优化工艺指标提高盐水质量

介绍了通过优化工艺指标,如精确控制化盐温度、增加粗盐水的过碱量、减少助沉剂的投加量等提高了盐水质量并降低了生产成本。

影响一次盐水制备质量的因素

介绍了影响一次盐水质量的因素及为提高一次盐水质量而采取的技术措施。

对影响我厂盐水质量问题的探讨

1 情况简介 我厂从1987年引进日本德山曹达离子膜电解装置以后,几乎每年冬季都会因为一次盐水质量问题造成离子膜电解装置停产,特别是1996年冬季尤为严重,从2月中旬至5月下旬连续3个月,因盐水质量问题,离子膜电解开开停停,全厂其它氯碱产品也被迫停产,给全厂造成极大的经济损失。 2 原因分析 2.1 原盐质量问题 从目前国内氯碱厂家调查的数据来看,原盐的质量对保证一次盐水的质量是十分重要的。

Three-Dimensional Structure of Optimal Nonlinear Excitation for Decadal Variability of the Thermohaline Circulation

The decadal variability of the North Atlantic thermohaline circulation(THC) is investigated within a three-dimensional ocean circulation model using the conditional nonlinear optimal perturbation method. The results show that the optimal initial perturbations of temperature and salinity exciting the strongest decadal THC variations have similar structures: the perturbations are mainly in the northwestern basin at a depth ranging from 1500 to 3000 m. These temperature and salinity perturbations act as the optimal precursors for future modifications of the THC, highlighting the importance of observations in the northwestern basin to monitor the variations of temperature and salinity at depth. The decadal THC variation in the nonlinear model initialized by the optimal salinity perturbations is much stronger than that caused by the optimal temperature perturbations, indicating that salinity variations might play a relatively important role in exciting the decadal THC variability. Moreover, the decadal THC variations in the tangent linear and nonlinear models show remarkably different characteristics, suggesting the importance of nonlinear processes in the decadal variability of the THC.

Influence of Synthesis Temperature on Phosphate Adsorption by Zn-Al Layered Double Hydroxides in Excess Sludge Liquor

A group of Zn-Al layered double hydroxides (LDHs) were synthesized at different temperatures from 25-90 °C in order to investigate the influence of synthesis temperature on characteristics of the LDHs and their phosphate adsorption behaviour. The results reveal that an increase in the synthesis temperature generally improves the specific surface area of the sample and the phosphate adsorption capacity. The significantly enhanced crystallin- ity of the Zn-Al-30, synthesized at 30 °C, leads to a remarkable decrease in the specific surface area and consequently a poor phosphate adsorption capacity. It is suggested that the surface adsorption plays an important role in the phosphate uptake by the Zn-Al LDHs. Zn-Al-70 presents a relatively higher crystallinity and a lower specific surface area, compared with Zn-Al-60 and Zn-Al-80, but the highest phosphate adsorption capacity, indicating that surface adsorption is only one of the pathways for phosphate removal. The phosphate adsorption by the Zn-Al follows a pseudo-second-order kinetic equation. The adsorption isotherms fit Langmuir models, and the maximum a dsorption capacities of the Zn-Al-25, Zn-Al-50 and Zn-Al-70 are estimated to be 17.82, 21.01 and 27.10 mg·g-1 adsorbent, respectively.

Interannual variability of the sea surface salinity and its related freshwater flux in the tropical Pacific:A comparison of CMIP5 and CMIP6

This paper assesses the interannual variabilities of simulated sea surface salinity(SSS)and freshwater flux(FWF)in the tropical Pacific from phases 5 and 6 of the Coupled Model Intercomparison Project(CMIP5 and CMIP6).The authors focus on comparing the simulated SSS and FWF responses to El Nino–Southern Oscillation(ENSO)from two generations of models developed by the same group.The results show that CMIP5 and CMIP6 models can perform well in simulating the spatial distributions of the SSS and FWF responses associated with ENSO,as well as their relationship.It is found that most CMIP6 models have improved in simulating the geographical distribution of the SSS and FWF interannual variability in the tropical Pacific compared to CMIP5 models.In particular,CMIP6 models have corrected the underestimation of the spatial relationship of the FWF and SSS variability with ENSO in the central-western Pacific.In addition,CMIP6 models outperform CMIP5 models in simulating the FWF interannual variability(spatial distribution and intensity)in the tropical Pacific.However,as a whole,CMIP6 models do not show improved skill scores for SSS interannual variability,which is due to their overestimation of the intensity in some models.Large uncertainties exist in simulating the interannual variability of SSS among CMIP5 and CMIP6 models and some improvements with respect to physical processes are needed.

Effects of temperature and salinity on the development of embryos and larvae of the veined rapa whelk Rapana venosa(Valenciennes, 1846)

The major population of the veined rapa whelk Rapana venosa （Valenciennes, 1846）, which is an important fishery resource, is facing a large decline in China. We studied the effects of incubation temperature （16-34℃ at salinity 30） and salinity （5-45 at 25℃） on the incubation period and subsequent larval development. In the temperature experiment, the shortest incubation period was 12 days at 34℃, the lower temperature limit was 16~C, the longest mean shell length （1 193＋17 pan） occurred at 25℃ and the highest survival rate 72.28%＋5.62% was observed at 28℃. In the salinity experiment, the shortest incubation period was 15 days at 25. The salinity tolerance range was 15-40, the longest mean shell length （855-4-9 μm） and the highest survival rate 72.93%~4.85% were both observed at 35. This study demonstrated that, during the egg-mass stage, temperature and salinity regimes influence later growth and survival of larvae. These observations deepen our understanding of the ecology and conservation of natural populations of Rapana venosa.

Microwave absorbing characteristics and temperature increasing behavior of basic cobalt carbonate in microwave field

The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temperature increasing curves were measured,and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field.Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy,while cobalt oxide has very strong capability to absorb microwave energy.It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields.The capability to absorb microwave energy of sample increases with an increase in mixing ratio of Co3O4.

Paleotemperature variations at Lake Caohai, southwestern China, during the past 500 years:Evidence from combined δ^(18)O analysis of cellulose and carbonates

The oxygen isotopic values of aquatic plant cellulose and carbonates in Lake Caohai sediments were measured using a continuous flow isotopic ratio mass spectrometer(CF-IRMS).Because of predictable oxygen isotopic fractionation between cellulose and its source water,the oxygen isotopic composition of paleo-lake water has been established quantitatively.Combined oxygen isotopic values of cellulose and carbonates were used in the‘Craig’equation to determine paleotemperatures and their variation in the lake during the past 500 years.Results show that the paleotemperature trend correlates well with meteorological records from Weining.There are four notable cold intervals at Lake Caohai over the past 500 years,namely 1540–1570AD,1670–1715AD,1780–1870AD and 1900–1930AD,and the former three cold intervals have been observed in the conventional Little Ice Age(LIA).These cold periods at Lake Caohai correspond well with those recorded from tree ring,peat,and ice core data from adjacent regions,particularly temperature those inferred fromδ18O of peat cellulose from Hongyuan Southwestern China.The trend in paleotemperature variations at Lake Caohai are also consistent with both the change of Indian summer monsoon,derived fromδ18O values of a stalagmite in Dongge,and a recorded shift in solar activity.The findings of this study illustrate that coupled analysis ofδ18O values of cellulose and carbonates from lake sediments may be used as a paleotemperature proxy.These results also provide further evidence of the existence of LIA in southwestern China.

Numerical simulation study of temperature change over East China in the past millennium

Despite many studies on reconstructing the climate changes over the last millennium in China,the cause of the China's climate change remains unclear.We used the UVic Earth System Climate Model(UVic Model),an Earth system model of intermediate complexity,to investigate the contributions of climate forcings(e.g.solar insolation variability,anomalous volcanic aerosols,greenhouse gas,solar orbital change,land cover changes,and anthropogenic sulfate aerosols) to surface air temperature over East China in the past millennium.The simulation of the UVic Model could reproduce the three main characteristic periods(e.g.the Medieval Warm Period(MWP),the Little Ice Age(LIA),and the 20th Century Warming Period(20CWP)) of the northern hemisphere and East China,which were consistent with the corresponding reconstructed air temperatures at century scales.The simulation result reflected that the air temperature anomalies of East China were larger than those of the global air temperature during the MWP and the first half of 20CWP and were lower than those during the LIA.The surface air temperature of East China over the past millennium has been divided into three periods in the MWP,four in the LIA,and one in the 20CWP.The MWP of East China was caused primarily by solar insolation and secondarily by volcanic aerosols.The variation of the LIA was dominated by the individual sizes of the contribution of solar insolation variability,greenhouse gas,and volcano aerosols.Greenhouse gas and volcano aerosols were the main forcings of the third and fourth periods of the LIA,respectively.We examined the nonlinear responses among the natural and anthropogenic forcings in terms of surface air temperature over East China.The nonlinear responses between the solar orbit change and anomalous volcano aerosols and those between the greenhouse gases and land cover change(or anthropogenic sulfate aerosols) all contributed approximately 0.2℃ by the end of 20th century.However,the output of the energy-moisture balance atmospheric model from UVic showed no obvious nonlinear responses between anthropogenic and natural forcings.The nonlinear responses among all the climate forcings(both anthropogenic and natural forcings) contributed to a temperature increase of approximately 0.27℃ at the end of the 20th century,accounting for approximately half of the warming during this period;the remainder was due to the climate forcings themselves.

Two-dimensional Modeling of a Salt-gradient Solar Pond with Wall Shading Effect and Thermo-physical Properties Dependent on Temperature and Concentration

In this paper,the behavior of a salt-gradient solar pond with the square cross-section has been studied experimentally and numerically.A small-scale solar pond were designed and built to provide quantitative data.A two-dimensional,transient heat and mass transfer model has been solved numerically by using finite-control-volume method.In this study,all the thermo-physical properties are variable as the function of temperature and salt concentration.Numerical results as obtained for the experimental pond have been satisfactorily compared and validated against measured data.Furthermore,the wall shading effect has been elaborated to improve the agreement between two sets of results.The temperature of the storage zone is predicted well by the model.It also can be observed that the initial concentration profile is preserved with time.The stability of the pond in time has been investigated in order to distinguish the critical zones.Finally,the application of an energy analysis gives an efficiency of about 12%for the pond.