黄冶窑白瓷的物相和微观结构研究

以黄冶窑四个时期的白瓷样品作为研究对象,利用X射线衍射仪（XRD）和扫描电子显微镜（SEM）对样品进行分析,结果表明:黄冶窑白瓷胎的物相基本相同,主要是莫来石、α石英和方石英、未熔石英和少量的粘土相;黄冶窑白瓷釉中有气泡存在,釉中气泡为圆形,釉中存在微米级的针状或柱状钙长石晶体,釉存在分相结构,且分相结构与析晶相伴而生;黄冶窑白瓷胎中有气孔、未熔的石英颗粒、较大的Ti颗粒、莫来石晶体和石英晶体。The white porcelain samples of the four periods of Huangye kiln were studied in this paper, and the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the material phase is basically the same of the white porcelain bodies from Huangye kiln, and mainly mullite, alpha quartz and cristobalite, unmelted quartz and a small amount of clay phase; There are some round bubbles in HuangYe kiln white porcelain, glazes, so are some feldspathic crystals with micro-level needles or columnar. It is evident to observe phase separation structure, which is accompanied by the birth. Apart from some pores, unfused quartz particles, larger Ti particles, mullite crystals and quartz crystals can also be found in the embryo of Huangye kiln white porcelain.     

The influence of defects in the crystal structure on helium diffusion in quartz

The solubility and diffusion of helium in quartz crystals are investigated as functions of the distribution and density of structural defects. The types of defects in the crystals are identified and their distribution over growth sectors is determined by x-ray diffraction topography and phase radiography with a synchrotron radiation source. The effective solubility and effective diffusion coefficients for helium in quartz are estimated from the experimental data on the amount of helium extracted from samples with different contents of defects. It is revealed that the effective diffusion coefficient of helium depends on the number of dislocations.     

On the phenomenological theory of the linear electrooptical effect in uniaxial crystals

The linear electrooptical effect in uniaxial crystals is considered with the aid of direct tensor methods. Covariant expressions for finding biradials and ray refractive indices are developed. A general expression is derived relating the nonlinear optical polarizability parameters and the electrooptical properties of a crystal. The results are applied to cuts of uniaxial ammonium dihydrogen phosphate (ADP), potassium dihydrogen phosphate (PDP), and quartz crystals often used for light modulation. The induced phase differences between the light waves propagating in such crystals are found for the field orientations considered.     

Changes in the Physical Properties of Neutron-Irradiated Quartz

The influence of irradiation on a set of physical (absorbing, luminescent, paramagnetic, and structural) properties of quartz crystals is studied. The nonmonotonic kinetics of changes in the optical and x-ray parameters of the crystal in the region of radiation-stimulated phase transition is established. The possible mechanism of radiation-induced reorganization of the crystal structure is discussed.     

Changes in the surface structure of the heterogeneous body (diorite) under friction

Raman, infrared, and photoluminescent spectroscopy has been used to study changes in the surface structure of quartz diorite caused by friction. Before friction, the diorite surface layer has contained mainly quartz and feldspar crystals. After friction, some quartz and feldspar crystals have been destructed and replaced by a newly formed hydromica mineral with a low friction coefficient such as illite.     

Fourier Transform Infrared Study of A C18 Modified Quartz Surface

In reversed-phase liquid chromatography the separation mechanism depends on the solute-stationary phase and solute-solvent interactions. These interactions can be studied under near-normal chromatographic conditions by total internal reflection fluorescence (TIRF) spectroscopy. Quartz crystals chemically modified with n-octadecyl-substituted-silanes, which are common derivatizing reagents used to modify chromatographic surfaces, can be used as a model stationary phase in TIRF studies. To facilitate study of the separation mechanisms using TIRF, surfaces of quartz crystals were chemically modified with silylating reagents and characterized by Fourier Transform Infrared Spectroscopy (FT-IR). Susceptibility tests of the modified surfaces were performed using protic and aprotic solvents. Siloxane bonds were formed, between the reagent and the quartz surface, at high reaction temperature in the absence of any solvent. Siloxane bond formation in the presence of organic solvent at room temperature was observed only when the crystal was previously dehydrated at high temperature.     

The effect of the crystalline perfection of quartz on the rotation of the plane of polarization of light

The wavelength dependence of the specific rotation of the plane of polarization of light by quartz crystals is experimentally studied. The chirality coefficients determined from the plots δ(1/λ²) are found to be different for different crystals. The differences between these plots are associated with the perfection of the crystal structure of quartz. The rotation of the plane of polarization is more sensitive to imperfection of the medium and makes it possible to reveal this imperfection without additional irradiation of crystalline quartz by γ quanta.     

Propagation of a Pearcey beam in uniaxial crystals

An analytical propagation expression of a Pearcey beam in uniaxial crystals orthogonal to the optical axis is derived.The propagations of the Pearcey beam in the tourmaline and the quartz are investigated. The phase distribution and the angular momentum of the Pearcey beam in the tourmaline are also performed. The result shows that the positions of the auto-focusing and the inversion simply relate to the extraordinary refractive index of the crystals. In other words, we can choose the suitable crystals to adjust the positions of auto-focusing and inversion of the Pearcey beam to meet the actual needs.     

Generation of coherent terahertz phonons by sharp focusing of a femtosecond laser beam in the bulk of crystalline insulators in a regime of plasma formation

The generation of coherent terahertz phonons in a regime of plasma formation by a femtosecond laser radiation with an intensity of 10¹³ W/cm² in the bulk of crystalline quartz has been detected by the method of probing by a probe pulse of the third harmonic. A smooth increase in the frequency of coherent terahertz phonons from 2.2 to 5.5 THz has been detected, along with its subsequent sharp decrease down to 2.2 THz due to an α-β phase transition in crystalline quartz. The generation of 1-THz coherent phonons has been detected in BaF₂ crystals. A smooth variation of the frequency of coherent phonons from 2 to 2.5 THz has been detected in leucosapphire. The generation of coherent phonons during local laser excitation in CaF₂ and LiF crystals develops at the frequencies of 2.3 and 0.1 THz, respectively.     

Nonlinear spatially resolved phase spectroscopy

A new method for the determination of spatially resolved phase differences of nonlinear susceptibilities is presented. The technique is based on the interference of the signal field with a reference field. A phase-shifting element that directly changes the phase difference between the two second-harmonic fields is introduced. The reliability of the method is tested by an experiment with two quartz crystals. As a first application, a measurement of the phase difference between domains in antiferromagnetic YMnO(3) is presented.     

石英消偏器紫外-真空紫外消偏特性研究

在Lyot消偏器的基础上 ,设计研制了由两块楔角相同的楔形石英晶体构成的石英消偏器 ,用于降低光谱仪偏振响应度。根据矩阵光学理论 ,数值模拟计算了紫外 真空紫外波段石英消偏器消偏特性随其中心厚度以及入射光偏振状态、光谱带宽等的变化规律。利用氟化锂偏振器作为起偏器和检偏器 ,在 1mSeya Namioka单色仪上实验研究了石英消偏器在紫外 真空紫外波段的消偏特性 ,经过石英消偏器后 ,出射光的偏振度小于 1% ,可满足石英消偏器用于光谱辐射测量的工作要求。     

Growth and characteristics of some new varieties of coloured quartz single crystals

Abstract

Methods for the hydrothermal synthesis of four new coloured varieties of quartz have been developed. Two of these varieties are very rare in nature. They are a bi-coloured amethyst-citrine quartz (ametrine) and a phosphorous-bearing low-temperature pink quartz. The other two varieties have no natural counterparts. They are a pink-violet Ni-bearing quartz, and a Cu-bearing quartz which resembles aventurine. The principal conditions for producing these varieties of quartz single crystals are described.     

Structure perfection of single-crystal quartz intended for experiments on finding the electrical dipole moment of neutrons by the crystal diffraction method

The perfection of quartz crystals of different origins intended for experiments on finding the electrical dipole moment of neutrons is studied. The study is carried out using the crystal diffraction method by passing a neutron through the crystal under near-Bragg conditions at a diffraction angle of about 90°. It is shown that optical-grade quartz grown at the All-Russia Research Institute for Synthesis of Mineral Raw Materials (VNIISIMS, Aleksandrov, Vladimir oblast) offers the highest perfection and homogeneity. Of a total of 22 crystals, 15 best ones with a spread in the interplanar distance of Δd/d ₀ ≤ 5 × 10⁻⁶ were selected for experiments. The crystals measure 100 × 100 × 500 mm.     

Chemical resistance and cleanability of glazed surfaces

Adhesion of soil on glazed surfaces and their cleanability depends on chemical composition, phase composition, and roughness of the surface. The surface can be glossy consisting mainly of a smooth glassy phase. A matt and rough surface consists of a glassy phase and one or more crystalline phases. The origin and composition of the crystalline phases affect the chemical resistance and the cleanability of the surface. Fifteen experimental glossy and matt glazes were soaked in a slightly alkaline cleaning agent solution. The surfaces were spin-coated with sebum, i.e. a soil component typical for sanitary facilities. After wiping out the soil film in a controlled manner, the surface conditions and the soil left were evaluated with colour measurements, SEM/EDXA and COM. The results show that wollastonite-type crystals in the glaze surfaces were attacked in aqueous solutions containing typical cleaning agents. This corrosion led to significant decrease in the cleanability of the surface. The other crystal types observed, i.e. diopside and quartz crystals were not corroded, and the cleanability of glazes containing only these crystals was not changed in the cleaning agent exposures. Also the glassy phase was found to be attacked in some formulations leading to a somewhat decreased cleanability. The repeated soiling and cleaning procedures indicated that soil is accumulated on rough surfaces and surfaces which were clearly corroded by the cleaning agent.     

The growth of crystals by the chemical transport of material I. A new method of preparing magnetite single crystals

The paper describes the preparation of single crystals of magnetite (Fe₃O₄) by transport over the gaseous phase, in a sealed quartz ampoule. Growth occurs at 800°C, i.e. about 750°C below the melting point of magnetite. The crystals obtained, which are octahedral in form, are up to 2 mm in size; as a rule they are bounded by straight, shiny surfaces. Apart from the most frequent surfaces of an octahedron {111} we also see {110}, {hkk} and {hhk} surfaces. The quality of the surface enables the domain structure to be studied by the colloid technique without any further treatment.     

The low-temperature solubility of helium in quartz

Technical Physics - The solubility of helium in α- and β-quartz single crystals, optical quartz crystals, and Pyrex glass has been studied by the method of thermal desorption of helium...     

Mechanism of the transition between 1<Emphasis Type="Italic">q</Emphasis> and 3<Emphasis Type="Italic">q</Emphasis> phases in a two-dimensional crystal model

The previously proposed model of a crystal with rotational degrees of freedom is extended to the two-dimensional case. The model contains two nonlinear terms that allow for the stability of 1q, 2q, or 3q modulated phases, depending on the ratio between the model parameters. A numerical treatment is performed for the transition between the 1q and 3q phases that is characteristic of crystals with hexagonal symmetry. This model makes it possible to reconstruct the sequence of phase transitions occurring in quartz crystals upon cooling and offers a satisfactory explanation of the experimentally observed increase in the temperature range of existence of the 1q phase under external uniaxial loading.     

Effect of fast neutrons on structural rearrangement in crystalline quartz

IR spectroscopy has been used to study the effect of reactor radiation on the structural state of different specimens of synthetic quartz crystals. The patterns have been established for modification of the spectral characteristics of the bending vibrations of the crystal lattice as a function of the orientation of the crystals and the fast neutron fluence. It is hypothesized that the identified features of radiation-induced modification of the parameters of the bending modes for the different quartz specimens are due mainly to structural rearrangement occurring in the crystals. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 122–125, January–February, 2009.     

Generation of surface-voltage by charged crystal defects and applications

Abstract

Working mainly on quartz crystals it has been found that crystal defects present inherently or generated deliberately on the surface and in the bulk give rise to surface voltage (called by us self-voltage) due to charged electron and hole traps produced by the defects, the self-voltage thus forming monitor of presenceof crystal defects. The self-voltage could be measured by FET instrumentation.

Based on the above the crystal defects (and hence self-voltage) were reduced or practically eleminated by combination of processes of etching and annealing of the quartz, allthis reseulting in improvements of electronic characteristics of quartz crystals such as resistivity and frequency stability.