[en] This paper presents a dynamical model of high speed motorized spindles in free state and work state. In the free state, the housing is modeled as a rotor with equivalent masses including bearing pedestals, motor stator and rear end cover. As a consequence, a double rotor dynamics can be modeled for high speed motorized spindles by a bearing element which connects the housing and bearing pedestals. In the work state, the housing is fixed and the system becomes a bearing-rotor dynamical model. An excitation-measurement test in the free state is designed to analyze the cross spectral density and auto spectral density of input and output signals. Then the frequency response function of system and coherence function of input and output signals which are used to analyze the inherent characteristics of the double- rotor model can be obtained. The other vibration test in the work state is designed to research the dynamical supporting characteristics of bearings and the effects from bearings on the inherent characteristics of the system. The good agreement between the experimental data and theoretical results indicates that the dynamical model in two states is capable of accurately predicting the dynamic behavior of high speed motorized spindles

[en] Objective: To analyze the angiographic findings of refractory cryptogenic hemoptysis (CH) and to assess the value of embolization therapy. Methods: From January 2002 through June 2012, 17 patients underwent bronchial artery embolization (BAE) for treatment of refractory CH. Bilateral bronchial arteries were embolized with PVA particles (500-700 μm) and gelatin sponge chippings. All patients were followed up for 0.5-10 years. Results: Ground-glass opacities were noted on the preoperative contrast-enhanced CT in 11 patients. Angiography showed a total of 40 abnormal bronchial arteries causing CH. After BAE, the hemoptysis ceased immediately in 13 patients and hemoptysis was diminished in 4 patients. No severe complication occurred and no recurrent hemoptysis was observed during the 0.5-10 year follow-up. Conclusions: Bronchial arteries are the main vessels responsible for CH and BAE is an effective treatment for refractory CH. (authors)

[en] Objective: To discuss the therapeutic effect of selective uterine artery chemoembolization (UACE) for the treatment of placenta accreta. Super-selective catheterization of bilateral uterine arteries was accomplished one after another, which was followed by transcatheter infusion of Methotrexate 25 mg and subsequent injection of Gelfoam particles into each side. The efficacy, complications and prognoses were observed. The clinical data were retrospectively analyzed. Results: In all cases the blood human chorionic gonadotrophin (HCG) was restored to normal within 2-4 weeks after the chemoembolization. The bleeding was stopped immediately after the procedure in 5 cases with postpartum hemorrhage. No recurrent hemorrhage or severe complications occurred in all cases. All patients were followed up for one year and normal menstrual cycle was regained in all cases. Conclusion: Selective uterine artery chemoembolization is an effective, minimally-invasive method for the treatment of placenta accreta. (authors)

[en] Objective: To compare long-term (5 years) therapeutic effect of thyroid arterial embolization with surgical thyroidectomy in treating Graves' disease. Methods: A total of 54 patients with Graves' disease, who were encountered during the period from Jan. 2003 to Dec. 2010 and received thyroid arterial embolization treatment, were collected and were used as interventional group. While 40 patients with Graves' disease, who were encountered during the same period and received surgical thyroidectomy, were used as surgical group. The 1-year, 3-year and 5-year cure rates and efficiency rates (improved and cure) were calculated and the results were compared between the two groups. Results: The 1-year, 3-year and 5-year cure rates of the interventional group were 68.52%, 61.18% and 47.88%, respectively. The 1-year, 3-year and 5-year cure rates of the surgical group were 97.50%, 78.54% and 69.48%, respectively. The 1-year, 3-year and 5-year efficiency rates in the interventional group and in the surgical group were 98.15%, 80.48%, 60.90% and 97.50%, 76.42%, 67.60%, respectively. By using Ridit analysis, statistically significant difference in the 1-year, 3-year and 5-year cure rates and efficiency rates existed between the interventional group and the surgical group (P<0.05%), while no statistically significant difference in the occurrence of hypothyroidism existed between the two groups (P>0.05%). Conclusion: For the treatment of Graves' disease, thyroid arterial embolization has satisfactory short-term and mid-term result, although its long-term result is less effective than that of thyroidectomy. (authors)

[en] Adding dampers is a commonly adopted seismic risk mitigation strategy for modern buildings, and the corresponding design procedure of dampers has been well established by the Chinese Building Code. Even though all types of dampers are designed by the same procedure, actual seismic performance of the building may differ from one to the others. In this study, a nine-story benchmark steel building is established, and three different and typical types of dampers are designed according to the Chinese Building Code to realize structural vibration control under strong earthquake excitation. The seismic response of the prototype building equipped with a viscoelastic damper, viscous damper and buckling-restrained brace (BRB) subjected to 10 earthquake records are calculated, and Incremental Dynamic Analysis (IDA) is performed to describe progressive damage of the structure under increasing earthquake intensity. In the perspective of fragility, it shows that the viscoelastic damper has the highest collapse margin ratio (CMR), and the viscous damper provides the best drift control. Both the BRB and viscoelastic dampers can effectively reduce the floor acceleration responses in the mid-rise building.

[en] The first-principles calculations are performed for both Li_2FeSiO_4 and Li_2FeSiO_3S compounds to elucidate their delithiation mechanism for a full extraction of two Li ions. The structural, electronic and electrochemical characteristics of both compounds are studied in detail, and the feasibility in removal of two Li ions from the hypothetical Li_2FeSiO_3S is explored. The calculated results reveal that the delithiation mechanism of Li_2FeSiO_4 is significantly modified by S substitution because of its larger radius. The bond lengths between Li–O and Li–S in the hypothetical Li_2FeSiO_3S compound become longer, and the gap between the pseudo-layers [Fe_2Si_2O_6S_2]_∞ becomes wider, leading to lower delithiation voltages and minor structural deformations in Li_2FeSiO_3S. The extraction of the first Li ion involves Fe"2"+/Fe"3"+ for both Li_2FeSiO_4 and Li_2FeSiO_3S, with a lower delithiation voltage 2.90 V and a slight expansion in cell volume up to 4.0% for Li_2FeSiO_3S. The extraction of the second Li ion is associated with combined redox couples of Fe"3"+/Fe"("4"−"α")"+ and O"2"−/O"γ"− (0 < α < 1 and 1 < γ < 2) for Li_2FeSiO_4 or a redox couple of S"2"−/S"− for Li_2FeSiO_3S. The difference in redox reactions corresponded to the extraction of the second Li ion for both compounds is the major reason leading to a drop of delithiation voltage from 4.85 V for Li_2FeSiO_4 to 4.19 V for Li_2FeSiO_3S, which is well in the stable range of voltages for conventional and commercial electrolytes, and a reduction in volume variation from a large volume expansion up to 11.5% for Li_2FeSiO_4 to a slight reduction of volume up to 2.3% for Li_2FeSiO_3S