CANDELS Sheds Light on the Environmental Quenching of Low-mass Galaxies

Guo, Yicheng,Bell, Eric F.,Lu, Yu,Koo, David C.,Faber, S. M.,Koekemoer, Anton M.,Kurczynski, Peter,Lee, Seong-Kook,Papovich, Casey,Chen, Zhu,Dekel, Avishai,Ferguson, Henry C.,Fontana, Adriano,Giavalis American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.841 No.2

<P>We investigate the environmental quenching of galaxies, especially those with stellar masses (M-*) < 10(9.5) Me-circle dot, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, which is a demonstration of environmental quenching. We use CANDELS data to test whether or not such a dwarf QG-massive central galaxy connection exists beyond the local universe. For this purpose, we only need a statistically representative, rather than complete, sample of low-mass galaxies, which enables our study to z greater than or similar to 1.5. For each low-mass galaxy, we measure the projected distance (d(proj)) to its nearest massive neighbor (M-* > 10(10.5) M-circle dot) within a redshift range. At a given z and M-*, the environmental quenching effect is considered to be observed if the d(proj) distribution of QGs (d(proj)(Q)) is significantly skewed toward lower values than that of star-forming galaxies (d(proj)(SF)). For galaxies with 10(8) M-circle dot < M-* < 10(10) M-circle dot, such a difference between d(proj)(Q) and d(proj)(SF) is detected up to z similar to 1. Also, about 10% of the quenched galaxies in our sample are located between two and four virial radii (R-Vir) of the massive halos. The median projected distance from low-mass QGs to their massive neighbors, d(proj)(Q)/R-Vir, decreases with satellite M-* at M-* less than or similar to 10(9.5) M-circle dot, but increases with satellite M-* at M-* greater than or similar to 10(9.5) M-circle dot. This trend suggests a smooth, if any, transition of the quenching timescale around M-* similar to 10(9.5) M-circle dot at 0.5 < z < 1.0.</P>

ANALYSIS OF FORCE TRANSMISSION CHARACTERISTICS OF MODULAR DEFORMABLE TIRE

Kongshu Deng,Lu Zeng,Yicheng Ding,Zhurong Yin 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.5

In order to improve the explosion-proof, puncture-proof and safety performance of tires, a new type of modular deformable tires which can be used in complex road conditions has been put forward. The main innovation is the absence of so-called inner tubes and the modular design of the tire — which mainly consist of six petal-shaped connecting blocks and wheel frames. Firstly, this paper analyzes the structure and working principle of the tire. On this basis, the mechanical modeling of the tire under driving and braking conditions has been established. At last, through ADAMS software, the dynamic simulation of this tire under four circumstances of driving, accelerating, decelerating and braking has been carried out, and the response characteristic curves have been obtained The simulation results show that the force transmission performance of the modular deformable tire is rather good under the above four conditions. The simulation results provide a theoretical foundation and guidance for the structural design of new modular deformable tires.

Equivalent Vertical Stiffness Design of Modular Deformable Wheel

Kongshu Deng,Yicheng Ding,Lu Zeng,Zhurong Yin,Hailiang Wu,Dilei Qian 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.1

This study aims to determine the structural parameters of the equivalent vertical stiffness design of a modular deformable wheel. A gas stiffness model in the air cavity of the modular deformable wheel is established on the basis of the wheel’s structure and the ideal gas equation. Then, the change curve of the radial stiffness of the modular deformable wheel is obtained, and the design model of the equivalent vertical stiffness of the wheel is constructed on the basis of the gas stiffness model. Finally, some relevant design parameters of heavyweight and lightweight wheels are obtained through numerical calculation based on existing experimental data. The results show that the design parameters of the equivalent vertical stiffness of the modular deformable wheel can meet the ride comfort requirements of vehicles. The obtained wheel structure parameters and mechanical parameters will provide effective theoretical compliance for the selection of this type of wheel. Moreover, this modular deformable wheel not only meets the requirements of the riding comfort of pneumatic wheels, but also has the advantages that common pneumatic wheels do not have (such as explosion-proof and puncture-proof functions), which also provides the practical theoretical basis for the use and promotion of this wheel in the complex geological environment.

Recent Advances in Biosensors for Nucleic Acid and Exosome Detection

Zirui Fu,Yicheng Lu,James J. Lai 전남대학교 의과학연구소 2019 전남의대학술지 Vol.55 No.2

Biosensors are analytical devices for biomolecule detection that compromise three essential components: recognition moiety, transducer, and signal processor. The sensor converts biomolecule recognition to detectable signals, which has been applied in diverse fields such as clinical monitoring, in vitro diagnostics, food industry etc. Based on signal transduction mechanisms, biosensors can be categorized into three major types: optical biosensors, electrochemical biosensors, and mass-based biosensors. Recently, the need for faster, more sensitive detection of biomolecules has compeled researchers to develop various sensing techniques. In this review, the basic structure and sensing principles of biosensors are introduced. Additionally, the review discusses multiple recent works about nucleic acid and exosome sensing.

Force transmission performance for a novel deformation wheel with crank slider mechanism

Kongshu Deng,Hailiang Wu,Yicheng Ding,Lu Zeng,Zhurong Yin,Dilei Qian 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

This study aims to analyze the force transmission characteristics of a novel wheel composed of a mechanism of planar crank slider with virtual constraints. The principle of kinematic inversion is applied to analyze the force transmission characteristics of deformable wheel in an innovative way. First, the structural design of deformable wheel and diagram of mechanism motion are presented. Second, the model of force transmission characteristic of deformable wheel is established on the basis of principle of kinematic inversion. Third, the force changes in the two pairs of springs in the deformable wheel are investigated using MATLAB and ADAMS. Finally, the force transmission performance between the deformable and elastic wheel is compared. Results show that the possibility of a flat wheel can be avoided under severe geological conditions, and the force transmission performance is better than that of the traditional elastic wheel. The results of this study can provide theoretical guidance in designing a novel nonpneumatic wheel.

Ferromagnetic Properties of Nickel-Implanted Al0.35Ga0.65N

Mee-Yi Ryu,Jeremy Raley,Pan Wu,Robert Hengehold,Yicheng Lu,Yung Kee Yeo 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.5

Magnetic characterization studies of Ni-implanted Al$_{0.35}$Ga$_{0.65}$N have been made for various magnetic fields and sample temperatures by using a superconducting quantum interference device (SQUID). Ni ions were implanted at 200 keV to a dose of 3 $\times$ 10$^{16}$ cm$^{-2}$ at room temperature. The material was found to show clear signs of ferromagnetism after annealing between 675 and 775 $^\circ$C for 5 min. The ferromagnetic property persisted above room temperature, and a coercive field width of 118 Oe and a remanent field of 16 \% of the saturation magnetization of 2.6 $\times$ 10$^{-5}$ emu were obtained at 300 K after annealing at an optimum annealing temperature of around 750 $^\circ$C. This ferromagnetic property was also confirmed with field-cooled and zero-field-cooled magnetization measurements, and the Curie temperature was estimated to be around 350 K. Cathodoluminescence and X-ray diffraction (XRD) measurements showed that the significant implantation-related damage was recovered after annealing at 750 $^\circ$C, indicating a good Ni incorporation in the Al$_{0.35}$Ga$_{0.65}$N. Furthermore, the XRD measurements also showed no indication of secondary phase formation or Ni clusters, which implies that we had observed a dilute ferromagnetic semiconductor behavior.

Magnetic Properties of Transition Metal-implanted ZnO Nanotips Grown on Sapphire and Quartz

Jeremy A. Raley,Yung Kee Yeo,Robert L. Hengehold,Mee-Yi Ryu,Yicheng Lu,Pan Wu 한국자기학회 2008 Journal of Magnetics Vol.13 No.1

ZnO nanotips, grown on c-Al₂O₃ and quartz, were implanted variously with 200 keV Fe or Mn ions to a dose level of 5 × 10<SUP>16</SUP> ㎝?². The magnetic properties of these samples were measured using a superconducting quantum interference device (SQUID) magnetometer. Fe-implanted ZnO nanotips grown on c-Al₂O₃ showed a coercive field width of 209 Oe and a remanent field of 12% of the saturation magnetization (2.3 × 10?? emu) at 300 K for a sample annealed at 700 ℃ for 20 minutes. The field-cooled and the zero-field-cooled magnetization measurements also showed evidence of ferromagnetism in this sample with an estimated Curie temperature of around 350 K. The Mn-implanted ZnO nanotips grown on c-Al₂O₃ showed superparamagnetism resulting from the dominance of a spin-glass phase. The ZnO nanotips grown on quartz and implanted with Fe or Mn showed signs of ferromagnetism, but neither was consistent.

Inhalation of panaxadiol alleviates lung infl ammation via inhibiting TNFA/ TNFAR and IL7/IL7R signaling between macrophages and epithelial cells

Yifan Wang,Hao Wei,Zhen Song,Liqun Jiang,Mi Zhang,Xiao Lu,Wei Li,Yuqing Zhao,Lei Wu,Shuxian Li,Huijuan Shen,Qiang Shu,Yicheng Xie 고려인삼학회 2024 Journal of Ginseng Research Vol.48 No.1

Background: Lung inflammation occurs in many lung diseases, but has limited effective therapeutics. Ginseng andits derivatives have anti-inflammatory effects, but their unstable physicochemical and metabolic propertieshinder their application in the treatment. Panaxadiol (PD) is a stable saponin among ginsenosides. Inhalationadministration may solve these issues, and the specific mechanism of action needs to be studied. Methods: A mouse model of lung inflammation induced by lipopolysaccharide (LPS), an in vitro macrophageinflammation model, and a coculture model of epithelial cells and macrophages were used to study the effectsand mechanisms of inhalation delivery of PD. Pathology and molecular assessments were used to evaluate efficacy. Transcriptome sequencing was used to screen the mechanism and target. Finally, the efficacy andmechanism were verified in a human BALF cell model. Results: Inhaled PD reduced LPS-induced lung inflammation in mice in a dose-dependent manner, includinginflammatory cell infiltration, lung tissue pathology, and inflammatory factor expression. Meanwhile, the dose ofinhalation was much lower than that of intragastric administration under the same therapeutic effect, which maybe related to its higher bioavailability and superior pharmacokinetic parameters. Using transcriptome analysisand verification by a coculture model of macrophage and epithelial cells, we found that PD may act by inhibitingTNFA/TNFAR and IL7/IL7R signaling to reduce macrophage inflammatory factor-induced epithelial apoptosisand promote proliferation. Conclusion: PD inhalation alleviates lung inflammation and pathology by inhibiting TNFA/TNFAR and IL7/IL7Rsignaling between macrophages and epithelial cells. PD may be a novel drug for the clinical treatment of lunginflammation.

Label‐Free Polypeptide‐Based Enzyme Detection Using a Graphene‐Nanoparticle Hybrid Sensor

Myung, Sung,Yin, Perry T.,Kim, Cheoljin,Park, Jaesung,Solanki, Aniruddh,Reyes, Pavel Ivanoff,Lu, Yicheng,Kim, Kwang S.,Lee, Ki‐,Bum WILEY‐VCH Verlag 2012 Advanced Materials Vol.24 No.45

<P><B>A graphene‐nanoparticle (NP) hybrid biosensor</B> that utilizes an electrical hysteresis change to detect the enzymatic activity and concentration of Carboxypeptidase B was developed. The results indicate that the novel graphene‐NP hybrid biosensor, utilizing electrical hysteresis, has the ability to detect concentrations of targeted enzyme on the micromolar scale. Furthermore, to the knowledge of the authors, this is the first demonstration of a graphene‐based biosensor that utilizes a hysteresis change resulting from metallic NPs assembled on a graphene surface.</P>