真空蒸馏-电位滴定法测定钠中碳

快堆冷却剂钠中碳的含量对结构材料的物理和机械性能有影响,为检测钠中碳含量,建立了真空蒸馏-电位滴定测定钠中碳的方法.在氩气气氛下取1～2 g钠于石英坩埚内,在400℃及6.7×10-3 Pa下真空蒸馏除钠,残渣在1 100℃下通净化的氧燃烧40 min,生成的二氧化碳通入pH为10的BaCI2 (10％)和Ba(OH)...     

JEFF-3.1.1 Nuclear Data Validation for Sodium Fast Reactors

The JEFF-3.1.1 Nuclear Data Library is the latest version of the Joint Evaluated Fission and Fusion Library. We present the status of the validation of this library using the Monte Carlo Code TRIPOLI 4.5 and the deterministic code package ERANOS 2.2 for fast reactor calculations. For this purpose, we reanalyze a selected set of integral experiments performed in the MASURCA mock-up (CEA/CADARACHE), in the ZPPR mock-up at ANL (USA), and in the SUPERPHENIX Power Reactor. Furthermore, we also present the analysis of pure sample irradiation experiments PROFIL and PROFIL-2 performed in the PHENIX reactor, as this kind of experiment provides a direct feedback on nuclear capture data. We observe good performances of these calculation tools for criticality calculations and fuel inventory prediction. From this validation work, some required improvements on nuclear data are highlighted, as well as the need for new specific integral experiments. The main trends observed are the following:

—Reactivity of clean and fresh cores: the results obtained with JEFF-3.1.1 are consistent with those obtained using JEFF-3.1 within 80 pcm, but there is an overestimation of the calculated reactivity of all the experiments between 40 and 800 pcm depending on the spectrum hardness (Pu content) and fuel composition, the discrepancy being larger in hard spectra. Additional investigations are in progress to understand this behaviour.

—Integral capture cross sections (PROFIL and PROFIL-2):/C/E - 1/≤ 3%, except for ²⁴¹Pu (C/E ≈ 1:08), ²⁴²Pu (C/E ≈ 1:18), ²³⁷Np (C/E ≈ 0:92), ²⁴³Am (C/E ≈ 0:93), ²⁴⁴Cm (C/E ≈ 1:35); impact of the trends observed on the individual fission products put in PROFIL and PROFIL-2 is ≈ 4% on the part of Δ_ρburnup due to fission products.     

DEGRADATION RATE OF WATER-SOLUBLE POLYMERS BY OZONE

Water-soluble polymers were degraded by ozone, and the degradation rate defined by the change of weight average polymerization degree per unit time was obtained. The degradation rate of poly(oxyethylene) (PEG) was proportional to the 1.5 to 2.0 power of the polymerization degree, and was 20 to 60 times that of poly(acrylamide) (PAAm). The experimental results of PEG and PAAm were correlated as a function of polymerization degree, temperature, dissolved ozone concentration and OH^? ion concentration. The degradation rate of poly(sodium acrylate)(PANa) was proportional to the 2.0 power of the polymerization degree when no other electrolyte was added. However, the degradation rate of PANa decreased with the increase in NaCl concentration, and approached that of PAAm in the range of high NaCl concentrations.     

过碳酸钠的生产和应用

综述了过碳酸钠的生产、性能及应用，重点讨论了在洗涤剂中的应用，并以２ｋｔ／ａ生产装置为例进行了经济效益分析，认为生产过碳酸钠有较好的社会效益和经济效益。     

Irrigation of grapevines with saline water at different growth stages: Effects on leaf,wood and juice composition

Background and Aims: This study reports on the effects that timing of saline irrigation has on leaf and wood tissue concentrations of Na⁺ and Cl^– and on juice composition. Methods and Results: Colombard vines on Ramsey rootstock were drip irrigated with saline water during any one of four annual growth stages: pre‐flowering, berry formation, berry ripening and postharvest. At other times, vines were irrigated with non‐saline water as was the control. Salts were annually flushed from the rootzone. Over six seasons, saline irrigation caused five‐ and sevenfold rises, respectively, in the leaf and juice Na⁺ concentrations and two‐ and fourfold rises in respective Cl^‐ concentrations. Saline irrigation raised juice pH and this was associated with a rise in juice Na⁺. Normalising responses for inter‐treatment differences in the seasonal salt load to isolate the effects of timing showed that juice Cl^‐ concentration was most sensitive to saline irrigation during berry formation and juice malate concentration most sensitive to saline irrigation pre‐flowering. Conclusion: Cl^‐ uptake was greatest when saline irrigation was applied early in organ formation, whereas Na⁺ uptake reflected seasonal salt load in irrigation water. Significance of the Study: In vines on the chloride excluding rootstock Ramsey, yield loss under saline irrigation was associated with high concentrations of sodium in the leaf.     

浅析食盐的健康摄入

人们食盐摄入过量,对身体会造成伤害。如何减少食盐的摄入量成为当前健康饮食的当务之急。本文主要介绍了健康食盐的必要性,并对合理摄入食盐作了一定的阐述,     

Expanded Industrial Experiments of Free-alkali Recovery from Sodium Tungstate Solution by the Membrane Electrolysis Process

The technology of electrolysis with ion-exchange membrane has been widely applied in industry [11. The free-alkali recovery from sodiumtungstate solution by electyolysis with ion-exchange membrane has been stUdied in our laboratory. After success in exploratory test, furtherstudies were made on the anode of the electfolysis, the structUre of the electrolytic tank and theassemblage of the electfolytic cell, and someachievements have been obtained [2--4]. Basedon these results, the expanded exp…     

Kinetics of the dissolution of silica in aqueous sodium hydroxide solutions at high pressure and temperature

The kinetic of the reaction of sand with aqueous NaOH corresponding to the ratio SiO₂/Na₂O = 2 was studied in a pressure vessel at 220°C and 2.7 MPa. Since the kinetic curves could not be obtained directly from the experimental data, a new method is proposed to plot the entire kinetic graph from experimental data. An analytical expression of the type α = A [1 -exp(-Bt)] describes the system perfectly. The constants A and B were calculated for a silica sample having a narrow granulometric distribution (range i.e. 300–315 μm). The value of A is found to be almost constant, between 0.95 to 0.99 and B ranges from 0.03 to 0.14 when [OH-] increases from 0.5 to 12.5 mol/L. The kinetic order with respect to OH^? is equal to 0.470 + 0.013 and the kinetic constant at 220°C is 3.933 × 10^?6 g/m².s.     

国内外钼酸钠应用和产耗概况

叙述了国内外钼酸钠的应用、生产、消费、生产工艺、技术标准、主要生产厂家及中国出口情况，并对国内钼酸钠今后的发展提出了建议。     

A new methodology for studying the performance of products against ruminal acidosis

This paper describes a new and convenient methodology for studying the performance of products used in the treatment of ruminal acidosis. The method is based on potentiometric titration of the increase in buffer capacity and acid consuming capacity after the addition of products to a suitable medium at physiological rumen pH values. The testing medium is a mixture of buffer substances (phosphate, maleate and volatile fatty acids) that mimics real ruminal fluid in chemical composition, pH and temperature, providing useful experimental results allowing easy testing of antacids. This methodology was applied to the testing of four raw materials (sodium bicarbonate, two calcium carbonates and magnesium oxide). Results in good agreement with theoretical predictions and field experience were obtained. Copyright © 2003 Society of Chemical Industry