Seek to translate an English chemical literature, find a chemical literature translation

Ekeberg discovered tantalum in the form of an oxide 200 years ago. However, the discovery and study of the properties of potassium hexafluorotanate (K2TAF7) is the real beginning of tantalum chemistry and production development.

Tantalum production technology has been around for about 80 years. Developments include the application of liquid-liquid extraction instead of fractional precipitation and sodium reduction instead of electrolysis. However, tantalum technology is still based on potassium fluorotanatalate-K2Taf7 (trade name K-salt) as an intermediate material.

At present, tantalum-containing raw materials are dissolved in HF solution and separated and purified by liquid extraction in organic solvents. This purification protocol is used to produce K2TaF7 (K salt) in small crystals, which is used as a starting material for the reduction of tantalum in the form of melt sodium.

The purpose of this paper is to collect and discuss the main properties of k-salt crystallization, dissolution and molten salt forms. This information can be used by tantalum producers and researchers to apply tantalum chemistry.

The latest material developments are aimed at further compounding fibers or whiskers with ceramics to increase the strength of these ceramics.

Whisker-reinforced ceramic composites have quasi-ductile strength properties.

The whisker reinforcement principle is based on the following activation principle: the pressure is transferred from the matrix material to the high-strength reinforcement component by introducing a whisker with Young's modulus; Compressive stress is generated in the matrix by introducing whiskers with a high coefficient of thermal expansion; Resist crack propagation through whiskers, and transfer cracks along the whisker-matrix interface. and induce microcracks by differences in mechanical and thermodynamic behavior between whiskers and matrix materials. However, the adhesion between the whiskers and the substrate should be kept low enough to ensure that the dynamic pressure only pulls the whiskers out of the substrate and not tears them.

In whisker-reinforced ceramics, these described mechanisms may overlap.

Find a translation software that can translate 80% of the way, and you just need to straighten out the word order.

· Human translation, please review.

4-dimethoxybromobenzene (bromorescarf) has been prepared from the bromination of phthalenes (veratrolis) in one step, brominated with air-diluted bromine vapor in glacial acetic acid, with bromine in carbon tetrachloride and with n-bromosuccinimide in carbon tetrachloride. The latter approach appears to be the most preferable, as the mild bromination of bromimide will eliminate or minimize the two disadvantages of the other two methods, i.e., demethylation of aryl ethers and/or debromination. However, Buu-Hoi's procedure (1) was not entirely satisfactory as more than 100 excess veratrol ethers were used.

As a result, the process wastes resveratrol ether and has unnecessary complexity in isolating the introduced product. The method has been modified, 1) by using an equal molar amount of reactant, and 2) by reducing the volume of solvent relative to bromide. These modifications increased the yield of 4-Resver from a theoretical 61% to 83-86, as described in the experimental section.

A small amount of 4,5-dibromoresveratrol ether is produced as a by-product.

Experiment 69 g (mol) of veratrol ether (Eastman Kodak 274), 80 ml of carbon tetrachloride (Merck Reagent), and 89 g (mol) of N-bromosuccinimide (Matheson 6123) were placed in a 500 ml round-bottom flask fitted with a reflux condenser (protected by a desiccating tube of calcium chloride). The mixture is heated under reflux on a steam bath for 6 h and left overnight at room temperature. The succinimide was separated from the dark red solution by suction filtration, sintered with a glass funnel with medium porosity, and washed with three parts of 20 ml of carbon tetrachloride.

Carbon tetrachloride is removed from the combined filtrate and scrubbing by distillation at atmospheric pressure.

The residue is fractionated with vaczlo to obtain 93 grams (8670) of 4-bromoresveratrol, a colorless to pale yellow oil with a boiling point of 761 mm at 5 mm; The estimate is the refractive index). After distillation is complete and the system has cooled, a small amount of light yellow material crystallizes on the upper wall of the retort. A part of this substance, recrystallized from ethanol, was identified by a melting point of 88-90C (alone) and a melting point of 90-92C in a real sample with a melting point of 91-92C was identified as 4,5-dibromoresver.

Refraction of a fraction of 4-bromoresver ether yields a colorless product, boiling point: at millimeters for ; n：; d2：，。

4-bromoveratrole has been prepared in one step from the brorni national air dilution of brorni from veratrol ether in glacial acetic acid (2), with bromine. carbon tetrachloride (4) and carbon tetrachloride with N-bromosuccinin ide (1). The latter method seems to be the most ideal since mild bromination of its brother noimide should be eliminated or reduced by other methods, i.e., methylation and or the aromatic ether of nickel NAT ions.

However, the Buu Sea"；Procedure (1) is not entirely satisfactory because more than 100% excess of methoxybenzene has been used. This process is to make the product introduction of wasting veratrol ether and unnecessary complexity in separating cations. The method is modified (a) with an equal molar amount of reactant, and (b) by reducing the relative volume of the solvent bromoimide.

The 4-bromoveratrole yield of these modifications increased from 61% to 83-86% theory ( ) is described in the experimental section. A by-product of the formation of a small amount of 4,5-di-bromomethoxybenzene (3).

Experiments with 609 g (mol) of resveratrol ether (Eastman Kodak 274), 80 ml of carbon tetrachloride (Merck's reagent), and 89 g (mol) of bromosuccinimide (Yanghang 6123) were placed in a 500 ml round-bottom flask equipped with a reflux condenser protected by a calciunl chloride drying tube. The mixture is heated back under reflux in a steam bath for six hours and allowed to stand at room temperature overnight. This is the State Environmental Protection Administration rated succinimide for the crimson solution by suction filtration, with a medium porosity porous glass funnel, and three 20 ml.

Partial carbon tetrachloride wash. Carbon tetrachloride is distilled from atmospheric pressure of the combined filtrate and wash. Residual fractionation yields 93 g in vaczlo.

8670) as a colorless to pale 4-bromoveratrole.

Yellow oil, bp"；at 5 mm. （ "；at 761 mm. ）；CNC -

After distillation, the complete system has cooled the upper walls of a small amount of yellowish crystallization kettle material. This part of the recrystallized substance, ethanol, was identified by the gendarmerie 88-90" 4,5-dibromoveratrole；c.Alone and gendarmerie 90-92"；The melting point of the admixture is 91-92 for the authentic sample (3).

Part of the 4-bromoveratrole pleats gives a colorless product, the company"；in millimeters. n：；；Kind.

Can be translated with Ringers software.

Artificial translation, rest assured Figure 2(a) shows that there is not only row spacing, but also ridge spacing like that of crops. Why does the spatial distance occur and the material does not grow during the growth of SiO2 nanowires? In an earlier article, we reported that in order to maintain thermodynamic equilibrium during growth, multiple hollow fibers accumulate together and form a multi-core.

For this reason, when a large number of SiO2 nanowires are grown, effective heat dissipation must be provided during growth in order to maintain thermodynamic equilibrium. In this case, there are some SiO2 nanowires that have enough space around them so that heat can be transferred efficiently, so Figure 2(a) shows an increase in growth species. Figure 4(a) shows the performance of SiO2 nanowires at low temperature (25?).

Three-dimensional plot of X-ray-induced isothermal photoluminescence at 240 K. The two wide emission peaks correspond to the emission characteristics at 430 and 570 nm, similar to those reported by the group of Helperin bulk Siox materials, but slightly shifted to 392 (nm?). ）。

Science in China (Series B), vol. 45. Longer wavelengths.