Identification of the alkalide,Na−, in Na/NH3 matrices using MCD

Codeposition of Na and NH₃ at ≈ 35 K gives rise to an absorption band at ≈ 16950 cm⁻¹ with a positive MCD å term. This band is assigned to the ¹S → ¹P transition of Na⁻ marking the first direct evidence for the existence of an alkalide in NH₃. The absorption and MCD of the solvated electron band are also observed in the near infrared at ≈ 8000 cm⁻¹.     

Sodium ion-conducting solid electrolytes in the system Na3PO4Na2SO4

In the system Na₃PO₄Na₂SO₄, the high-temperature, cubic γ form of Na₃PO₄ forms an extensive range of solid solutions: Na_3−x(P_1−xS_x)O₄, 0 < x < (0.57 to 0.70, depending on temperature). For compositions in the range x = ca. 0.33 to 0.57, these γ solid solutions are thermodynamically stable at all temperatures. The conductivity of the γ solid solutions increases with increasing x and reaches a maximum at x = 0.5 to 0.6, with values of 2 × 10⁻⁵ ohm⁻¹ cm⁻¹ at 100°C, rising to 1.3 × 10⁻² ohm⁻¹ cm⁻¹ by 300°C; this conductivity increase with x is attributed to an increase in the sodium ion vacancy concentration, associated with the solid solution mechanism Na + PS. The phase diagram for the system Na₃PO₄Na₂SO₄ is given together with lattice parameters of the γ solid solutions.     

25 oC下Na2CO3/Na2SO4/NaCl混合盐的溶解动力学研究

研究了25℃时,搅拌速度,加样量及氯化钠的量等不同实验条件下,Na2CO3, Na2SO4, NaCl混合盐的溶解过程,对不同时刻液相的化学组成进行分析并鉴定其平衡时的固相,结果表明：混合盐溶解前期搅拌速度占主导因素,当溶液中三种盐达到一定浓度后,同离子效应占主导因素,随着加样量的增加,碳酸钠和硫酸钠浓度达到一定程度之后反应生成碳钠矾。结合动力学模型计算得到体系中NaCl的溶解动力学方程,得出在25℃条件下溶解符合Stumm模型,溶解过程属于扩散过程控制,同时还伴随着界面反应和化学反应。     

Easylyte Na/K/Cl电解质分析仪常见故障的排除

叙述Easylyte Na／K／Cl电解质分析仪的常见液路、定标、机械故障,无法测定、测定值不准等故障及故障排除方法。     

An investigation of the polythermal diagram of the H2ONa2HPO4Na2SO4 system

The polythermal diagram of the ternary system H₂ONa₂HPO₄Na₂SO₄ has been established, setting up nine isotherms obtained between 0 and 25°C by conductimetric analysis. The solubility domains of the various solid phases have been determined. One eutectic, three stable and one metastable transitional transformations have been observed. Temperature and composition of the eutectic point have been obtained by thermal analysis at constant flow.     

Theoretical Study on the Long-lived Complexes for the Na＋I2 Collision System

For the Na I2 collision system, theoretical study is performed on the QCISD(T) level by using ab initio method. The ab initio potential energy surfaces are got and on them the long-lived complexes are found and optimized. These results verify the crossed molecule beam experimental phenomenon and the detailed geometry structures are given for the first time. The role of the complexes in the reaction path is also described in detail.     

水化Na-蒙脱石和Na/Mg-蒙脱石的分子动力学模拟

利用分子动力学方法(MD)研究了Na-蒙脱石和Na/Mg-蒙脱石层间的补偿阳离子和水分子的结构及扩散性质. 模拟结果表明, 在一定水含量范围内Na-蒙脱石和Na/Mg-蒙脱石表现出不同的膨胀形式, 特别是层间水分子数目在48～72之间时, Na/Mg-蒙脱石的层间距比Na-蒙脱石有较为明显的增大. Na/Mg-蒙脱石两层水化物的层间水分子与Mg2+形成了明显的两层水合壳; 而与Na+只形成了一层平面的水合壳. 在Na/Mg-蒙脱石中, Na+和 Mg2+的扩散方式不同, Na+的扩散范围相对更广, 自扩散系数更大. Na/Mg-蒙脱石比相同水含量下的Na-蒙脱石层间水的自扩散系数小. 由于Mg2+和Na+对层间结构的强烈影响, 从而使有少量Mg2+取代Na+的Na/Mg-蒙脱石与Na-蒙脱石表现出不同的膨胀性质和层间物质的扩散性质.     

炔烃与Na/NH_3的还原反应不是催化氢化

某些有机化学教科书,甚至一些使用较广的教科书。都把在液氨中用金属钠还原炔烃得到烯烃这一反应编写在催化氢化的标题下,与用 Lindlar 催化剂的炔烃的部分氢化反应相提并论,而不加以任何说明。甚至用如下的方程式表述这一反应:N_(?)+NH_(?)(液氨)→XaNH_(?)+(1/2)H_(?)(?)这往往给读者造成两点误解。其一,把这一反应认为是催化氢化反应;其二,认为氢化所需的氢来自于钠与液氨生成氨基钠和氢气的反应。实际上此反应不是催化氢化反应,其反应历程应为 C≡C 被钠原子提供的两个电子所还原,第一个电子进入反键的π轨道,生成一个游离基负离子(Ⅰ),此负离子是强碱,     

Preparation and Characterization of Intercalated Polymethacrylamide/Na‐Montmorillonite Nanocomposites

Polymethacrylamide/Na‐montmorillonite nanocomposites have been prepared by free‐radical polymerization. All the nanocomposites were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and differential thermal analysis. The thermal properties of nanocomposites are notably improved by the presence of the montmorillonite layers in comparison with pure polymethacrylamide. X‐ray diffraction and scanning electron microscopy confirmed that polymethacrylamide could be easily inserted between the layers of Na‐montmorillonite to form intercalated nanocomposites, and significantly large d‐spacing expansions from 1.19 to 2.93 nm of the nanocomposites. Adsorptive properties of nanocomposites were also investigated.     

Phase complex of the Na,K‖Br,MoO4 system

The Na,K‖Br,MoO₄ system was studied by differential thermal analysis and X-ray powder diffraction. It was established that the liquidus surface consists of the crystallization fields of the initial components and the incongruently melting compound NaKMoO₄. The coordinates of three nonvariant points were determined, which represent one eutectic, E ^Δ, and two peritectics, P ₁ ^Δ , and P ₂ ^Δ , with the melting points 472, 512, and 538°C, respectively, and the specific enthalpies of melting Δ_melt H = 177, 230, and 184 kJ/kg, respectively.     

Na− formation by dissociative electron attachment in Na2

Dissociative electron attachment on an effusive beam of Na₂ is studied in the energy range 0–10 eV. A single Na⁻ process is observed at a peak energy of 0.05 ± 0.05 eV. The attachment seems to concern mainly rovibrationally excited Na₂. An absolute energy-integrated cross section of (3.6 ± 1.8) × 10⁻¹⁸ cm² eV is determined by comparison with the known Na positive-ionization cross section.     

Phase equilibria in the Na, K∥SO4, CO3, F-H2O system at 0°C

Phase equilibria in the Na, K‖SO₄, CO₃, F-H₂O system at 0°C are studied by the translation method. Eighteen divariant fields, 16 monovariant curves, and five invariant points are distinguished in the system. The first closed phase diagram (phase complex) of the title system is designed on the basis of these results. Original Russian Text ? Sh.Kh. Avloev, L. Soliev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 6, pp. 1046–1051.     

Phase equilibria in the Na,Ca||SO4,CO3,F-H2O system at 25°C

Phase equilibria in the Na,Ca|SO₄,CO₃,F-H₂O system at 25°C have been studied using the translation method. The existence of seven invariant points, 21 monovariant curves, and 22 divariant fields has been established. These data were used to construct a looped phase diagram (phase complex) for the title system at 25°C.     

Phase equilibria in the Na,K,Mg,Ca‖SO4,Cl-H2O system at 50°C in the anhydrite crystallization region

Phase equilibria at invariant points of the Na,K,Mg,Ca‖SO₄,Cl-H₂O system at 50°C in the anhydrite (CaSO₄) crystallization region were studied. Anhydrite as an equilibrium phase at the six-component level is involved in formation of 22 invariant points, 58 monovariant curves, and 49 divariant fields. A fragment of an equilibrium phase diagram of the title system was constructed in the anhydrite crystallization region at 50°C.     

惰性气氛下准东煤Na/Ca释放特性的研究

基于准东煤中Na/Ca的赋存形态，采用管式加热炉研究了准东煤中Na/Ca在惰性气氛下的释放特性和形态转变。结果表明，水溶态Na_w在加热温度t ≤ 600℃时先转变成不可溶态Na_re，随着温度升高，不可溶态Na_re又重新转变成水溶态Na_w，当加热温度t > 800℃时，Na大量释放。酸溶态Ca_ac在加热温度t ≤ 700℃时先分解生成CaO并且与其他矿物组分反应转变成不可溶态Ca_re，随着温度升高，不可溶态Ca_re逐渐转变成酸溶态Ca_ac和水溶态Ca_w。相同温度条件下，Ca的释放率低于Na的释放率，少量酸溶态有机Ca随挥发分释放而以气相形式释放。     

Na+₋sensing quantum dots for cell-based screening of intracellular Na+ concentrations ([Na+]i)

We have developed a Na-quantum dot (QD) nanosensor for [Na⁺]i measurements. Using this Na-QD, we determined the dynamic physiological responses of [Na⁺]i in nonexcitable human HEK-293F cells and excitable primary rat cardiac myocytes by pharmacologically manipulating the membrane permeability to Na⁺, the Na-K-2Cl cotransporter, and the Na⁺/H⁺ antiporter. These data suggest that the mechanisms of [Na⁺]i homeostasis can now be elucidated with this novel Na-QD nanosensor. This could have a broad impact on Na⁺ channel drug discovery.     

Phase equilibria in the Na,K∥SO4,CO3,HCO3-H2O system at 0°C

Phase equilibria in the Na,K∥SO₄,CO₃,HCO₃-H₂O system at 0°C are studied by the translation method. Twenty two divariant fields, 21 monovariant curves, and seven invariant points are distinguished in the system at 0°C. The first global phase diagram (phase complex) of the title system is constructed on the basis of these results.     

光热效应增强的Au/RGO/Na2Ti3O7光催化加氢性能

将典型的光热等离激元石墨烯和纳米金简便地负载在钛酸钠(Na₂Ti₃O₇)载体上, 构建出具有较窄禁带宽度和较高光催化活性的Au/RGO/Na₂Ti₃O₇光热辅助光催化体系. 研究发现, 石墨烯片层与金纳米颗粒在光照下, 通过局域表面等离激元共振效应诱导产生大量的热电子, 以活化反应物并降低反应活化能, 其引发的光热效应还可精准提升光催化体系中反应位点附近的温度, 从而大幅提升光催化反应速率. 通过构建特殊微支结构, 进一步增强了Au/RGO/Na₂Ti₃O₇催化剂对光的捕获, 并限域锚定高表面能催化剂以增强体系的稳定性. 在光热、 光催化的高效协同增强下, Au/RGO/Na₂Ti₃O₇催化剂体系对对硝基苯酚和肉桂醛的加氢反应均表现出增强的光催化活性. 光热辅助下的Au/RGO/Na₂Ti₃O₇光催化剂在对硝基苯酚反应中的转换频率（TOF）值高达54.4 min^-1, 反应活化能显著降低至15.78 kJ/mol, 且其在长效测试中表现出良好的稳定性（4次循环催化后, 转化率的保持率近90%）.     

Na对PtSn/ZSM-5催化丙烷脱氢反应性能的影响

以HZSM-5分子筛为载体, 利用分步浸渍法制得不同Na含量的PtSnNa/ZSM-5催化剂, 用于丙烷脱氢反应. 利用XRD、吡啶吸附红外光谱、NH3-TPD、氢化学吸附、TPR等手段, 研究了Na的添加对PtSn/ZSM-5催化剂物化性质的影响. 结果表明: Na的添加对PtSn/ZSM-5催化剂的反应性能影响明显. 适量Na的添加不仅降低了催化剂中的Brönsted酸中心和Lewis中强/强酸中心, 抑制了积碳的发生, 提高了催化反应的稳定性; 而且提高了催化剂表面的Pt金属裸露度, 增加了反应活性. 当Na含量为1.0%(w)时, 催化剂的丙烯选择性和收率达到最大, 反应30 h后, 丙烷转化率仍然保持很高(36.4%). 继续增加Na含量, 催化剂中的Lewis弱酸中心有所增加, 同时Sn组分易于被还原成Sn0, 丙烷裂解、氢解等副反应增加, 不利于脱氢反应的进行.