[en] Highlights: • This paper reviews the state of the art of wind energy conversion systems. • Different types of common wind energy conversion systems are classified and compared. • The four most popular MPPT control methods are reviewed and compared. • The latest development of wind energy conversion technologies is introduced. • Future trends of the wind energy conversion technologies are discussed. - Abstract: This paper gives a comprehensive review of the state of the art of wind energy conversion systems (WECS) and technologies, with an emphasis on wind power generator and control. First, different types of common WECSs are classified according to their features and drive train types. The WECSs are compared on the basis of the volume, weight, cost, efficiency, system reliability and fault ride through capability. The maximum power point tracking (MPPT) control, which aims to make the generator speed meet an optimum value to ensure the maximum energy yield, plays a key role in the variable speed WECSs. A comprehensive review and comparison of the four most popular MPPT control methods are carried out and improvements for each method are presented. Furthermore, the latest development of wind energy conversion technologies is introduced, such as the brushless doubly fed induction generator (BDFIG), the stator permanent magnet synchronous generators, the magnetic-geared generators, dual power flow WECS with the electrical variable transmission (EVT) machine, and direct grid-connected WECS. Finally, the future trends of the technologies are discussed

[en] Laser-induced fluorescence method for rapid determination of uranium in soil and rock was studied with a focus on the experimental steps of using the analyzer to detect trance uranium. The calculation formula was proposed and the effects of pH and temperature on the fluorescence intensity, was discussed and a number of different levels of national standard samples were used to control the quality in the determination of large quantities. the test result are satisfied. (authors)

[en] A new method of non-waterdrop decides is studied to determine the inorganic carbon and organic carbon continously in samples for uranium geology and an optimum system of determination has been established. The recovery rate of inorganic carbon is in range of 99.4%-100.1% and the recovery rate of organic carbon is in range of 98.54%-103.1%. This method has been applied to production with satisfactory results. (authors)

[en] Concentration quenching processes and the resulting influence on the photoluminescence properties of Ca₃Si₂O₇:Tb³⁺ green-emitting phosphors are investigated in this work. Cross relaxation between activators and energy migration from activators to quenching center, are assigned to be the quenching mechanism for ⁵D₃ emissions and ⁵D₄ emissions of Tb³⁺ ions, respectively. Concentration quenching processes and the corresponding energy transfer are discussed in detail. The intensity ratio of the emissions from ⁵D₄ to that from ⁵D₃ is tuned by the concentration quenching processes. As a result, bluish-green, green and yellow–green emitting color is induced by concentration quenching effects for Tb³⁺ ions doped Ca₃Si₂O₇ phosphors. -- Highlights: • Concentration quenching and its influence on Ca₃Si₂O₇: Tb³⁺ phosphors were demonstrated. • Two concentration quenching mechanisms, cross relaxation and energy migration were investigated. • Bluish-green, green and yellow–green emission was traced owing to the concentration quenching effects

[en] Based on the leaching experiments on mobile uranium from U-source rock samples of sandstone type U-deposits, the reasonable leaching reagent has been selected, and factors which may effect the leaching rate of mobile uranium such as the grain-size of the sample, the solid-liquid ratio, the sample weight, the temperature, and the leaching time etc, have been discussed, and a widely applicable and quality-stable leaching system and analytic scheme have been developed. The relative standard deviation of the method for the measurement of leaching rate of mobile uranium from U-source rocks of different types is less than 10% (n=11). (authors)

[en] A pre-processing method was researched for uranium bearing sandstone specimen. Specimen was resolved with sodium peroxide and anglomercted with CTMAB, so as to eliminate the effection of silica acid gel to the separation and concentration of uranium and thorium connected with polaragraphic, the uranium and thorium can be determined simultaneously. Linearity for uranium and thorium were found in ranges of 0.001-0.500 μg/10mL with their detection limits of 8.63 x 10^-6 μg/mL and 5.16 x 10^-6 μg/ mL. This method has been used in the continuous determination of uranium and thorium with the content less than 5 x 10^-6 in sandstones-type uranium deposit and satisfactory results has been gotten. (authors)

[en] A method for the simultaneous determination of micro uranium and thorium in rocks by polarography is reported in this paper. Sample was fused with Na₂O₂ and the fusion cake was digested with nitric acid solutions. Cetyl trimethyl ammonium bromide was added into the solution to coacervate silica gel. After remove the silicon by filter, uranium and thorium were separated and enriched by CL-TBP extraction resin. Then micro uranium and thorium were determinated simultaneously in a buffer solution of acetic acid-sodium acetate of pH=5 and with 0.02 g/L tetrabutyliodic ammonium and 4 g/L cupferron. The linear range of uranium and thorium is 0.001-0.500 μg/10 mL. The method has been applied to the simultaneous determination of micro uranium and thorium in rocks with satisfactory results. (authors)

[en] Graphical abstract: Hydroxyapatite nanorods are synthesized using biocompatible biomolecule pyridoxal-5′-phosphate as a new organic phosphorus source by the hydrothermal method. - Highlights: • Hydrothermal synthesis of hydroxyapatite nanorods is reported. • Biocompatible pyridoxal-5′-phosphate is used as an organic phosphorus source. • This method is simple, surfactant-free and environmentally friendly. - Abstract: Hydroxyapatite nanorods are synthesized by the hydrothermal method using biocompatible biomolecule pyridoxal-5′-phosphate (PLP) as a new organic phosphorus source. In this method, PLP biomolecules are hydrolyzed to produce phosphate ions under hydrothermal conditions, and these phosphate ions react with pre-existing calcium ions to form hydroxyapatite nanorods. The effects of experimental conditions including hydrothermal temperature and time on the morphology and crystal phase of the products are investigated. This method is simple, surfactant-free and environmentally friendly. The products are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric (TG) analysis

[en] Objective: To evaluate MRI in the diagnosis of the bone contusion of the knee .joint and its clinical significance. Methods: Using special coil for knee joint, coronal, sagittal, axial and oblique sagittal plane scanning with fast spin-echo sequence(T₁WI, T₂WI, PDWI + FS) was performed on knee joint in 205 patients in three days after injury. According the distributing bone marrow edema and injury mechanism, bone contusion were classified five types as pivot shift injury, clip injury, dashboard injury, hyperextension injury and lateral patellar dislocation. Results: One hundred and forty-five cases of the 205 patients were found bone marrow edema without fracture on X-ray films. Among them, pivot shift injury was found in 43 cases accompanied with anterior cruciate ligament rupture in 30 cases, tear of the posterior horn of the lateral or medial meniscus in 12 and tears of the medial collateral ligament in 8 cases; clip injury in 53 cases accompanied with anterior cruciate ligament rupture in 10 cases, tear of the posterior horn of the lateral or medial meniscus in 15 and tears of the medial collateral ligament in 38 cases; dashboard injury 40 cases accompanied with posterior cruciate ligament rupture in 16 cases, hyperextension injury. 9 cases accompanied with anterior cruciate ligament rupture in 2 cases, posterior cruciate ligament rupture in 3 cases. No lateral patellar dislocation was found. Forty-eight of 145 patients had undergone arthroscopy, 43 cases (89.6%) of them were in accordance with Mill diagnosis. Bone contusion were defined as geographic regions of abnormal signal intensity, that is, low signal intensity in T₁-weighted images and high signal intensity in PD-weighted or T₂-weigeted images with fat saturation. Conclusion: MRI can accurately display the location and area of bone contusion of the knee joint as well as its adjunctive structure injury and deduce their injury mechanism. MRI should be used routinely for knee trauma. (authors)

[en] This paper presents ab initio self-consistent field crystal orbital calculations on the structures, stabilities, elastic and electronic properties of the double-wall nanotubes made of SiO₂ nanotubes encapsulated inside zigzag carbon nanotubes based on density functional theory. It is found that formation of the combined systems is energetically favorable when the nearest distance between the two constituents is in the area of the van der Waals effect. The obtained band structures show that all the combined systems are semiconductors with nonzero energy gaps. Based on the deformation potential theory and effective mass approximation, the mobilities of charge carriers are calculated to be in the range of 10²-10⁴ cm ² V ^-1 s ^-1, the same order of magnitude as those of the corresponding zigzag carbon nanotubes. The Young’s moduli are also calculated for the combined systems. (paper)