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国际上最早使用的微型探测器是盖革-缪勒计数器,并用它首次对活体内的肿瘤进行了测试。六十年代以来,它逐步为半导体探测器所代替。七十年代以来,微型半导体探测器已广泛地用于血流动力学、肺功能研究以及食管、胃和眼睛等体内和体表器官的诊断。我们也曾用半导体硅探测器对甲状腺节结进行过测试,效果良好。 相似文献
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离子注入技术在植物育种中的应用与研究进展 总被引:1,自引:0,他引:1
离子束作为一种新的诱变源,具有突变谱广、突变率高、生理损伤小的特点,并且具有一定的重复性和方向性。文章阐述了离子注入的特点、诱变机理和诱变效应,综述了诱变育种取得的进展,展望了离子注入技术的应用前景。 相似文献
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本文介绍了液态铀离子选择电极的制备及其功能。讨论了载体的孔隙度、载体长度、活性溶液中交换剂浓度和苯甲酸浓度等与电极功能的关系。电极斜率分别为56.4±2mV(活性溶液铀浓度5×10~(-4)M)和52±1mV(活性溶液铀浓度1×10~(-4)M),在2×10~(-6)-1×10~(-4)M铀浓度范围内呈线性关系。该电极具有灵敏、响应迅速、温度效应小、选择性好和使用寿命长等优点。用于矿水及工艺液流中微量铀的测定,获得了较满意的结果。 相似文献
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O、C离子注入n型GaN的黄光发射研究 总被引:1,自引:1,他引:0
采用光致发光(Photoluminescencc,PL)谱的测量,研究了1012~1017cm-2的O和C两种离子注入和退火对非有意掺杂的n型GaN黄光发射(Yellow luminescence,YL)的影响,注入后的样品在流动N2的保护下进行退火,退火温度950℃,退火时间30 min.对比相同剂量下N离子注入GaN黄光发射,结果表明O、C两种离子的注入在GaN中分别引入了与黄光发射相关的不同的深能级中心,当C离子注入剂量高达1017cm-2时,能引起黄光发射的C相关的深能级中心显著增多. 相似文献
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I.O. Usov D. Koleske K.E. Sickafus 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(17):2962-2964
We present a method of ion implantation doping of GaN, which permits reduced residual damage. The method consists of performing implantation in several steps with annealing between each step. Residual damage was analyzed by RBS/channeling and compared to a traditional implantation and annealing procedure. Better lattice recovery is clearly achieved using the alternating implantation and annealing approach. We attribute the efficient recovery to smaller damage amounts introduced during each implantation step, as well as to suppression of secondary defect formation. 相似文献
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E. Alves C. Marques N. Franco L.C. Alves M. Peres T. Monteiro 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(19):3137-3141
In this study we compare and discuss the defects and optical behaviour of sapphire and magnesium oxide single crystals implanted at room temperature with different fluences (1 × 1015-1 × 1016 cm−2) of europium ions.Rutherford backscattering channelling shows that for fluences above 5 × 1015 cm−2 the surface disorder level in the Al-sublattice reaches the random level. Implantation damage recovers fast for annealing in oxidizing atmosphere but even for the highest fluence we recover almost completely all the damage after annealing at 1300 °C, independently of the annealing environment (reducing or oxidizing). Annealing above 1000 °C promotes the formation of Eu2O3 in the samples with higher concentration of Eu. The optical activation of the rare earth ions at room temperature was observed after annealing at 800 °C by photoluminescence and ionoluminescence. In Al2O3 lattice the highest intensity line of the Eu3+ ions corresponds to the forced electric dipole 5D0 → 7F2 transition that occurs ∼616 nm. For the MgO samples the Eu3+ optical activation was also achieved after implantation with different fluences. Here, the lanthanide recombination is dominated by the magnetic dipole 5D0 → 7F1 transition near by 590 nm commonly observed for samples were Eu3+ is placed in a high symmetry local site. The results clearly demonstrate the possibility to get Eu incorporated in optical active regular lattice sites in wide gap oxides. 相似文献
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C. Marques N. Franco A. Kozanecki R.C. da Silva E. Alves 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2006,250(1-2):90-94
Sapphire single crystals were implanted at room temperature with 180 keV manganese ions to fluences up to 1.8 × 1017 cm−2. The samples were annealed at 1000 °C in oxidizing or reducing atmosphere. Surface damage was observed after implantation of low fluences, the amorphous phase being observed after implantation of 5 × 1016 cm−2, as seen by Rutherford backscattering spectroscopy under channelling conditions. Thermal treatments in air annealed most of the implantation related defects and promoted the redistribution of the manganese ions, in a mixed oxide phase. X-ray diffraction studies revealed the presence of MnAl2O4. On the contrary, similar heat treatments in vacuum led to enhanced out diffusion of Mn while the matrix remained highly damaged. The analysis of laser induced luminescence performed after implantation showed the presence of an intense red emission. 相似文献
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D. Sanyal Mahuya Chakrabarti Vaishali Naik Tapatee Kundu Roy Debasis Bhowmick Siddhartha Dechoudhury Arup Bandyopadhyay Alok Chakrabarti 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(10):1783-1786
Room temperature ferromagnetic ordering has been observed in ZnO by implanting 1.63 MeV 56Fe6+ ions. The total number of implanted Fe ions in ZnO is 1 × 1016, which is effectively 1 at.% doping of Fe in ZnO. The amount of saturation magnetic moment in Fe implanted ZnO, annealed to 500 °C, has been found to be two orders of magnitude more than that observed earlier in chemically prepared Zn0.98Mn0.02O and Zn0.96Mn0.02Fe0.02O samples. 相似文献