Study on the Thermal Decomposition of Waste Polystyrene in Motor Oil Using Microwave Energy

Liu, Xiao Yun,Kang, Tae Won 公州大學校 工學硏究院 生産技術硏究所 2003 論文集 Vol.11 No.-

A novel microwave-induced pyrolysis of waste polystyrene in motor oil was performed in quartz tube reactor. Different pyrolysis conditions were investigated, such as time range from 30 minutes to 1 hour and effective microwave power range from 180 to 250 watt. The distillate components were analyzed with GC-MS, and styrene, 1-methyl styrene, toluene, ethyl benzene were the four main products. Among these distillate products, styrene took over 70 percentages. Temperature of pyrolysis suing microwave was much lower than that of conventional thermal pyrolysis method.

The Molecular Mechanism of Safrole-induced DNA Adducts and its Role to Oral Carcinogenesis

Liu,Tsung-Yun 한국환경성돌연변이발암원학회 2003 한국환경성돌연변이·발암원학회지 Vol.23 No.3

基於CiteSpace視角的漢語四字格成語 曆時研究可視化圖譜分析及研究展望 ― 以1979年-2021年爲中心

劉柳(Liu Liu),劉耘(Liu Yun) 중국어문학연구회 2022 중국어문학논집 Vol.- No.134

The idiom, which is short but powerful, is a set phrase accepted through common practices for a long period of time. The idiom has various forms, and are mainly of four-character structure. Aiming at important issues about the diachronic situation, current hot spots and future trend of four-character idiom research, etc., this paper sorts out the relevant literature published in CNKI from 1979 to 2021, and utilizes CiteSpace to develop the author collaboration network, research institution cooperation network, keyword co-appearance network, clustering map and other visualized knowledge maps in respect to diachronic research situation of four-character idioms. Then, those visualized knowledge maps are quantitatively analyzed to obtain their development trend that rises steadily as a whole. After analysis of current research hot spots, it’s found that the academic circles are currently focusing on researches about ontology and translation of the Chinese. Based on the analysis results, this paper makes a scientific prediction for future idiom development, and deduces that the idioms will evolve towards the direction of construction grammar, cognitive science, etc., in the future.

Non-Organ Specific Cancer Preventive Effect of Long-Term Administration of Korean Red Ginseng Extracts on the Incidence of Malignant Neoplasms

Taik-Koo Yun(윤택구),Shu Zheng,Soo-Yong Choi,Shan Rong Cai,Yun-Sil Lee,Xi Yong Liu,Kyung Ja Cho,Kun Young Park,Hyo Young Yun,Ji Young Yun 고려인삼학회 2009 고려인삼학회 학술대회 Vol.2009 No.5

Influence of Endurance tests on Space Charge Distribution of 160kV HVDC XLPE Cable

Liu, Yun-Peng,Liu, He-Chen The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.1

The ageing of XLPE cable insulation will lead to the accelerating accumulation of space charge, which will greatly affect the safe operation of the HVDC cable. In order to investigate the influence of different ageing modes on the space charge distribution of the HVDC cable, thermal stressed, electrical stressed and electro-thermal stressed endurance tests were carried out on the XLPE peelings. The tested XLPE peelings were obtained from 160kV HVDC cable insulation. The endurance tests were carried at thermal stress of 363K, electrical stress of 20kV/mm DC and a combination of both. The Pulsed Electro-Acoustic (PEA) method was used to measure the space charge distribution of the samples. The influences of ageing on the trap energy distribution were analyzed based on the isothermal relaxation theory and the decay characteristics of the space charge. The results showed that thermal ageing would help to improve the crystalline morphologies of the XLPE at the early stage. The total amount of space charge decreased compared to the ones before thermal ageing. The long term of electrical stress would result in the cleavage of polymer molecule chains which would intensify the accumulation of space charge and increase the density and depth of electron traps. With a combination of electrical and thermal stress, the injection and migration of space charge were more significant. Besides, the depth and density of electron traps increased rapidly with the increase of endurance time.

Sample Preparation and Stability of Human Serum and Urine Based on HPLC-DAD for Metabonomics Studies

Liu, Yun,Sun, Xiaoming,Di, Duolong,Feng, Yuxiang,Jin, Fengling Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.7

Many literatures focus on the biological relevance and the identification of biomarkers for disease activity assessment while less attention has been paid to the development of standard procedures for sample preparation and storage based on liquid chromatography technique. The influencing factors including protein precipitation, storage temperature, storage time, and reconstitution by ultra pure water were analyzed employing HPLC-DAD. The effects were investigated from five participants over three months by principal components analysis (PCA) and the values of percent changes (PC). The samples with protein precipitation might slow the rate of bacterial enzymatic conversion. After protein precipitation, the average PC of urine samples ($0.136{\pm}0.013$, n = 5) is relatively less than that of the serum samples ($0.173{\pm}0.026$, n = 5) for three months. Minimal effects on metabolic profiles of serum and urine (PC < 0.15) are reasonable for metabolomic studies after protein precipitation and storage at $-20^{\circ}C$ for two months.

Metabolism of Safrole, a Betel Quid Component, and its Role in the Development of Oral Cancer in Taiwan

Liu, Tsung-Yun,Chen, Chiu-Lan,Chung, Yu-Ting,Chi, Chin-Wen The Korean Society of Toxicology Korea Environment 2001 Toxicological Research Vol.17 No.-

Chewing betel quid is associated with an increased risk of oral cancer. The betel quid chewed in Taiwan includes the inflorescence of Piper betle, which contains high concentrations of safrole (15 mg/fresh weight). Piper betle leaf is also used in betel quid; however, the concentration of safrole in betel leaf has not been documented. Chewing betel quid may contribute to safrole exposure in man (420 mm in saliva). Using $a^{32}$P-postlabeling method, we have recently demonstrated the presence of stable safrole-like DNA adducts in human oral tissues following betel quid chewing. Safrole is a rodent hepatocar-cinogen, and the real nature of safrole-DNA adducts in human tissues beside oral has not been elucidated. In this paper, we tested the safrole DNA adducts forming potential in human hepatic and oral derived cells by the ${32}^P$-postlabeling technique. The results suggest that oral cancer derived cell OC-2 alone is not able to form safrole-DNA adduct. However, safrole DNA adducts can be detected following I'-hydroxysafrole, a proximate safrole metabolite, treatment. In addition, pretreament of cytochrome P450 inducers also enhanced the formation of previously undetectable safrole DNA adducts. This finding couples with our previous results suggest that oral may serve as a target tissue for safrole, and safrole may be involved in oral carcinogenesis.

The Molecular Mechanism of Safrole-induced DNA Adducts and its Role to Oral Carcinogenesis

Liu, Tsung-Yun Korean Environmental Mutagen Society 2003 한국환경성돌연변이·발암원학회지 Vol.23 No.3

IARC classified areca quid as a human carcinogen. Areca quid chewed in Taiwan includes Piper betle inflorescence, which contains high concentrations of safrole (15 mg/fresh weight). Safrole is a documented rodent hepatocarcinogen, and chewing areca quid may contribute to human exposure (420 $\mu$m in saliva). The carcinogenicity of safrole is mediated through 1'-hydroxysafrole formation, followed by sulfonation to an unstable sulfate that reacts to form DNA adducts. Using human liver microsomes and Escherichia coli membranes expressing bicistronic human P450s, CYP2E1 and CYP2C9 were identified as the main P450s involved in the activation of safrole. We have demonstrated the presence of stable safrole-dGMP adducts in human oral tissues following areca quid chewing using $^{32}$ P-postlabeling and HPLC mass spectrometry methods. By studying 88 subjects with a known AQ chewing history and 161 matched controls, we have demonstrated that the presence of safrole-DNA adducts in peripheral blood cells was correlated to AQ chewing, and CYP2E1 seemed to play an important role in the modulation of safrole-DNA adduct formation. We have also shown that safrole can form stable safrole-DNA adducts as well as oxidative damages in rodent liver. However, the stable safrole-DNA adducts may represent a more significant initial lesion as compared to the rapidly repaired safrole-induced 8-hydroxy-2'-deoxyguanosine. This oxidative DNA damage is mediated through the formation of hydoryxchavicol, the major safrole metabolite in human urine. Hydroxychavicol may have gone through two-electron oxidation to the o-quinone; then via one-electron reduction to semiquinone radicals to generate oxidative DNA damage. However, these reactive metabolites can be efficiently conjugated by GSH. These data suggest that safrole may contribute to the initiation of oral carcinogenesis through safrole-DNA adduct and not oxidative DNA damage. In addition, CYP2E1 may modulate this adduct formation.

Corona generated Radio Interference of the 750 kV AC Bundle Conductors in Sandy and Dusty Weather Condition in the High Altitude Area

Yun-Peng Liu,Lei Zhu,Fang-Cheng Lv,Bao-Quan Wan,Chun-Ming Pei 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

Sandy and dusty weather condition often occurs in the high altitude areas of China, which may greatly influence the corona generated radio interference (RI) characteristics of the bundle conductors of 750 kV AC power transmission lines. Corona generated RI of the conductors of the 750 kV AC power transmission lines used in practice is measured by EMI receiver with a coupling circuit and a coupling capacitor connected between the high voltage side and the earth side in fine and sandy and dusty condition. The measuring frequency is 0.5 MHz, and the quasi-peak detection is used. RI excitation function is calculated based on the corona RI current measured by the EMI receiver. Corona generated RI characteristics were analyzed from sand concentration and sand particle size. The test result shows that the corona generated RI excitation function is influenced by the sandy and dusty condition. Corona discharge of the conductors is more serious in sandy and dusty condition with an ultraviolet (UV) detector. Corona generated RI excitation function increases with the increase of sand concentration and also increases with the increase of particle size.

Negative Corona Onset Characteristic of the UHV Conductors Based on the Corona Cage

Yun-Peng Liu,Lei Zhu,Fang-Cheng Lv,Xiongjie Xie 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.6

Negative corona onset characteristics of the stranded conductors based on the ultra-high voltage (UHV) corona cage were studied in the paper. Based on the corona self-sustaining criterion in extreme uneven electric fields and the secondary emission process of the photoelectrons, the corona onset calculation model in the UHV corona cage is established and the corona current tests of the single LGJ900-75, 6 bundle LGJ900-75, 8 bundle LGJ400-35 conductors in dry and rain conditions were done in the UHV corona cage, and the rain rates are 2.4 mm/h, 20 mm/h and 30 mm/h. Corona onset electric field strength is gained by E-I tangent method, and the onset electric field strength in dry condition proves that the calculation model can be used to calculate the corona onset characteristics of the bundle conductors in the UHV corona cage. A further analysis proves that: the negative corona onset voltage of the conductor increases with the bundle number and the diameter of the sub conductor, but decreases with the bundle space in the corona cage. The onset electric field strength is influenced little by bundle space and bundle number, but decreases with the increase of the diameter of the sub-conductor. The surface irregularity coefficient decreases with the rain rate.