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| 1 | Vertical structures of PM_(10) and PM_(2.5) and their dynamical character in low atmosphere in Beijing urban areas显示文摘The vertical structures and their dynamical character of PM2.5 and PM10 over Beijing urban areas are revealed using the 1 min mean continuous mass concentration data of PM2.5 and PM10 at 8, 100, and 320 m heights of the meteorological observation tower of 325 m at Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP CAS tower hereafter) on 10―26 August, 2003, as well as the daily mean mass concentration data of PM2.5 and PM10 and the continuous data of CO and NO2 at 8, 100 (low layer), 200 (middle layer), and 320 m (high layer) heights, in combination with the same period meteorological field observation data of the meteorological tower. The vertical distributions of aerosols observed on IAP CAS tower in Beijing can be roughly divided into two patterns: gradually and rapidly decreasing patterns, I.e. The vertical distribution of aerosols in calm weather or on pollution day belongs to the gradually decreasing pattern, while one on clean day or weak cold air day belongs to the rapidly decreasing pattern. The vertical distributive characters of aerosols were closely related with the dynamical/thermal structure and turbulence character of the atmosphere boundary layer. On the clean day, the low layer PM2.5 and PM10 concentrations were close to those at 8 m height, while the concentrations rapidly decreased at the high layer, and their values were only one half of those at 8 m, especially, the concentration of PM2.5 dropped even more. On the clean day, there existed stronger turbulence below 150 m, aerosols were well mixed, but blocked by the more stronger inversion layer aloft, and meanwhile, at various heights, especially in the high layer, the horizontal wind speed was larger, resulting in the rapid decrease of aerosol concentration, I.e. Resulting in the obvious vertical difference of aerosol concentrations between the low and high layers. On the pollution day, the concentrations of PM2.5 and PM10 at the low, middle, and high layers dropped successively by, on average, about 10% for each layer in comparison with those at 8 m height. On pollution days, in company with the low wind speed, there existed two shallow inversion layers in the boundary layer, but aerosols might be, to some extent, mixed below the inversion layer, therefore, on the pollution day the concentrations of PM2.5 and PM10 dropped with height slowly; and the observational results also show that the concentrations at 320 m height were obviously high under SW and SE winds, but at other heights, the concentrations were not correlated with wind directions. The computational results of footprint analysis suggest that this was due to the fact that the 320 m height was impacted by the pollutants transfer of southerly flow from the southern peripheral heavier polluted areas, such as Baoding, and Shijiazhuang of Hebei Province, Tianjin, and Shandong Province, etc., while the low layer was only affected by Beijing's local pollution source. The computational results of power spectra and periods preliminarily reveal that under the condition of calm weather, the periods of PM10 concentration at various heights of the tower were on the order of minutes, while in cases of larger wind speed, the concentrations of PM2.5 and PM10 at 320 m height not only had the short periods of minute-order, but also the longer periods of hour order. Consistent with the conclusion previously drawn by Ding et al., that air pollutants at different heights and at different sites in Beijing had the character of 'in-phase' variation, was also observed for the diurnal variation and mean diurnal variation of PM2.5 and PM10 at various heights of the tower in this experiment, again confirming the 'in-phase' temporal/spatial distributive character of air pollutants in the urban canopy of Beijing. The gentle double-peak character of the mean diurnal variation of PM2.5 and PM10 was closely related with the evident/similar diurnal variation of turbulent momentum fluxes, sensible heat fluxes, and turbulent kinetic energy at various heights in the urban canopy. Besides, under the condition of calm weather, the concentration of PM2.5 and PM10 declined with height slowly, it was 90% of 8 m concentration at the low layer, a little lesser than 90% at the middle layer, and 80% at the high layer, respectively. Under the condition of weak cold air weather, the concentration remarkably dropped with height, it was 70% of 8 m concentration at the low layer, and 20%―30% at the middle and high layers, especially the concentration of PM2.5 was even lower. | CHAN Chuenyu LI Yoksheung WONG Kamhang | 2005 | Science China Earth Sciences2005，48，z2： | 18 |
| 2 | Respective and interactive effects of doubled CO2 and O3 concentration on membrane lipid peroxidation and antioxidative ability of soybean显示文摘Effects of doubled CO2 and O3 concentration on Soybean were studied in open-top chambers (OTC). Under doubled CO2 concentration, grain yield and biomass increased, the SOD activity, vitamin C (Vc) and carotenoid (Car) content also increased; Superoxide (O2-.) generating rate decreased, relative conductivity and malondialdehyde (MDA) content significantly declined.But under doubled O3 concentration, the SOD activity, Vc and Car contents declined, resulting in imbalance of activated-oxygen production, enhanced O2-. generating rate and accelerated process of lipid peroxidation and increase in MDA content and ion leakage of leaves. The final result was decreased grain yield and plant biomass. Interactive effects of doubled CO2 and O3 concentrations on soybean were mostly counteractive. However, the beneficial effects of concentration-doubled CO2 are more than compensate the negative effects imposed by doubled O3, and the latter in its turn partly counteracted the positive effects of the former. | ZHAO Tianhong, SHI Yi, HUANG Guohong, WANG Yan & SUN Bei Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China Shenyang Agricultural University, Shenyang 110161, China | 2005 | Science China(Life Sciences)2005，48，z1： | 14 |
| 3 | Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter显示文摘Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from China's Mainland to the north, and the polluted air mass led to poor air quality. | NIU Yuwen1,2,HE Lingyan1,2,HU Min2,ZHANG Jing2 & ZHAO Yunliang2 1. Shenzhen Graduate School of Peking University,Shenzhen 518055,China 2. State Joint Key Laboratory of Environmental Simulation and Pollution Control,College of Environmental Sciences,Peking University,Beijing 100871,China | 2006 | Science China Chemistry2006，49，5： | 12 |
| 4 | Vertical dynamic and thermodynamic characteristics of urban lower boundary layer and its relationship with aerosol concentration over Beijing显示文摘By utilizing observational data from a 325 m tower of the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences (CAS) on March 19-29, 2001 and August 11-25, 2003, a comprehensive study was conducted on the vertical dynamical and thermodynamic characteristics of the urban lower boundary layer (ULBL) and its relationship with aerosol concentration over Beijing. Firstly, a comparative analysis was made on the gradient data (wind, temperature and humidity), ultrasonic data (atmospheric turbulences) and air-quality observations at different tower heights (47, 120 and 280 m). Secondly, a diagnosis was made to reveal the major features of normalized variances of velocity and temperature, turbulence kinetic energy as well as their relationship with aerosol concentrations. Furthermore, the characteristics of the ULBL vertical structure and the TSP concentration/distribution variations during a sand/dust weather process were also analyzed. The outcome of the study showed that under unstable stratification, the normalized variances of velocity (σu/u*, σv/u*, σw/u*) and temperature (σT/T*) at 47 and 120 m heights fit the Monin-Obukhov similarity (MOS) framework and the fitting formulas were given out accordingly. According to the stratification parameter (z′/L), the stable ULBL could be divided into 2 zones. With z′/L<0.1, it was a weakly stable zone and MOS framework was applicable. The other was a highly stable zone with z′/L>0.1 and the normalized velocity variances tended to increase along with higher stability, but it remained constant for normalized temperature variances. At daytime, the near-surface layer includes two heights of 47 and 120 m, while 280 m has been above it. The ULBL analysis in conjunction with a sand/dust weather process in Beijing in March 2001 indicated that the maximum concentration of Total Suspended Particulates (TSP) at 320 m reached 913.3 μg/m3 and the particles were transported from the upper to lower ULBL, which was apparently related to the development process of a low-level jet and its concomitant strong sinking motion. | ZHOU Mingyu, YAO Wenqing, XU Xiangde & YU Haiqing State Key Laboratory on Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China National Marine Environment Forecasting Center, Beijing 100081, China National Meteorological Center, Beijing 100081, China | 2005 | Science China Earth Sciences2005，48，z2： | 11 |
| 5 | Study on patterns and chemical features of NO effect on marine phytoplankton growth显示文摘This article discusses the patterns of NO effect on marine phytoplankton growth from chemical perspective.The experimental results of four algae,which are Platymonas hal-golandica var.tsingtaoensis,Platymonas subcordiformis,Skeletonema costatum and Nitzschia closterium farma minutissima,are as follows:(i) In f/2 medium or f/50 medium,the growth of these four algae was obviously promoted or inhibited when nitric oxide of different concentrations was added once or twice each day during the cultivation;(ii) The NO effects on the growth of marine phytoplankton are in normal distribution.Different phytoplankton has different optimum NO concentration,which is consistent with the influence of NO on the growth of high plants;(iii) The effect of NO on Platymonas halgolandica var.tsingtaoensi,which is a food alga,is different from that on the red tide algae Skeletonema costatum and Nitzschia closterium farma minutis-sima.The authors put forward a new opinion that every alga has its own NO threshold concen-tration.All the above results may provide new clues to understand the formation of red tide. | ZHANG Zhengbin LIN Cai LIU Chunying XING Lei WU Zhenzhen SUN Feng | 2005 | Science China Chemistry2005，48，4： | 9 |
| 6 | Record Low Sea-Ice Concentration in the Central Arctic during Summer 2010显示文摘The Arctic sea-ice extent has shown a declining trend over the past 30 years. Ice coverage reached historic minima in 2007 and again in 2012. This trend has recently been assessed to be unique over at least the last 1450 years. In the summer of 2010, a very low sea-ice concentration(SIC) appeared at high Arctic latitudes—even lower than that of surrounding pack ice at lower latitudes. This striking low ice concentration—referred to here as a record low ice concentration in the central Arctic(CARLIC)—is unique in our analysis period of 2003–15, and has not been previously reported in the literature. The CARLIC was not the result of ice melt, because sea ice was still quite thick based on in-situ ice thickness measurements.Instead, divergent ice drift appears to have been responsible for the CARLIC. A high correlation between SIC and wind stress curl suggests that the sea ice drift during the summer of 2010 responded strongly to the regional wind forcing. The drift trajectories of ice buoys exhibited a transpolar drift in the Atlantic sector and an eastward drift in the Pacific sector,which appeared to benefit the CARLIC in 2010. Under these conditions, more solar energy can penetrate into the open water,increasing melt through increased heat flux to the ocean. We speculate that this divergence of sea ice could occur more often in the coming decades, and impact on hemispheric SIC and feed back to the climate. | JinpingZHAO David BARBER Shugang ZHANG Qinghua YANG Xiaoyu WANG Hongjie XIE | 2018 | Advances in Atmospheric Sciences2018，35，1： | 7 |
| 7 | Characteristics of Suspended Sediment Concentrations over the Areas Adjacent to Changjiang River Estuary, the Summer of 1998显示文摘A major flood event occurred within the drainage basin of the Changjiang River in June-August, 1998. Survey over the East China Sea adjacent to the Changjiang River estuary shows that during the flood the turbid water (with a suspended sediment concentration of higher than 10 mg l-1) °°′reached 123E. Stratification of the concentration layers was present near 12215E, with the concentration in the bottom layer being 3 times that in the upper layer, in response to sediment °°settling processes. The concentration is the lowest in the area of 126E^127E, representing a characteristic of the Kuroshio water. Although there was some expansion of the turbid water extension compared with the winter situations with low freshwater discharges, the suspended sediment does not appear to disperse towards the northeast from the Changjiang River. Further, several secondary high suspended sediment concentration centers were present on the East China Sea continental shelf, which may result from resuspension of the seabed sediment or advection of seawater containing suspended matter. In order to understand the processes of fine-grained sediment transport/deposition and their impact on the flux of chemical constituents on the shelf, further studies on the hydrodynamics, temperature, salinity and nutrient characteristics are required. | 高抒 程鹏 汪亚平 曹奇源 | 2000 | Marine Science Bulletin2000，2，1： | 4 |
| 8 | Water exchange between the subpolar and subtropical North Pacific in an OGCM显示文摘The water exchange between the subpolar and subtropical gyres of the North Pacific is demonstrated by the simulation of chlorofluorocarbon (CFC) using an ocean general circulation model. The simulated CFC concentration in the North Pacific is in good agreement with observations. The water exchange is clearly illustrated by the tongues of CFC concentration. The subpolar waters with high CFC are transported southward into the eastern subtropical gyre, whereas the subtropical waters with low CFC are transported northward into the western subpolar gyre. The simulated exchange transport along 42°N in the layer of σθ< 26.8 indicates that the northward mass transport is about 15 Sv (1 Sv = 106 m3·s-1) west of 165°E, and about 5 Sv between 175°W and 150°W. The southward mass transport is about 5 Sv between 165°E and 175°W, and about 2 Sv east of 150°W. | Van Scoy Kim | 2004 | Science China Earth Sciences2004，47，1： | 3 |
| 9 | Characteristics and quantitative of negative ion in salt aqueous solution by Raman spectroscopy at-170℃显示文摘The results from Raman spectroscopy analysis of salt aqueous solutions at ?170℃ demonstrate that for those clearly sharp iron peaks whose Raman wavenumber is close to each other such as NO 3? and CO 32?, their original shape could be restorable by the stripping technique, and that ice’s sharp characteristic peak (3090―3109 cm?1) is steady, while the spectrum band of the complex compound (nCl?―[H+―OH?]n) chlorine ion combined chemically with water molecule is 3401―3413 cm?1. On the other hand, the research shows that the higher the negative iron concen-tration, the stronger its Raman characteristic peak intensity and the smaller the ice’s. Based on the number of data and theoretical work, the strong correlation of the molar concentration of negative ion with the Si /SH 2 O band area ratio is built up. Moreover, the developed Raman method is successfully used in the component analysis of the field fluid inclusions from Silurian sandstone in Tarim basin. | ZHANG Nai ZHANG Dajiang ZHANG Shuichang ZHANG Dijia | 2006 | Science China Earth Sciences2006，49，2： | 2 |
| 10 | APPLICATION OF THE ANNEXATION PRINCIPLE TO THE STUDY OF THERMODYNAMIC PROPERTIES OF TERNARY METALLIC MELTS Cd-Pb-Sb显示文摘Based on the phase diagrams, measured activities and the annezation principle, the calculating models of mass action concentrations for Cd-Pb, Pb-Sb and Cd-Sb binary as well as Cd-Pb-Sb ternary metallic melts have been formulated. The results of calculation both agree with practice and obey the mass action law. This in turn testifies that the models formulated can reflect the structural reality of corresponding melts and the annexation principle is applicable to these melts. | J.Zhang Metallurgical Engineering School, University of Science and Technology Beijing, Beijing 100083, China | 2001 | Acta Metallurgica Sinica(English Letters)2001，14，5： | 2 |
| 11 | EXPERIMENTAL STUDY ON EQUILIBRIUM CONCENTRATION OF DEBRIS FLOWS显示文摘The paper presents experimental study of debris flows. The equilibrium concentration of solid particle in the flow is a function of the energy slope, density of solid particle and kinetic friction angle of particles. The kinetic friction angle is a function of internal friction angle, the concentration of solid particles and the maximum possible concentration. To determine the function between the kinetic friction angle and internal friction angle is the aim of this research. Flume experiments of equilibrium concentration about particles in water and slurry were conducted. The large density slurry made the coarse particles be able to move in small slope. The function between the kinetic friction angle and internal friction angle was found from these experiments. The coarse particles and fine particles are well mixed. D50 demarcation line was suggested in this paper to demarcate the coarse particle and fine particle of debris flows. The equilibrium concentration of debris flows was calculated by using D50 demarcation for the debris flows in field. The equilibrium concentration of debris flows calculated by the function between the kinetic friction angle and internal friction angle was close to the equilibrium concentration data of debris flows in field. | Bin YU1 1Assoc Prof., Chengdu Institute of Mountain Disaster and Enviromnent, CAS, 610041, P.O. Box 417, P. R. China.E-mail: drbinyu@sc.homeway.com.cn | 2001 | International Journal of Sediment Research2001，16，2： | 1 |
| 12 | Variations of near-surface atmospheric CO_(2)and H_(2)O concentrations during summer on Muztagata显示文摘Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO2 and H2O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO2 concentrations (of about 5 μmol·mol?1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO2 concentrations occur between 02:30―05:30 AM (local time) and the minimum levels occur between 12:00―15:30 PM. The atmospheric CO2 concentrations in the summer of 2002 were around 5 μmol·mol?1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H2O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO2 and H2O con-centrations. We therefore suggest that the near-surface atmospheric CO2 concentration is affected not only by photosynthesis and respiration, but also by the air H2O content in the glaciated region around Muztagata. | XU Baiqing1,2, YAO Tandong1,2, LU Anxin2, GUO Xuejun, LIU Xianqin2 & LI Zhen2 1. Laboratory of Environment and Process on Tibetan Plateau, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China 2. Key Laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research Institute and Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences, China Meteorological Administration, Lanzhou 730000, China | 2006 | Science China Earth Sciences2006，49，1： | 1 |
| 13 | Measurement of cytoplasmic Ca^(2+) concentration in Saccharomyces cerevisiae induced by air cold plasma显示文摘In this study, a novel approach to measure the absolute cytoplasmic Ca^(2+) concentration([Ca^(2+) ]cyt) using the Ca^(2+) indicator fluo-3 AM was established. The parameters associated with the probe fluo-3 AM were optimized to accurately determine fluorescence intensity from the Ca^(2+) -bound probe. Using three optimized parameters(final concentration of 6 m M probe,incubation time of 135 min, loading probe before plasma treatment), the maximum fluorescence intensity(F_(max)?=?527.8 a.u.) and the minimum fluorescence intensity(F_(min)?=?63.8 a.u.) were obtained in a saturated Ca^(2+) solution or a solution of lacking Ca^(2+) . Correspondingly, the maximum [Ca^(2+) ]cytinduced by cold plasma was 1232.5 n M. Therefore, the Ca^(2+) indicator fluo-3 AM was successfully applied to measure the absolute [Ca^(2+) ]cytin Saccharomyces cerevisiae stimulated by cold plasma at atmospheric air pressure. | 董晓宇 | 2018 | Plasma Science and Technology2018，20，4： | 0 |
| 14 | Dependence of reaction rate of pyrite oxidation on temperature,pH and oxidant concentration显示文摘The kinetic sstudy of pyrite oxidation was performed in a series of experiments by a mixed flow reactor. The release rates of Fe(II) are in the order of 3.22×10?9-5.51×10?7 mol·m?2·s?1 at temperature (T ) 25 to 44℃, initial pH (pH )1.4 to 2.7, and initial Fe(III) concen-tration ([Fe(III)]i) 10?5 to 5×10?3 mol·kg?1. The release rate of Fe(II) increased with increasing T or/and pH or/and [Fe(III)]i in the above range. The rate law and activation energy of pyrite oxida-tion were derived by statistical analyses of RFe(II) vs. [Fe(III)]i, RFe(II) vs. pH and RFe(II) vs. T, and are given as (1) Rate law: RFe(II) 4.65 64.54 103 8.310.600.4510 e[Fe(III)][H ]? ×Ti= +; (2) activation energy: 64.54 ± 8.07 kJ·mol?1. The expression can be applied to more cases (e.g., quantifying the pollutant re-leased from sulfide-rich mining waste and assessing reliable performance of underground re-pository sites where pyrite acts as an engineered barrier material). Using the rate law derived from this study, the magnitude of the pollutants transferred to secondary phases, soil and water from oxidized pyrite during Jiguanshan mine waste weathering was preliminarily estimated. The estimated magnitude is very high, suggesting that the pile has possibly posed significant impact on the water quality in this region. | LU Long1, WANG Rucheng2, XUE Jiyue2, CHEN Fanrong1 & CHEN Jun2 1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Department of Earth Sciences, Nanjing University, Nanjing 210093, China | 2005 | Science China Earth Sciences2005，48，10： | 0 |
| 15 | Assessing the effects of different dielectrics onenvironmentally conscious powder-mixed EDM of difficult-to-machine material (WC-Co)显示文摘Electrical discharge machining (EDM) is awell-known nontraditional manufacturing process tomachine the difficult-to-machine (DTM) materials whichhave unique hardness properties. Researchers havesuccessfully performed hybridization to improve thisprocess by incorporating powders into the EDM processknown as powder-mixed EDM process. This processdrastically improves process efficiency by increasingmaterial removal rate, micro-hardness, as well as reducingthe tool wear rate and surface roughness. EDM also hassome input parameters, including pulse-on time, dielectriclevels and its type, current setting, flushing pressure, and soon, which have a significant effect on EDM performance.However, despite their positive influence, investigating theeffects of these parameters on environmental conditions isnecessary. Most studies demonstrate the use of kerosene oilas dielectric fluid. Nevertheless, in this work, the authorshighlight the findings with respect to three differentdielectric fluids, including kerosene oil, EDM oil, anddistilled water using one-variable-at-a-time approach formachining as well as environmental aspects. The hazardand operability analysis is employed to identify theinherent safety factors associated with powder-mixedEDM of WC-Co. | Jagdeep SINGH Rajiv Kumar SHARMA | 2016 | Frontiers of Mechanical Engineering2016，11，4： | 0 |
| 16 | Initial results for urban metal distributions in house dusts of Syracuse, New York, USA显示文摘A program of house dust sample collection and analysis has begun in Syracuse,New York, USA, in order to determine the feasibility of a geography-based exposure assessment for urban metals. The sampling program, and the protocols it employs, is described for two different types of wipe media, Ghost Wipes and Whatman Filters. Preliminary results show that strong spatial patterns of floor dust loading (mg dust per square foot) can be observed for data aggregated at a spatial scale of about 1600 m (~2.5 kin2). Floor dust metal concentrations were similar to those found in other urban environments, with some regional variation. The median floor dust Pb concentration was ~108 mg· kg-1 for this initial data set of ~264 sampled residential locations, and varied from 50 to 1100 mg Pb · kg-1. | D. L. Johnson J. Hager A. Hunt D. A. Griffith S. Blount S. Ellsworth J. Hintz R. Lucci A. Mittiga D. Prokhorova L. Tidd M. M. Millones M. Vincent | 2005 | Science China(Life Sciences)2005，48，z1： | 0 |
| 17 | SCATTERING FUNCTION OF POLYMER BLENDS显示文摘For a system of flexible polymer molecules, the concepts of two concentrations, namely the segmental and the molecular concentrations, have been proposed in this paper. The former is equivalent to the volume fraction. The latter can be defined as the number of the gravity centers of macromolecules in a unit volume. The two concentrations should be correlated with each other by the conformational function of the polymer chain and should be discussed in different thermodynamic equations. On the basis of these concepts it has been proved that the Flory-Huggins entropy of mixing should be the result of the mixing 'ideal gases of the gravity centers of macromolecules'. The general correlation between the free energy of mixing and the scattering function (structural factor) of polymer blends has been studied based on the general fluctuation theory. When the Flory-Huggins free energy of mixing is adopted, the de Gennes scattering function of a polymer blend can be derived. | 赵得禄 | 2004 | Chinese Journal of Polymer Science2004，22，6： | 0 |
| 18 | TEMPORAL VARIATION OF SUSPENDED SEDIMENT CONCENTRATION FOR WAVES OVER RIPPLES显示文摘Variations of suspended sediment concentration over ripples in regular waves were described using an existing numerical model system. Nielsen's (1992) empirical formula for sediment entrainment rate from the bed surface was used with an additional scale factor in the model system. The model system was applied to two typical laboratory experimental conditions selected for description of the variation of suspended sediment concentration.The flow model results are described with regard to wave orbital velocities, vorticity, shear stress, and pressure. The suspended sediment model results show that the suspended sediment concentrations have four or more peak values in a wave period depending on flow and sediment conditions. The model results suggest that the suspended sediment concentrations have four peaks when the ratio of the orbital excursion length amplitude and ripple length is close to 1, and more than four peaks when the ratio of the orbital excursion length amplitude over the ripple length is larger than 1. The computed temporal variations of the suspended sediment concentration for Bosman's (1982) case were compared with measurements, and agreements between them were reasonably good. The computed profiles of the wave-period average suspended sediment concentrations also agreed well with measurements near the beds for the two experimental conditions. | Hyoseob KIM | 2003 | International Journal of Sediment Research2003，18，3： | 0 |
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