[en] Drawability of Nickel 200 wires in laser dieless drawing was investigated. Influencing factors under consideration include the laser power, the heat-treatment state (as-drawn or annealed), and the initial wire diameter. Microstructural evolutions in laser dieless drawing were studied by scanning electron microscopy (SEM). The wires exhibit optimal drawability at an intermediate laser power range corresponding to the wire temperature in the range of 1000-1300 K. The as-drawn precursor wire has better drawability than that of the annealed wire. The drawability decreases as the precursor wire diameter deceases. Microcrystalline structures were found in nickel 200 wires after being laser-drawn from as-drawn precursor wires. These experimental observations are explained using the concepts of dynamic recovery and recrystallization

[en] As an important bulk material of nuclear power plant, cable is of large dosage, widely used, mainly used in the reactor buildling, auxiliary building, turbine building and BOP of the plant, laying way of cable generally use cable tray, pipe or cable trough. Nuclear power engineering cable must have reliable service life, thermal stability, moisture resistance, chemical stability and radiation resistance, provided the reliable safeguard for the safe operation of the plant. AP1000 as the third generation of nuclear power technology nuclear power plant, compared with the second generation nuclear power technology, puts forward higher technical requirements on cable, this thesis will analyze the reliability of the cable inside the shell combining with the characteristics of AP1000 nuclear power plant cable structure, characteristic and test requirements. (author)

[en] The RCP circuit breakers of AP1OOO NPP is a kind of Class 1 E switchgear can disconnect (RCP) motor loads upon a safety system command. This thesis thoroughly expound the Circuit Design and parameter characteristics to improve the reliability of the RCP circuit breakers. (authors)

[en] For medical preparedness and response, nuclear and radiological accidents were classified into small-, medium- and large-scale according to their damage characteristics and emergency classification. The central tasks and procedure for controlling contamination and rescue wounded persons attacked by 'dirty bomb' are described. Furthermore, principles for organization and direction of medical emergency are suggested, for example, quick response, dose limit, balance of advantages and disadvantages, radiation survey, contamination control, decontamination and victim rescue. (authors)

[en] Objective: To study the size of normal lateral geniculate nucleus (LGN) and its relationship with age. Methods: 47 healthy volunteers underwent 3 T MRI of the head using the gray matter (GM) and proton density (PD) sequences in the oblique coronal plane perpendicular to the long axis of hippocampus. The number of slices containing the LGN, height and volume of LGN were recorded by two neuroradiologists. Results: The average maximum height of LGN was 4.81 ± 0.54 mm on the left and 4.88 ± 0.57 mm on the right on the PD images compared to 4.58 ± 0.52 mm and 4.66 ± 0.62 mm on the GM images, respectively. The average volume of LGN was 134.09 ± 25.20 mm³ on the left and 135.13 ± 24.30 mm³ on the right on the PD images compared to 122.53 ± 24.33 mm³ and 120.81 ± 22.20 mm³ on the GM images, respectively.The maximum number of slices containing the LGN was 3.96 ± 0.41 on the left and 4.02 ± 0.44 on the right using both PD and GM sequences.The volume and maximum height of LGN were negatively correlated with the age of volunteers (P < 0.05). There was no significant correlation between the maximum number of slices and age (P > 0.05). Conclusions: The LGN decreases in size with aging, which should be considered in the study of diseases with LGN atrophy. (authors)

[en] The overmining of groundwater makes the aquifer in a coastal area prone to seawater intrusion and further leads to deterioration of water quality and ecosystem degradation. However, the vulnerability evaluation of seawater intrusion can provide a scientific basis for the prevention of seawater intrusion, and then ensure the sustainable use of groundwater. In this paper, Baihai City was taken as the study area, and the analytic hierarchy process (AHP), variable power theory, and fuzzy comprehensive evaluation method were used synthetically. The vulnerability of seawater intrusion in the study area was divided into lowest vulnerability, low vulnerability, medium vulnerability, and high vulnerability, and these correspond to 1739.98, 133.88, 664.32, and 737.55 km². On this basis, combined with the groundwater quality and quantity and ecosystem of the study area, the groundwater is divided into concentrated groundwater supply area (8.16%), decentralized groundwater supply area (12.44%), protected area (78.94%), and reserved zone (0.45%), which can provide the basis for the rational exploitation and management of groundwater. By analyzing the results of constant right and variable weight evaluation, combined with the history of seawater intrusion, it is proved that the variable weight evaluation model can effectively solve the unreasonable situation caused by the internal differences of the indicator, so that the evaluation results are more in line with reality. In addition, the application of the fuzzy comprehensive evaluation method makes the evaluation results clearer.

[en] Highlights: • A two-step selection strategy was proposed, using three selection algorithms to evaluate informative variables. • iPLS was introduced to efficiently eliminate uninformative variables without destroying synergistic effects among spectrum. • Combining variable combination population analysis and permutation analysis, a new selection strategy was proposed. • Experimental results showed the superiority of iPCPA and its wide application potential. As one of the most important preprocessing procedures in spectral detection, wavelength selection approaches play an irreplaceable role in reducing the model overfitting and prediction errors. In this paper, we propose a two-step wavelength selection method called interval permutation combination population analysis (iPCPA), which improves the selective performance by combining three different wavelength selection algorithms. First, interval partial least squares (iPLS) is used as the rough selection step to efficiently exclude the uninformative variables in the spectrum, which reduces the variable space and ensures that the following selection step can focus on selecting informative variables. Then, permutation combination population analysis (PCPA) is proposed, which introduces the core idea of permutation analysis into the variable combination population analysis (VCPA) and hence improves its ability in evaluating the importance of informative variables. Six state-of-the-art wavelength selection methods are used to compare with iPCPA and their performances are tested by using three real spectral datasets: corn, beer, and soil datasets. The final experimental results prove that iPCPA has the best predictive abilities, combined with a good selective performance.

[en] Objective: To study the radiological features and biomechanics of stress fracture. Methods: The X-ray, CT, MRI, and ECT signs in 20 cases of stress fracture and its correlation to biomechanics were analyzed. Results: Of the 20 cases, 14 cases occurred in the tibia, 2 cases in the metatarsal bone, 1 case in the rib, 1 case in the neck of femur and ribs, 1 case in the middle-inferior part of the femur, and 1 case in the fibula. Tow early cases of stress fracture demonstrated a characteristic sign of 'gray cortex'. The spherical or abnormal generation of bony callus and periosteum proliferation that demonstrated 'double cortex' sign in 2 cases were the sign of bone remodeling and the 'button sign' was the sign of bone healing. CT scan could clearly show the pathologic changes of bone and the soft tissue edema. Bone callus showed low signal on T₁WI and slight high signal on T₂WI. The area of bone edema on MRI that demonstrated low signal on T₁WI and high signal on T₂WI was larger than that on CT. MRI showed a linear band of low signal on both T₁WI and T₂WI in the area of bone fracture. ECT showed a focal area of increased uptake in the abnormal areas. The areas of bone stress fracture were characteristic and accorded with the biomechanical weak area in the bone. Conclusion: Stress fracture occurs in the special parts of the bone and has characteristic imaging features. X-ray should still be used to find the fracture of bones in the first inspection. CT and MRI are very helpful in the differentiation. Although sensitive, bone scan has lower specificity than either CT or MRI. (authors)

[en] Objective: To explore CT,MRI findings of extraskeletal mesenchymal chondrosarcoma (EMC). Methods: Imaging information of all 8 cases of EMC verified by pathology were retrospectively analyzed. Results: The location of lesions included lower extremity in 4 cases, forearm in 1 case,trunk in 2 cases and right lung in 1 case. The CT examination was performed in 7 cases, and 5 cases contained different patterns of ring-and-arc, granular, clump or irregular streaky mineralization. Dense calcification was detected in 3 cases,and focal in 2 cases. The nonmineralized component had slightly lower attenuation on CT scans than adjacent muscle. Four cases of peripheral located EMC demonstrated isointense on T_1WI, and mixed signal intensity on T_2WI. For the cases of fine and dense calcification in 2 cases,numbers of dot-like low-intensity signals were detected resembling 'pepper sign'; while for the cases of focal mineralization in 1 case, the low intensity area was located centrally in the high intensity area. Heterogeneous enhancement was found both in the calcified and uncalcified areas. One case of central located tumor exhibited low and high intensity on T_1 and T_2 weighted images, and nodular enhancement was observed. Conclusion: EMC has several characteristic imaging features, including various mineralization pattern, enhancement of calcified area and signal intensity, which might have diagnostic value for this rare tumor. (authors)

[en] Objective: To discuss the indications, long-term outcomes and complications of microendoscopy discectomy (MED) and percutaneous lumbar discectomy (PLD) in treating central lumbar intervertebral disc herniation, and to compare the advantages of the two procedures. Methods: During the period from Jan. 2001 to March 2002 surgical procedure was carried out in sixty-three patients with single central lumbar disc herniation. The surgeries included MED (n=23) and PLD (n=40). The clinical data were retrospectively analyzed. The lesion site, the operation time, the blood loss in operation, the time staying in bed, the hospitalization cost and the postoperative hospitalization days were recorded. Oswestry disability index (ODI) and MacNab score were determined. Statistical analysis was performed by using pair sample t-test, κ-test and Fisher exact test. All patients were followed up. Results: A mean follow-up time was (5.1±0.6) years for patients receiving MED and (6.6±0.7) years for patients receiving PLD. The ODI and MacNab scores of patients receiving MED were better than these of patients receiving PLD. The hospitalization cost and the postoperative hospitalization days of MED group was higher and longer than these of PLD group, the differences between the two groups were statistically significant. The occurrence of long-term complication in MED group was 3.49%, while no complication was seen in PLD group. Conclusion: For the treatment of central lumbar intervertebral disc herniation, both MED and PLD are safe and minimally-invasive procedures with satisfactory long-term effectiveness, and the patients recover from clinical symptoms quickly. The PLD has used more common than MED. The performance of MED needs more skill and experience. Therefore, an interventional radiologist has to follow a relatively long learning curve in order to get the sufficient training and practice before he or she can master the technique of MED with full confidence. However, the long-term effect of MED for lumbar disc herniation is definitely better than that of PLD. (authors)