RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      선택해제
      • 좁혀본 항목 보기순서

        • 원문유무
        • 원문제공처
          펼치기
        • 등재정보
          펼치기
        • 학술지명
          펼치기
        • 주제분류
          펼치기
        • 발행연도
          펼치기
        • 작성언어
        • 저자
          펼치기

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • UNNOTICED MAGNETIC FIELD OSCILLATIONS IN THE VERY QUIET SUN REVEALED BY SUNRISE/IMaX

        Martí,nez Gonzá,lez, M. J.,Asensio Ramos, A.,Manso Sainz, R.,Khomenko, E.,Martí,nez Pillet, V.,Solanki, S. K.,,pez Ariste, A.,Schmidt, W.,Barthol, P.,Gandorfer, A. IOP Publishing 2011 ASTROPHYSICAL JOURNAL LETTERS - Vol.730 No.2

        <P>We present observational evidence for oscillations of magnetic flux density in the quiet areas of the Sun. The majority of magnetic fields on the solar surface have strengths of the order of or lower than the equipartition field (300-500 G). This results in a myriad of magnetic fields whose evolution is largely determined by the turbulent plasma motions. When granules evolve they squash the magnetic field lines together or pull them apart. Here, we report on the periodic deformation of the shapes of features in circular polarization observed at high resolution with SUNRISE. In particular, we note that the area of patches with a constant magnetic flux oscillates with time, which implies that the apparent magnetic field intensity oscillates in antiphase. The periods associated with this oscillatory pattern are compatible with the granular lifetime and change abruptly, which suggests that these oscillations might not correspond to characteristic oscillatory modes of magnetic structures, but to the forcing by granular motions. In one particular case, we find three patches around the same granule oscillating in phase, which means that the spatial coherence of these oscillations can reach 1600 km. Interestingly, the same kind of oscillatory phenomenon is also found in the upper photosphere.</P>

      • KCI등재

        Methanol to gasoline (MTG): Parametric study and validation of the process in a two-zone fluidized bed reactor (TZFBR)

        A. Sanz-Martínez,J. Lasobras,J. Soler,J. Herguido,M. Menéndez 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.113 No.-

        Methanol to Gasoline (MTG) process transforms methanol to hydrocarbons within the boiling point rangeof gasoline. The result is a wide spectrum of products (olefins, paraffins, aromatics and naphthenics,among others), with the total conversion of methanol to hydrocarbons and water. Catalyst deactivationby coke is a main problem in this process. This work aims to determine the feasibility of carrying out theproduction of gasoline from methanol in a two-zone fluidized bed reactor (TZFBR). The hypothesis is thatthe formation of carbonaceous deposits (coke) on the catalyst particles can be counteracted by its combustionin the regeneration zone that this novel reactor presents, thus achieving stable and continuousoperation. In this way, both processes (reaction and regeneration) would be being carried out simultaneouslyin the same reactor (process intensification). The comparison of results between a conventional fluidizedbed reactor and a TZFBR shows that the second one actually provides a better stability over time.

      • KCI등재

        Synthesis of Bi₂W₂O9 from an amorphous complex precursor: characterization and evaluation of its photocatalytical properties

        A. Martínez-de la Cruz,S. Obregón Alfaro,Leticia M. Torres-Martínez,I. Juárez Ramírez 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.5

        Bismuth tungstate Bi2W2O9 has been synthesized using diethylenetriaminepentaacetic acid (H5DTPA), an organic chelating agent of metals in an aqueous solution. The formation of the oxide was followed through characterization techniques such as XRD, TGA/DTA, and SEM. The optimum temperature to decompose the organic matrix and to form Bi2W2O9 was determined to be around 720 oC. Below this temperature, Bi2W2O9 was formed with a high content of Bi2WO6. At 720 oC particles of the Bi2W2O9 with a surface area four times higher than that obtained by a solid-state reaction were obtained. The oxide was tested as a photocatalyst on the degradation of aqueous solutions of rhodamine B under VIS radiation. The photodegradation of the dye followed a kinetic first order with an apparent constant, k = 2.8 × 10−3 minute−1and t1/2= 247 minutes for an aqueous solution of 5 mg l−1 of rhodamine B. Bismuth tungstate Bi2W2O9 has been synthesized using diethylenetriaminepentaacetic acid (H5DTPA), an organic chelating agent of metals in an aqueous solution. The formation of the oxide was followed through characterization techniques such as XRD, TGA/DTA, and SEM. The optimum temperature to decompose the organic matrix and to form Bi2W2O9 was determined to be around 720 oC. Below this temperature, Bi2W2O9 was formed with a high content of Bi2WO6. At 720 oC particles of the Bi2W2O9 with a surface area four times higher than that obtained by a solid-state reaction were obtained. The oxide was tested as a photocatalyst on the degradation of aqueous solutions of rhodamine B under VIS radiation. The photodegradation of the dye followed a kinetic first order with an apparent constant, k = 2.8 × 10−3 minute−1and t1/2= 247 minutes for an aqueous solution of 5 mg l−1 of rhodamine B.

      • THE UNAM-KIAS CATALOG OF ISOLATED GALAXIES

        Herná,ndez-Toledo, H. M.,,zquez-Mata, J. A.,Martí,nez-Vá,zquez, L. A.,Choi, Yun-Young,Park, Changbom American Institute of Physics 2010 The Astronomical journal Vol.139 No.6

        <P>A new catalog of isolated galaxies from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) is presented. A total of 1520 isolated galaxies were found in 1.4 sr of sky. The selection criteria in this UNAM-KIAS catalog are a variation on the criteria developed by Karachentseva, including full redshift information. Through an image processing pipeline that takes advantage of the high-resolution (~0<img entity='farcs' SRC='http://ej.iop.org/icons/Entities/farcs.gif' ALT='farcs' ALIGN='BOTTOM' />4 pixel<SUP>–1</SUP>) and high dynamic range of the SDSS images, a uniform g-band morphological classification for all these galaxies is presented. We identify 80% (Sa-Sm) spirals (50% later than Sbc types) on one hand, and a scarce population of early-type E (6.5%) and S0 (8%) galaxies amounting to 14.5% on the other hand. This magnitude-limited catalog is ~80% complete at 16.5, 15.6, 15.2, 14.6, and 14.4 mag in the ugriz bands, respectively. Some representative physical properties including SDSS magnitudes and color distributions, color-color diagrams, absolute magnitude-color, and concentration-color diagrams as a function of morphological type are presented. The UNAM-KIAS Morphological Atlas is also released along with this paper. For each galaxy of a type later than Sa, a mosaic is presented that includes (1) a g-band logarithmic image, (2) a g-band filtered-enhanced image where a Gaussian kernel of various sizes was applied, and (3) a red giant branch color image from the SDSS database. For E/S0/Sa galaxies, in addition to the images in (1), (2), and (3), plots of r-band surface brightness and geometric profiles (ellipticity ε, position angle PA, and A<SUB>4</SUB>/B<SUB>4</SUB> coefficients of the Fourier series expansions of deviations of a pure ellipse) are provided. The size of the sample, the redshift completeness, the availability of high-quality multicolor photometric data and detailed morphological and spectroscopic information make the UNAM-KIAS catalog of isolated galaxies a suitable sample to address important issues such as (1) comparative studies of environmental effects, (2) constraining the currently competing scenarios of galaxy formation and evolution, (3) the nature and evolution of elliptical and spiral galaxies in the field, (4) the spectral properties of a statistically significant number of isolated galaxies and their evolution as a function of redshift, and (5) the fraction of active galactic nuclei in isolated environments, among other important topics. The optimization and estimation of new structural parameters as well as important information to complement existing ones in other wavelengths is being carried out.</P>

      • KCI등재

        Improving the electrical properties of Er-doped CeO2: effect of sintering aids CaO, MgO, and TiO2 on conductivity

        Puente-Martínez D. E.,Díaz-Guillén J. A.,González-García K. A.,Montemayor S. M.,Díaz-Guillén J. C.,Burciaga-Díaz O.,Bazaldúa-Medellín M. E.,Padmasree K. P. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

        This research reports the synthesis, characterization, and electrical properties of the systems EryCe1−yO2−δ (y = 0.05, 0.1, and 0.15), and the effect of the incorporation of sintering aids (2 wt.% of CaO, MgO, and TiO2) on the electrical properties of the composition Er0.1Ce0.9O1.95, to be used as ceramic solid electrolytes in low-temperature solid oxide fuel cells (LT-SOFC). All EryCe1−yO2−δ samples were obtained by mechanochemistry (20 h of milling) and characterized by XRD. The morphology of the pure sintered compositions and with the incorporation of sintering aids (sintered at 1200 °C) was evaluated by FE-SEM. Electrical properties as a function of temperature (200–650 °C) and frequency (100 Hz–1 MHz) were evaluated by impedance spectroscopy. It reveals an increase of bulk ionic conductivity for higher contents of Er, as the number of oxygen vacancies increases. The higher value of conductivity (6.7 × 10–3 S cm−1) at 650 °C was for the composition Er0.15Ce0.85O1.925, while the ionic conductivity of Er0.1Ce0.9O1.95 at 650 °C increased from 2.68 × 10–3 S cm−1 to a maximum of 1.54 × 10–2 S cm−1 with the incorporation of CaO as additive. These improvements in bulk ionic conductivities can contribute to the development of more efficient electrolytes for the LT-SOFC technology.

      • SCIESSCISCOPUSKCI등재

        Clinical, Psychopathological, Physical, and Sleep Evolution in Adolescents with Restrictive Anorexia Nervosa Participating in a Day Hospital Program

        Sofí,a M Martí,nez-Sá,nchez,Tomá,s E Martí,nez-Garcí,a,Diego Munguí,a-Izquierdo 대한신경정신의학회 2020 PSYCHIATRY INVESTIGATION Vol.17 No.4

        Objective To analyze the clinical, psychopathological, physical, and sleep-related evolution of adolescents with restricting-type of anorexia nervosa (AN-R) after 10 weeks of a daytime hospital program. Methods Body composition, physical activity and sleep were measured objectively before and after 10 weeks of treatment. In addition, psychopathology and body image disturbances were measured with a self-report questionnaire. Results Fourteen female adolescents with AN-R (14.3±1.6 years old) participated in the study. A significant increase was found in eight of the ten variables for body composition (p<0.05). There were no significant changes in psychopathology, body image disturbances or physical activity. Concerning sleep, a significant, moderately standardized and substantial increase in night latency was found (p=0.002), and there was a significant, small standardized and substantial decrease in night efficiency (p=0.035). Conclusion After 10 weeks of follow-up with adolescent patients with AN-R who attended a day hospital program, there was a positive evolution of body composition. However, with regard to sleep patterns, there was a worsening of latency and night efficiency. Therefore, sleep care should be addressed in acute treatment programs for adolescents with AN-R.

      • KCI등재

        Subclavian-Brachial Bypass for Chronic Limb Threatening Ischemia Associated with an Old Motorcycle Accident

        Jose I. Martínez-Quesada,Javier E. Anaya-Ayala,Santiago Mier y Terán-Ellis,Montserrat Miranda-Ramírez,Luis H. Arzola,Christopher Ruben-Castillo,Juan C. Aramburo,Jesus M. de los Ríos,Carlos A. Hinojosa 대한혈관외과학회 2022 Vascular Specialist International Vol.38 No.2

        Chronic limb-threatening ischemia is rarely associated with previous traumatic injury. We present a case of a 28-year-old male with progressive digit ulcers, a weak pulse, cyanosis, and a cold limb. Eight months prior, he had a motorcycle accident resulting in a right clavicle fracture and brachial plexus injury. Computed tomography angiography revealed occlusion of the right subclavian artery near a surgically implanted reduction plate. The patient underwent an open subclavianbrachial bypass with a reversed saphenous vein graft. His postoperative recovery was uneventful. After 3 months, he had a euthermic right hand with a palpable pulse and his ulcers had completely healed. This case reinforces the need for patients with a neurological deficit in the upper extremity caused by blunt trauma to undergo thorough vascular examination to identify potential arterial injury and compromised perfusion.

      • KCI등재

        Artificial light impacts the physical and nutritional quality of lettuce plants

        Daymi Camejo,Antonio Frutos,Teresa C. Mestre,María del Carmen Piñero,Rosa M. Rivero,Vicente Martínez 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.1

        Leafy vegetables, including lettuce (Lactuca sativa L.), are considered to be healthy due to their high content of fiber, folate, carotenoids, phenolic and antioxidant compounds, minerals, and vitamins A, C, and K. Recently, LEDs are being used extensively as a supplementary light source in indoor agriculture due to the economical and physiological advantages that this artificial illumination offers compared to traditional fluorescence illumination. In this work, two commercially important lettuce varieties, Batavia Lettony (green leaves) and Batavia Diablotin (red leaves), were used to study the impact of LEDs (white and red–blue lights) and fluorescent illumination on their quality and health properties. Changes in the photosynthetic photon flux density from 250 to 400 µmol m−2 s−1 of fluorescent light increased growth parameters (leaf number, fresh and dry weight, and percentage of dry matter) of B. Lettony plants. We observed a positive impact of red–blue LED illumination on growth parameters analyzed in B. Diablotin plants compared to plants grown under fluorescent light at 250 µmol m−2 s−1. Leaf texture significantly increased in B. Lettony plants grown under 400 µmol m−2 s−1 fluorescent and LED illumination compared to that of plants grown under 250 µmol m−2 s−1 fluorescent light. This variable was only increased under red–blue LED illumination in B. Diablotin plants. Accumulation of bioactive compounds, such as anthocyanins and vitamin C, was higher in B. Diablotin plants grown under 250 µmol m−2 s−1 fluorescent light. Nutrient content in the foliar part was not modified under the light conditions used, except the Ca2+ content of B. Lettony plants grown under PPFD 400 µmol m−2 s−1 fluorescent light. Catalase (CAT) and peroxidase (POX) activities were differentially modified by light conditions in B. Lettony plants. However, POX activity was only modified in response to light conditions in B. Diablotin plants. Thus, this study demonstrates that LEDs could be used as an alternative to produce food under sustainable conditions. In this sense, although several horticultural studies have been conducted to establish the effectiveness of LEDs in lettuce growth, additional investigations are necessary to determine the optimal conditions for the use of LEDs to promote lettuce production and the accumulation of beneficial components, such as vitamins, minerals, fiber, and antioxidant compounds.

      • KCI등재

        Effect of Fiber Orientation on the Fatigue Behavior of Steel Fiber-Reinforced Concrete Specimens by Performing Wedge Splitting Tests and Computed Tomography Scanning

        Dorys C. González,Álvaro Mena-Alonso,Jesús Mínguez,José A. Martínez,Miguel A. Vicente 한국콘크리트학회 2024 International Journal of Concrete Structures and M Vol.18 No.2

        This paper shows the relationship, in steel fiber-reinforced concrete, between fiber orientation and fatigue response through the combined use of computed tomography (CT), digital image processing (DIP) software and wedge splitting test (WST). The WST cubes were extracted from conventional 150 × 150× 600 concrete prisms and a groove and notch were carved on different faces in such a way that in half of the test specimens the fibers are oriented mostly perpendicular to the breaking surface and, in the other half, the fibers are mostly oriented parallel to the breaking surface. Fiber orientation was obtained using a CT device and DIP software from a miniprism extracted from the previously mentioned concrete prisms. The results show that there is a strong correlation between the crack-sewing fiber orientation on the one hand and fatigue life and crack opening rate per cycle on the other hand. Cubes with a higher percentage of fibers perpendicular to the crack surface (i.e., with a higher efficiency index) show a longer fatigue life and a lower crack opening rate per cycle, while cubes with a lower efficiency index show a shorter fatigue life and a higher crack opening rate per cycle.

      • KCI등재

        Effect of the In₂O₃ content on the photodegradation of the alizarin dye using TiO₂-In₂O₃ nanostructured semiconductors

        V. Rodríguez-González,F. Paraguay-Delgado,X. García-Montelongo,L.M. Torres-Martínez,R. Gómez 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6

        The photocatalytic degradation of the synthetic red mordant dye alizarin on TiO2-In2O3 semiconductors as a function of the In2O3 content (1-12 wt%) was studied. High specific surface areas varying from 122 to 178 m2 g−1, depending on the In2O3 content, were obtained. A modification of the Eg band gap from 3.12 to 3.50 eV was obtained for low and high In2O3 contents. The XRD spectral patterns of the solids showed that anatase is the main crystalline titania phase. STEM-EDX chemical maps show that the In2O3 was found highly dispersed on the surface of the TiO2-In2O3 mixed oxide. By means of TEM images, nanostructured materials with crystallite sizes between 8 and 12 nm were identified. The photocatalytic activity for the alizarin degradation showed a maximum with the catalyst with 3.0 wt% of In2O3. The role of the In2O3 developing an optimal alizarin adsorption on the TiO2-In2O3 semiconductors is discussed. The photocatalytic degradation of the synthetic red mordant dye alizarin on TiO2-In2O3 semiconductors as a function of the In2O3 content (1-12 wt%) was studied. High specific surface areas varying from 122 to 178 m2 g−1, depending on the In2O3 content, were obtained. A modification of the Eg band gap from 3.12 to 3.50 eV was obtained for low and high In2O3 contents. The XRD spectral patterns of the solids showed that anatase is the main crystalline titania phase. STEM-EDX chemical maps show that the In2O3 was found highly dispersed on the surface of the TiO2-In2O3 mixed oxide. By means of TEM images, nanostructured materials with crystallite sizes between 8 and 12 nm were identified. The photocatalytic activity for the alizarin degradation showed a maximum with the catalyst with 3.0 wt% of In2O3. The role of the In2O3 developing an optimal alizarin adsorption on the TiO2-In2O3 semiconductors is discussed.

      연관 검색어 추천

      이 검색어로 많이 본 자료

      활용도 높은 자료

      해외이동버튼