Influence of mixed layer depth on chlorophyll-a concentration in the Southern Ocean

The element iron limitation is one of the crucial factors contributing to high nutrient low chlorophyll in the Southern Ocean(SO).Mixed layer dynamics regulate the availability of iron to phytoplankton.In this paper,we investigate the influence of surface iron supplementation triggered by the mixed layer depth(MLD)variation on chlorophyll-a(Chl-a)concentration in the SO on seasonal and interannual timescales.This analysis is based on the Biogeochemical Southern Ocean State Estimate for the period from 2013 to 2021.We provide a comprehensive and systematic mapping of the regions within the SO,where Chl-a is affected by iron input related to MLD deepening.The relationship between the MLD and the Chl-a varies with the latitude on the seasonal time scale.Both the MLD and sea ice melting affect the distribution of Chl-a.On the interannual scale,iron supply due to MLD deepening occurs primarily north of 60°S.Horizontal advection-induced entrainment enhances the surface iron input during the austral summer,which favors Chl-a increase.In addition to the MLD,the melting of sea ice and cooling of the sea surface can also alter iron input and subsequently affect Chl-a distribution in the austral summer.During the austral winter,entrainment can boost iron stocks,stimulating a subsequent spring increase of Chl-a in the SO.Furthermore,sea surface temperature declines during the austral winter,promoting an increased iron supply and creating favorable conditions for the subsequent spring Chl-a increase in the SO.

Study on Roasting Decomposition of Mixed Rare Earth Concentrate in CaO-NaCl-CaCl_2

The decomposed process of bastnaesite, monazite and mixed rare earth concentrate in CaO-CaCl-CaCl2 was studied by means of TG-DTA method. The relationship among decomposition ratio, roasting temperature, and CaO-NaCl addition was studied by the quadratic regression orthogonal analysis, and then the regression equation was obtained. Through analysis, the optimum process conditions of mixed rare earth concentrate decomposed by CaO-CaCl-CaCl2 were obtained as follows: roasting temperature: 700℃, CaO addition: 15%, NaCl-CaCl2 addition: 10%, roasting time: 60 min, the decomposition ratio: 91.3%.

Study on Escaping Fluorine Inhibition in Calcining Process of Mixed Rare Earth Concentrate

GC technology was used to study escaping fluorine in calcined process of mixed rare earth concentrate. The mixed rare earth concentrate and it adding assistant of CaO-NaCl-CaCl2 were calcined at 400～750 ℃ for 30～120 min, and then total amount of fluorine, exhausting ratio of fluorine, decomposition ratio and the component were determined. The results showed that adding CaO-NaCl-CaCl2 the decomposition ratio was up to 90% at 700 ℃ in 1 h, and the escaping ratio of fluorine decreased from 29.52% to 0.948%. The average inhabitation ratio was 98.39%. This method supplied basis for low energy and clean decomposition of mixed rare earth concentrate.

Decomposing scheelite and scheelite-wolframite mixed concentrate by caustic soda digestion

Scheelite and scheelite-wolframite mixed concentrates with different grades were decomposed by caustic soda digestion, and the effects of caustic soda（NaOH） dosage, the ratio of water to ore and the stirring rate on tungsten recovery were studied. The results show that under the conditions that the ratio of water to ore is （0.8,） stirring rate is 500 r·min-1 and the heating time is 2.0 h at （160 ℃,） the recovery of tungsten reaches 98% for scheelite （w（WO3） is （65.04%）） and wolframite containing high proportion of calcium （w（WO3） is 65.58%, w（Ca） is （7.53%）,） when caustic soda dosage is 2.2 and 2.0 times of theoretical value, respectively; the recovery of tungsten can be more than 98%,98% and 96% respectively for low-grade scheelite-wolframite mixed concentrate with （55.78%,） 45.32% and 25.21% WO3, when caustic soda dosage is 2.6,3.2 and 5.5 times of theoretical value, respectively.

Effect of Pelleted Total Mixed Ration with Different Concentrate-roughage Ratios on Production Performance and Serum Biochemical Parameters of Fattening Hainan Black Goats

[Objective] This paper was to study effects of pelleted total mixed ration with different concentrate-roughage ratios on production performance and serum biochemical parameters of fattening Hainan black goats.[Method] Thirty-six fattening Hainan black goats with the same genetic background and similar initial weight of(14.08±0.13) kg were randomly assigned into three treatments. Goats were fed with Juncao + concentrate(control group), pelleted total mixed ration I(concentrate: roughage 50 ∶50, group Ⅰ) and Ⅱ(concentrate: roughage 45∶55, group Ⅱ), respectively. The test lasted 45 d.[Result] The final weight, daily gain and feed intake of rams in experimental group Ⅰ were significantly higher than those of control group and experimental group Ⅱ(P<0.05);the final weight and daily gain of rams in experimental group Ⅰ were also markedly higher than those of experimental group Ⅱ(P<0.05);the feed/gain of rams in experimental group Ⅰ was significantly lower than those in control group and experimental group Ⅱ(P<0.05). The feed gain cost of rams in experimental group Ⅰ was markedly lower than that in experimental group Ⅱ( P<0.05), but was significantly higher than that in experimental group Ⅰ(P<0.05);the gross profit of rams in experimental group Ⅰ was significantly higher than those in control group and experimental group Ⅱ(P<0.05). Compared with control group and experimental group Ⅱ, the serum total protein and glucose lev-els in experimental group Ⅱ increased significantly(P<0.05), but the urea nitrogen content reduced(P>0.05).[Conclusion] When the concentrateroughage ratio of pelleted total mixed ration was 50∶50, the fattening effect of Hainan black goat was better, and the serum total protein and glucose levels were evidently improved.

Bio-dissolution of Cu,Mo and Re from molybdenite concentrate using mix mesophilic microorganism in shake flask

The application of the response surface methodology and the central composite design（CCD） technique for modeling and optimization of the influence of some operating variables on copper,molybdenum and rhenium recoveries in a bioleaching process was investigated.Three main bioleaching parameters,namely pH,solid concentration and inoculum percent,were changed during the bioleaching tests based on CCD.The ranges of the bioleaching process variables used in the design were as follows：pH1.46-2.14,solid concentration 0.95%-11.05%,and inoculum percent 1.59%-18.41%.A total of 20 bioleaching tests were carried out by the CCD method according to software-based designed matrix.Empirical model equations were developed according to the copper,molybdenum and rhenium recoveries obtained with these three parameters.Model equations of responses at the base of parameters were achieved by using statistical software.The model equations were then individually optimized by using quadratic programming to maximize copper,molybdenum and rhenium recoveries individually within the experimental range.The optimum conditions for copper recovery were pH 1.68,solid concentration 0.95% and the inoculum 18.41%（v/v）,while molybdenum and rhenium recoveries were 2.18% and 24.41%,respectively.The predicted values for copper,molybdenum and rhenium recoveries were found to be in good agreement with the experimental values.Also jarosite formation during bioleaching tests was also investigated.

Metallogeny of the Baiyangping Lead-Zinc Polymetallic Ore Concentration Area, Northern Lanping Basin of Yunnan Province, China

The Lanping Basin in the Nujiang-Lancangjiang-Jinshajiang （the Sanjiang） area of northeastern margin of the Tibetan Plateau is an important part of eastern Tethyan metallogenic domain. This basin hosts a number of large unique sediment-hosted Pb-Zn polymetallic deposits or ore districts, such as the Baiyangping ore concentration area which is one of the representative ore district. The Baiyangping ore concentration area can be divided into the east and west ore belts, which were formed in a folded tectogene of the India-Asia continental coUisional setting and was controlled by a large reverse fault. Field observations reveal that the Mesozoic and Cenozoic sedimentary strata were outcropped in the mining area, and that the orebodies are obviously controlled by faults and hosted in sandstone and carbonate rocks. However, the oreforming elements in the east ore belt are mainly Pb-Zn -Sr-Ag, while Pb-Zn-Ag-Cu-Co elements are dominant in the west ore belt. Comparative analysis of the C-O-Sr-S-Pb isotopic compositions suggest that both ore belts had a homogeneous carbon source, and the carbon in hydrothermal calcite is derived from the dissolution of carbonate rock strata; the ore- forming fluids were originated from formation water and precipitate water, which belonged to basin brine fluid system; sulfur was from organic thermal chemical sulfate reduction and biological sulfate reduction; the metal mineralization material was from sedimentary strata and basement, but the difference of the material source of the basement and the strata and the superimposed mineralization of the west ore belt resulted in the difference of metallogenic elements between the eastern and western metallogenic belts. The Pb-Zn mineralization age of both ore belts was contemporary and formed in the same metaliogenetic event. Both thrust formed at the same time and occurred at the Early Oligocene, which is consistent with the age constrained by field geological relationship.

Reaction process of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl_2

The decomposition reactions of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2 were studied by means of TG-DTA and XRD. The results show that the process of the minerals decomposed by CaO involves two steps. The first step occurs in the temperature range of 425-540 ℃, and the main reactions are bastnaesite decomposition, i.e. REOF reacts with CaO to produce RE2O3 and CaF2, and Ce2O3 is oxidized to CeO2. During this step, CaCO3 is formed at about 500 ℃. The second step takes place in the temperature range of 610-700 ℃, and the reactions are monazite decomposition into RE2O3, Ca5F(PO4)3 and Ca3(PO4)2 by CaO and CaF2. In this process, the decomposition ability is improved because CaO from CaCO3 decomposing has high chemical activity. In calcining process, the new formed Ca5F(PO4)3 restrains fluorine that can escape in form of gaseous compound. The decomposition ratio of the mixed rare earth minerals reaches 90.8% at 700 ℃.

Mixed Conduction in BaCe0.8Pr0.2O3-α Ceramic

BaCe0.8Pr0.2O3-α ceramic was synthesized by high temperature solid-state reaction. The structural characteristics and the phase purity of the crystal were determined using powder X-ray diffraction analysis. By using the methods of AC impedance spectroscopy, gas concentration cell and electrochemical pumping of hydrogen, the conductivity and ionic transport number of BaCe0.8Pr0.2O3-α were measured, and the electrical conduction behavior of the material was investigated in different gases in the temperature range of 500-900℃. The results indicate that the material was of a single perovskite-type orthorhombic phase. From 500℃ to 900 ℃, electronic-hole conduction was dominant in dry and wet oxygen, air or nitrogen, and the total conductivity of the material increased slightly with increasing oxygen partial pressure in the oxygen partial pressure range studied. Ionic conduction was dominant in wet hydrogen, and the total conductivity was about one or two orders of magnitude higher than that in hydrogen-free atmosphere （oxygen, air or nitrogen）

Syntheses of Coordination Compounds of 2-Amino-3-Methylbutanoic Acid Their Mixed Ligand Complexes and Antibacterial Activities

Coordination compounds of 2-amino-3-methylbutanoic acid were synthesized with chromium(III) and oxovanadium(IV) ions. M:L;1:2. Adducts of these complexes using 1,10-phenantroline and ethylenediamine were further synthesized, M:L, (1:2). These compounds were characterized using electronic, infra-red spectrophotometry, magnetic susceptibility measurement and percentage metal analyses. The zones of inhibition and minimum inhibitory concentrations of the compounds against eight microbes were studied. The results obtained indicated an octahedral geometry for the Cr(III) complexes, indicative of additional coordination of two water molecules. On the other hand a square pyramid geometry was obtained for the binary oxovanadium complex and its 1,10-phenantroline adduct. However, for the oxovanadium ethylenediamine adduct a distorted octahedral geometry was proposed. The result for the antibacterial studies indicated that both mixed ligand complexes of 1,10-phenantroline exhibited good antibacterial activity, and in some cases better activity than the standard, streptomycin.

Selective leaching of calcium from mechanically activated mixed rare earth concentrate

The loss of rare earths(REs)takes place during the pre-decalcification process of mixed rare earth concentrate.In an effort to reduce such RE loss,a novel idea to improve the leaching selectivity of Ca to REs by applying selective mechanical activation was proposed.First,regarding the key minerals affecting the leaching selectivity of Ca to REs,the differences in the mechanical activation behaviors of CaF_(2) and REFCO_(3) were studied,and we find that the lattice strain of CaF_(2) increases from 0.21%to 0.42%,whereas that of REFCO_(3) increases from 0.31%to 0.40%.Notably,CaF_(2) demonstrates a larger lattice strain than REFCO_(3),indicating greater mechanical activation energy storage and higher leaching activity.Next,the HCl leaching process was studied.A significant leaching selectivity of Ca to REs,from 21.6 to 35.1,is achieved through mechanical activation.The Ca leaching rate reaches 80.7%when the RE loss is 2.3%in the activated sample.This study provides an novel approach for achieving selective extraction of specific components via mechanical activation pretreatment.

Efficient recovery of tungsten from scheelite concentrates using a sulfur-phosphorus mixed acid leaching system

In recent years,a new process for leaching scheelite concentrates with sulfur-phosphorus mixed acid has been successfully industrialized.This process suffers from the elimination of the retarding effect of calcium sulfate,the selective extraction of tungsten from the H_(3)PW_(12)O_(40)-H_(2)SO_(4)-H_(3)PO_(4)mixture solution,and the removal of introduced phosphorus.Therefore,in this paper,we investigated the inhibition measures of a calcium sulfate-blocking membrane,the selective extraction of tungsten by ion exchange,and the removal of phosphorus by the magnesium ammonium salt method.The results showed that the addition of calcium sulfate whisker seeds and a higher H_(3)PO_(4)concentration inhibited spontaneous diffuse nucleation,promoted crystal growth,and avoided the formation of a dense blocking film.About 98 wt.%of the scheelite concentrate was digested by H_(2)SO_(4)-H_(3)PO_(4).The selective adsorption of PW_(12)O_(40)^(3-)was realized using D301 resin,and the extraction efficiency of tungsten exceeded 99.9%.After desorption with ammonia water,PW_(12)O_(40)^(3-)was depolymerized into WO_(4)^(2-)and PO_(4)^(3-).99.9 wt.%of phosphorus was removed in the form of MgNH_(4)PO_(4)by the magnesium ammonium salt method,and the residual phosphorus concentration in the solution was lower than 10 mg·L^(-1).After purification,the highest-grade ammonium paratungstate product was prepared by evaporative crystallization.

混合热力学促进剂对水合物法分离回收瓦斯的影响

水合物法在分离瓦斯混合气体方面具有清洁、高效、安全的优势,为突破水合物储气效率的瓶颈问题,在磁力搅拌体系中考察了水合物法分离30%CH4/70%N2混合气(摩尔分数)的动力学规律与储气效率。四氢呋喃(THF)、环戊烷(CP)与四丁基溴化铵(TBAB)、四丁基氟化铵(TBAF)二元混合体系作为水合物形成热力学促进剂,0.06%L-色氨酸(Trp)作为动力学促进剂。结果表明:与THF或CP单一添加的实验体系相比,THF-TBAF或CP-TBAB、CP-TBAF体系均能延续水合物形成、提高储气量、降低形成速率,其中CP-TBAF改善效果最为明显,3h内的储气量提高了1.33倍,而水合物初期形成速率下降3倍以上。THF-TBAB-Trp、THF-TBAF-Trp体系增大了N2在水合物相的储集量,使CH4/N2的分离效果低于THF-Trp体系;CP与TBAB或TBAF在瓦斯水合分离过程中具有耦合促进作用,CP-TBAF使水合物储气量、分离因子、CH4回收率等关键指标全面提升,其中平均CH4回收率最高可达68.5%,CP-TBAF组合为突破瓦斯水合分离效率提供了参考。

近红外光谱-补水技术法测定半导体用高浓度混酸含量

本研究创新性地采用补水技术,结合近红外光谱法快速测定半导体刻蚀工艺使用的高浓度混酸中各组分的含量,在1 min之内即可完成一个样品的检测并同时给出各组分的含量结果。实验通过在高浓度混酸样品中加入适量的超纯水来显著降低样品的腐蚀性,确保样品装入光学玻璃指管中在1 min之内不发生明显的腐蚀反应,即玻璃样品管中因强烈腐蚀而产生连续性的大量气泡。加入的超纯水不参与任何计算,也不影响各组分的计算结果。该实验方案巧妙的利用了补水技术,适用于高浓度混酸样品的检测。

Study on concentration and turbulence of solid-liquid FAE in dispersal process

This paper describes numerical simulation on dispersion of the solid-liquid mixed fuel driven by explosion load. A model used in numerical calculation for dispersion of solid-liquid mixed fuel was established in this study. The concentration and turbulent intensity in the multiphase cloud of the solidliquid mixed fuel were obtained by numerical simulation. It was found that the fuel concentration tended to be 0.15 kg/m^3, the turbulence intensity tended to be 7 in 90 ms. The numerical results agree with those measured in the experiment.

Microwave strengthens decomposition of mixed rare earth concentrate: Microwave absorption characteristics

The potential application of microwave heating technology for processing the mixed rare earth concentrate was systematically investigated by analyzing the microwave absorption characteristics in this study. The complex permittivity was measured through resonant cavity perturbation method. The variations of permittivity, the loss factor, loss tangent and the penetration depth with the increasing temperature were investigated numerically. The results indicate that the permittivity increases as the temperature increases, and temperature has a pivotal effect on it. The mixed concentrate is high loss material at the temperature range from 600 to 800℃ according to theoretical analyses of loss tangent and penetration depth. The results of phase transition analysis prove that the variation of microwave absorption characteristics of mixed concentrate is caused by the changes of crystal and lattice structures.The reflectivity, loss factor and penetration depth of the mixed concentrate were also calculated, and the results indicate that processing the mixed concentrate by microwave heating is of high feasibility and industrial potential.

An experimental study on metal precipitation driven by fluid mixing: implications for genesis of carbonate-hosted lead–zinc ore deposits

A type of carbonate-hosted lead–zinc(Pb–Zn)ore deposits, known as Mississippi Valley Type(MVT)deposits, constitutes an important category of lead–zinc ore deposits. Previous studies proposed a fluid-mixing model to account for metal precipitation mechanism of the MVT ore deposits, in which fluids with metal-chloride complexes happen to mix with fluids with reduced sulfur, producing metal sulfide deposition. In this hypothesis, however, the detailed chemical kinetic process of mixing reactions, and especially the controlling factors on the metal precipitation are not yet clearly stated. In this paper, a series of mixing experiments under ambient temperature and pressure conditions were conducted to simulate the fluid mixing process, by titrating the metal-chloride solutions, doping withor without dolomite, and using NaHS solution. Experimental results, combined with the thermodynamic calculations, suggest that H_2S, rather than HS^-or S^(2-),dominated the reactions of Pb and/or Zn precipitation during the fluid mixing process, in which metal precipitation was influenced by the stability of metal complexes and the pH. Given the constant concentrations of metal and total S in fluids, the pH was a primary factor controlling the Pb and/or Zn metal precipitation. This is because neutralizing or neutralized processes for the ore-forming fluids can cause instabilities of Pb and/or Zn chloride complexes and re-distribution of sulfur species, and thus can facilitate the hydrolysis of Pb and Zn ions and precipitation of sulfides. Therefore, a weakly acidic to neutral fluid environment is most favorable for the precipitation of Pb and Zn sulfides associated with the carbonate-hosted Pb–Zn deposits.

Thermodynamic properties and mixing thermodynamic parameters of binary homogeneous metallic melts

After the investigation on the thermodynamic properties and mixingthermodynamic parameters of binary homogeneous metallic melts involving compound, peritectic as wellas solid solution, it was found that the equations of mixing free energy DELTA G^m and excess freeenergy DELTA G^(XS) of them can he expressed by the following equations: DELTA G^m = SIGMA x [SIGMAN_i DELTA G_I^(THETA) + RT(SIGMA N_j ln N_j + SIGMA N_i ln N_i )] and DELTA G^(XS) = DELTA G^m -RT(a ln a + b ln b), respectively.

Thermodynamic properties and mixing thermodynamic parameters of two-phase metallic melts

Based on the calculating model of metallic melts involving eutectic, the calculating equations of mixing thermodynamic parameters for two phase metallic melts have been formulated in the light of those equations of homogeneous solutions. Irrespective as to whether the activity deviation relative to Raoultian behavior is positive or negative, or the deviation is symmetrical or unsym-metrical, the evaluated results not only agree well with experimental values, but also strictly obey the mass action law. This testifies that these equations can authentically reflect the structural reality and mixing thermodynamic characteristics of two-phase metallic melts. The calculating equations of mixing thermodynamic parameters for the model of two phase metallic melts offer two practical criteria (activity and mixing thermodynamic parameters) and one theoretical criterion (the mass action law).

Thermodynamic Properties and Mixing Thermodynamic Parameter of Binary Metallic Melt Involving Compound Formation

Based on the coexistence theory of metallic melts involving compound formation, the theoretical calculation equations of mixing thermodynamic parameters are established by giving up some empirical parameters in the associated solution model. For Fe-Al, Mn-Al and Ni-Al, the calculated results agree well with the experimental values, testifying that these equations can exactly embody mixing thermodynamic characteristics of these melts.