A fast method to prepare water samples for<Superscript>15</Superscript>N analysis

Automatic element analyser is often used to prepare organic matters for¹⁵N analysis. It is seldom used to prepare water samples. Water samples are conventionally dealt with by Kjeldahl-Rittenberg technique. But it requires tedious and labor-intensive sample-preparation. A fast and reliable method is proposed in this paper to prepare water samples for¹⁵N analysis.     

A fast method to prepare water samples for ~(15)N analysis

Automatic element analyser is often used to prepare organic matters tor 15N analysis. It is seldom used to prepare water samples. Water samples are conventionally dealt with by Kjeldahl-Rittenberg technique. But it requires tedious and labor-intensive sample preparation. A fast and reliable method is proposed in this paper to prepare water samples for 15N analysis.     

Strontium isotopic geochemistry of the Changjiang estuarine waters: Implications for water-sediment interaction

The Sr concentrations and⁸⁷Sr/⁸⁶Sr ratios have been measured for the Changjiang estuarine waters with a main purpose to understand physical and chemical processes at the estuary. The result shows that the Changjiang River water has higher Sr concentration (150 ng/g) and lower⁸⁷Sr/⁸⁶Sr ratio (0.7105) when compared with the average values (0.7119 for⁸⁷Sr/⁸⁶Sr and 78ppb for Sr, respectively) of large world rivers. In the mixing process, no simple mixing of two end-members has been found according to the variations of Sr concentration and isotope ratios. There is an abrupt rise of Sr isotope ratios at the salinity about 1mg/g during river-sea water mixing at the estuary. This abrupt rise of Sr isotope ratios is mostly ascribed to the strong water-sediment interaction, because there exists the same rise of suspended particulate materials due to energetic resuspension of bottom sediments.

     

Strontium hydrogeochemistry of thermal groundwaters from Baikal and Xinzhou

This paper reports our work on the strontium hydrogeochemistry of thermal groundwaters in the Baikal Rift System (BRS) in Russia and Mongolia and the Xinzhou basin of the Shanxi Rift System (SRS) in northern China. Though similar in geological background, groundwaters from the BRS and the Xinzhou basin have different strontium isotope compositions. Both the strontium contents and the⁸⁷Sr/⁸⁶Sr ratios of thermal water samples from Xinzhou are higher than those of most samples from Baikal. The major reason is the difference in hostrock geochemistry. The hostrocks of the Xinzhou waters are Archaean metamorphic rocks, while those of the Baikal waters except the Kejielikov spring are Proterozoic or younger rocks. In the study areas, cold groundwaters usually show lower⁸⁷Sr/⁸⁶Sr ratio due to shorter water-rock interaction history and lower equilibration degree. Strontium hydrogeochemistry often provides important information about mixing processes. Ca/Sr ratio can be used as an important hydrogeochemical parameter. Case studies at Xinzhou show that thermal waters with lowest Ca/Sr ratios are most weakly affected by mixing with shallow groundwaters, as supported by our hydrochemical and sulfur isotope studies.

     

Trace element geochemistry and stable isotopic (δ13C and δ15N) records of the Paleocene coals,Salt Range,Punjab, Pakistan

The Paleocene coals of the Salt Range in the Punjab Province of Pakistan have great economic potential; however, their trace element and stable isotopic characteristics have not been studied in detail except for a few sporadic samples. In this study, a total of 59 coal samples of which 14 are obtained from open cast mines have been investigated for elemental composition and δ¹³C-δ¹⁵N isotopic signatures. Average contents of trace elements such as Co, Cr, Cu, Pb, Sr, Th, U, V, and Zn are 7.4, 41.7, 11.2, 12.5, 90.2, 4.0, 1.9, 128, and 31.1 mg/kg, respectively. These values, when compared with the World Coal Clarke values, were relatively higher in low-rank coals in comparison with Clarke values for brown coals. Likewise, As (20.4 mg/kg), Co (6.6 mg/kg), Cr (22.4 mg/kg), Cu (13.3 mg/kg), Pb (19.2 mg/kg), Sr (154.7 mg/kg), Th (2.5 mg/kg), V (47.8 mg/kg), and Zn (75.1 mg/kg) were significantly higher in the sub-bituminous to bituminous coals of the Salt Range. Mineralogical analysis, based on X-ray diffraction and energy dispersive X-ray spectroscopy, revealed that the studied samples contain illite, kaolinite calcite, gypsum, pyrite, and quartz. Elemental affinity with organic and inorganic phases of coals calculated by an indirect statistical approach indicated a positive association of ash content with Ag, Al, Co, Cr, Cs, Cu, Mn, P, Rb, Pb, Th, U, and V, suggesting the presence of inorganic components in studied coals. However, As, Fe, Sr, and Zn exhibit negative correlations that imply their association with the organic fraction. The δ¹³C and δ¹⁵N isotopic range and average ?24.94‰ to ?25.86‰ (?25.41‰) and ?2.77‰ to 3.22‰ (0.96‰), respectively, reflecting 3C type modern terrestrial vegetation were common in the palaeomires of studied coal seams. In addition, the trivial variations of 0.92‰ and 0.45‰ among ¹³C and ¹⁵N values can be attributed to water level fluctuations and plant assemblies.     

Chlorofluorocarbons and3H/3He in groundwater

Based on the CFC concentration, the fraction of young groundwater in a mixture with old groundwater can be defined if the age of the young component is known. The authors argued that the ratio of [³He_t]/[³H_t] in a young water is independent of its mixing with old waters. Hence, the³H−³He can be used to determine age of the young groundwater, though mixing with old groundwater may occur. CFC concentrations are susceptible to change by mixing of young and old water. The combination of CFCs and tritium/helium can provide confidential apparent age of the young groundwater and fraction of the young water in the mixture with old groundwater.

     

Origin,migration and mixing of oilfield brines: Stable isotopic evidence from Kuqa Foreland Basin

⁸⁷Sr/⁸⁶Sr, δD and δ¹⁸O together with chemistry of oilfield brines, were measured from Cambrian to Neogene strata in the Kuqa Foreland Basin, northwest China. The brines have⁸⁷Sr/⁸⁶Sr ratios ranging from 0.70944 to 0.71716, δD values from −33‰ to −67‰ and δ¹⁸O from −9.0‰ to 3.9‰. The most radiogenic⁸⁷Sr brines have relatively heavy δ¹⁸O in the Cambro-Ordovician carbonates, and are suggested to originate from crystalline basement. δD and δ¹⁸O systematics show that all the brines slope to Global Meteoric Water Line, and intersect at δD=−60‰ and δ¹⁸O=−8.8‰, close to that of present-day local meteoric water, suggesting that meteoric water has mixed with evaporated ancient meteoric water. More saline samples have the lowest δD and δ¹⁸O contents and molar Na/Cl ratios of more than 0.9, resulting from salt dissolution.

     

Isotope and hydrochemical study of seawater intrusion in Laizhou Bay,Shandong Province

Seawater intrusion on the northern coast of Laizhou City is featured by “three sources and three dimensions”. Modern sea water, ancient saline water and brine contained both in the Quaternary aquifer and in the bedrock fissures or crevice have been identified as possible sources. The ratio of γ SO₄/γ Cl is used to distinguish the origin of the different types of saline water. The correlation between³H and γ SO₄/γ Cl provides a quantitative differentiation on the origin of the saline water, which makes it possible to take counter protection measures in different areas affected by sea water intrusion.

     

Silicon isotope study of thermal springs in Jiaodong Region,Shandong Province

Based on δ³⁰Si and δ³²Si isotope geochemistry, the origin and evolutionary mechanism of thermal springs in Jiaodong region are studied. The mean value of δ³⁰Si of dissolved silica of thermal spring water in Jiaodong is 0.1‰. Thermal spring water ages using δ³²Si dating method range from 387a to 965a.

     

Liquid Phase Sintering （LPS） and Dielectric Constant of α-Silicon Nitride Ceramic

The spark plasma sintering （SPS） was applied to prepare α-Si3 N4 ceramics of different densities with magnesia, silicon dioxide, alumina as the sintering aids. The mechanism of liquid phase sintering （LPS） wus discussed and the factors influencing the density of the prepared samples were analyzed. The dielectric constant of sintered samples was tested. The experimental results show that the density can be controlled from 2.48 g/ cm^3 to 3.09 g/ cm^3 while the content of the sintering aids and the sintering temperature alter and the dielectric constant is closely dependent on the density of obtained samples.     

The source of replenishment of geothermal water around Xi'an

The meteoric origin of the geothermal water in Xi'an is evidenced by its H and O isotope composition. Based on the temperature dependence of isotopic composition, the temperature of meteoric water that replenishes the geothermal aquifers in Xi'an and its neighboring regions is calculated to be −13.28°C. The age of the geothermal water based on¹⁴C dating method is 10–30 kaBP, belonging to a secondary glacial period in Late Quaternary. The source of replenishment is considered to have mainly derived from glacial snow melt water from elevations higher than 2,000m (ASL) in Qinling Mountains.

     

普通小麦淀粉粒蛋白与籽粒硬度的关系

测定了38个小麦品种(系)的粗蛋白、粗淀粉及其组分、硬度和相对分子质量为15 000的水洗小麦淀粉粒蛋白的含量.统计分析结果表明:相对分子质量为15000的水洗小麦淀粉粒蛋白的含量与小麦硬度的相关性达极显著水平(R=0.923 9;N=38;P＜0.01),用该蛋白质的含量来预测小麦籽粒的硬度是可靠的.     

The biological promotion effect of a new biological promotive ceramsite

Tourmaline can promote the growth of microorganisms under the temperature less than 900 °C by experiment. However, this promotion effect will vanish at 900 °C as a result of denaturation. Through the XRD analysis the crystal form change can explain the vanishment of tourmaline’s biological promotion effect at high temperature. Therefore, tourmaline as a biological promoter was used to prepare a kind of biological promotive ceramsite with the surface area of 7.914 m²/g, pore volume of 0.1002 mg/L, superficial pH value of 7.8, Zeta potential of 25 mV, unit water absorption of 0.1365 g/g, biocompatibility of 0.023 A/g and SICE of 0.8456. The experimental results show that the biomass of biological promotive ceramsite is 3.58 times more than that of ordinary ceramsite, and the treatment effect of the biological promotive ceramsite is better than the ordinary ceramsite. These features of this new biological promotive ceramsite makes it a preferable biovector.     

Noble gas constraints on hydrocarbon accumulation and groundwater flow in the central area of Western Sichuan Basin

The noble gas concentrations and isotope ratios of seven natural gas samples from the central area of the Western Sichuan Basin were measured. The samples all have⁴⁰Ar/³⁶Ar ratios greater than the atmospheric values, and the³He/⁴He ratios (RIR _a ) are entirely consistent with the crustal radiogenic He values. The vertical variation of the calculated Ch₄/³⁶Ar ratios with depth clearly indicates that the CH₄ and³⁶Ar are intimately associated, indicating a common reservoir intermediate to the sampled reservoirs, where they are well mixed and stored together prior to entrapment into gas reservoirs. Meanwhile, the calculated CH₄/³⁶Ar ratios range between 8×10⁶ and 64×10⁶ very much greater than the CH₄/³⁶Ar values for pure water and 5 mol/L NaCl brine at low temperature and hydrostatic conditions, reflecting the presence of “excess” thermogenic CH₄ over that supplied by a CH₄-saturated groundwater at low temperature, and the excess CH₄ saturation and dissolution to be at depth greater than the sampled reservoirs. This conclusion is consistent with the δ¹³C(CH₄) and δ¹³C(C₂H₆) values. In addition, the⁴He/³⁶Ar ratio is correlated with depth, showing that the crustal radiogenic⁴He are well mixed with the atomosphere-derived³⁶Ar before introducing into gas reservoirs. The⁴He/³⁶Ar ratio vertical variation with depth can be attributed to the preferential transport of⁴He relative to³⁶Ar in fluxes from lower aquifers through water-filled pores into the upper one. The increasing⁴He/⁴⁰Ar ratios with decreasing depth, from 1.3 times to 29 times greater than the crustal production ratio, are also assumed to be the results of preferential transport⁴He relative to⁴⁰Ar from the production site into groundwater.

     

Preparation and antimicrobial ability of natural proous antibacterial materials

The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montmorillonite, respectively. Atomic absorption spectrum and X-ray diffraction analysis were carried out to investigate the effects of Ag⁺, Cu²⁺ and Zn²⁺ on antimicrobial abilities of natural porous minerals, and the effect of preparation method on ion exchange capacity of antimicrobial material, respectively. The results show that for the ion exchange capacity, clay mineral is higher than fibrous mineral, i. e. both zeolite and montmorillonite are higher; the antimicrobial ability of material with Ag⁺ is the best; the exchange capacities of materials with Cu²⁺ or Zn²⁺ are all higher, but the antimicrobial ability of Cu²⁺ is better than that of Zn²⁺. Foundation item: Project (40072020) supported by the National Natural Science Foundation of China; project (2001AA322070) supported by the National High Technology Research and Development Program of China     

Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1982–1998, soil moisture of all layers of soil-profile (0–1 m) in the Yellow River basin over the 17 years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1982 to 1988 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km³, the evapotranspiration of 3000–3500 km³, and the soil moisture transformation of −500–500 km³. Consequently, we analyzed the process of the water cycle in the Yellow River over the 17 years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

     

Two-dimensional PtRu Nanoclusters Carbon Based Electrocatalysts for Methanol Oxidation

A novel method to prepare an electrocatalyst with a new structure and high catalytic performance was reported. Two-dimensional (2D) PtRu nanoclusters have been successfully deposited on graphene oxide and carbon black supports. Compared with the commercial 3D E-TEK PtRu samples, the prepared 2D PtRu composites have larger electrochemically active surface area and display much higher catalytic activity toward methanol oxidation reaction. The preparation method mainly includes the following procedures: oxidation of carbon matrix, Pb²⁺ adsorption on the surface of carbon support, Pb²⁺ electrochemical reduction and galvanic displacement of Pb⁰ by Pt²⁺ and Ru³⁺. The method developed in this study could be viable for solving the problem of low electrocatalytic activity in direct methanol fuel cell anodes.     

Synthesis and adsorption properties of chitosan-crown ether resins

1　INTRODUCTIONTheeffectiveremovalorrecoveryoftoxicmetalsstillremainsamajortopicofpresentresearch .In creasedawarenessofthetoxicityofmetalshaspromptedtheimplementationofstrictregulationsforitsdisposal,causingtraditionaltreatmentprocessessuchaschemicalprecipitationtoundergochanges .Modernmetal removaltechnologiessuchasionex change ,reverseosmosis ,andmembranesystemsthatproduceeffluentsofbetterqualitymakeitpossibletorecoverandreusemetals[1,2 ] .Chitosan ,whichiseasilyderivedfromchitinbyN de…     

Preparation of ultrafine Ti(C, N)-based cermet using oxygen-rich powders

The availability using oxygen-rich powders to prepare ultrafine Ti(C,N)-based cermets was investigated. The deoxidation process, denitrification phenomenon and the effect of deoxidation on microstructure and mechanical properties of sintered samples were discussed, respectively. The results show that oxygen in the samples prepared even with high oxygen contained in starting powders can be almost completely cleaned away through suitable sintering process. The ultrafine oxygen-rich powders have a significant effect on microstructure, which promotes the formation of white core phase. A ultrafine Ti(C,N)-based cermet with mean particle size of 0.30 μm, uniform microstructure and excellent mechanical properties is successfully prepared. It is also found that there exists severe denitrification phenomenon in the preparation process of ultrafine Ti(C,N)-based cermet. Foundation item: Project(50323008) supported by the National Natural Science Foundation of China     

The effect of OH~- groups on the spectroscopic properties of erbium-doped tellurite glasses

With the rapid development of computer networks and other data-transmitting ser-vices, the demand for the increase of transmission capacity of the long distance trans-mission system is urgent. However, the conventional SiO2-based EDFA is limited for its small bandwidth. The Er3+-doped tellurite glass exhibits a larger stimulated-emission cross section and a broader emission bandwidth at the third communication window (1.55 μm) than that of silicate, phosphate, and germanate glasses, which c…