Analysis/Reduction of Residual Amplitude Modulation in Phase/Frequency Modulation by an EOM

Summary form only given. Frequency modulation (FM) is a powerful tool for sensitive spectroscopy and laser frequency stabilization. The high potential modulation frequency and FM format makes it easier to achieve shot-noise limit detection. Usually the laser frequency is modulated by an external frequency modulator such as an electrooptic modulator (EOM). However to obtain a pure FM signal is not easy because of residual amplitude modulation (RAM) arising by several effects: 1) etalon effects by light scattering within and at surfaces of the EOM crystal; 2) piezo-electric response of the EOM crystal, leading to beam steering and/or spatial position dither; 3) spatial inhomogeneity of modulation field in EOM crystal, leading to angular deviation of the beam and/or impure FM when part of the beam is selected; 4) and temperature dependence of the RAM associated with changes of the EOM crystal\u27s optical path and birefringence. RAM can easily be in the percent domain, and degrades the sensitivity in the FM spectroscopy, and also gives undesirable frequency offsets from the frequency reference. To solve the RAM problem, we measured and analyzed the RAM experimentally. A new active RAM suppression system is suggested

Study on the Effect of Atomic Bomb Radiation on Thyroid Function

The thyroid function of 6112 cases directly exposed to the atomic bomb within 1.5 km (exposed group) and of 3047 cases directly exposed beyond 3.0 km from the hypocenter (control group) was analyzed and the following results were obtained. 1) The frequency distribution curves of TSH values of both groups closely resembled each other in males, but the curve of the exposed group deviated to the right due to high TSH values. In females, the distribution width of TSH values of the exposed group was wide with a low peak and when compared to the control group, the curve was remarkably deviated to the right due to TSH values. 2) The frequency of hypothyroidism was 1.22% in males of the exposed group and 0.35% in males of the control group, while in females it was 7.08% and 1.18%, respectively, showing a significantly higher rate in the exposed group in both sexes. By exposure dose, the frequency was 1.03% in males of the 1-99 rad group and with increase of exposure dose the frequency elevated, being 3.67% at exposure dose of 200 rad or more. In females, the frequency was 6.23% and 7.76%, respectively, showing a significantly higher frequency when compared to the control group. 3) The prevalence rate of positive MCHA among the cases of hypothyroidism was 16.4% in males of the exposed group and 88.9% in males of the control group, while in females the prevalence was 25.3% and 63.3%, respectively, showing a remarkably low rate in the exposed group

実習指導者-教員の協働状況とユニフィケーション活動との関係

本研究の目的は、実習における実習指導者?教員の協働に関わる現状を把握し、指導体制およびユニフィケーション活動が実習指導者?教員の協働的な活動に及ぼす影響を明らかにすることである。A大学看護教員と実習先の2施設の実習指導者（以下、指導者）に無記名自記式質問紙調査を実施した。51の有効回答を分析した結果、意思決定、協調性、情報共有において、教員が指導者よりも協働の認識は高く、協調性、情報共有に有意差が見られた。実習指導者?教員の協働に、ユニフィケーション活動の企画・実施した者が3因子とも高く、協調性に有意差があった。ユニフィケーション活動の場や機会が両者のコミュニケーションを促進し、実習指導の協働に影響を与えることが示唆された

地域において働き盛り世代が青少年の育成活動に参加する意義

本研究の目的は働き盛り世代の住民が地域において青少年の育成活動に参加する意義を明らかにし、 これからの地域づくりについて考察することである。地区の青少年育成部の活動に今年度参加した9名（全員）を対象に構造化インタビューを行った。また、 フイールドワークとして青少年育成部の活動に参加した保健師養成課程の学生10名が、その特長についてラベルに書き出した。KJ法を用いて分析した結果、活動は対象となる子どもだけでなく、地域住民や活動する働き盛り世代にも良い影響を与えていた。このような活動は今後の生き生きとした地域づくりのきっかけになると考えられる

OBSERVATION OF DRESSED MOLECULES IN NEAR INFRARED-RF DOUBLE RESONANCE SPECTROSCOPY OF CH3ICH_{3}I

$^{a}$M. de Labachelerie, K. Nakagawa, and M. Ohtsu, Opt. Lett. 19, 840 (1994) $^{b}$J. Ye, L. S. Ma, and J. L. Hall, Opt. Lett. 21, 1000 (1996) $^{c}$C. Cohen-Tannoudji, J. Dupont-Roc, and G. Grynberg. ``Atom-Photon Interactions'', Wiley Interscience, New York (1992).Author Institution: Department of Physics, Faculty of Science and Technology, Keio UniversityNear infrared-radio frequency (rf) double-resonance spectroscopy of the vibrational overtone band of $CH_{3} I$ molecules has been carried out. To record saturated absorption lines of the near-infrared transitions, we employed and optical Fabry-Perot cavity absorption $cell^{a}$ and a frequency modulation $technique^{b}$. The rf field tuned with the hyperfine transition was applied through a pair of copper plates inserted in the Fabry-Perot cavity cell. Then the saturated absorption lines were split into two components separated by 1 MHz due to the ac-Stark effect. Two types of crossover reosnances were also observed; one appears at the center frequency of the two near-infrared transitions that share either upper or lower level of the rf transition, and the others lie at the middle of the two components split by the ac-Stark effect. Quantum interference phenomena were also observed. All the spectral features have been well expressed in terms of the dressed-molecule picture of a four-level $system^{c}$

PRECISE TRANSITION FREQUENCY MEASUREMENTS OF CH4CH_{4} IN THE 1.66μm1.66 \mu m REGION

$^{a}$C. Ishibashi and H. Sasada, Proc. of 54th Ohio State Univ. Int. Symp. Molec. Spectrosc. RJ04, 237 (1999) $^{b}$C. Ishibashi and H. Sasada, Jpn. J. Appl. Phys. 38, 920 (1999) $^{c}$K. Suzumura, C. Ishibashi, and H. Sasada. Opt. Lett. 22, 1356 (1999) $^{d}$C. Ishibashi, M. Kourogi. K. Imai, B. Widiyatmoko. A. Onae, and H. Sasada, Opt. Commun. 161, 223 (1999)Author Institution: Department of Physics, Faculty of Science and Technology, Keio University; Graduate School at Nagatsuta, Tokyo Institute of Technology; Graduate School at Nagatsuta, National Research Laboratory of MetrologySub-Doppler resolution laser spectroscopy with high sensitivity and wide tunability was presented by some of the authors (C.I. and H.S.) last $year^{a}$. There we used a Fabry-Perot cavity absorption cell, an external-cavity diode laser (ECDL), and a frequency modulation technique, which drastically improved the performance of the $spectrometer^{b}$. Because the spectral resolution was attained as high as 320 kHz, the corresponding precision has been required in the frequency measurement. To this end, we stabilized the ECDL's frequency to the narrow saturation dip of $CH_{4}$ of the $2\nu_{3}$ band in the $1.66 \mu m$ region, and made two kinds of precise frequency measurements. First, we stabilized two ECDL's frequency to different spectral lines respectively, and measured the frequency of the optical beat note between the ECDL's. Sixty-six frequency differences were measured with an accuracy of 40 $kHz.^{c}$ The second is the absolute frequency measurement. We used a $1.54- \mu m$ saturated absorption line of $^{13}C_{2}H_{2}$ as a frequency reference and an optical frequency comb generator for bridging the 14-THz frequency gap between the $1.66 \mu m$ and $1.54 \mu m$ radiations. The absolute frequencies of the R(0) and Q(1) transitions were determined to be 180.345 065 08(37) and 180.021 253 10(61) THz, respectively.$^{d}