A novel polarization modulator for a Moire system with grating imaging

A polarization modulator based on splitting with a Savart plate and rotation of an analyzer for a moire system with grating imaging is presented, and its modulation principle is analyzed. The polarization modulator is simple and achromatic. It is composed of a polarizer, a Savart plate, and an analyzer. The polarizer and the Savart plate are placed in front of the index grating to split the image of the scale grating in the moire system. The analyzer is placed behind the grating and rotated to realize the modulation of the moire signal. The analyzer can be rotated either continually with high speed or step by step with low speed to form different modulation modes. The polarization modulator makes the moire system insensitive to the change of initial intensity. In experiments, we verified the usefulness of the polarization modulator.

Diário da Constituinte [gravação de vídeo] : [programa n. 230]

O prazo de entrega do anteprojeto da Constituição acaba amanhã e não há acordo sobre o tema "sistema de governo". O Senador José Richa (PMDB-PR) acredita que a mudança de sistema de governo trará um governo mais eficiente. O Deputado Israel Pinheiro (PMDB-MG) defende a implantação do parlamentarismo gradual. O Líder do Governo, Deputado Carlos Sant'anna (PMDB-BA) considera difícil um acordo relativo ao tema e prevê que deverá haver votação de destaques na Comissão de Sistematização da Assembleia Nacional Constituinte (ANC). O Deputado Osvaldo Coelho (PFL-PE) apresenta na Comissão de Sistematização a ideia do voto ponderado para o cargo de presidente da república. O Deputado Rodrigues Palma (PMDB-MT) discorda da proposta por avaliar que o presidente da república é representante de todo o povo brasileiro. O Deputado Aloísio Vasconcellos (PMDB-MG) aprova a ideia dos Estados menores terem maior participação no voto, como forma de diminuir o domínio dos grandes Estados. O atual projeto de Constituição prevê a criação do Sistema Único de Saúde descentralizado, no qual os Estados e Municípios teriam autonomia para administrar os serviços médicos locais. O Deputado Osvaldo Almeida (PL-RJ) relata sua opinião sobre o Sistema Único de Saúde. O Deputado Naphtali Alves (PMDB-GO) acredita que o Estado deve interferir exclusivamente na medicina preventiva e não na medicina curativa. O Deputado Milton Lima (PMDB-MG) não acredita que a privatização da saúde trará prejuízos aos mais necessitados.

~(230)Acβ-延发裂变概率的测定

由60MeV/μ18O离子照射天然钍靶所引起的232Th-2p反应产生230Ra,通过放射化学分离方法从被照射的靶中提取出镭元素并制成薄源,经230Ra230Ac得到230Ac.用云母裂变径迹探测器和PHGeγ射线探测器对来自源中的裂变碎片和γ谱进行记录和测量,借助于所测得的两个裂变事件和γ谱,鉴别了β-延发裂变核230Ac,得到了它的β-延发裂变概率为（1.19±0.85）×10-8.

~(230)Ac β延发裂变

本文叙述了远离beta稳定线新核素合成尤其是beta延发裂变研究的重要意义,介绍了beta延发裂变先驱~(230)Ac的搜索及其延发裂变几率的测定。

寻找~(230)U的集团衰变

使用35MeV质子轰击ThO2,通过232Th(p,3n)230Pa反应产生目标核。用放射化学分离法从靶材料和其它反应产物中分离Pa,制备薄的Pa源。用HPGe探测器测量Pa源的γ能谱,使用聚乙烯对苯二酸酯(PTEP)固体径迹探测器记录重离子径迹,首次发现了230U发射22Ne离子的稀有衰变模式,并获得了它相对于α粒子发射的分支比为(1.3±0.8)×10-14。

~(230)Ac的β延发裂变

用 6 0MeV/u18O离子轰击ThO2 ,通过多核子转移和靶的耗散碎裂反应产生2 3 0 Ra。利用放射化学分离技术 ,将镭与钍及其它反应产物分离并制备成薄镭源。该源对云母裂变径迹探测器暴光 ,用高纯锗探测器测量镭源的γ活度 ;用氢氟酸溶液对云母箔进行蚀刻 ,使用光学显微镜观测云母箔中的裂变径迹。首次观测到了可能来自2 3 0 Acβ延发裂变的两个事件 ,获得它的 β延发裂变几率为 (1 19± 0 85 )× 10 -8。

~(230)Acβ延发裂变的观测(英文)

搜索了２３０Ａｃβ延发裂变．由 ６０ＭｅＶ／ｕ１８Ｏ离子照射２３２Ｔｈ，通过多核子转移反应产生２３０Ｒａ．经放射化学分离和薄的２３０Ｒａ→β－２３０Ａｃ源的制备，获得了 １０８ 个２３０Ａｃ原子．该源对云母裂变径迹探测器曝光．借助于所测的γ能谱和两个裂变事件，鉴别了β延发裂变核２３０Ａｃ，得到了它的β延发裂变几率为（１． １９± ０．８５）× １０－８．

Production cross-section of Ra-230 in the reaction of 60 MeV/u O-18 ions with U-238

A thick natural uranium target was bombarded with a 60 MeV/u O-18 beam. The neutron-rich isotope Ra-230 as the target residue was produced through the multinucleon transfer reaction (U-238-4p-4n). The barium and radium fraction as BaCl2 precipitate were radiochemically separated first from the mixture of uranium and reaction products. Then, the radium fraction was separated from BaCl2 precipitate by using cation exchange technique. The gamma-ray spectra of the Ra fraction were measured using an HPGe detector. The production cross sections of Ra-230 were obtained by a combination of the radiochemical separation technique and off-line gamma-ray spectroscopy. The cross section of Ra-230 has been determined to be 66 +/- 20 mu b.

Effects of annealing on the photoluminescence of He ion implanted sapphire after 230-MeV Pb ion irradiation

Single crystal sapphire (Al2O3) samples implanted with 110 keV He and irradiated at 320 K by Pb-208(27), ions with energy of 1.1 MeV/u to the fluences ranging from 1 X 10(12) to 5 X 10(14) ion/cm(2) and subsequently annealed at 600, 900 and 1100 K. The obtained PL spectra showed that emission peaks centred at 375, 390, 413, and 450 nm appeared in irradiated samples. The peak of 390 ran became very intense after 600 K annealing. The peak of 390 nm weakened and 510 nm peak started to build up at 900 K annealing, the peak of 390 nm vanished and 510 nm peak increased with the annealing temperature rising to 1100 K. Infrared spectra showed a broadening of the absorption band between 460 cm(-1), and 510 cm(-1) indicating strongly damaged regions being formed in the Al2O3 samples and position shift of the absorption band at 1000-1300 cm(-1) towards higher wavenumber after Pb irradiation.