硝酸酸化处理对MCMB碳材料性能的影响

根据现有制造高密度高强度碳材料的工艺流程,以硝酸酸化处理中间相碳微球,并用酸化处理过的微粉制备高密度高强度碳材料,对样品进行性能测试。实验表明,以硝酸溶液对中间相颗粒酸化后能提高样品的肖氏硬度和抗压强度。当硝酸酸化处理溶液浓度为3mol/L时,可制备出密度1.72g/cm3、抗压强度104.9MPa和肖氏硬度82.6的高密度碳材料。

外源性一氧化氮对鸡柔嫩艾美尔球虫的作用

用酸化亚硝酸钠作为一氧化氮(NO)供体处理新收取的柔嫩艾美尔球虫未孢子化和已孢子化卵囊,来探讨外源性NO对球虫卵囊的抑杀作用。另外通过内服亚硝基谷胱甘肽(GSNO)试验来观察外源性NO对球虫病的防治作用。结果表明,酸化亚硝酸钠溶液(pH=1)对球虫卵囊的孢子生殖具有明显的抑制作用,20mmol/L酸化亚硝酸钠溶液对卵囊孢子生殖的抑制率可达100%;但不经酸化的亚硝酸钠溶液和相同pH的盐酸溶液对卵囊的孢子生殖没有明显影响。经20mmol/L以上浓度酸化亚硝酸钠处理的孢子化卵囊也失去了对雏鸡的致病力,但直接内服GSNO溶液则没有明显的抗球虫作用。这提示外源性NO对鸡柔嫩艾美尔球虫未孢子化和孢子化卵囊均有抑杀作用,但直接内服没有明显的抗球虫病作用。

碱熔融分光光度法测定氮化铝中硅的质量分数

试样采用碳酸钠-硼酸高温碱熔融,将熔融试样硝酸溶解后,在PH0.8~0.9的硝酸介质中,用钼酸盐使试样中的硅形成硅钼黄络合物,然后在PH值约0.9~1.0硫酸介质中(提高酸度)以1-氨基-2-奈酚-4-磺酸或抗坏血酸还原成硅钼蓝络合物,在波长810nm处于分光光度仪器上测定氮化铝中硅的含量,测定范围:0.005%~0.3%。

Preparation of high pure tellurium from raw tellurium containing Cu and Se by chemical method

High pure tellurium was prepared from raw tellurium containing copper and selenium by chemical method containing oxidation with concentrated nitric acid, leaching with hydrochloric acid, reducing with sulfur dioxide and treating in hydrogen atmosphere at high temperature. Removal ratio of Cu in raw tellurium reaches 99% after raw tellurium is oxidized and leached with HNO3（69%） under the following conditions： 0.96 times stoichiometric quantity of concentrated nitric acid, 4：1 of ratio of liquid to solid, 20 °C of reaction temperature and 30 min of reaction time. Leaching ratio of Te reaches 99% after Te is leached with hydrochloric acid under the following conditions： 1.67 times stoichiometric quantity of hydrochloric acid, 4：1 of ratio of liquid to solid, 20 °C of reaction temperature and 30 min of reaction time. Tellurium powder（99.95%） is obtained when Te（IV） in leachate is reduced with sulfur dioxide. The purity of tellurium increases from 99.954% to 99.999 6% after tellurium（99.95%） is treated in hydrogen atmosphere at 723.15 K for 30 min.

Possible link between new coronavirus variants and atmospheric lightning and seawater intrusion

SARS-CoV-2(COVID-19) has been affecting the world for more than one year.The appearance of the new coronavirus variants makes the current situation full of uncertainty.In this respect,the authors discuss the connection between virus mutation and atmospheric factors.Based on the process of nitrogen fixation and transformation of nitrate inside the human body,the authors propose that the new coronavirus variants might be related to lightning and seawater intrusion.This study provides a new perspective in terms of the possible mechanism underlying the emergence of new coronavirus variants.

Effect of Compost Amendment on Heavy Metals, Nitrogen and Phosphorus in a Peat-Based Container Medium

A laboratory study was conducted to evaluate the effect of compost amendment on mobility and leaching potential of heavy metals, nitrogen （N） and phosphorus （P） from a peat-based commercial container medium containing 700 g kg^-1 peat, 200 g kg^-1 perlite and 100 g kg^-1 vermiculite at varying amendment rates of compost （0, 0.25, 0.50, 0.75 and 1.00 L L^-1）. Increasing compost amendment significantly and linearly increased the pH （P 〈 0.01）, the total concentrations of organic carbon （P 〈 0.05）, copper （Cu） （P 〈 0.01）, cadmium （ca） （P 〈 0.01）, and lead （Pb） （P 〈 0.01）, and increased the bulk density （P 〈 0.01） of the medium. The electrical conductivity （EC）, and total N and P of the medium increased significantly （P 〈 0.01） and quadratically with increasing compost amendment. The relationship of the C/N ratio of the medium with the compost amendment rate was decreasing, significant （P 〈 0.01） and cubic, while that of the total Zn was increasing, significant （P 〈 0.01） and cubic. Extractable P, NO3-N, and NH4-N increased initially with an increasing compost amendment of up to 0.50 L L^-1 and then decreased with further increasing compost rate. Increasing compost rates resulted in a highly significant （P 〈 0.01） and linear increase in total Cd, Cu, and Pb, and a highly significant （P 〈 0.01） and cubic increase in total Zn in the medium. Increasing compost rates also significantly （P 〈 0.01） increased extractable Cu （linearly） and Zn （quadratically）, but significantly （P 〈 0.01） decreased extractable Pb （linearly）. There was no significant effect of compost amendment on the extractable Cd concentration in the medium. However, with increasing compost rates from 0.25 to 1.00 L L^-1, extractability of P, Cd, Cu, Pb and Zn （extractable concentration as a percent of total） was decreased, indicating that compost amendment could lower the leachability of these elements from the medium.

Liquid-solid Equilibria in Quinary System Na^＋,K^＋,Mg^2＋//Cl^-,NO3^--H2O at 25°C

The solubilities of the quinary system Na^＋ ,K^＋ ,Mg^2＋ //Cl ,NO 3 ^-H2O and its two quaternary subsystems, Na^＋ ,K^＋ ,Mg^2＋ //NO 3 -H2O and K^ ＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,were studied by isothermal method at 25°C and their phase diagrams were plotted.In the equilibrium phase diagram of quaternary system Na^ ＋ ,K^ ＋ ,Mg ^2＋ //NO 3 ^-H2O, there are one invariant point,three univariant curves and three regions of crystallization with one salt：NaNO3, KNO3 and Mg（NO3）2·6H2O.In the equilibrium phase diagram of quaternary system K ^＋ ,Mg ^2＋ //Cl ,NO 3 ^-H2O,there are three invariant points,seven univariant curves and five regions of crystallization with one salt：KNO3,KCl, Mg（NO3）2·6H2O,MgCl2·6H2O and KCl·MgCl2·6H2O.In the equilibrium phase diagram of the quinary system Na ^＋ , K^ ＋ ,Mg ^2＋ //Cl ,NO 3^ -H2O,there are four invariant points,and seven regions of crystallization with one salt：NaCl, KCl,NaNO3,KCl·MgCl2·6H2O,KNO3,MgCl2·6H2O and Mg（NO3）2·6H2O.

Effect of Anions on Adsorbability and Extractability of Lead Added in Soil

The effect of accompanying anions on the adsorbability and extractability of Pb added in soils was studied by using bach equilibria and incubation-extraction mothods.Pb concentration ranged between 0.48-2.41 mM in the adsorption experiment,and Pb added to soil from 2.14 to 19.31mM Pb/kg with an incubation time of 2-16 weeks in the incubation-extraction test in which 1M NH4OAc(pH 7) was taken as an extraction agent,and the Pb compounds used are PbCl2,Pb(NO3)2 and Pb(OAc)2.The values of pH50 for Pb retention and the parameters,b and k values,of Langmuir equation were used to distinguish the difference of adsorbability and extractability of Pb affected by anions,respectively.Judging from the results of either pH50 value or b value,the influences of Cl^- and NO3^- on the adsorbability and extractability of Pb in soils were similar but quite different from those of OAc^-.The relative loading capacities of soils to Pb calculated according to the extraction rate showed that the values of Pb(OAc)2 were higher than those of PbCl2 and Pb(NO3)2.

Seasonal Cycle Analysis of the Nitrate Nitrogen and Nitrite Nitrogen in the Bohai Sea

During 1985-1987, the concentration of nitrate nitrogen was higher in the Laizhou Bay and the Bohai Bay while that of nitrite nitrogen was higher in the Liaodong Bay and the Bohai Bay. The concentration of nitrate nitrogen was highest in winter and lowest in summer while that of nitrite nitrogen was highest in autumn and lowest in spring. The seasonal variation of the concentration of nitrate nitrogen was maximum in the Laizhou Bay and the Bohai Bay while that of the concentration of nitrite nitrogen was maximum in the Liaodong Bay. There was a great difference in the concentration of nitrate nitrogen between the surface and the bottom in autumn and in the concentration of nitrite nitrogen between the surface and the bottom in summer. The main reason for the seasonal variations of the concentration of nitrate nitrogen and nitrite nitrogen was the marine biochemical process. The nitrate nitrogen and nitrite nitrogen in the Bohai Sea basically maintained a quasi-equilibrium state seasonal cycle. The quasi-equilibrium state seasonal cycle of nitrate nitrogen and nitrite nitrogen at the bottom was stable while that at the surface was liable to variations caused by other factors.

Effects of Sodium Nitrate and Sodium Acetate Concentrations on the Growth and Fatty Acid Composition of Brachiomonas submarina

One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L -1 CH 3COONa and 0.88 mmol L -1 NaNO 3 in heterotrophic condition, and 4 mmol L -1 CH 3COONa and 3.52 mmol L -1 NaNO 3 in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T.P.U.F.As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH 3COONa and NaNO 3 at 3 mmol L -1 and 3.52 mmol L -1 should respectively be used in order to achieve the highest growth rate and fatty acid content.

DYNAMIC CHANGES OF INORGANIC NITROGEN AND ASTAXANTHIN ACCUMULATION IN HAEMATOCOCCUS PLUVIALIS

This study on dynamic changes of culture color, astaxanthin and chlorophylls, inorganic N including N NO - 3, N NO - 2 and N NH + 4 in batch culture of Haematococcus pluvialis exposed to different additive nitrate concentration showed (1) ast/chl ratio was over 0.8 for brown and red algae, but was usually less than 0.5 for green and yellow algae; (2) N NO - 3, in general, was unstable and decreased, except for a small unexpected increase in nitrate enriched treatment groups; (3) measurable amounts of N NO - 2 and N NH + 4 were observed respectively with three change modes although no external nitrite and ammonia were added into the culture; (4) a non linear correlation between ast/chl ratio (or color) changes and the levels of N NO - 3 , N NO - 2 , N NH + 4 in H. pluvialis culture; (5) up and down variation of the ast/chl ratio occurred simultaneously with a perceptible color change from yellow to brown (or red) when N NO - 3, N NO - 2 and N NH + 4 fluctuated around 30, 5, 5 μmol/L respectively; (6) existence of three dynamic modes of N NO - 3, N NO - 2 and N NH + 4 changes, obviously associated with initial external nitrate; (7) the key level of total inorganic N concentration regulating the above physiological changes during indoor cultivation was about 50 μmol/L; and (8) 0.5-10 mmol/L of nitrate was theoretically conducive to cell growth in batch culture.

Preparation,Characterization of Dawson-type Heteropoly Acid Cerium（Ⅲ） Salt and Its Catalytic Performance on the Synthesis of n-Butyl Acetate

A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential thermal analyses(TG/DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),pyridine infrared spectroscopy(Py-IR) and scanning electron microscopy(SEM).Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol.The effects of various parameters such as molar ratio of n-butanol to acetic acid,reaction temperature,reaction time,and catalyst amount have been studied by single factor experiment.The results show that Ce2P2W18O62·16H2O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate.The optimum synthetic conditions were determined as follows︰molar ratio of n-butanol to acetic acid at 2.0︰1.0,mass of the catalyst being 1.44% of the total reaction mixture,reaction temperature of 120 ℃ and reaction time of 150 min.Under above conditions,the conversion of acetic acid was above 97.8%.The selectivity of n-butyl acetate based on acetic acid was,in all cases,nearly 100%.The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction.It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products.Compared with using sulfuric acid as catalyst,the present procedure with Ce2P2W18O62·16H2O is a green productive technology due to simple process,higher yield,catalyst recycling and no corrosion for the production facilities.

Arbuscular mycorrhizal fungi protect a subtropical tree species exposed to simulated acid rain by accelerating photosynthetic ability,antioxidant enzymes and osmolyte accumulation

Acid rain(AR),which occurs frequently in southern China,negatively affects the growth of subtropical tree species.Arbuscular mycorrhizal fungi(AMF)mitigate the detrimental effects induced by AR.However,the mechanisms by which AMF protect Zelkova serrata,an economically important tree species in southern China,from AR stress remain unclear.We conducted a greenhouse experiment in which Z.serrata plants were inoculated with AMF species Rhizophagus intraradices and Diversispora versiformis,either alone or as a mixed culture,or with a sterilized inoculum(negative control).The plants were subjected to three levels of simulated sulfuric AR and nitric AR(pH 2.5,4.0 and 5.6)to examine any interactive effects on growth,photosynthetic capabilities,antioxidant enzymes,osmotic adjustment and soil enzymes.AR significantly decreased dry weight,chlorophyll content,net photosynthetic rate and soluble protein(SP)of non-mycorrhizal plants.Mycorrhizal inoculation,especially a combination of R.intraradices and D.versiformis,notably improved dry weight,photosynthetic capabilities,catalase,peroxidase,superoxide dismutase,SP and root acid phosphatase activity of Z.serrata under harsh AR stress.Moreover,the benefits from AMF symbionts depended on the identity of AM fungal species and the gradient of AR stress.Our results indicate that AM fungi protect z.serrata against AR stress by synchronously activating photosynthetic ability,antioxidant enzymes and osmolyte accumulation.These findings suggest that a combination of R.intraradices and D.versiformis may be a preferable choice for culturing Z.serratain southern China.

Studies on the roles of vanadyl sulfate and sodium nitrite in catalytic oxidation of benzyl alcohol with molecular oxygen

An efficient catalytic system consisting of vanadyl sulfate/sodium nitrite was disclosed previously for the oxidation of benzylic alcohols into aldehydes with molecular oxygen.However,the roles of catalyst components were not investigated.In this paper,we examined catalytic oxidation of benzyl alcohol as a model reaction,especially by infrared spectroscopy.The role of each component is discussed including nitrite,vanadyl,sulphate,and water.Sodium nitrite could be converted into nitrate and nitric acid.The vanadium(IV)could be smoothly oxidized into vanadium(V)under mild and acidic conditions without any organic ligands.The transformation of sulfate and bisulfate,the cessation of an induction period,and the oxidation of benzyl alcohol were closely interrelated.The multiple roles of water are discussed,including reduction of the induction period,participation in redox cycles of nitric compounds,deactivation of vanadium,and as a byproduct of oxidation.This study contributes to further development of aerobic oxidation using vanadium based catalysts.