长期施用猪粪对红壤酸度的改良效应

土壤酸化严重限制了我国南方红壤区土壤的农业利用。本研究应用江西鹰潭红壤生态实验站长期猪粪养分淋失试验,分析了不同施肥处理(对照处理:N 0 kg/hm2;低量有机肥:N150 kg/hm2;高量有机肥:N 600 kg/hm2;高量有机肥+石灰处理:有机肥N 600 kg/hm2+石灰3000 kg/(hm2.3a))长期施用对红壤酸度的改良效应。研究结果表明,9年高量有机肥施用中土壤pH值平均每年上升0.085个单位,而低量有机肥施用对土壤pH没有显著影响。有机肥长期施用增加了土壤盐基离子浓度,其中Ca、Mg增加幅度较大,使得长期施肥后土壤盐基以Ca为主,其次是Mg,而K、Na比例较低。长期有机肥施用有效降低了红壤旱地表层土壤交换性酸含量,尤其是对交换性铝含量的降低程度较大,且随施肥量的增加而增大,在施肥4年后可基本消除铝毒。高量施肥基础上的石灰添加进一步提高了土壤pH值,加快了土壤酸度改良。红壤旱地猪粪施用显著提高了玉米产量,达到酸度改良效果的最低猪粪用量为Ca 162 kg/hm2。在施肥初期添加一次石灰,将土壤pH值迅速提高,然后通过有机肥对pH的稳定作用保持和逐步提高土壤pH,可在最短时间、用最少投入消除土壤酸害。

邻氨基酚-邻苯二胺共聚物/PVC膜电极直接电位法测定高酸度

以邻氨基酚和邻苯二胺为聚合物前体,过硫酸铵为引发剂,在中性介质、100℃恒温条件下回流8h,化学聚合法合成了邻氨基酚-邻苯二胺共聚物,利用红外光谱表征了其结构.以该共聚物为高酸度敏感物、PVC为成膜材料制成对溶液酸度有特效响应的高酸度离子选择电极,采用直接电位法研究了该电极对不同浓度的HCl及H2SO4的电位响应,结果表明:对HCl在1.00~7.00mol/L、对H2SO4在1.00~10.00mol/L浓度范围内,电位与浓度分别呈线性关系,线性回归方程分别为E(mV)=21.3cHCl(mol/L)-88.4(r=0.999)和E(mV)=32.3cH2SO4(mol/L)-105(r=0.999).高酸度环境中常见离子不干扰酸度测定,将本方法应用于模拟稀土离子提取生产工艺参数的监控,平均值的相对误差为-1%(n=5),相对标准偏差为2.0%.该电极制备简单,使用方便,5~10s内快速响应,为研制高酸体系在线实时监测电化学传感器奠定了基础.

pH对养殖生境的影响及其调控

这里所说的生境指水生动物养殖池塘的环境,它的内容包括适宜养殖对象生存的pH范围以及其他生态因素。大家知道,水中能与强碱反应所有酸性物质构成的总和称酸度,它主要包括弱酸性物质（如碳酸H2CO3、碳酸钠Na2CO3、碳酸氢钠NaHCO3等）构成的分子酸度,以及由弱酸游离的氢离子（H+）构成的离子酸度,其中离子酸度又称pH。pH是养殖水体重要的水质指标,它直接或间接影响到水体的诸多化学和生物学过程。

Imaging Isocyanic Acid Photodissociation at 193 nm:the NH(a^1△)+CO(X^1∑^+)Channel

The photodissociation dynamics of isocyanic acid （HNCO） has been studied by the time- sliced velocity map ion imaging technique at 193 nm. The NH（a1△） products were measured via （2＋1） resonance enhanced multiphoton ionization. Images have been accumulated for the NH（a1△） rotational states in the ground and vibrational excited state （v=0 and 1）. The center-of-mass translational energy distribution derived from the NH（a1△） images implies that the CO vibrational distributions are inverted for most of the measured 1NH（v｜j） internal states. The anisotropic product angular distribution observed indicates a rapid dissociation process for the N-C bond cleavage. A bimodal rotational state distribution of CO（v） has been observed, this result implies that isocyanic acid dissociates in the S1 state in two different pathways.

Factors Affecting Diffusion of Ions in Soils

In this work the diffusion coefficients of Na+, K+, Ca2+, NO3- and Cl- ions were estimated in terms of measuring apparent direct current (DC) conductivities of latosol, red soil and yellow-brown earth containing, respectively, NaNO3, KCI, and CaCl2 of different concentrations (0.005, 0.05, 0.10, and 0.15 mol / L) in the case of moisture contents ranging from wet to water saturation. The results showed that when bulk density, moisture content, and electrolyte concentration were constant, the diffusion coefficients of cations were in the order Na+> K+> Ca2+ except for Na+ and K+ in latosol, while the order for anions was NO3- > Cl-. The diffusion coefficients (Di) of cations and anions were linearly proportional to volumetric moisture content (θ) as electrolyte concentration and bulk density were unchanged. When moisture content and bulk density were constant, the diffusion coefficients of cations decreased, to varying extents, with the increase of electrolyte concentration, and the decrement in different soils followed the order yellow-brown earth > red soil > latosol, but the decrement order of different cations was Na+> K+ > Ca2+.

Equilibrium concentration of lithium ion in sodium aluminate solution

Excess lithium in alumina is significantly bad for aluminum reduction.In this study,the concentration variation of lithium ion in sodium aluminate solution with addition of synthetic lithium aluminate was investigated.Elevating temperature,increasing caustic soda concentration,reducing alumina concentration or raising molar ratioαk improved equilibrium concentration of lithium ion in sodium aluminate solution.Agitation speed had a minimal effect on lithium ion concentration.Over 0.65 g/L lithium ion equilibrium concentration was observed in digestion process,whereas 35 mg/L lithium ion concentration remained in solution after precipitation time of 9 h.Moreover,equilibrium concentration decreased sharply from digestion of boehmite or diaspore to seed precipitation,about 95%lithium was precipitated into red mud(bauxite residue)and aluminum hydroxide.This study provides a valuable perspective in removal or extraction of lithium from sodium aluminate solution in alumina refineries.

Influence of high concentration Zn^(2+) on floatability of sphalerite in acidic system

The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectron spectroscopy.The results indicated that Zn^(2+) was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn^(2+) concentration of 4×10^(-2) mol/L.The zeta potential increased and the contact angle decreased from 84.80°to 36.48°,strongly inhibiting the floatability of sphalerite.When S^(2−) or Cu^(2+) activator was used alone,sphalerite was not activated after Zn^(2+) was adsorbed,and its contact angle did not change significantly.However,by using a combination of S^(2−) and Cu^(2+) activators,its floatability was realized after Zn^(2+) adsorption.This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S^(2-).After this removal,Cu^(2+) was adsorbed on the sphalerite surface to form a Cu_(2)S·S^(0) hydrophobic film.

Measurement of trace nitrate concentrations in seawater by ion chromatography with valve switching

An ion chromatographic method with a valve switching facility was developed to determine trace nitrate concentrations in seawater using two pumps, two different suppressors, and two columns. A carbohydrate membrane desalter was used to reduce the high concentrations of sodium salts in samples. In this method, trace nitrate was eluted from the concentrator column to the analytical columns, while the matrix fl owed to waste. Neither chemical pre-treatment nor sample dilution was required. In the optimized separation conditions, the method showed good linearity( R >0.99) in the 0.05 and 50 mg/L concentration range, and satisfactory repeatability(RSD<5%, n =6). The limit of detection for nitrate was 0.02 mg/L. Results showed that the valve switching system was suitable and practical for the determination of trace nitrate in seawater.

Simulation for Transesterification of Methyl Acetate and n-Butanol in a Reactive and Extractive Distillation Column Using Ionic Liquids as Entrainer and Catalyst

A new reactive and extractive distillation process with ionic liquids as entrainer and catalyst （RED-IL）was proposed to produce methanol and n-butyl acetate by transesterification reaction of methyl acetate with n-butanol. The RED-IL process was simulated via a rigorous model, and high purity products of methanol and n-butyl acetate can be obtained in such a process. The effects of reflux ratio, feed mode, holdup, feed location, entrainer ratio and catalyst concentration on RED-IL process were investigated. The conversion of methyl acetate and purities of products increase with the holdup in column, entrainer ratio and catalyst content. An optimal reflux ratio exists in RED-IL process. Comparing to the mixed-feed mode, the segregated-feed mode is more effective, in which the optimal feed locations of reactants exist.

Proton Dissociation from Surfaces of Variable Charge Soil andMnierals

Experiments on proton dissociation from the surfaces of goethite, amorphous Al oxide, kaolinite and latosolwere carried out, showing amphoteric behavior with reactions of proton dissociation-association on the surfaces andbuffering capacity in such a sequence as amorphous Al oxide > latosol > kaolinite > goethite. Dissociation con-stants of surface proton, pK_(sa) are significantly correlated with surface charge density, which has been proved with anelectrochemical model. Tbe intrinsic constants of proton dissociation, K_(sa)(int), gained by extrapolation to zero charconditions of plots of pK_(sa) against σ_o, could be used to estimate the acidity strength of variable charge surfaces. Thevalue of pK_(sa)(int) is 8.08 for goethite, 1 .2 for amorphous Al oxide, 6.62 for kaolinite and 5 .32 for latosol.

Hydrochemical characteristics of aquifers in Northern Gezira State,Central Sudan

This paper presents an assessment of the hydrochemical characteristics of groundwater in Northern Gezira State, Central Sudan. The approaches followed here include the chemical analyses for major ions chemistry and construction of hydrochemical maps of total dissolved solids (TDS), sodium (Na +), bicarbonate (HCO 3 -), and chloride (Cl -) ions. The hydrochemical characteristics of the groundwater in each aquifer and management consideration are discussed. Sources of major ions in groundwater are analyzed. The hydrochemical maps of important species are constructed. The relationship of groundwater to use is elaborated. High concentrations of the chemical and hydrochemical constituents and the occurrence of calcretes (CaCO 3) in upper zones suggest a long history of evaporation and increasing leachates.

Modification of Grey Water Treatment Using Combination of Cascade Aeration and Biofiltration

A combination of cascade aeration and biofiltration systems is one of the available ecological treatments to reduce the concentration of pollutants in grey water and resolve the problem of acute water crisis supply in Iraq. An experimental constructed grey water treatment system has been installed at AI-Mustansiriya University, College of Engineering during the period from January to December 2012. The performance of the treatment schemes has been evaluated by monitoring the quality of the raw grey water and effluent on these samples which are： pH, COD （chemical oxygen demand）, TSS （total suspended solids）, TDS （total dissolved solids）, PO43 （phosphates）, NO32 （nitrates）, NO （nitrites）, oils ＆ grease, NH3-N （ammonia-nitrogen） and some anions and cations. The average removal rate of COD was more than 60% that of NH3-N, NO3-N, NO2-N, TDS and TSS that were 55%-89%, 59%-74%, 79%-98%, 17%-52% and 51%-87%, respectively. Also the results indicate that the removal efficiency of ions concentrations such as Ca2＋, Mg2＋, Na＋, K＋ were 78%-96%, 73%-97%, 14%-47% and 44%-64%, respectively, while for cations such as SO42, Cl and PO43-, the removal efficiencies were 33%-79%, 27%-61% and 81%-99%, respectively. Finally oils ＆ grease was 79%-88%.

Homogeneous Acetylation of Cellulose at Relatively High Concentrations in an Ionic Liquid

At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.

Study on Improving Storage Stability of Marine Engine Oil

According to the conductivity test results,it is found that oil conductivity increases with an increasing additive content,and the turbidity of engine oil is also augmented with an increasing additive content.After testing the turbidity and stability of oils containing the typical conventional calcium sulfonate,the overbased calcium sulfonate and the mixture of the above two calcium sulfonates,the results show that at the same amount of additives used,the oil with a higher turbidity demonstrated a worse stability.A nonionic dispersant that was added into lube oils at a definite concentration could improve the detergent compatibility.For this reason,the sediment volume in three kinds of oils all decreased obviously,resulting in successful improvement of storage stability of marine engine oils.

Corrosion behavior of AZ31 magnesium alloy in simulated acid rain solution

The corrosion mechanism of AZ31 magnesium alloy used as automobile components and the influence of the concentration of Cl- ion in simulated acid rain(SAR)were studied by electrochemical tests and SEM.The results show that pitting corrosion happens around the AlMn phases locating at the grain boundary.The corrosion of AZ31 magnesium alloy in SAR is controlled by the rate of anodic dissolution and hydrogen evolution,and the corrosion rate of AZ31 increases with increasing concentration of Cl- ion.However,the Cl- ion in SAR is not the main influencing factor inducing the pitting corrosion.

Succession of Bacterial Community Inhabited Acid Mine Drainage under High Fe（Ⅱ） Concentration

To reveal the effects of Fe2＋ on bacterial communities in the early stages of minerals dissolution, two different acid mine drainage （AMD） samples were collected at Dabaoshan Mine and Shenbu Mine. Community successions of AMD niches were analyzed by Amplified Ribosomal DNA Restriction Analysis （ARDRA）, sequencing, and phylogenetic analysis in original AMD samples and their subculture under Fe2＋ concentrations. Although geochemical properties and community structures were greatly different between the two original AMD samples, bacterial community successions were still very similar under high Fe2＋ concentrations. The results showed that Acidithiobacillus ferrooxidans have competitive relationship with other bacterial species living in the AMD, including species that were also capable of oxidizing ferrous ion. A competitive relationship among different At. ferrooxidans strains likewise existed. Some of At. ferrooxidans can grow first under conditions of high ferrous ion concentration, and other At. ferrooxidans species decreased gradually and disappeared. This suggested that these species of At. ferrooxidans are most acidophilic bacteria and afford Fe3＋ to leach other metallic ion in the early stages of minerals dissolution.

Influence of Calcium Sources and Concentration on the Storage Performance of Strawberry Fruit

Chemical application after harvest is an important method to preserve strawberry fruit quality and extend shelf life. The strawberry fruits harvested at red stage were treated with three different sources of calcium, i.e., calcium nitrate, calcium gluconate and calcium chloride at calcium concentration of 0% （distilled water）, 0.5%, 1.0% and 1.5%. The strawberry fruits were dipped for 30 s. The calcium sources, calcium concentration and the interaction of calcium sources and calcium concentration significantly affected the storage performance of strawberry fruits. All the three sources and concentrations were effective in decreasing the storage associated changes, i.e., weight loss, decline in marketable fruits, loss of organoleptic quality, increase in total soluble solids （TSS）, decline in reducing sugars, total sugars, acidity and increase in sugar/acid ratio in strawberry fruit, thus extending the shelf life. Calcium gluconate at 1.5% calcium concentration was more effective. Treatment of strawberry fruit with 1.5% calcium from calcium gluconate source resulted in the highest number of marketable fruit （100%）, extended shelf life （10 d）, and total soluble solid （7.80%） with the minimum weight loss （5.45%）. Calcium dips result in higher calcium concentration in strawberry fruits, which delays ripening in fruits by maintaining the structure and function of cell walls and membranes. It can be concluded that calcium gluconate at 1.5% concentration is an effective calcium treatment to retain the quality and extend the shelf life of strawberry fruit.

Study of Anti-Myocardial Cell Oxidative Stress Action and Effect of Tanshinone IIA on Prohibitin Expression

Objective:To investigate the protective action of tanshinone IIA (TSN) on myocardial apoptosis induced by hydrogen peroxide (H2O2) and its effect on prohibitin (PHB) expression to probe the role of PHB in the oxidation stress of myocardial cells. Methods: Primary cultured neonate rat myocardial cells were cultured with TSN (1×10-4 mol/L) for 24 hours, and then the medium was supplemented with 200 μmol/L hydrogen peroxide for 2 h to initiate myocardial cell oxidative stress injury. PHB in myocardial cells was knocked down by small interfering RNA (siRNA), and the expression level of PHB was determined by western blot analysis. Flow cytometry was used to detect the apoptosis rate, intracellular calcium ion concentration ([Ca2+]i) and mitochondrial membrane potential (MMP). Results: The PHB expression, [Ca2+]i and the apoptotic rate significantly increased, and the MMP significantly decreased in the oxidative stress group compared with the control. The PHB expression, apoptosis rate and [Ca2+]i decreased, and MMP increased significantly in the TSN group compared with the oxidative stress group. Compared with the siRNA negative control group, the PHB expression level in myocardial cells was down-regulated, and the apoptosis rate and [Ca2+]i increased, and MMP decreased significantly in the siRNA group. Conclusion: TSN can reduce PHB expression in oxidative stress-injured myocardial cells hence protecting the myocardial cells.

Effects of external stimuli on the pacemaker function of the sinoatrial node in sodium channel gene mutations models

Loss of function and gain of function mutations of the sodium channel were investigated using an intact two-dimensional rabbit sinoatrial node (SAN) and atrial cell model. The effects of three external stimuli (acetylcholine secretion by the vagal nerve, acid-base concentration, and tissue temperature) on cardiac pacemaker function and conduction were studied. Our results show that these two groups of mutations have different effects on pacemaker function and conduction. Furthermore, we found that the negative effects of these mutations could be altered by external stimuli. The bradycardic effects of mutations were magnified by an increase in acetylcholine level. Changes in acid-base concentration and tissue temperature increased the ability of the SAN to recover its pacemaker function. The results of this study increase our understanding of sodium channel disorders, and help to advance research on the treatment of these conditions.

Modeling for tungstic precipitation and extraction based on Pitzer equation

This work presented the results of tungstic precipitation from Na2WO4-Na2SO4-H20 system at 293.15 K, with which the Pitzer parameters of β（0）Na2wo4 and β（1）Na2wo4 were determined from Pitzer equation by regression. Thus the mean ionic activity coeffi- cients of sodium tungstate were calculated. The obtained β（0）Na2wo4 and β（1）Na2wo4 were substituted as fixed values in extraction modeling from Na2WO4-H2SO4-H20 system by primary amine （N1923） in toluene as diluent. Meanwhile the activity coeffi- cient expressions in organic phase were varied based on Pitzer theory that the interaction term for the solvent should not be in- cluded. The Pitzer parameters for organic phase were re-regressed in order to make the model more accurate. The average ab- solute relative deviation （AARD） for calculated and experimental molality of WO42 in aqueous phase was 5.24%. The results showed that the model can not only correlate but also predict the liquid-liquid equilibrium （LLE） data.