Aerosol Observation with Raman LIDAR in Beijing, China

Chen-Bo Xie,Jun Zhou,Nobuo Sugimoto,Zi-Fa Wang 한국광학회 2010 Current Optics and Photonics Vol.14 No.3

Aerosol observation with Raman LIDAR in NIES (National Institute for Environmental Studies, Japan) LIDAR network was conducted from 17 April to 12 June 2008 over Beijing, China. The aerosol optical properties derived from Raman LIDAR were compared with the retrieved data from sun photometer and sky radiometer observations in the Aerosol Robotic Network (AERONET). The comparison provided the complete knowledge of aerosol optical and physical properties in Beijing, especially in pollution and Asian dust events. The averaged aerosol optical depth (AOD) at 675 nm was 0.81 and the Angstrom exponent between 440 nm and 675 nm was 0.99 during experiment. The LIDAR derived AOD at 532 nm in the planetary boundary layer (PBL) was 0.48, which implied that half of the total AOD was contributed by the aerosol in PBL. The corresponding averaged LIDAR ratio and total depolarization ratio (TDR) were 48.5sr and 8.1%. The negative correlation between LIDAR ratio and TDR indicated the LIDAR ratio decreased with aerosol size because of the high TDR associated with nonspherical and large aerosols. The typical volume size distribution of the aerosol clearly demonstrated that the coarse mode radius located near 3 μm in dust case, a bi-mode with fine particle centered at 0.2 μm and coarse particle at 2 μm was the characteristic size distribution in the pollution and clean cases. The different size distributions of aerosol resulted in its different optical properties. The retrieved LIDAR ratio and TDR were 41.1sr and 19.5% for a dust event, 53.8sr and 6.6% for a pollution event as well as 57.3sr and 7.2% for a clean event. In conjunction with the observed surface wind field near the LIDAR site, most of the pollution aerosols were produced locally or transported from the southeast of Beijing, whereas the dust aerosols associated with the clean air mass were transported by the northwesterly or southwesterly winds.

Facile and highly effective synthesis of nitrogen-doped graphene quantum dots as a fluorescent sensing probe for Cu2+ detection

Bo Gao,Da Chen,Bingli Gu,Ting Wang,Zihao Wang,Feng xie,Yongsheng Yang,Qinglei Guo,Gang Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.4

Nitrogen-doped graphene quantum dots (N-GQDs) with high blue fluorescence efficiency were synthesized by the hydrothermal method from p-Phenylenediamine and p-Coumaric acid. The N-GQDs possess several superiorities, most significantly in excellent solubility and superior photostability. Besides, the as-prepared N-GQDs exhibit a uniform size distribution with a diameter of about 3.8 ± 0.5 nm. After dispersing the N-GQDs in water, the formed aqueous solution still presents a stable and homogeneous phase even after 2 months at room temperature. The N-GQD dispersion was further utilized as sensing probes for the selective detection of copper ions (Cu2+), which is realized by the photoluminescence (PL) quenching of N-GQDs after adding Cu2+. The detection limit for Cu2+ was found to be 57 nM L−1, with superior selectivity in the presence of other commonly interfering metal ions. The presented results in this study provide a facile and high-efficiency method for synthesizing N-GQDs, with ultra-high detectivity and selectivity for Cu2+ detection, offering numerous opportunities for the development of biosensing, bioimaging, environment monitoring, and others.

A novel method for the discrimination of Hawthorn and its processed products using an intelligent sensory system and artificial neural networks

Xie, Da-Shuai,Peng, Wei,Chen, Jun-Cheng,Li, Liang,Zhao, Chong-Bo,Yang, Shi-Long,Xu, Min,Wu, Chun-Jie,Ai, Li 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6

Hawthorn (CFS) has commonly been applied as an important traditional Chinese medicine and food for thousands of years. The raw material of CFS is commonly processed by stir-frying to obtain yellow (CFY), dark brown (CFD), and carbon dark (CFC) colored products, which are used for different clinical uses. In this study, an intelligent sensory system (ISS) was used to obtain the color, gas, and flavor samples data, which were further employed to develop a novel and accurate method for the identification of CFS and its processed products using principal component analysis. Moreover, this research developed a model of an artificial neural network, which could be used to predict the total organic acid, total flavonoids, citric acid, hyperin, and 5-hydroxymethyl furfural via determination of the color, odor, and taste of a sample. In conclusion, the ISS and the artificial neural network are useful tools for rapid, accurate, and effective discrimination of CFS and its processed products.

Multiband and Broadband Absorption Enhancement of Monolayer Graphene at Optical Frequencies from Multiple Magnetic Dipole Resonances in Metamaterials

Liu, Bo,Tang, Chaojun,Chen, Jing,Xie, Ningyan,Tang, Huang,Zhu, Xiaoqin,Park, Gun-sik Springer US 2018 NANOSCALE RESEARCH LETTERS Vol.13 No.1

<P>It is well known that a suspended monolayer graphene has a weak light absorption efficiency of about 2.3% at normal incidence, which is disadvantageous to some applications in optoelectronic devices. In this work, we will numerically study multiband and broadband absorption enhancement of monolayer graphene over the whole visible spectrum, due to multiple magnetic dipole resonances in metamaterials. The unit cell of the metamaterials is composed of a graphene monolayer sandwiched between four Ag nanodisks with different diameters and a SiO<SUB>2</SUB> spacer on an Ag substrate. The near-field plasmon hybridizations between individual Ag nanodisks and the Ag substrate form four independent magnetic dipole modes, which result into multiband absorption enhancement of monolayer graphene at optical frequencies. When the resonance wavelengths of the magnetic dipole modes are tuned to approach one another by changing the diameters of the Ag nanodisks, a broadband absorption enhancement can be achieved. The position of the absorption band in monolayer graphene can be also controlled by varying the thickness of the SiO<SUB>2</SUB> spacer or the distance between the Ag nanodisks. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.</P>

The effect of HCP on the formation of twin boundaries and dislocations in Ni–Co alloys

Ma Rui-bo,Zhou Li-li,Liang Yong-chao,Chen Qian,Tian Ze-an,Liu Rang-su,Mo Yun-fei,Gao Ting-hong,Xie Quan 한국물리학회 2021 Current Applied Physics Vol.29 No.-

In this study, molecular dynamics (MD) was used to simulate the rapid solidification process of Ni47Co53 and Ni48Co52 alloys at a cooling rate of 1012 K/s. The effects of HCP on the formation of twin boundaries and dislocations in two Ni–Co alloys are studied. It is found that the difference of HCP clusters is the main effect that producing discrepancies on microstructure of two alloys. The number of HCP clusters accounted for 9.23% in Ni47Co53 alloy. They are regularly arranged to form the number of single-layer twin boundaries, and each twin boundary ends in a dislocation. The FCC and HCP structures coexist in the same atomic layers, which is easy to create dislocations. The relatively standard FCC crystal and only 0.32% HCP clusters are formed in Ni48Co52 alloy at 300 K. That small amount of HCP clusters are dispersed on the surface, and cause the formation of dislocation in the border with FCC clusters.

Exogenous Morphine Inhibits Human Gastric Cancer MGC-803 Cell Growth by Cell Cycle Arrest and Apoptosis Induction

Qin, Yi,Chen, Jing,Li, Li,Liao, Chun-Jie,Liang, Yu-Bing,Guan, En-Jian,Xie, Yu-Bo Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Morphine is not only an analgesic treating pain for patients with cancer but also a potential anticancer drug inhibiting tumor growth and proliferation. To gain better insight into the involvement of morphine in the biological characteristics of gastric cancer, we investigated effects on progression of gastric carcinoma cells and the expression of some apoptosis-related genes including caspase-9, caspase-3, survivin and NF-${\kappa}B$ using the MGC-803 human gastric cancer cell line. The viability of cells was assessed by MTT assay, proliferation by colony formation assay, cell cycle progression and apoptosis by flow cytometry and ultrastructural alteration by transmission electron microscopy. The influences of morphine on caspase-9, caspase-3, survivin and NF-${\kappa}B$ were evaluated by semi-quantitative RT-PCR and Western blot. Our data showed that morphine could significantly inhibit cell growth and proliferation and cause cell cycle arrest in the G2/M phase. MGC-803 cells which were incubated with morphine also had a higher apoptotic rate than control cells. Morphine also led to morphological changes of gastric cancer cells. The mechanism of morphine inhibiting gastric cancer progression in vitro might be associated with activation of caspase-9 and caspase-3 and inhibition of survivin and NF-${\kappa}B$.

Development of High Spectral Resolution Lidar System for Measuring Aerosol and Cloud

Ming Zhao,Chen-Bo Xie,Zhiqing Zhong,Bang-Xin Wang,Zhenzhu Wang,Pang-Da Dai,Zhen Shang,Min Tan,Dong Liu,Yingjian Wang 한국광학회 2015 Current Optics and Photonics Vol.19 No.6

A high spectral resolution lidar (HSRL) system based on injection-seeded Nd:YAG laser and iodineabsorption filter has been developed for the quantitative measurement of aerosol and cloud. The laserfrequency is stabilized at 80 MHz by a frequency locking system and the absorption line of iodine cellis selected at the 1111 line with 2 GHz width. The observations show that the HSRL can provide verticalprofiles of particle extinction coefficient, backscattering coefficient and lidar ratio for cloud and aerosolup to 12 km altitude, simultaneously. For the measured cases, the lidar ratios are 10~20 sr for cloud,28~37 sr for dust, and 58~70 sr for urban pollution aerosol. It reveals the potential of HSRL to distinguishthe type of aerosol and cloud. Time series measurements are given and demonstrate that the HSRL hasability to continuously observe the aerosol and cloud for day and night

A novel method for the discrimination of Hawthorn and its processed products using an intelligent sensory system and artificial neural networks

Da-Shuai Xie,Wei Peng,Jun-Cheng Chen,Liang Li,Chong-Bo Zhao,Shi-Long Yang,Min Xu,Chun-Jie Wu,Li Ai 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6

Hawthorn (CFS) has commonly been applied as an important traditional Chinese medicine and food for thousands of years. The raw material of CFS is commonly processed by stir-frying to obtain yellow (CFY), dark brown (CFD), and carbon dark (CFC) colored products, which are used for different clinical uses. In this study, an intelligent sensory system (ISS) was used to obtain the color, gas, and flavor samples data, which were further employed to develop a novel and accurate method for the identification of CFS and its processed products using principal component analysis. Moreover, this research developed a model of an artificial neural network, which could be used to predict the total organic acid, total flavonoids, citric acid, hyperin, and 5-hydroxymethyl furfural via determination of the color, odor, and taste of a sample. In conclusion, the ISS and the artificial neural network are useful tools for rapid, accurate, and effective discrimination of CFS and its processed products.

Austenite Grain Growth Behavior of 30BF Steel Before Rough Rolling

Yong‑feng Chen,Jian‑bo Xie,Yan‑xin Wu,Jian‑xun Fu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

To investigate the eff ect of heat treatment on the grain size of austenite in 30BF steel, the comparisons of the morphologiesand sizes of austenite grains between heating samples were made with a high-temperature electric resistance furnace, andthe austenite growth models were built with method of mathematics. The results show that most grains in original specimenwith the sizes below 70 μm uniformly distributed. At a heating rate ( v ) of 10 °C/s, the grain size ( d ) value under a certain time( t ) increased by 60–100 μm with raising temperature ( T ) from 850 to 1100 °C, whereas the d value under a certain T merelyincreased by 70–120 μm with raising time to 60 min. Under v = 0.1 °C/s, T = 850 °C, and t = 0 s, the occupied ratio of grainswith sizes of 40–50 μm was 0.165, whereas at 900 °C, the occupied ratio was 0.125. The evolutions of ln (d5.8− d5.80 ) with1/ T were in negative linear correlations, whereas the ln (d5.8− d5.80 ) with ln t were in positive linear correlations. To sum up,the grain growth behavior of steel was elucidated.

An Iterative Algorithm to Estimate LIDAR Ratio for Thin Cirrus Cloud over Aerosol Layer

Zhenzhu Wang,Dong Liu,Chen-Bo Xie,Jun Zhou 한국광학회 2011 Current Optics and Photonics Vol.15 No.3

A new iterative algorithm is developed to estimate LIDAR ratio for a thin cirrus cloud over an aerosol layer. First, the thin cirrus cloud is screened out and replaced by a modeled LIDAR signal and the extinction coefficients of the aerosol layer are derived using the Fernald backward method. These aerosol coefficients are referred as the “actual values”. Second, the original LIDAR signal which includes the thin cirrus cloud is also inverted by the Fernald backward method down to the aerosol layer but using different LIDAR ratio for the thin cirrus cloud. Depending on the different assumptions about the LIDAR ratio of the thin cirrus cloud, different sets of aerosol extinction can be derived. The “actual values” which are found in the first step can be used to constrain this iterative progress and the correct LIDAR ratio of the thin cirrus cloud can be found. The detailed description of this method and retrieval examples are given in the paper. The cases compared with other methods are presented and the statistical result is also shown and agrees well with other studies.