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Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

《环境科学与工程前沿（英文）》 2016年 第10卷 第4期 doi: 10.1007/s11783-016-0840-3

摘要： We modeled the impact of haze radiative effects on precipitation in North China. Shortwave heating induced by haze radiative effects would reduce heavy rainfalls. Convection was the key factor that whether precipitation was enhanced or suppressed. Precipitation was often suppressed where CAPE, RH and updraft velocities were high. The impact of haze radiative effect on summertime 24-h convective precipitation over North China was investigated using WRF model (version 3.3) through model sensitivity studies between scenarios with and without aerosol radiative effects. The haze radiative effect was represented by incorporating an idealized aerosol optical profile, with AOD values around 1, derived from the aircraft measurement into the WRF shortwave scheme. We found that the shortwave heating induced by aerosol radiative effects would significantly reduce heavy rainfalls, although its effect on the post-frontal localized thunderstorm precipitation was more diverse. To capture the key factors that determine whether precipitation is enhanced or suppressed, model grids with 24-h precipitation difference between the two scenarios exceeding certain threshold (>30 mm or<-30 mm) were separated into two sets. Analyses of key meteorological variables between the enhanced and suppressed regimes suggested that atmospheric convection was the most important factor that determined whether precipitation was enhanced or suppressed during summertime over North China. The convection was stronger over places with precipitation enhancement over 30 mm. Haze weakened the convection over places with precipitation suppression exceeding 30 mm and caused less water vapor to rise to a higher level and thus further suppressed precipitation. The suppression of precipitation was often accompanied with relatively high convective available potential energy (CAPE), relative humidity (RH) and updraft velocities.

关键词： Haze     Aerosol radiative effects     Convective precipitation    

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Augmentation of natural convective heat transfer by acoustic cavitation

Jun CAI, Xiulan HUAI, Shiqiang LIANG, Xunfeng LI,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 313-318 doi: 10.1007/s11708-009-0064-3

摘要： An experimental study was conducted to investigate the effects of acoustic cavitation on natural convective heat transfer from a horizontal circular tube. The experimental results indicated that heat transfer could be enhanced by acoustic cavitation and had the best effect when the head of the ultrasonic transducer was over the midpoint of the circular tube, and the distance between the head and the tube equaled 15 mm. The augmentation at low heat flux was better than that in the case of high heat flux. Based on experimental results, the correlation formula of Nusselt number for water was obtained.

关键词： heat transfer enhancement     augmentation     acoustic cavitation     acoustic streaming     convective heat transfer    

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锯材高频-对流联合加热干燥传热传质数学模型

贾潇然,赵景尧,蔡英春

《中国工程科学》 2014年 第16卷 第4期   页码 106-112

摘要：

本文以多孔介质传热传质理论为基础，结合高频-对流联合加热干燥过程中热质传递的机理及特 性，通过质量、动量、能量守恒方程等建立了高频-对流联合加热干燥过程中锯材热质传递数学模型并给出相应定解条件。模型中每个自变量及因变量都有独立的控制方程，利用控制容积法建立相应控制方程的差分格式，将耦合偏微分方程按步骤解耦，以便于利用Matlab 或FORTRAN等编程求解时，达到每个自变量均可以独立求解的目的。

关键词： 锯材     高频-对流干燥     数学模型     差分方程    

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Convective heat transfer in helical coils for constant-property and variable-property flows with high

Yufei MAO, Liejin GUO, Bofeng BAI, Ximin ZHANG

《能源前沿（英文）》 2010年 第4卷 第4期   页码 546-552 doi: 10.1007/s11708-010-0116-8

摘要： Forced convection heat transfer of single-phase water in helical coils was experimentally studied. The testing section was constructed from a stainless steel round tube with an inner diameter of 10 mm, coil diameter of 300 mm, and pitch of 50 mm. The experiments were conducted over a wide Reynolds number range of 40000 to 500000. Both constant-property flows at normal pressure and variable-property flows at supercritical pressure were investigated. The contribution of secondary flow in the helical coil to heat transfer was gradually suppressed with increasing Reynolds number. Hence, heat transfer coefficients of the helical tube were close to those of the straight tube under the same flow conditions when the Reynolds number is large enough. Based on the experimental data, heat transfer correlations for both incompressible flows and supercritical fluid flows through helical coils were proposed.

关键词： convective heat transfer     helical coils     high Reynolds number     supercritical pressure     variable property    

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Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the

Lin LUO, Zhongjing WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 756-768 doi: 10.1007/s11783-013-0563-7

摘要： The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.

关键词： precipitation intensity     Mann-Kendall rank statistic     spatial and temporal distribution     climatic change    

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Effect of Joule heating on electro-osmotic flow in a closed-end micro-channel with isothermal and convective

Liang ZHAO, Linhua LIU,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 381-388 doi: 10.1007/s11708-009-0057-2

摘要： The effect of Joule heating on the steady state electro-osmotic flow in a closed-end micro-channel is studied through numerical simulation with the finite volume method. The velocity field and the temperature field are described by a rigorous mathematical model. Thermophysical properties including viscosity and thermal conductivity are considered to be temperature-dependent. The simulations show that the presence of Joule heating causes an increase in temperature and a decrease in viscosity in the whole micro-channel, which, thereafter, induce a large velocity near the wall and an increase in fluid velocity at the central region in order to maintain a zero flow rate at the cross section of the micro-channel. The effect of Joule heating on the induced pressure gradient is also studied, which is very important for the application of the closed-end micro-channel as a micro-actuator. The results reveal that the induced pressure gradient, taking into consideration Joule heating, is significantly smaller than that without considering Joule heating when the wall temperature of the micro-channel is constant. The induced pressure gradient difference between considering Joule heating and without considering Joule heating is small under the convective boundary condition.

关键词： closed-end micro-channel     electrical double layer     electro-osmotic flow     induced pressure gradient     Joule heating    

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Evaluation of precipitation behavior of zirconium molybdate hydrate

Liang ZHANG, Masayuki TAKEUCHI, Tsutomu KOIZUMI, Izumi HIRASAWA

《化学科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 65-71 doi: 10.1007/s11705-013-1314-9

摘要： In the dissolution step of spent nuclear fuel, there is a world-concern problem that zirconium molybdate hydrate precipitates as a byproduct, and accumulates in some reprocessing equipments. In order to prevent this accumulation, we have developed a new method based on the controlled reaction crystallization of zirconium molybdate hydrate (ZMH) in the reprocessing solution, followed by solid liquid separation. In order to measure the particle size of ZMH, batch crystallization experiments were conducted by varying nitric acid concentration and operating temperature. In result, almost all particle sizes scatter around 1 μm on average, despite the higher concentration of nitric aid and operating temperature, and then small particles grow up as an aggregate sticking to the crystallizer. Moreover, polymorph and color changing were observed by varying the concentration of nitric acid and reaction time. These results suggest that crystal color and adhesiveness are closely related to the particle size of ZMH. And the control of nitric acid concentration and small particle growth would be the useful technique to prevent the ZMH sticking.

关键词： spent nuclear fuel     zirconium molybdate hydrate     cleaning method     accumulation    

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of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

《化学科学与工程前沿（英文）》 2020年 第14卷 第5期   页码 902-912 doi: 10.1007/s11705-019-1887-z

摘要： High-manganese containing vanadium wastewater (HMVW) is commonly produced during the vanadium extraction process from vanadium titano-magnetite. HMVW cannot be reused and discharged directly, and is harmful to the environment and affect product quality due to heavy metals in the wastewater. The wastewater is usually treated by lime neutralization, but valuable metals (especially V and Mn) cannot be recovered. In this study, an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process. In the solvent extraction process, 98.15% of vanadium was recovered, and the V O product, with a purity of 98.60%, was obtained under optimal conditions. For the precipitation process, 91.05% of manganese was recovered as MnCO which meets the III grade standard of HG/T 2836-2011. Thermodynamic simulation analysis indicated that MnCO was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated. The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V O and MnCO displayed a good degree of crystallinity. The treated wastewater can be returned for leaching, and resources (V and Mn) in the wastewater were utilized efficiently in an environmentally friendly way. Therefore, this study provides a novel method for the coextraction of V and Mn from HMVW.

关键词： high-manganese containing vanadium wastewater     solvent extraction     carbonate precipitation     vanadium titano-magnetite     valuable metal recovery    

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LiFePO/C cathode materials synthesized by co-precipitation and microwave heating

XU Yunlong, TAO Lili, MA Hongyan, HUANG Huaqing

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 422-427 doi: 10.1007/s11705-008-0082-4

摘要： LiFePO/C cathode materials were synthesized by a combination of co-precipitation and microwave heating using polyethylene glycol (PEG) as a carbon resource and the influence of microwave heating time on the structure and electrochemical performance of the materials was also discussed. The samples were characterized by X-ray diffraction (XRD), TEM, particle-size analysis and constant current charge-discharge experiment. The results show that the LiFePO/C heated for 9 min has a pure olive-type phase and excellent electrochemical performance. The initial discharge capacities of this sample are 154.3, 139.7, 123.9 mAh/g at the rates 0.1C, 0.2C, 1C at room temperature, respectively, and after 20 cycles remain 152.3, 134.3, 118.5 mAh/g, respectively.

关键词： polyethylene     electrochemical performance     combination     co-precipitation     diffraction    

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CLIMATE-CHANGE-INDUCED TEMPORAL VARIATION IN PRECIPITATION INCREASES NITROGEN LOSSES FROM INTENSIVE CROPPING

《农业科学与工程前沿（英文）》 2022年 第9卷 第3期   页码 457-464 doi: 10.15302/J-FASE-2022452

摘要：

● A simple model was used to evaluate how increasing temporal variability in precipitation influences crop yields and nitrogen losses.

关键词： crop yield     fertilizer timing     nitrogen loss     precipitation variability     toy model    

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热带测雨卫星搭载的仪器及其探测结果

傅云飞,刘奇,王雨,孙亮,李锐,马明,刘国胜

《中国工程科学》 2012年 第14卷 第10期   页码 43-50

摘要：

针对降水遥感和探测，简要介绍了卫星红外遥感方法和被动微波遥感方法，着重讨论了热带测雨卫星及其搭载仪器。随后介绍了热带测雨卫星多仪器探测结果的应用，并以夏季热对流降水为例，分析了其降水结构、云顶高度和雨顶高度及其与地表降水之间的关系，同时也阐述了如何利用热带测雨卫星和测雨雷达长时间资料，来分析亚洲地区降水的气候分布。最后对卫星主动微波探测降水的发展做了简要展望。

关键词： 热带测雨卫星     测雨雷达     微波成像仪     光谱     降水    

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EFFICIENT CONTAMINANT REMOVAL FROM LIQUID DIGESTATE OF PIG MANURE BY CHEMICAL PRECIPITATION AND CO MINERALIZATION

《农业科学与工程前沿（英文）》 2023年 第10卷 第3期   页码 479-491 doi: 10.15302/J-FASE-2023480

摘要：

● LFD was treated by fly ash-based chemical precipitation and CO2 mineralization.

关键词： anaerobic digestion     chemical oxygen demand     fly ash     ion removal     total phosphate    

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Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation

GAO Sujun, SUN Yaqin, XIU Zhilong

《化学科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 202-207 doi: 10.1007/s11705-007-0037-1

摘要： The separation of 1,3-propanediol from the glycerol-based fermentation broth of plays an important role during the microbial production of 1,3-propanediol. In this paper, the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investigated. The broth was first filtered by ultrafiltration, and 99% of cells, 89.4% of proteins and 69% of nucleic acids were removed. The obtained broth was further condensed by vac uum distillation, and then alcohol was added. The macromolecular impurities, such as nucleic acids, polysaccharides and proteins, were precipitated, and inorganic and organic salts were crystallized. The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1. As a result, proteins, nucleic acids and electric conductivity decreased by 97.4%, 89.7% and 95.8%, respectively, compared with the fermentative broth. The influences of pH and water content in condensed broth on alcohol precipitation and dilution crystallization were also investigated. The experimen tal results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth.
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Combined Fenton process and sulfide precipitation for removal of heavy metals from industrial wastewater

Huosheng Li, Hongguo Zhang, Jianyou Long, Ping Zhang, Yongheng Chen

《环境科学与工程前沿（英文）》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1130-7

摘要：

Addition of alkali to pH 10 is effective for precipitation of precipitable metals.

Fenton treatment is effective for substantial removal of Tl, Cd, Cu, Pb, and Zn.

Sulfide precipitation is a final step for removal of trace Tl, Cd, Cu, Pb, and Zn.

Bench and pilot studies demonstrated the effectiveness of this combined technique.

关键词： Thallium     Pilot     Fenton     Sulfide precipitation     Heavy metal     Industrial wastewater    

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Preparation of ultrafine α-AlO using precipitation-azeotropic distillation method

XIAO Jin, QIN Qi, ZHOU Feng, CHEN Yanbin, WAN Ye

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 226-231 doi: 10.1007/s11465-008-0029-y

摘要： Ammonium aluminum carbonate hydroxide (AACH) was prepared by a precipitation-azeotropic distillation method, which uses aluminum sulfate as the Al source and ammonium carbonate as the precipitant. Then, AACH was calcined into ultrafine ?-AlO powder. The factors that influence the dispersion property of ultrafine ?-AlO powder are discussed in this paper, such as the methods of adding materials, surfactant, and drying methods. The changes of the structure and property of ultrafine alumina in the thermal treatment process are also studied. The morphological structure and properties of AACH are characterized by DTA/TGA, SEM, XRD, and ICP measurements. The results show that ultrafine ?-AlO powder with a uniform particle size and well-distributed property can be synthesized only after aluminum sulfate atomizes into ammonium carbonate, proper amount of PEG1000 is added as the dispersant, and the product is treated by azeotropic distillation. The phase transformation of alumina during the calcination process can be described as amorphous AlO → ?-AlO → ?-AlO → ?-AlO. The crystal grain size and density of ultrafine alumina powder increase with the increase of the calcination temperature. After AACH has been calcined at 1200°C for 2 h, the ultrafine ?-AlO with uniform particle size, spherical shape, and more than 99.97% purity is obtained and its powder is well dispersed.

关键词： calcination temperature     spherical     AACH     carbonate hydroxide     ammonium carbonate    

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标题 作者 时间 类型 操作

Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

期刊论文

Augmentation of natural convective heat transfer by acoustic cavitation

Jun CAI, Xiulan HUAI, Shiqiang LIANG, Xunfeng LI,

期刊论文

锯材高频-对流联合加热干燥传热传质数学模型

贾潇然,赵景尧,蔡英春

期刊论文

Convective heat transfer in helical coils for constant-property and variable-property flows with high

Yufei MAO, Liejin GUO, Bofeng BAI, Ximin ZHANG

期刊论文

Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the

Lin LUO, Zhongjing WANG

期刊论文

Effect of Joule heating on electro-osmotic flow in a closed-end micro-channel with isothermal and convective

Liang ZHAO, Linhua LIU,

期刊论文

Evaluation of precipitation behavior of zirconium molybdate hydrate

Liang ZHANG, Masayuki TAKEUCHI, Tsutomu KOIZUMI, Izumi HIRASAWA

期刊论文

of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

期刊论文

LiFePO/C cathode materials synthesized by co-precipitation and microwave heating

XU Yunlong, TAO Lili, MA Hongyan, HUANG Huaqing

期刊论文

CLIMATE-CHANGE-INDUCED TEMPORAL VARIATION IN PRECIPITATION INCREASES NITROGEN LOSSES FROM INTENSIVE CROPPING

期刊论文

热带测雨卫星搭载的仪器及其探测结果

傅云飞,刘奇,王雨,孙亮,李锐,马明,刘国胜

期刊论文

EFFICIENT CONTAMINANT REMOVAL FROM LIQUID DIGESTATE OF PIG MANURE BY CHEMICAL PRECIPITATION AND CO MINERALIZATION

期刊论文

Separation of 1,3-propanediol from glycerol-based fermentations of Klebsiella pneumoniae by alcohol precipitation

GAO Sujun, SUN Yaqin, XIU Zhilong

期刊论文

Combined Fenton process and sulfide precipitation for removal of heavy metals from industrial wastewater

Huosheng Li, Hongguo Zhang, Jianyou Long, Ping Zhang, Yongheng Chen

期刊论文

Preparation of ultrafine α-AlO using precipitation-azeotropic distillation method

XIAO Jin, QIN Qi, ZHOU Feng, CHEN Yanbin, WAN Ye

期刊论文