30 results about "Cadmium tungstate" patented technology

A container inspection equipment with cobalt-60 gamma-ray source and cesium iodide or cadmium tungstate detector includes a cobalt-60 gamma-ray source, a cask, a front collimator, a rear collimator, a cesium iodide or cadmium tungstate detector, signal and image processing systems, container trailer system, and automatic control system. The cask of the cobalt-60 gamma-ray source, the beam shutter, and the front collimator are fixed on the same chassis to form an integration and placed in the source room. The rear collimator, cesium iodide or cadmium tungstate array detector and the radiation catcher are fixed on the same chassis to form an integration and placed in the detector room. A container inspection tunnel is formed between the source room and the detector room. The equipment is mainly used for inspecting smuggling goods and contrabands etc., in large containers, container trucks, train carriage and air containers. The equipment either can be installed in the sea port and land frontier customs or installed at the air port, vital communication line, and railway station.

The present invention belongs to the field of radiation detection technology. The radiation imaging array solid detector includes flash crystal of cesium iodide or cadmium tungstate, photodiode coupled with the flash crystal and casing holding the flash crystal and the photodiode. The casing consists of metal cover plate, metal bottom plate, front end cover, back end cover and two side plates. The metal cover plate is provided with several slots for heavy metal partitions to set in and to separate flash crystals to form several solid detectors. The photodiode is led out through insulators penetrating the metal bottom plate and rubber pad, and there are rubber pads for insulation between different parts. Compared with available technology, the present invention has high detection efficiency, simple production process, less dead area and other advantages.

The invention discloses a cadmium tungstate crystal with near-infrared broadband luminescence property and a preparation method thereof. The cadmium tungstate crystal adopts CdWO4 single crystal as matrix and 0.1 to 2.0mol% of Bi ion is doped into the matrix; the Bi:CdWO4 oxide crystal grows by a crucible descending method; the temperature of the furnace for growing the crystal is 1330 to 1380 DEG C, the inoculating temperature is 1280 to 1300 DEG C, the temperature gradient for growth area is 20 to 40 DEG C and the descending rate is 0.5 to 2mm / h; after the growth of the crystal is ended, the furnace temperature is descended to room temperature by 20 to 80 DEG C / h and the Bi:CdWO4 crystal is obtained; the Bi-doped cadmium tungstate oxide crystal has good physical-chemical stability, and the structural characteristics of the crystal thereof can provide luminous environment with higher efficiency for luminescence center; the invention is beneficial to realizing laser output with high efficiency and can be widely applied to the optical fields of infrared broadband optical amplifiers, tunable lasers and the like.

The invention discloses a process of cadmium tungstate scintillation single crystal growth by the Bridgman-Stockbarge method, and the technology belongs to the single crystal growth field. High-purity CdO(99.99 percent) and WO3(99.99 percent) are taken as the starting material; powder is made according to the mole ratio that CdO:WO3 is equal to 1:1; after through fully ballmilling and mixing, the powder is pressed into tablet with proper specification; the tablet is sintered for 2 to 6 hours at the high temperature of 1000 to 1150 DEG C; and CdWO4 ceramics-shaped polycrystalline tablet can be obtained. The seed crystal and the tablet are stored through a special platinum crucible with 0.1 to 0.3 mm of wall thickness; the crucible is positioned in a single crystal growth furnace after being sealed; the furnace temperature is controlled within 1340 to 1400 DEG C; the position of the crucible is adjusted to ensure the tablet and the top part of the seed crystal are weld to form a stable solid liquid interface with 20 to 60 DEG C / cm of temperature gradient; growth is performed by the Bridgman-Stockbarge method at a speed lower than 2 millimeters / hour; annealing treatment is performed to the grown crystal at the temperature of 950 to 1050 DEG C; and then the scintillation single crystal with high quality and large size can be obtained. The process effectively avoids the inherent harmful melt composition during the process of crystal growth from volatilizing, the melt composition during the process of crystal growth keeps invariable, and the process can be applied to the bath-growth of the cadmium tungstate single crystal with various specifications and shapes.

The invention discloses a preparation method of a cadmium tungstate monocrystal nanoribbon, wherein the cadmium tungstate nanoribbon with unique shape and better uniformity in dimensional distribution is prepared by taking a soluble cadmium salt and sodium tungstate as raw materials, a surfactant SDBS (Sodium Dodecyl Benzene Sulfonate) as an additive and water as a medium, and strictly regulating reaction temperature, addition amount of the surfactant SDBS and a solution pH value. The nenoribbon is small in width and good in shape, has a wolframine nomocrystal structure, and is 60-120nm in width, 1.2-2.5mum in length and 20nm in thickness. The preparation method disclosed by the invention has the advantages of easily obtainable raw materials, simple equipment, low energy consumption, short cycle, low preparation cost, high yield, and safety and reliability for operation; the product has the characteristics of unique shape and dimension, good technical repeatability and sable quality, is easy to prepare on a large scale, and can be widely applied to various fields of nanometer-device XCT (X-ray Transcission Computed Tomography) detectors, radioactive nucleus spectrum and radioactivity determining and nuclear medical instruments and the like.

The invention relates to a tungsten trioxide / cadmium tungstate nanofiber photocatalytic material and a preparation method and applications thereof. The method comprises the following steps: dissolvingammonium metatungstate and cadmium acetate in a mixed solvent consisting of absolute ethyl alcohol and N,N-dimethylformamide, and adding polyvinylpyrrolidone to obtain spinnable precursor sol; controlling rheological property and spinning process parameters of the spinnable precursor sol to prepare precursor fibers, and calcining the precursor fibers at different temperatures to obtain a tungstentrioxide / cadmium tungstate nanofiber photocatalytic material; finally, producing a nanofiber photocatalytic material with a tube-in-tube structure through a preferable experimental scheme. The photocatalytic material realizes efficient photocatalytic degradation of tetracycline under visible light, and the degradation rate can reach 93.1% within 120 min. The preparation method has the advantagesof simple steps, low cost and recyclability, and greatly reduces the application cost.

The invention provides a method for green synthesis of N-benzylidenebutyramide by highly-selective oxidation of benzylamine. The method comprises the following steps: weighing cadmium tungstate and bismuth tungstate, carrying out dissolving in an alcohol solution, and carrying out uniform mixing under stirring; subjecting the mixed solution to crystallization, and carrying out cooling, filtering, separating, drying and the like so as to prepare a cadmium tungstate-bismuth tungstate composite photocatalyst; and weighing the cadmium tungstate-bismuth tungstate composite photocatalyst, carrying out dispersing in benzylamine, introducing oxygen, and carrying out illumination so as to obtain the N-benzylidenebutyramide. The method provided by the invention can improve the conversion rate of benzylamine by controlling the ratio of a catalyst; and the N-benzylidenebutyramide prepared by using the method has selectivity larger than 99%. The method provided by the invention has the characteristics of greenness, no solvent, high efficiency, low energy consumption, simple synthetic process, etc.

The invention discloses a method of preparing a cadmium tungstate nanowire by a microwave method. The method comprises the following steps: respectively preparing sodium tungstate and cadmium chloride into liquor, and carrying out suction filtration after stirring; and enabling precipitates to react under action of microwaves to obtain the cadmium tungstate nanowire. The cadmium tungstate nanowire obtained by the method disclosed by the invention has the advantages of being greater in nanocrystal slenderness ratio, high in purity, excellent in luminescence property, and simple in process, quick and efficient, low in cost, environment-friendly, easy for industrialization, and the like.

The present invention belongs to the field of radiation detection technology. The radiation imaging array solid detector includes flash crystal of cesium iodide or cadmium tungstate, photodiode coupled with the flash crystal and casing holding the flash crystal and the photodiode. The casing consists of metal cover plate, metal bottom plate, front end cover, back end cover and two side plates. The metal cover plate is provided with several slots for heavy metal partitions to set in and to separate flash crystals to form several solid detectors. The photodiode is led out through insulators penetrating the metal bottom plate and rubber pad, and there are rubber pads for insulation between different parts. Compared with available technology, the present invention has high detection efficiency, simple production process, less dead area and other advantages.

An embodiment of the invention provides a laser induced cadmium tungstate crystal growing method. The laser induced cadmium tungstate crystal growing method comprises the following steps: placing CdWO4 seed crystal at the lower end of a crucible, and filling the crucible with a CdWO4 polycrystal material; placing the crucible in a ceramic tube, filling a gap between the crucible and the ceramic tube with Al2O3 powder, and placing the ceramic tube on a lifting table in a furnace body of a heating furnace; heating the furnace body to a set temperature, and carrying out welding of the seed crystal before growth of crystal; enabling the lifting table to fall, and meanwhile, radiating a solid-liquid interface by laser; and after growth of the crystal is finished, reducing the temperature of the furnace to room temperature, and stripping the crystal from the crucible to obtain CdWO4 single crystal. The CdWO4 crystal grows by a Bridgman-Stockbarger method, during growth of the crystal, the laser irradiates the solid-liquid interface between the growing crystal and melt to carry out induction, stable growth of the CdWO4 crystal is realized, the uniform and transparent CdWO4 single crystal can be obtained, and the single crystal has good optical quality.

The invention provides a method for green synthesis of N-benzylbutylamine by oxidizing benzylamine with high selectivity. The method includes: dissolving cadmium tungstate and bismuth tungstate in an alcohol solution, stirring and mixing evenly; crystallizing the mixed solution, and then performing cooling, filtration, separation, drying and other steps to prepare cadmium tungstate-bismuth tungstate. Composite photocatalyst: Take the cadmium tungstate-bismuth tungstate composite photocatalyst and disperse it in benzylamine, add oxygen and light to obtain N-benzylbutylamine. The present invention can improve the conversion rate of benzylamine by controlling the proportion of the catalyst, and the selectivity of the prepared N-benzylbutylamine is greater than 99%. The invention has the characteristics of green, solvent-free, high efficiency, low energy consumption and simple synthesis process.

The invention relates to a silver-modified cobalt tungstate / cadmium tungstate nanofiber photocatalytic material and a preparation method and application thereof. In the present invention, ammonium metatungstate, cadmium acetate, cobalt nitrate and polyvinylpyrrolidone are used as reaction raw materials to prepare spinnable precursor sol, and cobalt tungstate / cadmium tungstate nanofibers are obtained through electrospinning and calcination; silver nitrate is used as the The reaction raw materials deposit silver particles on the cobalt tungstate / cadmium tungstate nanofibers through a silver mirror reaction, thereby forming a silver-modified cobalt tungstate / cadmium tungstate composite nanofiber photocatalytic material. The silver-modified cobalt tungstate / cadmium tungstate composite nanofiber photocatalytic material prepared by the invention realizes efficient photocatalytic degradation of ciprofloxacin under visible light, and the degradation rate can reach 93.5% within 90 minutes. The preparation method has simple steps, low cost, and It can be recycled, which greatly reduces the application cost.

The invention relates to a scintillation crystal radiation detector with the high light extraction rate. According to the invention, the conception of designing the film layer in a targeted manner iscarried out aiming at the main emergent waveband of the scintillation crystal, the difficulty that the film research data volume is too large and is difficult to analyze is overcome, and a proper reflective film layer material is obtained; the detector has good adhesion with the crystal, the film layer number is less and is easy to realize, and the measurement efficiency and the measurement precision are correspondingly improved.

The invention relates to a radiation detector for scintillation crystals with special light emerging surfaces. Shapes of the light emerging surfaces of the scintillation crystals are optimized; an optical light guide structure is formed by an emerging end of each scintillator; the specific shape design of the light emerging surfaces considers matching of a refractive index and an emerging wavebandof the scintillation crystals; an emerging probability of emergent light totally reflected when emerging for the first time in the prior art can be improved; measurement efficiency and measurement accuracy are improved; and particularly, when a high-performance detector is developed, detection performance can be further improved.

The invention provides an oxygenating and decolorizing growth method of a cadmium tungstate scintillation single crystal. Cadmium tungstate polycrystalline powder is synthesized by adopting a solid-phase reaction. The method comprises the following steps: adding an alkali metal peroxide (M2O2) into the pre-synthesized polycrystalline powder, the adding dosage being 0.01-0.1% mol of the M2O2 for 1mol of polycrystalline powder; filling a platinum crucible with a cadmium tungstate polycrystalline material into which the M2O2 is added; under the condition that the platinum crucible is completelysealed, subjecting the cadmium tungstate polycrystalline material to a solid-phase reaction in a single crystal hearth, performing a lattice oxygenating reaction on the polycrystalline material by utilizing the strong oxidizing property of the additive M2O2, and growing the ultra-light-color large-size cadmium tungstate single crystal by combining a Bridgman method single crystal growth process. The method can effectively solve the problem of single crystal blackening and coloring caused by lattice oxygen atom deficiency, thereby obviously improving the optical quality and luminescence property of the cadmium tungstate scintillation single crystal.

The invention relates to a cadmium tungstate scintillation crystal radiation detector coated with a high refleting film and a special light emitting surface. The invention designs a film layer for themain emitting band of the scintillation crystal itself in a targeted manner, and overcomes the difficulty that the amount of research data of the film layer is too large to analyze, and obtains a suitable reflective film layer material, which not only has good adhesion to the crystal, but also has a small number of film layers and is easy to implement. The invention further provides a special light emitting surface design matching with the total reflection coating scheme, and accordingly improves the measurement efficiency and measurement accuracy.

The invention relates to a scintillation crystal radiation detector with a special light emitting surface matched with a lens group. A matched wide-angle and large-depth-of-field lens group is constructed, so the collection efficiency of the optical sensor on the scintillation light is improved, and the energy resolution is improved; the specific parameter design considers the matching with the emergent wave band of the scintillation crystal, so the incident light sensor for focusing and collecting the scintillation light can be increased, and the energy resolution is improved; the shape of the light emitting surface of the scintillation crystal matched with the lens group is correspondingly designed, the measurement efficiency and the measurement precision are further improved, and the detection performance can be further improved especially when a high-performance detector is developed.

The invention relates to a high-efficiency method for preparing cadmium tungstate powder. The method comprises the following steps: a precursor solution containing Na2WO4.2H2O and a soluble cadmium salt and using a mixture of water and a water-soluble alcohol as a reaction solvent is stirred at a temperature of 60-80 DEG C, so that a cadmium tungstate sol is obtained, wherein the volume ratio of the water-soluble alcohol to the water is (1-10):2; and the cadmium tungstate sol is subjected to vacuum filtration and drying to obtain a granular solid, and the granular solid is calcinated at a temperature of 800-1000 DEG C, so that the cadmium tungstate powder is obtained. The method uses the mixture of the water-soluble alcohol and the pure water as the reaction solvent relative to a conventional solution method of choosing water as a reaction solvent, so that the volume of the cadmium tungstate sol can be greatly reduced, vacuum filtration time is shortened, and vacuum filtration efficiency is effectively improved, and therefore the efficiency of preparing the cadmium tungstate powder is improved.

The invention discloses a thermistor raw material, a method for preparing the same and application of the thermistor raw material. The thermistor raw material comprises, by weight, 30-50 parts of cadmium tungstate (CdWO4), 49-69 parts of cadmium antimonate (Cd2Sb2O7) and 1-5 parts of zinc borosilicate glass. The thermistor raw material, the method and the application have the advantages that crystalline grains of thermistors prepared from the thermistor raw material are uniform and compact; as tested by experiments, resistance-temperature characteristics of the thermistors prepared from the thermistor raw materials can linearly vary.