• 제목/요약/키워드: $Z_2$

검색결과 7,101건 처리시간 0.038초

Probing the Feedback Process in Local Type-2 AGNs with Integral-Field Spectroscopy

  • Luo, Rongxin;Woo, Jong-Hak;Shin, Jaejin;Kang, Daeun;Bae, Hyun-Jin;Karouzos, Marios
    • The Bulletin of The Korean Astronomical Society
    • /
    • 제44권1호
    • /
    • pp.36.3-36.3
    • /
    • 2019
  • Feedback process is one of the most important topics in the study of AGNs since it plays a key role in linking the SMBHs and their host galaxies. In order to further understand the co-evolution of SMBHs and their host galaxies, we probe the feedback process in local type-2 AGNs with a series of integral-field-spectroscopy observations. In the first part of my talk, I will introduce our GMOS observations of luminous type-2 AGNs at z < 0.1, which are selected using the integrated [O III] kinematics. Based on the dedicated emission-line diagnostics and kinematic studies, we identify the signatures of AGN-driven outflows and quantify the outflow size in the targets with extreme [O III] kinematics. For the targets without extreme [O III] kinematics, we find the presence of weak AGN-driven outflows, which are indicated by the significant differences between the kinematics of gas and stars. Then, I will present our recent study of 40 type-2 AGNs based on the SNIFS IFU. By comparing the radial profile of velocity dispersion of gas and stars, we measure the size of AGN-driven outflows in these targets and extend the outflow size-AGN luminosity relation in our previous GMOS studies. We also discuss the feedback effect of AGN-driven outflows by connecting the outflow velocity and host galaxy properties. These results highlight the importance of spatially-resolved observation in investigating gas kinematics and identifying the signatures of AGN-driven outflows.

  • PDF

Numerical Simulation on the Formation and Pinching Plasma in X-pinch Wires on 2-D Geometry (자기유체역학 코드를 이용한 축 대칭 엑스 핀치 플라즈마 구조의 2차원 전산해석)

  • Byun, Sangmin;Na, Yong-Su;Chung, Kyoung-Jae;Kim, Deok-Kyu;Lee, Sangjun;Lee, Chanyoung;Ham, Seunggi;Ryu, Jonghyeon
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • 제24권2호
    • /
    • pp.211-218
    • /
    • 2021
  • This paper deals with the computational work to characterize the formation and pinching of a plasma in an X-pinch configuration. A resistive magnetohydrodynamic model of a single fluid and two temperature is adopted assuming a hollow conical structure in the (r,z) domain. The model includes the thermodynamic parameter of tungsten from the corrected Thomas-Fermi EOS(equation of state), determining the average ionization charge, pressure, and internal energy. The transport coefficients, resistivity and thermal conductivity, are obtained by the corrected Lee & More model and a simple radiation loss rate by recombination process is considered in the simulation. The simulation demonstrated the formation of a core-corona plasma and intense compression process near the central region which agrees with the experimental observation in the X-pinch device at Seoul National University. In addition, it confirmed the increase in radiation loss rate with the density and temperature of the core plasma.

Multi-condition optimization and experimental verification of impeller for a marine centrifugal pump

  • Wang, Kai;Luo, Guangzhao;Li, Yu;Xia, Ruichao;Liu, Houlin
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • 제12권1호
    • /
    • pp.71-84
    • /
    • 2020
  • In order to improve the performance of marine centrifugal pump, a centrifugal pump whose specific speed is 66.7 was selected for the research. Outlet diameter D2, outlet width b2, blade outlet angle β2, blade wrap φ and blade number z of the impeller were chosen as the variables. The maximum weighted average efficiency and the minimum vibration intensity at the base were calculated as objectives. Based on the Latin Hypercube method, the impeller was numerically optimized. The numerical results show that after optimization, the amplitudes of pressure fluctuation on the main frequency at different monitoring points decrease in varying degrees. The radial force on impeller decreases obviously under off-design flow rates and is more symmetrical during the operation of the pump. The variation of the axial force is relatively small, which has no obvious relationship with the rotating angle of the impeller. The energy performance and vibration experiment was performed for verifying. The test results show that the weighted average efficiency under 0.8Qd, 1.0Qd and 1.2Qd increases by 4.3% after optimization. The maximal vibration intensity at M1-M4 on the pump base reduced from 0.36 mm/s to 0.25 mm/s, decreasing by 30.5%. In addition, the vibration velocities of bracket in pump side and outlet flange also have significant reductions.

Fabrication of surface-enhanced Raman scattering substrate using black silicon layer manufactured through reactive ion etching (RIE 공정으로 제조된 블랙 실리콘(Black Silicon) 층을 사용한 표면 증강 라만 산란 기판 제작)

  • Kim, Hyeong Ju;Kim, Bonghwan;Lee, Dongin;Lee, Bong-Hee;Cho, Chanseob
    • Journal of Sensor Science and Technology
    • /
    • 제30권4호
    • /
    • pp.267-272
    • /
    • 2021
  • In this study, Ag was deposited to investigate its applicability as a surface-enhanced Raman scattering substrate after forming a grass-type black silicon structure through maskless reactive ion etching. Grass-structured black silicon with heights of 2 - 7 ㎛ was formed at radio-frequency (RF) power of 150 - 170 W. The process pressure was 250 mTorr, the O2/SF6 gas ratio was 15/37.5, and the processing time was 10 - 20 min. When the processing time was increased by more than 20 min, the self-masking of SixOyFz did not occur, and the black silicon structure was therefore not formed. Raman response characteristics were measured based on the Ag thickness deposited on a black silicon substrate. As the Ag thickness increased, the characteristic peak intensity increased. When the Ag thickness deposited on the black silicon substrate increased from 40 to 80 nm, the Raman response intensity at a Raman wavelength of 1507 / cm increased from 8.2 × 103 to 25 × 103 cps. When the Ag thickness was 150 nm, the increase declined to 30 × 103 cps and showed a saturation tendency. When the RF power increased from 150 to 170 W, the response intensity at a 1507/cm Raman wavelength slightly increased from 30 × 103 to 33 × 103 cps. However, when the RF power was 200 W, the Raman response intensity decreased significantly to 6.2 × 103 cps.

Hot Firing Test of a Quadrature NEA SSD9103S1 Configuration

  • Ja-Chun, Koo;Hee-Sung, Park;Max, Guba
    • International Journal of Aerospace System Engineering
    • /
    • 제9권2호
    • /
    • pp.1-9
    • /
    • 2022
  • The NEA release mechanism is used to provide restraint and release functions with low shock for critical deployment operations on solar arrays after launch. The GK3 solar array consists of 2 wings and 6 hold down points per panel. The NEA SSD9103S1 is a part of the GK3 solar array hold-down and release mechanism. Each NEA unit is equipped with two Z-diodes which provide power to a NEA unit connected in series after actuation of the fuse wire. This paper presents the hot firing test results of a quadrature NEA SSD9103S1 configuration. One output powers a maximum of 4 NEA SSD9103S1 units simultaneously. The necessary actuation pulse duration has been determined to meet margin requirement for thermal energy of minimum 4. Actuation thermal energy difference is about 6.6% between each half of two fired serial NEAs. Thermal energy margin at worst case is minimum 5.9 in case of an actuation pulse duration of 500 ms. Two series Zener impedance depend on current applied has been characterized by an additional actuation after all fuse wires are open circuit. Total number of actuation commands to the GK3 NEA unit reduce drastically from 24 in case of single NEA configuration down to 8 in case of parallel and quadrature NEA configurations. It can be accommodated by the existing HP2U Pyro design without any impact.

Improving hydration in elite male footballers during a national team training camp - an observational case study

  • Mohr, Magni;Nolsoe, Eli Leifsson;Krustrup, Peter;Fatouros, Ioannis G.;Jamurtas, Athanasios Z.
    • Korean Journal of Exercise Nutrition
    • /
    • 제25권4호
    • /
    • pp.10-16
    • /
    • 2021
  • [Purpose] The purpose of this study was to (i) assess hydration levels in elite male football players during a national team training camp before and during qualifying matches, (ii) evaluate the effect of coaching strategies for hydration based on feedback from hydration monitoring, and (iii) assess possible relationships between hydration status and training load or wellness markers. [Methods] Thirty-one male players (age 27±4 yrs; height 185±6 cm; weight 82.9±6.7 kg; body fat 10.4±2.3%) representing a national team from the Union of European Football Associations (UEFA) participated. The players were studied during three different national team training camps related to the UEFA Nations League tournament. Urine specific gravity (USG) was measured to assess hydration status. During all camps, the players were actively coached on improving strategies for hydration and given individual feedback on their test results. The training load was measured using GPS technology, and wellness questionnaires were completed. [Results] USG decreased progressively and significantly (p<0.005) during camp 1 and hydration status improved over the three camps, with fewer dehydrated and more well-hydrated players identified during the last part of camp 3. Significantly (p<0.05) higher USG values were observed 2 days prior to a match (MD-2) than on match day (MD); consequently, 52% of the players were dehydrated on MD-2 and only 6% on MD. No correlations were observed between hydration status and training load or wellness markers. [Conclusion] Dehydration is a challenge in elite male football, but continuous monitoring of hydration status and coaching on hydration strategies can lead to major improvements and reduce the degree of dehydration.

The Outcomes of an e-Wellness Program for Lupus Patients in Thailand: A Participatory Action Research Approach

  • Nop T. Ratanasiripong;Steven Cahill;Christine Crane;Paul Ratanasiripong
    • Journal of Preventive Medicine and Public Health
    • /
    • 제56권2호
    • /
    • pp.154-163
    • /
    • 2023
  • Objectives: Systemic lupus erythematosus (SLE) or lupus patients usually experience various physical and psychological challenges. Since the coronavirus disease 2019 pandemic, these challenges have become even harsher. Using the participatory action research approach, this study evaluated how an e-wellness program (eWP) impacted SLE-related knowledge and health behaviors, mental health, and quality of life among lupus patients in Thailand. Methods: A 1-group, pretest-posttest design study was conducted among a purposive sample of lupus patients who were members of Thai SLE Foundation. The 2 main intervention components were: (1) online social support, and (2) lifestyle and stress management workshops. Sixty-eight participants completed all the study requirements, including the Physical and Psychosocial Health Assessment questionnaire. Results: After being in the eWP for 3 months, participants' mean score for SLE-related knowledge increased significantly (t=5.3, p<0.001). The increase in sleep hours was statistically significant (Z=-3.1, p<0.01), with the percentage of participants who slept less than 7 hours decreasing from 52.9% to 29.0%. The percentage of participants reporting sun exposure decreased from 17.7% to 8.8%. The participants also reported significantly lower stress (t(66)=-4.4, p<0.001) and anxiety (t(67)=-2.9, p=0.005). The post-eWP quality of life scores for the pain, planning, intimate relationship, burden to others, emotional health, and fatigue domains also improved significantly (p<0.05). Conclusions: The overall outcomes showed promising results of improved self-care knowledge, health behaviors, mental health status, and quality of life. It is recommended that the SLE Foundation continues to use the eWP model to help the lupus patient community.

Food security and diet quality among urban poor adolescents in Kuala Lumpur, Malaysia

  • Janice Ee Fang Tay;Satvinder Kaur;Wui Wui Tham;Wan Ying Gan;Nik Norasma Che Ya;Choon Hui Tan;Serene En Hui Tung
    • Nutrition Research and Practice
    • /
    • 제17권2호
    • /
    • pp.269-283
    • /
    • 2023
  • BACKGROUND/OBJECTIVES: This study aimed to examine the food security status of urban poor adolescents and its association with diet quality. SUBJECTS/METHODS: A cross-sectional survey was conducted among 188 adolescents aged 13-18 yrs living in Kuala Lumpur, Malaysia. Household food insecurity and dietary intake data were collected using the Radimer/Cornell hunger and food insecurity instrument and 2-day 24-h dietary recalls, respectively. Diet quality was determined using the Malaysian Healthy Eating Index (HEI). Weight and height were measured and body mass index-for-age, as well as height-for-age z scores were calculated. RESULTS: The present study revealed that 47.9% of the adolescents experienced household food insecurity, 24.5% experienced individual food insecurity, 18.6% household food security, and 9.0% child hunger. The mean score of diet quality was 56.83 ± 10.09, with a significantly lower HEI score among food insecure adolescents (household food insecure, individual food insecure, and child hunger) than household food secure adolescents (P = 0.001). The differences between food secure and food insecure households were found to be significant for energy (P = 0.001) and nutrients including proteins (P = 0.006), carbohydrates (P = 0.005), dietary fiber (P = 0.001), folate (P < 0.001), and vitamin C (P = 0.006). The multiple linear regression showed that adolescents who experienced food insecurity (β = -0.328; P = 0.003) were found to be significantly associated with poor diet quality (F = 2.726; P < 0.01), wherein 13.3% of the variation in the diet quality was explained by the food security status. CONCLUSIONS: Experiencing food insecurity contributed to poor diet quality among urban poor adolescents. Further longitudinal studies are needed to comprehensively understand this association to improve food insecurity and diet quality among urban poor communities.

Applicability of Daoyin Exercise with Therapeutic Exercise for Shoulder Pain: A Systematic Review and Meta-analysis (치료적 운동을 포함한 도인운동의 어깨 통증에 대한 적용 가능성 탐색: 체계적 문헌고찰 및 메타 분석)

  • Hyeonsun Park;Sanghyeon Park;Jiho Lee;Seohyun Park;Dongho Keum
    • Journal of Korean Medicine Rehabilitation
    • /
    • 제33권4호
    • /
    • pp.79-93
    • /
    • 2023
  • Objectives The purpose of this study is to investigate therapeutic exercise and to provide the evidence of daoyin exercise for shoulder pain. Methods Electronic databases including PubMed, EMBASE, China National Knowledge Infrastructure, Science ON, Oriental Medicine Advanced Searching Integrated System were searched up to October 2022. We selected randomized controlled trials. The quality of studies was assessed by Cochrane risk of bias tool. Meta-analysis were perfomed by Review Manager software. Results Eighteen randomized controlled trials were collected in accordance with the selection and exclusion criteria. Among the 18 trials, 7 trials used strengthening exercise, 4 trials used stablilization exercise, 5 trials used both types of intervention, and 2 trials used daoyin exercise. The study characteristics, results and method of intervention were analyzed. Meta-analysis showed that therapeutic exercise appeared to more effective than no treatment group for shoulder pain (standardized mean difference=-1.18, 95% confidence interval=-1.44 to 0.91, Z=8.82, p<0.00001; chi2=2.71, p=0.61; I2=0%). Conclusions All of 18 selected studies reported the effectiveness of therapeutic exercise for shoulder pain. Combining strengthening and stablilization exercise is considered the most efficient way for shoulder pain. Based on this study, well-designed studies should be performed to be evidence of the use of daoyin exercise for shoulder pain.

Morphology Engineering for Compact Electrolyte Layer of Solid Oxide Fuel Cell with Roll-to-Roll Eco-production

  • Minho Jo;Seongyong Kim;Changwoo Lee
    • International Journal of Precision Engineering and Manufacturing-Green Technology
    • /
    • 제9권
    • /
    • pp.431-441
    • /
    • 2021
  • Gadolinium-doped ceria (GDC) is sought-after as an electrolyte layer in solid oxide fuel cells because of its high ionic conductivity and low treatment temperature. Recently, some studies have been reported to produce a component layer of solid oxide fuel cell using a Roll-to-Roll (R2R) system because of its characteristics of the cost-effective and eco-friendly advantages. However, the brittleness and low density of GDC prevent it from being mass-produced via the R2R continuous process. Therefore, we attempted to improve the density of GDC-based multi-electrolyte layers through an optimized R2R calendaring process. The finite element method was employed to determine suitable materials for the calendering rolls and the maximum calendering pressure that would reduce the thickness and porosity of the coated electrolyte layer without producing cracks in the layer. The effect of the number of calendering processes on the thickness and porosity of the electrolyte layers was examined as well. Silicon and steel were observed to be best-suited as the materials for the top and bottom rolls, respectively. Moreover, the maximum permissible calendering pressure was determined to be 15 MPa, while the ideal number of calendering processes was found to be 5. Experimental observations using scanning electron microscopy confirmed that the optimized calendering process reduced the thickness and porosity of the coated electrolyte layers by 16.99% and 7.04%, respectively. Thus, our findings suggest that large-area, high-density GDC-based multi-electrolyte layers with smooth surfaces can be produced via the R2R process, which can enable mass production of SOFCs.