柳大纲的广博与执著

柳大纲(1904-1991)是20世纪中国著名的化学家、卓越的科研组织者和领导者,是中国硅酸盐化学、盐湖化学和光谱学等方向的先驱,是中国近现代科技史上推动前科学向科学质变的代表人物。他的早期科研经历和成长过程显示,他不仅推动了传统手工业陶瓷、制盐等向现代工业的革新,还使用完善的科学范式与方法来研究陶瓷、玻璃和制盐过程。以上这些积累,使他于1958年以“赛马式”研发模式推动了盐湖钾肥和硼砂生产由手工业跃进到现代工业。他参与筹建并领导中科院化学所,规划和发展其研究领域,进而以中科院化学所为孵育基地,抽调该所力量,建设了中科院青海盐湖所等多个研究机构。他重视人才培养,重视发展中国化学会和期刊建设工作。     

Liquid-waveguide spectrophotometric measurement of low silicate in natural waters

This paper describes a robust, sensitive method for measurement of low silicate in natural water. The method is based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex, which is then reduced to silicomolybdenum blue by ascorbic acid. This method shows no refractive index effect and a small salinity effect that can be corrected for seawater samples. It was found that the use of poly-vinyl alcohol can prevent the precipitation formation in the ammonium molybdate solution and improve the stability of the silicomolybdenum blue complex. The sensitivity of this method is substantially enhanced by using a liquid-waveguide capillary cell. The detection limit is 0.1 μM, and working range is 0.1-10 μM for using 2-m liquid-waveguide capillary cell (LWCC). The method can be used for both freshwater and seawater samples and has been used to study the distribution of silicate in surface seawater of Gulf Stream in Florida straight.     

Distribution of ionic charge carriers and migration barriers in binary alkali silicate glasses

Likely spatial distributions of network-modifying (and mobile) cations in (oxide) glasses are discussed here. At very low modifier concentrations, the ions form dipoles with non-bridging oxygen centres while, at higher levels of modification, the cations tend to order as a result of Coulombic interactions. Activation energies for cation migration are calculated, assuming that the ions occupy (face-sharing) octahedral sites. It is found that conductivity activation energy decreases markedly with increasing modifier content, in agreement with experiment.     

Ion transport pathways in molecular dynamics simulated alkali silicate glassy electrolytes

The xM₂O-(1 − x)SiO₂ (M = Li, Na, and K, and 0.1 ≤ x ≤ 0.5) glass systems have been studied by constant volume molecular dynamics (MD) simulations. The bond valence (BV) method is applied to the equilibrated configurations to analyse the structural variation in these glass systems with increasing network modifier content, its consequence for M⁺ ion mobility, as well as the distribution of bridging and non-bridging oxygen atoms and the variation of the Q_i values. The contribution of non-bridging oxygen atoms to the BV sums exhibits a transition around x = 1/3 for Li₂O and Na₂O doped glasses. The observed Q_i variation is consistent with a bond order model. Despite slight deviations of the interatomic distances in the MD-simulated glasses, their BV analysis reveals characteristic features of the ion transport pathway. For complex disordered systems with low ion mobilities the bond valence analysis of the pathway characteristics for the mobile ion is thus a viable method to extract ion transport properties even if the mobilities are too low to be directly analysed from the mean square displacements over the simulated period.     

In situ study of magmatic processes: a new experimental approach

We present an internally heated autoclave, modified in order to permit in situ studies at pressure up to 0.5 GPa and temperature up to 1000 °C. It is equipped with transparent sapphire windows, allowing the observation of the whole experiment along the horizontal axis. In the experimental cell, the sample is held between two thick transparent plates of sapphire or diamond, placed in the furnace cylinder. The experimental volume is about 0.01 cm³. Video records are made during the whole experiment. This tool is developed mainly to study the magmatic processes, as the working pressures and temperatures are appropriate for subvolcanic magma reservoirs. However, other applications are possible, such as the study of subsolidus phase equilibria as we have used well-known phase transitions, such as the system of AgI, to calibrate the apparatus with respect to pressure and temperature. The principle of the apparatus is detailed. Applications are presented, such as studies of melt inclusions at pressure and temperature and an in situ study of magma degassing through the investigation of nucleation and growth processes of gas bubbles in a silicate melt during decompression.     

Nanocomposite polymer hydrogels

The technological need for new and better soft materials as well as the drive for new knowledge and fundamental understanding has led to significant advances in the field of nanocomposite gels. A variety of complex gel structures with unique chemical, physical, and biological properties have been engineered or discovered at the nanoscale. The possibility to form self-assembled and supramolecular morphologies makes organic polymers and inorganic nanoparticles desirable building blocks for the design of water based gels. In this review, we highlight the most recent (2004–2008) accomplishments and trends in the field of nanocomposite polymer hydrogels with a focus on creative approaches to generating structures, properties, and function within mostly biotechnological applications. We examine the impact of published work and conclude with an outline on future directions and challenges that come with the design and engineering of new nanocomposite gels.     

Site‐Selective Occupancy of Eu2+ Toward Blue‐Light‐Excited Red Emission in a Rb3YSi2O7:Eu Phosphor

Establishing an effective design principle in solid‐state materials for a blue‐light‐excited Eu²⁺‐doped red‐emitting oxide‐based phosphors remains one of the significant challenges for white light‐emitting diodes (WLEDs). Selective occupation of Eu²⁺ in inorganic polyhedra with small coordination numbers results in broad‐band red emission as a result of enhanced crystal‐field splitting of 5d levels. Rb₃YSi₂O₇:Eu exhibits a broad emission band at λ_max=622 nm under 450 nm excitation, and structural analysis and DFT calculations support the concept that Eu²⁺ ions preferably occupy RbO₆ and YO₆ polyhedra and show the characteristic red emission band of Eu²⁺. The excellent thermal quenching resistance, high color‐rendering index R_a (93), and low CCT (4013 K) of the WLEDs clearly demonstrate that site engineering of rare‐earth phosphors is an effective strategy to target tailored optical performance.     

基于分光光度法的海水原位硅酸盐微芯片分析传感器的研制

基于酸性条件下硅酸盐与钼酸铵反应生成硅钼黄后被还原成硅钼蓝的原理,借助微流控芯片平台,建立基于连续流动-分光光度法快速测定海水硅酸盐的分析传感器,传感器测定周期约为300 s,采用双光程方式拓展测量范围,线性测量范围可达0～400 μmol·L-1,双光程的检出限分别为45.1 nmol·L-1和1.6 μmol·L-1;当海水盐度大于15时,传感器测量准确度和稳定性基本不受盐度影响,且实际海水加标回收率在98.1%～104.0%之间。2015年11月在胶州湾开展了20个站点海试和同步比对试验,结果显示,该系统具有准确度高、简单、集成度高、水样消耗少、抗干扰能力强等优点,可用于海水原位硅酸盐的分析。     

Corrosion protection of carbon steel using a combination of Zr conversion coating and subsequent zinc-rich silicate coating with a flake ZnAl alloy

To improve the corrosion protection properties of zinc-rich silicate coatings on steel, zirconium pretreatment loaded with (3-aminopropyl)triethoxysilane (APTES) 0.025 % (v/v) and the partial replacement of spherical zinc by flake ZnAl alloy were investigated. DC polarization and electrochemical impedance spectroscopy (EIS) show that the zirconium pre-treated layer containing APTES improves the corrosion protection of the bare steel. Zinc-rich silicate coatings containing flake ZnAl with and without pretreatment were evaluated by EIS, salt spray test and pull-off test. Pretreatment with a zirconium conversion layer reduces corrosion products and adhesion loss (from 16.53% to 12.54%) while the performance of corrosion protection significantly increased from 2003 Ω.cm² to 2640 Ω.cm² in comparison with the non-pretreated samples. The results show that flake ZnAl pigment (5 wt%) significantly improves corrosion resistance and prolongs the duration of cathodic protection of zinc-rich silicate coatings.