객체 탐지를 통한 실내 공간의 위험도 산출 기법

궈쯔이(Ziyi Guo),권영우(Young-Woo Kwon) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6

지진이나 화재와 같은 재난 발생 시 실내에 설치된 물건으로 인하여 피해가 더욱 커지는 경향이 있다. 이에 본 논문에서는 실내 시설물로 인한 피해를 최소화하기 위해 객체 탐지 모델 사용하여 실내에 존재하는 위험물들을 식별하고 해당 장소의 위험등급을 계산할 수 있는 기법을 제안한다. 빠르고 정확한 객체 탐지를 위하여 Mask R-CNN을 이용하여 실내에 위치한 위험물을 식별 모델을 설계하였으며 재난의 종류에 따라 위험도를 다르게 계산할 수 있도록 위험도 계산 공식을 정의하였다. 이를 통해 자연재난 발생 시 실내물건의 위험성으로 인한 피해를 줄일 수 있을 것으로 기대한다.

Emission properties of sequentially deposited ultrathin CH3NH3PbI3/MoS2 heterostructures

Shao Ziyi,Xiao Junting,Guo Xiao,You Siwen,Zhang Yangyang,Li Mingjun,Song Fei,Zhou Conghua,Xie Haipeng,Gao Yongli,Sun Jiatao,Huang Han 한국물리학회 2022 Current Applied Physics Vol.36 No.-

Hybrid organic-inorganic perovskite materials have obtained considerable attention due to their exotic optoelectronic properties and extraordinarily high performance in photovoltaic devices. Herein, we successively converted the ultrathin PbI2/MoS2 into the CH3NH3PbI3/MoS2 heterostructures via CH3NH3I vapor processing. Atomic force microscopy (AFM)、Scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS) measurements prove the high-quality of the converted CH3NH3PbI3/MoS2. Both MoS2 and CH3NH3PbI3 related photoluminescence (PL) intensity quenching in CH3NH3PbI3/MoS2 implies a Type-II energy level alignment at the interface. Temperature-dependent PL measurements show that the emission peak position shifting trend of CH3NH3PbI3 is opposite to that of MoS2 (traditional semiconductors) due to the thermal expansion and electron-phonon coupling effects. The CH3NH3PbI3/TMDC heterostructures are useful in fabricating innovative devices for wider optoelectronic applications.

Heat transfer of a sustainable personal garment cooling system

Yijie Zhang,Ziyi Guo,Tao Li,Yexin Lyu,FengYuan Zou 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

This paper provides examines sustainable personal cooling systems. The impact of micro-fan configuration and inflow airspeed was tested. First, three different types of test models-a garment with side seam micro-fans, scatter-fans, and bottom-fans, was used to analyze and compare the heat transfer characteristic. Second, a new index of convective heat transfer was used to evaluate the cooling performance of these models. Third, the selected model was calculated with three different inflow properties, and the performance of efficiency and energy saving was analyzed. The results show that the bottom-fans model yields the best performance both on efficiency and cooling effect. The evaluation of thermal environment shows that the defined indexes are reliable to reflect heat transfer characteristics in the air gap. The comparison study of different airspeeds shows that the inflow air velocity should be set at a suitable range due to the view of energy saving.

Simultaneous immunoassays of dual prostate cancer markers using a SERS-based microdroplet channel

Gao, Rongke,Cheng, Ziyi,Wang, Xiaokun,Yu, Liandong,Guo, Zhongyi,Zhao, Gang,Choo, Jaebum Elsevier 2018 Biosensors & Bioelectronics Vol.119 No.-

<P><B>Abstract</B></P> <P>The simultaneous detection of multiple biomarkers plays an important role in the accurate diagnosis of cancer. In this study, we developed a novel, surface-enhanced Raman scattering (SERS)-based microfluidic device for the simultaneous detection of free prostate-specific antigen (f-PSA) and total PSA (t-PSA) markers. A fully automatic droplet-based microfluidic platform for the rapid and sensitive detection of f-PSA and t-PSA was designed. Magnetic immunocomplexes were aligned on one side of the channel using a permanent magnet embedded in the microfluidic device, and parent microdroplets containing magnetic immunocomplexes and supernatant solutions were split into two smaller daughter droplets at the Y-shaped junction of the channel. Then, Raman signals of sequential droplets including supernatant solutions were measured for the quantitative analysis of the PSA markers. Two parallel microfluidic channels were designed and fabricated for the simultaneous detection of f-PSA and t-PSA. Our results showed a good linear response for both PSA markers in the range from 0.05 to 100 ng mL<SUP>−1</SUP>. The limits of detection were estimated to be below 0.1 ng mL<SUP>−1</SUP> for both the f-PSA and t-PSA. This SERS-based assay in a microfluidic channel was completed in 10 min without any manual incubation and washing steps. Our method is a very promising clinical tool for PSA-based screening test of prostate cancer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We report a SERS-based microfluidic device for the detection of two prostate cancer markers. </LI> <LI> Quantitative analysis of two cancer markers in the low concentration range is possible using this device. </LI> <LI> This approach provides new insights into the accurate screening test of prostate cancer. </LI> </UL> </P>

Numerical investigation of heat transfer in a garment convective cooling system

Yijie Zhang,Jia Juhong,Ziyi Guo 한국의류학회 2022 Fashion and Textiles Vol.9 No.1

A personal microclimate management system is designed to maintain thermal comfort which allows people to overcome a harsh environment. It consists of several microfans placed in the garment side seam to provide cooling air. The computational fuid dynamics method was used to simulate the three-dimensional model and analysis the infuence of fan’s number and air gap distance. The obtained results depict that the introduced cool airfow will fnd its way along paths with fow resistance minimized and exhaust through several separated exit. The body heat fux is taken away at the same time. The convection efect is enhanced by the increase in the fans’ numbers, but the fans’ cooling efect varies a lot because of various air gap distances. When the air gap is small enough, the cooling air impact the body surface directly and causes ferce heat loss. While the air gap distance is large enough, the heat transfer along the skin surface could be enhanced by the eddy fow which is existed in the air gap between body and garment. These phenomena can maintain the body’s thermal comfort in a suitable range.

Nest-like Ag-doped NiMoO4/NF with rich oxygen vacancies as robust catalysts for highly efficient oxygen evolution

Jianzhi Wang,Yu Luo,Tong Xu,Ziyi Guo,Guopeng Chen,Yuchen Ren,Yanan Xue,Ning Cai,Hui Li,Faquan Yu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

The development of low-cost and highly efficient electrocatalysts for oxygen evolution reaction (OER)with good conductivity, high specific surface area and abundant oxygen vacancies is of great significancefor the future renewable energy conversion and storage system. Herein, Ag doped NiMoO4 materials onthe Ni foam (NiMoO4/Ag/NF) with rich oxygen vacancies were successfully prepared by hydrothermalstrategy and layer by layer assembly method. The Ag ions are doped in-situ to promote electron transferand compensate for the poor conductivity of metal oxides. The suitable air annealing treatment is used tocreate rich oxygen vacancies. The high specific surface area and one-dimensional characteristics of thecross mesoporous nanorod skeleton are responsible for the increased exposure of active centers andthe rapid charge transfer behavior. The NiMoO4/Ag/NF exhibits high activity for OER in alkaline solution(an overpotential of 275 mV at the current density of 20 mA cm2) and low Tafel slope (53.67 mV dec1),and a satisfying durability in 1.0 M KOH. This study provides an effective method for the preparation ofAg doped one-dimensional nanomaterials with excellent OER catalytic performance and electrochemicalstability.

DHA-enriched phosphatidylcholine suppressed angiogenesis by activating PPARγ and modulating the VEGFR2/Ras/ERK pathway in human umbilical vein endothelial cells

Yuanyuan Liu,Yingying Tian,Yao Guo,Ziyi Yan,Changhu Xue,Jingfeng Wang 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.12

Docosahexaenoic acid-enriched phosphatidylcholine(DHA-PC) is a new generation of omega-3 lipids,which contains an ester bond linking DHA at the sn-2position of phospholipid. DHA-PC has become the interestrecently as its better bioavailability and anti-oxidationcapacity. In this study, the anti-angiogenic effect of DHAPCwas evaluated. The capacities of proliferation, migration,tube formation of human umbilical vein endothelialcells were significantly declined after DHA-PC treatment. Furthermore, DHA-PC inhibited the neovascularization ofthe chick chorioallantoic membrane in vivo. Mechanismresults indicated that DHA-PC enhances the expression ofperoxisome proliferator-activated receptor c (PPARc) attranscriptional and translational level, subsequently downregulatesthe VEGFR2 expression and VEGFR2-mediateddownstream Ras/ERK pathway, resulting in significantreduction in proliferation and differentiation. Additionally,PPARc-specific antagonist GW9662 partly reversed theinhibition effects of DHA-PC on tube formation and neovascularization,suggesting that DHA-PC exerts anti-angiogenesiseffect through activating PPARc. Thesefindings indicated that DHA-PC has a great prospect ofanti-tumor angiogenesis therapy.

SET/PP2A signaling regulates macrophage positioning in hypoxic tumor regions by amplifying chemotactic responses

Zhang Shaolong,Zhou Jingping,Shang Pengzhao,Zhao Guomeng,Wang Anlei,Mao Jinlei,Tao Yuhang,Chen Ziyi,Wang Xuehao,Guo Changying 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Tumor-associated macrophages (TAMs) are one of the main cellular components in the tumor microenvironment (TME). In many types of solid tumors, TAMs tend to accumulate in hypoxic areas and are intimately related to poor patient prognosis. However, the underlying mechanisms by which TAMs infiltrate hypoxic tumor regions remain unclear. In this study, we report that genetic deletion of SE translocation (SET) in myeloid cells inhibited the entry of TAMs into the hypoxic tumor region and abated their proangiogenic and immunosuppressive functions, ultimately inhibiting tumor growth. Mechanistically, in response to hypoxic tumor supernatant stimulation, SET in macrophages shuttled between the nucleus and cytoplasm via the PKC-CK2α signaling axis. Cytoplasmic retention of SET increased ERK and P38 signaling by inhibiting PP2A, which promoted TAM migration into the hypoxic area and polarization toward the M2 phenotype. Therefore, we conclude that SET modulates tumor immunity by acting as a key regulator of macrophage positioning and function in the tumor.