The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical...The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical area of 384 cm^2 and an energy band from 0.7 to 13 ke V. In order to evaluate the particle induced X-ray background and the cosmic X-ray background simultaneously, LE adopts collimators to define four types of Field Of Views(FOVs), i.e., 1.6°×6°, 4°×6°, 50°-60°×2°-6 oand the blocked ones which block the X-ray by an aluminum cover. LE is constituted of three detector boxes(LEDs) and an electric control box(LEB) and achieves a good energy resolution of 140 e V@5.9 ke V, an excellent time resolution of 0.98 ms, as well as an extremely low pileup(<1%@18000 cts/s). Detailed performance tests and calibration on the ground have been performed,including energy-channel relation, energy response, detection efficiency and time response.展开更多
Atomistic characterization of chemical element distribution is crucial to understanding the role of alloying elements for strengthening mechanism of superalloy. In the present work, the site preferences of two alloyin...Atomistic characterization of chemical element distribution is crucial to understanding the role of alloying elements for strengthening mechanism of superalloy. In the present work, the site preferences of two alloying elements X -Y in γ-Ni of Ni-based superalloy are systematically studied using first-principles calculations with and without spin-polarization. The doping elements X and Y are chosen from the 27 kinds of 3 d, 4 d, 5 d group transition metals（Sc, Ti, V, Cr, Mn, Fe, Co,Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au） and Al. We find that the spin-polarized calculations for Re-Re, Re-Ru, Re-Cr, Ru-Cr show a strong chemical binding affinity between the solute elements and are more consistent with the experimental results. The binding energies of pairs between the 28 elements have an obvious periodicity and are closely related the electronic configuration of the elements. When the d-electrons of the element are close to the half full-shell state, two alloying elements possess attractive binding energies, reflecting the effect of the Hund＇s rule. The combinations of early transition metals（Sc, Ti, V, Y, Zr, Nb, Hf, Ta） have a repulsive interaction in γ-Ni. These results offer insights into the role of alloying elements for strengthening mechanism of superalloy.展开更多
Purpose:To investigate the therapeutic effect and indicatio n of silicone oil tamponade combined with lensectomy preserving anterior lens capsule.Methods:Silicone oil tamponade combined with lensectomy preserving ante...Purpose:To investigate the therapeutic effect and indicatio n of silicone oil tamponade combined with lensectomy preserving anterior lens capsule.Methods:Silicone oil tamponade combined with lensectomy preserving anterior lens capsule was performed in 33 cases (33 eyes)of high myopia ,proliferative vitroretinopathy(PVR)D grade and giant retinal tear(GRT).10 cases were onlyeye and 11 cases had harder nucleus of lens.The surgical methods included:1.smashing lens nucleus and lensectomy preserving complete anterior capsule;2,vitrectomy and membrane peeling;3,usage of liquid perfluorocarbin or retinotomy or drainage;4.silicone oil tamponade;5.postoperative Nd;YAG laser for anterior capsulectomy. Results:Follow-up time was 6 months or more in 29 cases.Total retinal reattachment was achieved in 22 cases,macular retinal reattachment in 5 cases.The visual acuity was 20/800 to 20/200 in 13 cases,20/100 to 20/50 in 12 cases.Visual acuity was significantly improved in GRT group(P<0.05).Complications included unexpected anterior capsule break intraoperatively,anterior capsule opacity,silicone oil emulsification and liquid perfluorocarbin remainig postoperatively.Conclusions:Silicone oil tamponade combined with lensectomy preserving anterior capsule was safe and can reduce the operative complications.The indications included:1.GRT complicated with high myopia;2,advanced PVR cases complicated with high myopia in which silicone oil must be used;3.severe lens opacity cases in which silicone oil must be used;4.complex retinal detachment of only ye.展开更多
基金the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA040102).
文摘The Low Energy X-ray telescope(LE) is one of the three main instruments of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT). It is equipped with Swept Charge Device(SCD) sensor arrays with a total geometrical area of 384 cm^2 and an energy band from 0.7 to 13 ke V. In order to evaluate the particle induced X-ray background and the cosmic X-ray background simultaneously, LE adopts collimators to define four types of Field Of Views(FOVs), i.e., 1.6°×6°, 4°×6°, 50°-60°×2°-6 oand the blocked ones which block the X-ray by an aluminum cover. LE is constituted of three detector boxes(LEDs) and an electric control box(LEB) and achieves a good energy resolution of 140 e V@5.9 ke V, an excellent time resolution of 0.98 ms, as well as an extremely low pileup(<1%@18000 cts/s). Detailed performance tests and calibration on the ground have been performed,including energy-channel relation, energy response, detection efficiency and time response.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFB0701501,2017YFB0701502,and 2017YFB0701503)
文摘Atomistic characterization of chemical element distribution is crucial to understanding the role of alloying elements for strengthening mechanism of superalloy. In the present work, the site preferences of two alloying elements X -Y in γ-Ni of Ni-based superalloy are systematically studied using first-principles calculations with and without spin-polarization. The doping elements X and Y are chosen from the 27 kinds of 3 d, 4 d, 5 d group transition metals（Sc, Ti, V, Cr, Mn, Fe, Co,Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au） and Al. We find that the spin-polarized calculations for Re-Re, Re-Ru, Re-Cr, Ru-Cr show a strong chemical binding affinity between the solute elements and are more consistent with the experimental results. The binding energies of pairs between the 28 elements have an obvious periodicity and are closely related the electronic configuration of the elements. When the d-electrons of the element are close to the half full-shell state, two alloying elements possess attractive binding energies, reflecting the effect of the Hund＇s rule. The combinations of early transition metals（Sc, Ti, V, Y, Zr, Nb, Hf, Ta） have a repulsive interaction in γ-Ni. These results offer insights into the role of alloying elements for strengthening mechanism of superalloy.
文摘Purpose:To investigate the therapeutic effect and indicatio n of silicone oil tamponade combined with lensectomy preserving anterior lens capsule.Methods:Silicone oil tamponade combined with lensectomy preserving anterior lens capsule was performed in 33 cases (33 eyes)of high myopia ,proliferative vitroretinopathy(PVR)D grade and giant retinal tear(GRT).10 cases were onlyeye and 11 cases had harder nucleus of lens.The surgical methods included:1.smashing lens nucleus and lensectomy preserving complete anterior capsule;2,vitrectomy and membrane peeling;3,usage of liquid perfluorocarbin or retinotomy or drainage;4.silicone oil tamponade;5.postoperative Nd;YAG laser for anterior capsulectomy. Results:Follow-up time was 6 months or more in 29 cases.Total retinal reattachment was achieved in 22 cases,macular retinal reattachment in 5 cases.The visual acuity was 20/800 to 20/200 in 13 cases,20/100 to 20/50 in 12 cases.Visual acuity was significantly improved in GRT group(P<0.05).Complications included unexpected anterior capsule break intraoperatively,anterior capsule opacity,silicone oil emulsification and liquid perfluorocarbin remainig postoperatively.Conclusions:Silicone oil tamponade combined with lensectomy preserving anterior capsule was safe and can reduce the operative complications.The indications included:1.GRT complicated with high myopia;2,advanced PVR cases complicated with high myopia in which silicone oil must be used;3.severe lens opacity cases in which silicone oil must be used;4.complex retinal detachment of only ye.
