水-盐酸两步法分离瓜环混合物

根据各元瓜环在水和盐酸两种溶剂中溶解度的不同,提出了一种通过水-盐酸两步分离混合瓜环的方法.探讨了溶剂用量、盐酸浓度等因素对分离效果的影响,确定了最佳的分离工艺条件,使CB[5],CB[6],CB[7]和CB[8]的分离产率分别达到78.9%,92.0%,88.0%和75.0%.分离得到的瓜环单体经核磁共振检测,纯度在95%以上,其中CB[5]的纯度达到98%.研究结果表明,本工艺是一种简单有效的分离混合瓜环的方法.

盐酸-硝酸水浴消解氢化物发生原子荧光光谱法测定钨矿石和钼矿石中的砷

应用氢化物发生原子荧光光谱法（HG-AFS）测定钨矿石和钼矿石中的砷,钨钼铜铅锌铋镉等共存元素在不经分离或不加掩蔽剂的情况下对砷测定产生严重干扰。本文采用盐酸-硝酸（5∶1）水浴加热分解样品,加入柠檬酸-碘化钾掩蔽共存元素,促进这些元素还原成低价离子或者直接形成沉淀以消除干扰;再加入硫脲-抗坏血酸还原后直接用HG-AFS测定砷量。砷的检出限为0.014μg/g,测定范围为0.2~2000μg/g,方法精密度为0.7%~7.5%,加标回收率为92.3%~102.9%。本方法与国家标准方法相比,检出限低,检测范围宽,干扰元素不经分离可直接测定砷的含量。

Characteristic and optimization of ferrite-rich sulfoaluminate-based composite cement suitable for cold region tunnels

To develop suitable grouting materials for water conveyance tunnels in cold regions,firstly,this study investigated the performance evolution of ferrite-rich sulfoaluminate-based composite cement(FSAC grouting material)at 20 and 3℃.The results show that low temperature only delays the strength development of FSAC grouting material within the first 3 d.Then,the effect of four typical early strength synergists on the early properties of FSAC grouting material was evaluated to optimize the early(£1 d)strength at 3℃.The most effective synergist,Ca(HCOO)_(2),which enhances the low-temperature early strength without compromising fluidity was selected based on strength and fluidity tests.Its micro-mechanism was analyzed by XRD,TG,and SEM methods.The results reveal that the most suitable dosage range is 0.3 wt%−0.5 wt%.Proper addition of Ca(HCOO)_(2)changed the crystal morphology of the hydration products,decreased the pore size and formed more compact hydration products by interlocking and overlapping.However,excessive addition of Ca(HCOO)_(2)inhibited the hydration reaction,resulting in a simple and loose structure of the hydration products.The research results have reference value for controlling surrounding rock deformation and preventing water and mud inrushes during the excavation in cold region tunnels.

Construction and Properties of the Me_(10)Q[5]/2,7-diaminofluorenedihydrochloride Supramolecular Hydrogel

Compared to traditional polymer hydrogels,supramolecular hydrogels exhibits superior reversibility and stimulus response due to the instantaneous and reversible nature of non-covalent bonds.In this paper,we utilized the host-guest exclusion interaction between Decamethylcucurbit[5]uril(Me_(10)Q[5])and the 2,7-diaminofluorenedihydrochloride(DAF·HCl)to construct a Q[n]-based hydrogel system.The composition,structure,and properties of the hydrogel were compre-hensively characterized using rheometer,nuclear magnetic resonance,scanning electron microscope.This cost-effective and straightforward hydrogel synthesis method paves the way for the scalable production of practical and commercially viable Q[n]-based hydrogels.

The Relationship of Sulfate-methane Interface,the Methane Flux and the Underlying Gas Hydrate

The sulfate-methane interface is an important biogeochemical identification interface for the areas with high methane flux and containing gas hydrate. Above the sulfate-methane interface, the sulfate concentration in the sediment is consumed progressively for the decomposition of the organic matter and anaerobic methane oxidation. Below the sulfate-methane interface, the methane concentration increases continuously with the depth. Based on the variation characters of the sulfate and methane concentration around the sulfate-methane interface, it is feasible to estimate the intensity of the methane flux, and thereafter to infer the possible occurrence of gas hydrate. The geochemical data of the pore water taken from the northern slope of the South China Sea show the sulfate-methane interface is relatively shallow, which indicates that this area has the high methane flux. It is considered that the high methane flux is most probably caused by the occurrence of underlying gas hydrate in the northern slope of the South China Sea.

不同氮水平下盐胁迫对大麦幼苗中某些氮化物积累的影响(简报)

在土培条件下,提高氮素供应水平和NaCl处理浓度后大麦幼苗地上部和根中的全氮,蛋白质氮和游离氨基酸总量增加;蛋白质氮占全氮的比值亦因NaCl处理浓度的增大而提高。在盐胁迫下,游离脯氨酸占氨基酸总量的百分比明显增加,而谷氨酸所占比例则下降。

Extraction of molybdenum and nickel from roasted Ni-Mo ore by hydrochloric acid leaching, sulphation roasting and water leaching

To extract molybdenum and nickel from the roasted Ni-Mo ore, a process of hydrochloric acid leaching, sulphation roasting and water leaching was investigated. The results showed that this process could get a high leaching rate of Mo and Ni. Under the optimum conditions of hydrochloric acid leaching （roasted Ni-Mo ore leached with 0.219 mL/g hydrochloric acid addition at 65 ℃ for 30 min with a L/S ratio of 3 mL/g）, sulphation roasting （51.9% sulfiaric acid addition, roasting temperature 240 ℃ for 1 h）, followed by leaching with the first stage hydrochloric acid leaching solution at 95 ℃ for 2 h, the leaching rates of Mo and Ni reached 95.8% and 91.3%, respectively.

Beneficial effect of sulphate-bicarbonate-calcium water on gallstone risk and weight control

AIM： To investigate the effect of drinking sulphate-bi- carbonate-calcium thermal water （TW） on risk factors for atherosclerosis and cholesterol gallstone disease.

Effect of Water Vapor Absorption on Measurements of Atmospheric Nitrate Radical by LP-DOAS

During the measurement of atmospheric nitrate radical by long-path differential optical absorption spectroscopy, water vapor strong absorption could affect the measurement of nitrate radical and detection limits of system. Under the tropospheric condition, the optical density of water vapor absorption is non-linearly dependent on column density. An effective method was developed to eliminate the effect of water vapor absorption. Reference spectra of water vapor based on the daytime atmospheric absorption spectra, when fitted together with change of cross section with water vapor column densities, gave a more accurate fitting of water vapor absorptions, thus its effect on the measurements of nitrate radical could be restricted to a minimum and detection limits of system reached 3.6 ppt. The modified method was applied during an intensive field campaign in the Pearl River Delta, China. The NO3 concentration in polluted air masses varied from 3.6 ppt to 82.5 ppt with an average level of 23.6±1.8 ppt.

Properties of Belite-Rich Portland Cement and Concrete in China

Performances of belite-rich Portland cement, or HBC （high belite cement）, and the resultant concrete are introduced by comparing with that of alite based PC （Portland cement） and concrete. The comparison study of cement properties indicates that HBC possesses the properties of less water demand for normal consistency, better compatibility with water reducer, higher later age strength after 28-day under standard curing temperature of 20 ℃, unique strength gain under elevated curing temperatures of 38-70 ℃, lower hydration heat evolution and temperature rise, lower drying shrinkage and excellent resistance to sulphate attack. These results have been demonstrated by the comparison performance evaluation of concretes prepared by HBC and PC in terms of workability, physical mechanical properties and durability when making high performance high strength concrete and massive concrete.

Estimating Hydrogeological Parameters in Covered Carbonate Rocks Using a Discrete-State Compartment Model and Environmental Tritium

Nowadays, isotope environmental technique tends to be used as a reconnaissance tool , both qualitative and quantitative, to calculate the aquifer parameters particularly in carbonate rock aquifers. But, the heterogeneous flow is still problematic when Lumped parameter Models are usually used to calculate the residence times and hydraulic parameters. However, Discrete State Compartment Model can provide a powerful model to heterogeneous medium. One such study was carried on in Dazha valley, where the environmental tritium was used as a tracer for determining hydrogeological parameters based on a discrete state compartment model

Preparation and characterization of metakaolin-phosphate cement

We prepared cold-setting cement with metakaolin from kaolin dehydrated at 800 ℃ and phosphate, and studied the phase composition, microstructure and setting reaction mechanism of the cementing material by means of infrared spectroscopy, thermogravimetry, X-ray diffraction, and scanning electron microscopy. The metakaolin-phosphate cement is predominantly amorphous, where the phases responsible for chemical setting are mainly amorphous aluminophosphate hydrates. The reactivity of metakaolin depends on the particle size. Metakaolin particles of 1.75 μm in D50 have an acid dissolution index up to 18.45%, and the reaction with phosphate at room temperature to form metakaolin-phosphate cement takes only 6 h. The so obtained cement shows a compressive strength of 92.5 MPa after 7 d and keeps its amorphous phase at 1 000 ℃, demonstrating better bonding and mechanical properties and higher stability at a medium or high temperature.

A novel dicobalt-substituted tungstoantimonate polyoxometalate: Synthesis,characterization,and photocatalytic water oxidation properties

The one-pot assembly reaction of a trilacunary,lone-pair-containing[B-α-SbW9O33]9.precursor with Co2+ions in an aqueous medium led to the isolation of a novel{SbO3(H2O)3}bridging,dicobalt-substituted,sandwich-type tungstoantimonate{Co2Sb2(H2O)10[B-β-SbW9O33]2}^4–(1a).This compound was structurally characterized in the solid state by single-crystal X-ray diffraction,elemental analyses,thermogravimetric analysis,and IR spectroscopy.The most remarkable feature was that 1a comprises two trilacunary[B-β-SbW9O33]9^-fragments trapping a novel,centrally symmetric,rhomb-like{Co2Sb2}belt with 10 terminal water molecules.When combined with the photosensitizer[Ru(bpy)3]^2+and the sacrificial electron acceptor S2O82.,1a exhibited efficient catalytic activity for water oxidation with a remarkable turnover number(TON)of 193,initial turnover frequency(TOFinitial)of 5.3 s^-1,O2 yield of 30.8%,and quantum yield(ФQY)of 36.2%under light-driven conditions.

Change of Ecological Characteristics Due to Decrease of COD/SO_4^(2-) Ratio During Sulfate-reduction

In order to investigate the change of ecological characteristics due to the decrease of COD/SO_4^(2-) ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium snlfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO_4^(2-) ratio decreasing from 4.2 to 2.0 were investigated. The experimental results demonstrated that, with decreasing COD/SO_4^(2-) ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable -type microbial community with high COD/SO_4^(2-) ratio was converted into a sub -stable -type one with low COD/SO_4^(2-) ratio.

Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.

Transformation of Flue-Gas-Desulfurization Gypsum to α-Hemihydrated Gypsum in Salt Solution at Atmospheric Pressure

Direct phase transformation of flue gas desulfurization gypsum in hot salt solution at atmospheric pres-sure was investigated.The effects of temperature,salt species,salt concentration,solids content,pH and modifier were examined.The crystals obtained under different conditions and solubility of calcium sulfate in contact with solid gypsum were also determined.α-Calcium sulfate hemihydrate crystals of stubby columnar shape and regular pentahedral sides were obtained under the following conditions：salt concentration 20%-30%,operation tempera-ture 95-100 °C,solids mass content in the slurry 10%-30% and neutral pH.Thermodynamic analysis revealed that phase transformation of calcium sulfate dihydrate to α-calcium sulfate hemihydrate occurs because of the difference in solubilities between the two solid gypsum phases in this system.

Study on coagulation property of metal-polysilicate coagulants in low turbidity water treatment

In order to remove the low turbidity present in surface water, a novel metal-polysilicate coagulant was used to treat the raw water taken from Tanjiang River in Guangdong Province. This study on the effects of Al/Fe molar ratio on the performance of a complex compound formed by polysilicic acid, aluminium and ferric salt (PAFS) showed that PAFS with Al/Fe ratio of 10:3 seemed to have the best coagulation performance in removing turbidity and color. Experimental results showed that under the conditions of polymerization time of 15 d, sedimentation time of 12 min, and pH of 6?8, PAFS with Al/Fe molar ratio of 10:3 had the best coagulation efficiency and lowest residual Al concentration. The turbid- ity decreased from 23.8 NTU to 3.23 NTU and the residual Al concentration was only 0.165 mg/L in the product water. It could be speculated that colloidal impurities and particulate Al were removed by adsorption bridging and electrical neu- tralization of long chain inorganic polymer coagulants.

Effects of Salinity Fluctuation Frequency on the Osmolarity,Na^+-K^+-ATPase Activity and HSP70 Expression in Juvenile Chinese Shrimp,Fenneropenaeus chinensis

Experiments were conducted to examine the effects of salinity fluctuation frequency on the osmolarity, Na^＋-K^＋-ATPase activity and HSP70 of Chinese shrimp Fenneropenaeus chinensis ruth initial wet body weight of 1.460g±0.091 g. The salinity in the control group （DO） was 28 throughout the experiment, whereas treatments D2, D4, D6 and D8 were subjected to different salinity fluctuation frequencies of 2, 4, 6 and 8d, respectively. The salinity in treatments D2, D4, D6 and D8 was kept at 28 for 2, 4, 6 and 8d, respectively, decreased abruptly to salinity 24, lasted for another 2 d, and then was raised to its initial value 28. This was a complete salinity fluctuation cycle that afterwards repeated itself. After 32 days, the osmolarity in treatments D2, D4, D6 and D8 was significantly lower than that in treatment DO （P〈0.05）. There were significant differences in both muscle and eyestalks HSP70 expression among groups. The HSP70 expressions in muscle and eyestalks in group D4 were 61.4% and 57.0% higher, respectively, than that in the control group DO （P〈0.05）. There were, however, no significant differences in gill or hepatopancreas Na^＋-K^＋-ATPase activity between the treatments and the control.

Hydrothermal Synthesis and Mechanism for Formation of Novel Micro-Micro-Mesoporous Aluminosilicate Composite Zeolite

A novel micro-micro-mesoporous aluminosilicate LS-BFMZ （low-silica-BEA（beta）-faujasite （Y）-mesoporous） composite zeolite with the MCM-41 type structure was synthesized through a novel process involving the self- assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of the beta zeolite. The physical properties of the LS-BFMZ composite zeolite were characterized using various techniques, including XRD, IR and SEM techniques. Meanwhile, a possible mechanism regarding the formation of the LS-BFMZ composite zeolite was proposed.

Nitrification-denitrification via nitrite pathway in biological treatment of hypersaline wastewater

Pilot-scale studies on biological treatment of hypersaline wastewater at low temperature were conducted and results showed that seawater salinity had a strong negative effect on notrouomonas and nitrobaeter growth, but much more on the nitrobaeter. The nitrification action was mainly accomplished by nitrosomonas. Bench-scale experiments using two SBRs were carried out for further investigation under different conditions of salinities, ammonia loadings and temperatures. Biological nitrogen removal via nitrite pathway from wastewater containing 30 percent seawater was achieved, but the ammonia removal efficiency was strongly related not only to the influent ammonia loading at different salinities but also to temperatures. When the ratio of seawater to wastewater was 30 percent, and the ammonia loading was below the critical value of 0. 15 kgNH4 ^＋ -N/（ kgMLSS · d） , the ammonia removal efficiency via nitrite pathway was above 90 %. The critical level of ammonia loading was 0. 15, 0. 08 and 0. 03 kgNH4 ^＋ -N/（ kgMLSS · d） respectively at different temperatures of 30℃, 25℃ and 20℃ when the influent ammonia concentration was 60 - 80 mg/L and pH was 7.5 - 8.0.