104 research outputs found
Insect Fauna of Island Gangwha-do with its nearby Islands, Incheon Metropolitan city, Korea
AbstractThis study was conducted to clarify the current status of insects of Is. Gangwha-do (Mt. Goryeo-san, 436 m) as well as some nearby islands (Is. Gyodong-do, Is. Boleum-do, Is. Jumun-do and Is. Seokmo-do (Mt. Haemyeong-san, 327 m)) through June and September, 2009. A total of 206 insects of 104 species of 38 families and 6 orders was investigated by this survey
Lepidopterous Insect Fauna of Gyeongju National Park in Korea
AbstractLepidopterous insect fauna of Gyeongju National Park, was investigated during 25-28 April and 10-11 August 2007, especially in Mt. Namsan Zone. In total, 150 species of 21 families belonging to Lepidoptera were identified through this study. Therefore, a total of 183 species under 25 families are recorded from Gyeongju National Park, including the previous studies
Review of the genus Liocrobyla (Lepidoptera, Gracillariidae, Ornixolinae) from Korea, with description of one newly-recorded species
Liocrobyla Meyrick, 1916 is a relatively small genus within the family Gracillariidae, consisting of nine species worldwide, including five species in Korea.In this study, we recognise five species belonging to the genus Liocrobyla Meyrick, 1916 from Korea. Amongst them, one species, L. indigofera Liu, Wang & Wang, 2018, is reported for the first time in Korea. Figures of adults, male and female genitalia, along with a key to the species of Liocrobyla in Korea, are provided
Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales
We report the initial results of our high-cadence monitoring program on the
radio jet in the active galaxy M87, obtained by the KVN and VERA Array (KaVA)
at 22 GHz. This is a pilot study that preceded a larger KaVA-M87 monitoring
program, which is currently ongoing. The pilot monitoring was mostly performed
every two to three weeks from December 2013 to June 2014, at a recording rate
of 1 Gbps, obtaining the data for a total of 10 epochs. We successfully
obtained a sequence of good quality radio maps that revealed the rich structure
of this jet from <~1 mas to 20 mas, corresponding to physical scales
(projected) of ~0.1-2 pc (or ~140-2800 Schwarzschild radii). We detected
superluminal motions at these scales, together with a trend of gradual
acceleration. The first evidence for such fast motions and acceleration near
the jet base were obtained from recent VLBA studies at 43 GHz, and the fact
that very similar kinematics are seen at a different frequency and time with a
different instrument suggests these properties are fundamental characteristics
of this jet. This pilot program demonstrates that KaVA is a powerful VLBI array
for studying the detailed structural evolution of the M87 jet and also other
relativistic jets.Comment: 10 pages, 9 figures, accepted for publication in PAS
The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)
We have carried out the first very long baseline interferometry (VLBI)
imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a
millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA
(KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI
Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in
imaging compact maser features with a synthesized beam size of 2.7
milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a
limited number of baselines within the length of shorter than approximately 650
km corresponding to 100 Mlambda in the uv-coverage. The central velocity and
the velocity width of the 44 GHz methanol maser are consistent with those of
the quiescent gas rather than the outflow traced by the SiO thermal line. The
minimum component size among the maser features is ~ 5 mas x 2 mas, which
corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc.
The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0
x 10^{10} K, which are higher than estimated lower limit from a previous Very
Large Array observation with the highest spatial resolution of ~ 50 mas. The 44
GHz class I methanol maser in IRAS 18151-1208 is found to be associated with
the MM2 core, which is thought to be less evolved than another millimeter core
MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure
High-quantum yield alloy-typed core/shell CdSeZnS/ZnS quantum dots for bio-applications
Abstract
Background
Quantum dots (QDs) have been used as fluorophores in various imaging fields owing to their strong fluorescent intensity, high quantum yield (QY), and narrow emission bandwidth. However, the application of QDs to bio-imaging is limited because the QY of QDs decreases substantially during the surface modification step for bio-application.
Results
In this study, we fabricated alloy-typed core/shell CdSeZnS/ZnS quantum dots (alloy QDs) that showed higher quantum yield and stability during the surface modification for hydrophilization compared with conventional CdSe/CdS/ZnS multilayer quantum dots (MQDs). The structure of the alloy QDs was confirmed using time-of-flight medium-energy ion scattering spectroscopy. The alloy QDs exhibited strong fluorescence and a high QY of 98.0%. After hydrophilic surface modification, the alloy QDs exhibited a QY of 84.7%, which is 1.5 times higher than that of MQDs. The QY was 77.8% after the alloy QDs were conjugated with folic acid (FA). Alloy QDs and MQDs, after conjugation with FA, were successfully used for targeting human KB cells. The alloy QDs exhibited a stronger fluorescence signal than MQD; these signals were retained in the popliteal lymph node area for 24h.
Conclusion
The alloy QDs maintained a higher QY in hydrophilization for biological applications than MQDs. And also, alloy QDs showed the potential as nanoprobes for highly sensitive bioimaging analysis.
Graphical Abstrac
Precessing jet nozzle connecting to a spinning black hole in M87
The nearby radio galaxy M87 offers a unique opportunity to explore the
connections between the central supermassive black hole and relativistic jets.
Previous studies of the inner region of M87 revealed a wide opening angle for
the jet originating near the black hole. The Event Horizon Telescope resolved
the central radio source and found an asymmetric ring structure consistent with
expectations from General Relativity. With a baseline of 17 years of
observations, there was a shift in the jet's transverse position, possibly
arising from an eight to ten-year quasi-periodicity. However, the origin of
this sideways shift remains unclear. Here we report an analysis of radio
observations over 22 years that suggests a period of about 11 years in the
position angle variation of the jet. We infer that we are seeing a spinning
black hole that induces the Lense-Thirring precession of a misaligned accretion
disk. Similar jet precession may commonly occur in other active galactic nuclei
but has been challenging to detect owing to the small magnitude and long period
of the variation.Comment: 41 pages, 7 figures, 7 table
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