respectively, with extreme 0.04 and 0.21 mm/d for both treatments. Also, the dew deposition on advanced biotic crust seemed stable and might rest for a longer time than that on primitive biotic crust and sand. The results suggest that the advanced biotic crust possibly facilitates evaporation and dew deposition. Therefore, the development of biotic crust may potentially enhance the hydrological circulation in the upper sand layer in sandy land.

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中国酸雨对陆地生态系统的影响和防治对策

冯宗炜

《中国工程科学》 2000年第2卷第9期页码 5-11

摘要：

我国是继欧洲、北美之后，在世界上出现的第三大酸雨区。长江以南各省是我国酸雨的主要分布区。酸雨对陆地生态系统的危害日益严重。文章阐述了酸雨对农作物、森林、土壤和水生生物的影响及其经济损失的估算。并根据可持续发展的战略思想，提出防治对策。

关键词：酸雨陆地生态系统经济损失防治对策

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SiO₂ passivation layer grown by liquid phase deposition for silicon solar cell application

Yanlin CHEN,Sihua ZHONG,Miao TAN,Wenzhong SHEN

《能源前沿（英文）》 2017年第11卷第1期页码 52-59 doi: 10.1007/s11708-016-0429-3

摘要： Surface passivation is one of the primary requirements for high efficient silicon solar cells. Though the current existed passivation techniques are effective, expensive equipments are required. In this paper, a comprehensive understanding of the SiO passivation layer grown by liquid phase deposition (LPD) was presented, which was cost-effective and very simple. It was found that the post-annealing process could significantly enhance the passivation effect of the LPD SiO film. Besides, it was revealed that both chemical passivation and field-effect passivation mechanisms played important roles in outstanding passivation effect of the LPD SiO film through analyzing the minority carrier lifetime and the surface recombination velocity of n-type and p-type silicon wafers. Although the deposition parameters had little influence on the passivation effect, they affected the deposition rate. Therefore, appropriate deposition parameters should be carefully chosen based on the compromise of the deposition rate and fabrication cost. By utilizing the LPD SiO film as surface passivation layer, a 19.5%-efficient silicon solar cell on a large-scale wafer (156 mm × 156 mm) was fabricated.

关键词： Si solar cell passivation SiO₂ liquid phase deposition carrier lifetime

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New kind of subarea-parallel scanning mode for laser metal deposition shaping

BIAN Hongyou, LIU Weijun, ZHAO Jibin

《机械工程前沿（英文）》 2007年第2卷第4期页码 417-422 doi: 10.1007/s11465-007-0071-1

摘要： A scanning mode is the key technology in a laser metal deposition shaping (LMDS) fabrication process. On the basis of the analysis of existing scanning modes and their influences on the fabrication efficiency and the quality of parts, some disadvantages of them are pointed out. A new kind of subarea-parallel scanning mode for LMDS based on a subdividing profiled outline into monotonous polygon subareas is presented. First, based on the principle of point visibility, inner loops are eliminated, and simple polygons are subdivided into monotonous polygons with the minimal zones. Second, the parallel scanning paths of all monotonous polygon subareas are finished, which diminishes the length of the scanning line. The practical application shows that the scanning mode can enhance the fabrication efficiency and quality.

关键词： scanning parallel scanning practical application fabrication efficiency LMDS

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Global sources, emissions, transport and deposition of dust and sand and their effects on the climate

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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Characterization of particle deposition during crossflow filtration as influenced by permeate flux and

Hongzhan Di, Gregory J. O. Martin, Dave E. Dunstan

《化学科学与工程前沿（英文）》 2021年第15卷第3期页码 552-561 doi: 10.1007/s11705-020-1962-5

摘要： Particle deposition during crossflow filtration is significantly influenced by the operating conditions, in particular the permeate flux and crossflow velocity. However, there is a lack of detailed knowledge about how deposit layer structures and distributions depend on operating parameters. This study uses a microfluidic visualisation filtration system to examine the influence of operating conditions on the deposition process during crossflow ultrafiltration from a microscopic perspective. Increasing the permeate flux caused an increasing amount of deposition and a thicker deposit layer. Higher crossflow velocities reduced the extent of deposition. The degree of deposition varied over a range of operating conditions due to the altered hydrodynamic forces exerted on the particles, which can be examined by the deposition probability according to an existing model. Building on this, an empirical correlation between the deposition probability and volume of deposition as function of filtration time was developed, which gave good agreement with experimental results. The effect of solution conditions was also involved in this correlation as a interaction energies. This could be useful for predicting the dynamic deposition process during crossflow filtration over a range of operating and solution conditions.

关键词： particle deposition crossflow filtration microfluidics confocal microscopy

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用于材料探索与优化的高通量多羽流脉冲激光沉积 Article

Samuel S. Mao,Xiaojun Zhang

《工程（英文）》 2015年第1卷第3期页码 367-371 doi: 10.15302/J-ENG-2015065

摘要：

笔者设计并实现了高通量多羽流脉冲激光沉积 (MPPLD) 系统，而且与传统的高通量薄膜材料合成技术进行了比较。目前大多数组合式脉冲激光沉积 (PLD) 系统为了使沉积的薄膜厚度均匀而采用掩膜法多层薄膜沉积和沉积后退火的工艺，MPPLD则同时利用了多个PLD羽流的方向性和沉积速率的空间变化，在一个衬底上直接沉积不同成分的化合物以形成薄膜材料库。这个新系统更适合以高通量的手段制备多组分化合物薄膜材料。

关键词：脉冲激光沉积高通量

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标题作者时间类型操作

Scaling up of cluster beam deposition technology for catalysis application

期刊论文

Effect of carbon deposition over carbonaceous catalysts on CH

Yongfa ZHANG, Meng ZHANG, Guojie ZHANG, Huirong ZHANG

期刊论文

Influence mechanism of dynamic and static liquid bridge forces on particle deposition behaviors in solar

Xueqing LIU, Xiaodong ZHAO, Luyi LU, Jianlan LI

期刊论文

ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION ON URBAN FORESTS: AN OVERVIEW