Elastic Properties of Taurine Single Crystals Studied by Brillouin Spectroscopy.

The inelastic interaction between the incident photons and acoustic phonons in the taurine single crystal was investigated by using Brillouin spectroscopy. Three acoustic phonons propagating along the crystallographic b-axis were investigated over a temperature range of -185 to 175 °C. The temperature dependences of the sound velocity, the acoustic absorption coefficient, and the elastic constants were determined for the first time. The elastic behaviors could be explained based on normal lattice anharmonicity. No evidence for the structural phase transition was observed, consistent with previous structural studies. The birefringence in the ac-plane indirectly estimated from the split longitudinal acoustic modes was consistent with one theoretical calculation by using the extrapolation of the measured dielectric functions in the infrared range.

Precursor Phenomena of Barium Titanate Single Crystals Grown Using a Solid-State Single Crystal Growth Method Studied with Inelastic Brillouin Light Scattering and Birefringence Measurements.

The nature of precursor phenomena in the paraelectric phase of ferroelectrics is one of the main questions to be resolved from a fundamental point of view. Barium titanate (BaTiO3) is one of the most representative perovskite-structured ferroelectrics intensively studied until now. The pretransitional behavior of BaTiO3 single crystal grown using a solid-state crystal growth (SSCG) method was investigated for the first time and compared to previous results. There is no melting process in the SSCG method, thus the crystal grown using a SSCG method have inherent higher levels of impurity and defect concentrations, which is a good candidate for investigating the effect of crystal quality on the precursor phenomena. The acoustic, dielectric, and piezoelectric properties, as well as birefringence, of the SSCG-grown BaTiO3 were examined over a wide temperature range. Especially, the acoustic phonon behavior was investigated in terms of Brillouin spectroscopy, which is a complementary technique to Raman spectroscopy. The obtained precursor anomalies of the SSCG-grown BaTiO3 in the cubic phase were similar to those of other single crystals, in particular, of high-quality single crystal grown by top-seeded solution growth method. These results clearly indicate that the observed precursor phenomena are common and intrinsic effect irrespective of the crystal quality.

Acoustic Anomalies and Phase Transition Behaviors of Lead-Free Piezoelectric (Na1/2Bi1/2)TiO3-xBaTiO3 Single Crystals as Revealed by Brillouin Light Scattering.

The elastic properties of unpoled and prepoled (Na1/2Bi1/2)TiO3-xBaTiO3 (NBT-xBT) single crystals near the morphotropic phase boundary were investigated as a function of temperature using Brillouin light scattering. The acoustic mode frequency and the related acoustic damping of unpoled NBT-xBT showed very broad minimum and maximum, respectively, consistent with typical relaxor behaviors. The frequency softening of the longitudinal acoustic mode together with the increase in acoustic damping was largest along the <100> direction, indicating that polarization fluctuations were most substantial along this crystallographic direction. The difference in acoustic behaviors between the unpoled NBT-xBTs with x = 0.05 and 0.08 were negligible, which means that the NBT-xBT system exhibits typical relaxor properties over a certain composition range of at least 5~8%. The obtained relaxation time of polar nanoregions in the paraelectric phase showed a gradual slowing-down character without any critical divergent behavior. The prepoling of NBT-xBT along the <100> direction induced drastic changes in both mode frequency and damping at ~110 °C when the poling field was larger than 1.4 kV/mm, corresponding to the depoling process from macroscopic/mesoscopic ferroelectric order to ergodic relaxor state upon heating. Phase coexistence of ferroelectric and relaxor states was observed at the intermediate poling field of 1.4 kV/mm.

Development of Psychiatric Computerized Medical Records System / 신경정신의학

OBJECTIVES: Computer-based patient record (CPR, Electronic medical record) improves the quality of medical record which reflects the quality of clinical practice. It provides more efficient and convenient way of input, retrieval, storage, communication and management of medical data. The purpose of this study was to develop a practical domestic model and theoretical basis for CPR for psychiatric patients. This model can be applied in other clinical departments. METHODS: The contents and types of items to be included in the data-base were determined through consensus meetings of investigators on the basis of our previous works on the 'comprehensive assessment of symptoms and history in psychiatric disorders' and analysis of structure and items of medical records. The computer program(Asan Medical Center Psychiatric Information System, APIS, version 1.0) was developed using Oracle 7-3-4, Power builder 4.0, Hangul Windows NT and TCP/IP as a programming, development tools, system operation and transmission protocol. RESULTS: The characteristics of APIS are as follows. 1) APIS ensures comprehensive and high quality psychiatric record through combinations of free-text and structured data format and through many available 'help pop-up windows' of required items for better documentations. 2) APIS provides convenient and efficient ways of data input, particularly for narrative input of texts, with various tools such as 'template copy', various 'pop-up lists for block or phrase copy'. 3) APIS enables users to create and modify the template files or scales for research. 4) APIS which adopted principles of POMR (Problem Oriented Medical Record) makes cumbersome management of problem titles very convenient 5) APIS also provides additional statistics necessary for hospital audit and managements as well as mail communication and schedule management of department. 6) Access to APIS requires authorized ID and password where several levels of privileges (view only, edit allowed, master) are assigned to secure the data. And also modification of data was not allowed after completion of medical record except by persons with master ID. User's password and the data before modification can be traced. CONCLUSIONS: Our study results demonstrate the practical model and theoretical basis for CPR for psychiatric patients. We believe that this model and methods contained in this program can also be applied for developments of CPR for other clinical departments.

Prevalence of Premenstrual Syndrome and Premenstrual Dysphoric Disorder among Korean College Women / 신경정신의학

OBJECT: More than 75% of women have been reported to experience premenstrual symptoms and three to eight percent of them suffer from premenstrual dysphoric disorder(PMDD). But little is known about prevalence of premenstrual syndrome(PMS) and PMDD among Korean women. The purpose of this study was to investigate the prevalence of PMDD and PMS in Korean women who attended universities at the time of survey. METHODS: One thousand four hundred and nineteen subjects were randomly selected with cluster sampling method among four women's university in Seoul. We measured the severity of premenstrual symptoms using six-point rating scale developed by the authors on the basis of the research criteria for PMDD in DSM-IV. Premenstrual worsening of symptoms was defined as increase in symptom scores of more than 75% from follicular to luteal phase score. And also, we compared characteristic symptoms, eating behaviors, and functional impairments between PMS and PMDD. RESULT: After excluding inadequate data according to our exclusion criteria, 873 of 1419 subjects(61.5%) were included in the estimation of the prevalence of PMS and PMDD. Each prevalence rate of PMS and PMDD was found to be 83.3% and 5.0% on the basis of 75% change method respectively. The most frequent symptom was physical symptoms such as headache or breast tenderness(56.4%) in PMS and 'felt irritable'(95.5%) in PMDD. Of the 44 subjects with PMDD, 39(88.6%) reported to have experienced the impairment in work or school at least once per month because of premenstrual symptoms. CONCLUSION: Our results indicate that prevalence and symptoms of PMDD in Korean university women are similar to those in western culture. The finding that mood symptoms were more frequent and severe in PMDD than in PMS implies that the former may be a disordered condition to be distinguished from the latter physiologic one.