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[en] The cerium doped lanthanum bromide crystal (LaBr3:Ce3+) is a new inorganic scintillator crystal developed recent years. The good characters such as high light yield, high energy resolution, fast decay time, have made it a potent competitor with traditional scintillator crystals such as NaI (Tl). In the article, I will principally compare the characters of LaBr3:Ce3+ crystal to NaI (Tl), and list examples to explain its applications, in order to reflect the characters of LaBr3:Ce3+ crystal comprehensively. (authors)
[en] Based on SCIENCE V1 code package imported from France, function expansion for reflector calculation is developed according to the requirements. The function modules beneath the graphical user interface are studied, and then the function of reflector calculation is developed. After the development, SCIENCE code package is used to investigate the reflector parameters for Unit 1 and 2 Qinshan Ⅱ. Compared with the measurements from the total 19 fuel cycles of Unit 1 and 2, the main theoretical calculation results fit well with the measured ones. Benefit from this study, reflector calculation function is added to SCIENCE V1 code package, the scope usage of SCIENCE code package is expanded, and some R and D experience of large scale code package is obtained. (authors)
[en] 15 cm long YBCO superconducting tapes with Jc of 104 A cm-2 were fabricated by the ultrasonic spray pyrolysis method. Predeposition for 15 min at 700 deg. C can effectively prevent the Ag substrate from vaporizing and diffusing into YBCO films, and improve the coarse surface of Ag, and the surface morphology and connectivity of YBCO films, and therefore increase the superconducting properties. Holding the temperature at 900 deg. C for 30 min after deposition improves the texture and connectivity of YBCO films
[en] We investigated the binding interaction between tetracycline hydrochloride (TCH) and bovine proteins β-casein (β-CN), α-lactalbumin (α-LA) in aqueous solution by multi-spectroscopic methods and molecular modeling techniques. Fluorescence and time-resolved fluorescence showed that TCH effectively quenched the intrinsic fluorescence of bovine proteins via static quenching, while there was a single class of binding site on protein. Thermodynamic parameters revealed that electrostatic forces played major roles in the interaction between β-CN and TCH, whereas α-LA-TCH complex were stabilized by hydrogen bonds and van der Waals forces. Moreover, circular dichroism spectra (CD spectra), ultraviolet visible absorption spectra (UV–vis absorption spectra), and fluorescence Excitation-Emission Matrix (EEM) spectra results indicated the secondary structure of bovine proteins was changed in the presence of TCH with the α-helix percentage of protein-TCH complexes decreased. Molecular modeling analysis supported the experimental results well. In addition, the research of surface hydrophobicity further verified tertiary structure of proteins was changed in the presence of TCH and the possible changes of protein function. These results achieved from experiments may be valuable in the milk industry and food safety.
[en] The timing properties of LaCl3:Ce3+ scintillation crystals, which were developed in China lately, have been tested. A positron annihilation lifetime spectrometer was constructed with these detectors. A time resolution of 350 ps was obtained. Besides the fast time response, the energy resolution of LaCl3:Ce3+ is also high, so there are many potential advantages of the positron annihilation lifetime spectrometer constructed with this kind of detectors. (authors)
[en] The code SCIENCE was introduced from France, but it lacks the function of calculating reflector parameter, so the range of the code SCIENCE was restricted. The structure of reflector parameter and the method for the calculation were described in the paper. Through the exploitation and utilization of the code APOLLO2-F, the reflector parameter for the code SMART was provided, so the range of the code SCIENCE was expanded. (authors)
[en] Objective: To analyze and summarize the characteristics of thyroid diseases on the MR diffusion-weighted imaging. Methods: Forty-two patients with thyroid lesions,including 10 males and 32 females [age range 20-72 years, mean age (42±13) years] underwent MR DWI before surgery and biopsy. The diagnoses of thyroid lesions were confirmed by pathological results. ADC values of benign and malignant nodules, with different b values (b values was 300, 500 and 800 s/mm"2), were generated by using post-processing software Functool of GE company (USA). The independent-samples t test was used and ROC curve was made to evaluate the diagnostic efficiency of the ADC values by using statistical software SPSS 12.0. Results: Histologically, there were 28 benign lesions and 14 malignant lesions. Benign lesions included 20 cases of thyroid adenoma, 6 cases of nodular goiter and 2 cases of Hashimoto's thyroiditis respectively. Malignant lesions consisted of 11 cases of thyroid papillary carcinoma, 2 cases of follicular thyroid cancer, and 1 case of dysplasia mean ADC value of benign thyroid lesions was (2.39 ±0.38) ×10"-"3 mm"2/s and mean ADC value of malignant thyroid lesions was ( 1.60 ± 0.56) × 10"-"3 mm"2/s with b value of 300 s/mm"2. The statistical difference was significant between them (t=5.35, P<0.05). The statistical difference of mean A DC values,between benign and malignant nodules with b value of 500 s/mm"2 [(1.85 +0.33 ) × 10"-"3 mm"2/s and (1.65 ± 0.42) × 10"-"3 mm"2/s], was insignificant (t=1.70, P>0.05). The statistical difference of mean ADC values, between benign and malignant nodules with b value of 800 s/mm"2 [(1.61± 0.30) × 10"-"3 mm"2/s and (1.44±0.29) × 10"-"3 mm"2/s], was insignificant (t=1.76, P>0.05). ROC curve indicated that the ADC value of 1.98 × 10"-"3 mm"2/s or higher was the cut-off value for differentiating benign from malignant cold thyroid nodules, with a sensitivity of 85.7%, and a specificity of 78.6%. Conclusions: The image quality is best with b value of 300 s/mm"2. Mean ADC value of benign lesions was significantly higher than mean ADC value of malignant lesions with b value of 300 s/mm"2. (authors)
[en] In this paper, we present an investigation of the memberships, distance and proper motion for the old open cluster NGC 188 using a machine-learning-based method. This method combines two widely used algorithms: spectral clustering (SC) and random forest (RF). The former one is used to construct a reliable training set, the membership probabilities are calculated based on the latter one. This method only depends on reliable training set, no prior knowledge about the cluster is needed. This method is based on the basic assumption that most if not all the information about the cluster members and field stars are contained in a reliable training set, this makes it highly suitable for handling high-dimensional data sets. We use this method to investigate the likely memberships of the old open cluster NGC 188 based on the high-precision astrometry and photometry from the Data Release 2 ( DR2). Based on seven-dimensional features (positions, parallax, proper motions and color-magnitude) of 3780 sample stars in the region of NGC 188, 645 likely members with high membership probabilities () are obtained. Further analysis confirms the effectiveness of our membership determination. Based on these high-probability memberships, the distance and proper motion of the cluster are determined to be pc and mas/yr, respectively.
[en] High-precision proper motions and radial velocities of 1046 stars are used to determine member stars using three-dimensional (3D) kinematics for open cluster NGC 188 based on the density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm. By implementing this algorithm, 472 member stars in the cluster are obtained with 3D kinematics. The color-magnitude diagram (CMD) of the 472 member stars using 3D kinematics shows a well-defined main sequence and a red giant branch, which indicate that the DBSCAN clustering algorithm is very effective for membership determination. The DBSCAN clustering algorithm can effectively select probable member stars in 3D kinematic space without any assumption about the distribution of the cluster or field stars. Analysis results show that the CMD of member stars is significantly clearer than the one based on 2D kinematics, which allows us to better constrain the cluster members and estimate their physical parameters. Using the 472 member stars, the average absolute proper motion and radial velocity are determined to be (PMα, PMδ) = (−2.58 ± 0.22, +0.17 ± 0.18) mas yr−1 and Vr = −42.35 ± 0.05 km s−1, respectively. Our values are in good agreement with values derived by other authors
[en] Objective: To analyze the X-ray and CT features of synovial osteochondromatosis and discuss the CT diagnostic value. Methods: CT scanning was performed in 11 cases with clinically and pathologically proved synovial osteochondromatosis, of which 8 cases underwent X-ray film. The clinical and imaging features were analyzed and compared with the pathological findings. Results: The knee joint was mostly involved in synovial osteochondromatosis (55%). The loose and pendulous bodies of the calcification and ossification were showed in 11 cases. The synovial showed villous and tubercular hyperplasia in 9 cases. The imaging features of the intra-joint hydrops were showed in 11 cases. The amount of the loose and pendulous bodies was from a few to hundred, the size and the calcification degree of the loose and pendulous bodies were closely related to the time of their formation and the course of synovial osteochondromatosis. Conclusion: The loose and pendulous bodies of the calcification and ossification are the X-ray and CT diagnostic basis in synovial osteochondromatosis. The diagnosis of typical synovial osteochondromatosis can be made with CT. CT can find more indication than X-ray and can help make differential diagnosis