Observation of small-scale processes over shelf break in the East China Sea

The turbulent dissipation along with temperature and salinity was measured on board R/V Dong Fang Hong 2 over the shelf break of the East China Sea from March 7 to 9, 2004. Applying the Turner angle, it is found that the ＇diffusive＇ double diffusion, salt-fingering, and stable stratification coexist in the upper water column of about 50 m. Below that depth, there exists weak salt-fingering. The turbulent dissipation rates are enhanced along the ray paths of M2 internal tides emanating from the shelf break with values ranging from 1.0×10^-9 W·kg^-1 to 1.2×10^-6 W·kg^-1. The corresponding diapycnal mixing rates are from 1×10^-6 m^2· s^-1 to 1×10^-2 m^2· s^-1. The spatially averaged mixing rate over the whole observation section is 2.3×10^-3 m^2· s^-1, which is much larger than 1×10^-5 m^2·s^-1 of the background diapycnal mixing rate in the open ocean.     

Spatial concentration, congener profiles and inhalation risk assessment of PCDD/Fs and PCBs in the atmosphere of Tianjin, China

Polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were monitored in a seasonal passive sampling scheme during June 2008 and January 2009 to investigate the spatial concentration, congener profiles and evaluate the potential inhalation risk in different functional areas in Tianjin, China. The spatial air concentrations and I-TEQs ranged 1.08×10²–8.19×10³ fg m^?3 (average 2.63×10³ fg m^?3) and 4.08–325 fg I-TEQ m^?3 (average 91.4 fg I-TEQ m^?3) respectively for PCDD/Fs. The concentration and I-TEQs of PCBs were 3.08×10⁴–3.01×10⁵ fg m^?3 (average 1.39×10⁵ fg m^?3) and 1.72–49.6 fg I-TEQ m^?3 (average 18.5 fg I-TEQ m^?3). It is obvious that PCB concentrations were several hundred times higher than the PCDD/Fs. However, the ambient air PCDD/Fs contributed a major part to the total toxicity equivalents, varying from 72.7% to 89.0% (average 81.8%). The atmospheric PCDD/F levels were observed to be higher in winter for most of sampling sites in the downtown. Besides, inhalation risk assessment showed that local residents might suffer more risk near the point sources than those in living area, industrial zones and background area in Tianjin City. However, the total daily dioxin intake was approximately several to hundreds of times lower than the WHO criteria, showing relatively low exposure risks from the impact of industry point sources in Tianjin City.     

Thermoluminescence of Al2O3 crystals grown by temperature gradient techniques

Color center concentrations of the Al2O3 crystal grown by temperature gradient techniques were calculated from Gaussian fits to absorption spectra. The concentrations for F- and F + -centers at 204, 232, and 255 nm were determined to be 1.361×10 17 , 0.098×10 17 , and 0.325×10 17cm-3 , respectively. Studies have shown that the thermoluminescence (TL) glow curve exhibits a prominent 450 K peak that matches well the first-order fitting curve. The thermal activation energy E and frequency factor s of the trap were determined to be 0.94456±0.00545 eV and 5.8703×10 11 s-1 . With this theoretical analysis, a simple one-trap/one-center TL model is presented to provide a theoretical explanation of the TL process.     

Effects of the rare earth ions on bone resorbing function of rabbit mature osteoclasts<Emphasis Type="Italic">in vitro</Emphasis>

The osteoclast plays initiating and vanguard roles in the course of bone remodeling. The resorption and formation of bone is the basic clues of bone remodeling, which results from the mutual dependent functions of osteoclasts and osteoblasts. When the osteoclasts are activated, the bone resorption function is increased. The excess bone resorption leads to osteoporosis, characterized by formation of many hollows, lacunae and tunnels on the bone surface or in depth[1,2]. The differentiation, pro…     

Magnetic granulometry of recent sediments from the Huguang Maar and its implication for provenience

To understand the origin and its climatic implications of the Huguang Maar sediments, we conducted laser grain size analysis and rock mangtic measurement for the recent deposits from the Huguang Maar and for the volcanic rocks of the caldera for comparison. The grain size distributions are dominated by clayey silts for both the bulk sediments and magnetic separates. Acquisition of isothermal remanent magnetization (IRM) and thermal demagnetization of IRM suggest (titano) magnetite as the dominating magnetic mineral in the sediments; high coercivity minerals are not detected. Therefore, the ratio of the susceptibility of anhysteretic remanent magnetization (k _ARM) to the weak field magnetic susceptibility (k), k _ARM/k can be used to estimate the grain size of magnetite. The sediments and volcanic rocks yield values of 13.7 and 11.8 for the k _ARM/_k, respectively, corresponding to grain size values of ～0.03 µm and ～0.05 µm. The magnetic granulometry of lake sediments is distinctive from one of the Chinese loess, in which published data suggest a value of 6.0 for k _ARM/_k, and grain size of ～0.1 µm, but is akin to the nearby volcanic rocks. Although a Loess Plateau source of the lake sediments cannot be fully ruled out, the catchment is most probably the main source. We explain the slightly finer magnetite grain size in sediments than in the volcanic rocks as being disintegrated of particles during erosion and transportation. We conclude that there is no evidence for aeolian input of the Loess Plateau dusts into the Huguang Maar, and the relationship between magnetic parameters of the lake sediments and winter monsoon intensity is probably more complicated than previously thought.     

江苏省农产品水足迹与虚拟水流动及其环境影响

在量化江苏省农业生产水足迹、消费水足迹及虚拟水流动基础上,分析与水资源消耗相关的环境影响,以及对人类健康、生态质量及资源的影响。江苏省农业生产水足迹、消费水足迹、虚拟水流出及流入分别为110.97亿m³、37.98亿m³、74.99亿m³和2.00亿m³,前三者主要受水稻和小麦的影响,后者主要受奶类、油料和牛肉的影响;其相关的人类健康影响分别为26.02万DALY、9.30万DALY、17.58万DALY和0.87万DALY,生态质量影响分别为19.02亿m²·a、6.69亿m²·a、12.85亿m²·a和0.53亿m²·a,资源影响分别为0、1.47亿MJ、0和1.47亿MJ。分析结果表明:节水技术应用及节水品种培育有助于减小生产水足迹,消费模式转变有助于降低消费水足迹,贸易结构调整及贸易地区选择有利于改变现有虚拟水流动模式;水足迹及虚拟水流动量值是影响江苏省水资源消费相关环境影响的重要因素,减少水资源消耗,降低农业用水比重,改变产品调入区域等均有助于减小环境影响。     

Effect of exogenous lanthanum on accumulation of cadmium and its chemical form in Tomatoes

In the condition that soil is polluted by Cd(20 mg·L-1),two varieties of tomato(Lycopersicon esculintum Mill.)(plant high Cd-enriched variety(Yufen109)and plant low Cd-enriched variety(4641))treated with LaCl3 of different concentration(0,10 and 20mg·L-1)were determined for their effect on plant dry weight,anti-oxidase activity(CAT,SOD and POD),tomato fruit Cd chemical form and Cd accumulation.The results show that 10 mg?L-1LaCl3 can increase dry weight of plant at various positions and can reduce the concentration of Cd of different forms.Spraying with LaCl3(10,20 mg·L-1)can reduce Cd concentration in leaves,stems,roots and fruits of tomato plants with lowering rates of 13.7%-31.9%,9.5%-30.6%,10.8%-44.5%and 19.4%-37.0%,respectively.Suitable amount of lanthanum(10 mg·L-1 LaCl3)can increase yield of tomatoes,reduce Cd accumulation in the fruit.In the two tomato varieties,Lanthanum and Cadmium react interactively,expressing to be coexisting of both synergism and antagonistic.     

Studies on reduced extent method for inhibited thermokinetics of enzyme-catalyzed reaction

The thermokinetic reduced extent equations of reversible inhibitions for Michaiels-Menten enzymatic reaction were deduced, and then the criteria for distinguishing inhibition type was given and the methods for calculating kinetic parameters,K _M,K _i andv _m were suggested. This theory was applied to inverstigate the inhibited thermokinetics of laccase-catalyzed oxidation ofo-dihydroxybenzene bym-dihydroxybenzene. The experimental results show the inhibition belongs to reversible competitive type,K _M=6.224×10⁻³ mol·L⁻¹,K _i=2.363×10⁻² mol·L⁻¹. Xiong Ya: born Sep. 1961, Ph. D. graduate student. Curent research interest is in biothermochemistry research Supported by the National Natural Science Foundation of China     

An explanation to the high efficiency ofm-THPC (temporfin) used in photodynamic therapy

Meso-tetrahydroxylphenyl chlorin (m-THPC) is one of the most efficient prospective sensitizers used in photodynamic therapy (PDT). ESR spectroscopy, fluorescence quenching experiments and cyclic voltammogram measurement were used to study its redox properties. The results showed that the ability of m-THPC generating superoxide radical anions was very strong, and the rate constant of m-THPC fluorescence quenching by oxygen k_q (O₂)=1.46×10¹⁰ mol^-1·s^-1. The values of fluorescence quen- ching rate constant of m-THPC by some other electron acceptors, such as methyl viologen (MV²⁺) and anthraquinone (An), were also measured. And they were k_q (MV²⁺)=5.51×10⁹ mol^-1·s^-1, k_q (An)=7.81×10⁹ mol^-1·s^-1. The oxidation potential of m-THPC was examined to be +0.62 V (vs. NHE) in acetonitrile. All these suggested that m-THPC should be a much stronger electron donor than photofrin, the currently used in clinical photodrug, and may react easily through electron transfer with biological matter to yield various radicals. So it seemed reasonable that the type Ⅰ reaction may play an important role in the high activity of m-THPC-PDT.     

The bulk transfer coefficients and surface fluxes on the western Tibetan Plateau

On the gradient observational data of the atmospheric surface layer from September 1997 to December 1998 collected by two sets of Automatic Weather Station (AWS) installed in Gaize and Shiquanhe on the western Tibetan Plateau, mean surface roughness lengths at the two stations above are determined to be 2.7 and 2.9 cm, respectively. The bulk transfer coefficients each day are computed by the profile-flux method, means of the bulk transfer coefficient for momentum (i.e. drag coefficient) in 1998 are 4.83×10⁻³ and 4.75×10³ at the two stations. The surface fluxes of momentum, sensible heat and latent heat each day are further estimated by the bulk formulas, annual mean of these fluxes is 3.4×10⁻² and 1.8×10²N/m², 73.1 and 67.2 W/m², 15.4 and 2.9 W/m², respectively. The diurnal and seasonal variations are obtained by a composite method and the relationships among the heat transfers between land and atmosphere, plateau monsoon and plateau rain season are also discussed.     

High-energy ion treatments of amorphous As40Se60 thin films for optical applic ations

The treatment of 100 MeV Ag swift-heavy ion(SHI) irradiation with five different fluences(3 1010, 1 1011, 3 1011, 1 1012, and3 1012ions/cm2) was used to design optical and structural properties of amorphous(a-) As40Se60 chalcogenide thin films. Swanepoel method was applied on transmission measurements to determine the changes in optical bandgap, Tauc parameter and linear optical parameters, i.e., linear optical absorption, extinction coefficient and linear refractive index. Dispersion of the material was determined by Wemple–DiDomenico relation.Changes in nonlinear optical parameters of third-order optical susceptibility and nonlinear refractive index were determined using semi-empirical relations. Changes in surface morphology of the films were investigated using SEM observation, which indicated that fluence 3 1012ions/cm2was upper threshold limit for these films for ion treatment. It is observed that optical bandgap reduces from 1.76 eV to 1.64 eV, and nonlinear refractive index increases from 1.31 10 10[esu] to 1.74 10 10[esu]. Linear refractive index initially increases from 2.80 to 3.52(for fluence3 1010ions/cm2) and then keeps decreasing. The observed changes in optical properties upon irradiation were explained in terms of structural rearrangements by Raman measurement. The study was compiled with the previous literature to propose SHI as an effective optical engineering technique to achieve desired changes according to the need of optical/photonic applications.     

Fluorescence Determination of Artemisinin Using Hemoglobin as Catalyst and Pyronine B as Substrate

0 IntroductionMaalnadria siusb atr ompajicosr .he aAltrthe pmrisoibnlienmi (n qtihneghtraoopsiucs,QHS,Fig.1) is a sesquiterpene endoperoxide isola-ted fromArtemisia annuaL., an ancient Chineseherbal medicine usedfor treatment of fever and ma-laria.Studies of the structure and activity relation-ship have shownthat endoperoxide groupis essentialfor anti malarial activity of QHS and absence of thismoiety lead to completely loss in activity of thedrug. Many techniques have been developed to de…     

The electronic structures, magnetism and metastable states of DNA

Molecular devices are the ultimate goal in the miniaturization of the electronic technology. Based on the unique properties of DNA (e.g. self-assembly and molecular recognition), people have made great efforts to develop molecular devices in the last few …     

α-(2,5-二甲基-3,4-二乙酰基吡咯基)萘的合成和晶体结构

 在酸性介质中,3,4-二乙酰基-2,5-己二酮与萘胺作用,合成得到了α-(2,5-二甲基-3,4-二乙酰基吡咯基)萘,用IR,1H-NMR,MS,HRMS对其进行了表征,并用X射线衍射测定了α-(2,5-二甲基-3,4-二乙酰基吡咯基)萘的晶体结构.该晶体属三斜晶系,P1空间群,晶体学数据为:a是0.8045(1)nm,b是1.0018(1)nm,c是2.0757(2)nm,α是80.09(1)°,β是82.66(1)°,γ是83.81(1)°,V是1.6281(3)nm³,Z是4,M_r是305.36,D_c是1.246×10³kg/m³,μ(M_oK_α)是0.080mm^-1,F(000)是648,在I>2σ(I)的独立可观测衍射点为3669个,最终偏差因子R是0.0406,W_R是0.0962.     

三聚磷酸二氢铝二水物的合成和表征

用磷酸和氢氧化铝为原料制备三聚磷酸二氢铝二水物。用X-衍射、红外光谱、化学分析、DTA-TG结合X-ray分析,证明产品的化学结构式为AlH2P3O10*2H2O。其晶体结构属正交晶系,空间群为PZ1/bZ1/aZ/m,D92h,晶胞参数a=15.919×10-8 cm,b=8.884×10-8cm,c=9.936×10-8 cm,单位晶胞体积V=1 405×10-8 cm3,Z=6。防绣性能测试表明其防锈能力与红丹颜料相当。毒理学试验表明该颜料半致死量LD50=18.0 g/kg(小白鼠),属实际无毒级,符合食品容器及儿童玩具涂装的要求。     

Low-temperature magnetic properties of horse spleen ferritin

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental magnetism. In this study, we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin (HoSF) to understand the relationships between the magnetic behavior of HoSF and temperature, applied field and grain-size distributions. The R-value from the Wohlfarth-Cisowski test for the investigated sample at 5 K was 0.46, indicating very weak magnetostatic interactions among the nanoparticles of HoSF. The nanoparticles of HoSF show superparamagnetic properties at room temperature, while below the blocking temperature of T _b ≈ 12 K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or spin-canting. The thermal relaxation process of HoSF follows the Néel-Arrhenius expression. From low-temperature AC susceptibility data, we calculated the effective magnetic anisotropy energy E _a=(5.52±0.16)×10^?21 J; the effective magnetic anisotropy energy constant K _eff =(4.65±0.14)×10⁴ J/m³ and the pre-exponential frequency factor f ₀=(4.52±2.93)×10¹¹ Hz. These values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.     

Biogeochemical sequestration of carbon within phytoliths of wetland plants: A case study of Xixi wetland, China

As an important long-term terrestrial carbon sequestration mechanism, biogeochemical sequestration of carbon within phytoliths may play a significant role in the global carbon cycle and climate change. The aim of this study is to explore the potential of carbon bio-sequestration within phytoliths produced by wetland plants. The results show that the occluded carbon content of phytoliths in wetland plants ranges from 0.49% to 3.97%, with a CV (coefficient of variation) value of 810%. The data also indicate that the phytolith-occluded carbon (PhytOC) content of biomass for wetland plants depends not only on the phytolith content of biomass, but also the efficiency of carbon occlusion within phytoliths during plant growth in herb-dominated fens. The fluxes of carbon bio-sequestration within phytoliths of herb-dominated fen plants range from 0.003 to 0.077 t CO2 equivalents t-e-CO2ha-1a-1 . In China, 0.04×106 to 1.05×106t CO2 equivalents per year may be sequestrated in phytoliths of herbaceous-dominated fen plants. Globally, taking a fen area of 1.48×108 ha and the largest phytolith carbon biosequestration flux (0.077 t-e-CO 2 ha-1a-1 ) for herb-dominated fen plants, about 1.14×10 7 t CO 2 equivalents per year would have been sequestrated in phytoliths of fen plants. If other wetland plants have similar PhytOC production flux with herb-dominated fen plants (0.077 t-e-CO2ha-1a-1 ), about 4.39×10 7 t-e-CO2a-1 may be sequestrated in the phytoliths of world wetland plants. The data indicate that the management of wetland ecosystems (e.g. selection of plant species) to maximize the production of PhytOC have the potential to bio-sequestrate considerable quantities of atmospheric CO2 .     

Positronium annihilation in oxygen and nitrogen mixture

Formed in silica aerogels, positronium annihilation in oxygen and nitrogen mixture is studied by a simple and convenient method. The results show that ortho-positronium (o-Ps) lifetime is significantly shortened when some oxygen is introduced into nitrogen gas and that the o-Ps collisional quenching rate for an oxygen molecule is (28.0±0.4) μs^?1·amagat^?1 (1 amagat = 2.69×10²⁵ m^?3). It is found that the o-Ps annihilation rate in oxygen of 1atm at room temperature is (25.5±0.5) μs^?1 and that the effective number of electrons per oxygen molecule available for 2γ annihilation of positron in the o-Ps is (34.6±0.4).     

Thermodynamic functions and growth constants of web-like ZnO nanostructures

Web-like ZnO nanostructures have been successfully synthesized using the potassium nitrate route at various temperatures to simplify conventional preparation methods. The structures and morphologies of the as-prepared products were characterized by X-ray powder diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The results showed that the reaction temperature was an important parameter, and that there was a feedback effect between nano-structure and growth parameters, combined with in situ micro-calorimetry, the reaction rate constants of the three systems were found to have been: 2.43×10-6, 2.70×10-8 and 3.12×10-7s-1 respectively. Furthermore, based on the relationship governing the potential differences between nanoand bulk ZnO, thermodynamic functions of nano-ZnO such as standard molar entropy (Sm,ZnO(nano)), standard molar Gibbs free energy of formation (△rGm,ZnO(nano)), and standard molar enthalpy of formation (△rHm,ZnO(nano)) have been calculated by the electrochemical method.     

Electrochemical corrosion behavior of the cobalt modified aluminide coating in 3.5 wt% NaCl solutions

In this paper, we achieved the Co modified aluminide coating on nickel base superalloys by pack cementation process. The corrosion currents(i_(corr)) of coated and uncoated substrate after 1 h of immersion tested by potentiodynamic polarization in 3.5 wt% NaCl solutions are 9.73 b × 10~(-7) A/cm~2 and 1.31 × 10~(-6) A/cm~2, respectively. With the immersion time extension, the icorrof the coating decreases and the values of |Z| by EIS increase, indicating that the electrochemical reaction rate of the coating becomes slower. The coating presents good corrosion resistance due to the Al_2O_3 formed on the surface.