Asymmetric Synthesis of Trisubstituted Tetrahydrothiophenes via in Situ Generated Chiral Fluoride-Catalyzed Cascade Sulfa-Michael/Aldol Reaction of 1,4-Dithiane-2,5-diol and α,β-Unsaturated Ketones

Duan, Mengying,Liu, Yidong,Ao, Jun,Xue, Lu,Luo, Shilong,Tan, Yu,Qin, Wenling,Song, Choong Eui,Yan, Hailong American Chemical Society 2017 ORGANIC LETTERS Vol.19 No.9

<P>A chiral, fluoride-catalyzed asymmetric cascade sulfaMichael/aldol condensation reaction of 1,4-dithiane-2,5-diol and a series of alpha,beta-unsaturated ketones is described to access chiral trisubstituted tetrahydrothiophene derivatives. The target products, including the spiro tetrahydrothiophene derivatives bearing a five-, six-, and seven-membered ring, were highly functionalized and showed high ee value. This established protocol realized a highly enantioselective reaction with a catalytic amount of KF and Song's chiral oligoEG via in situ generated chiral fluoride to construct useful heterocyclic skeletons with great complexity.</P>

Fluoride Anions in Self-Assembled Chiral Cage for the Enantioselective Protonation of Silyl Enol Ethers

Paladhi, Sushovan,Liu, Yidong,Kumar, B. Senthil,Jung, Min-Jung,Park, Sang Yeon,Yan, Hailong,Song, Choong Eui THE AMERICAN CHEMICAL SOCIETY 2017 ORGANIC LETTERS Vol.19 No.12

<P>The potential of Song's chiral oligoethylene glycol's (oligoEGs) as catalysts was explored in the enantioselective protonation of trimethylsilyl enol ethers in combination with alkali metal fluoride (KF and CsF) and in the presence of a proton source Highly enantioselective protonatigns of various silyl enol ethers of alpha-substituted tetralohes were achieved, producing chiral alpha-substituted-Jetralones in full conversion and with up to 99% ee. The established protocol was successfully exiended to the synthesis of biologically relevant chiral alpha-substituted chromanone and thiothromarione derivatives.</P>

Enantioselective Synthesis of <i>anti</i>–<i>syn</i>-Trihalides and <i>anti</i>–<i>syn</i>–<i>anti</i>-Tetrahalides via Asymmetric β-Elimination

Tan, Yu,Luo, Shilong,Li, Dongmei,Zhang, Nan,Jia, Shiqi,Liu, Yidong,Qin, Wenling,Song, Choong Eui,Yan, Hailong American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.18

<P>Structural motifs containing contiguous halide bearing stereocenters are common in natural products as well as bioactive molecules. A few successful examples have been reported in the area of asymmetric vicinal dihalogenation of alkenes for accessing dihalogenated products; in this report, an alternative generation method of contiguous halide-bearing stereocenters alpha,beta,gamma,delta relative to carbonyl group in excellent enantioselectivity is proposed by utilizing a Song's oligoEG catalyst-catalyzed asymmetric beta-elimination. According to this methodology, a wide range of anti-syn-trihalides and anti-syn-anti-tetrahalides with high levels of enantioselectivity were synthesized. The synthetic utility of the contiguous halide-bearing stereocenters was demonstrated by several transformations. The results of high-resolution mass spectrometry indicated that the favorable interaction between catalyst and one of the enantiomers of racemic contiguously multihalogenated ketone contributed to the original enantioselectivity of dehydrohalogenation. A deuterium kinetic isotope effect experiment revealed that this beta-elimination reaction proceeds by the E2 mechanism. This strategy opens a new pathway for the asymmetric synthesis of contiguous halide bearing stereocenters of great complexity.</P>

橋樑修建與士人參與

劉秋根(Liu Qiu-gen),宋燕鵬(Song Yan-peng) 경북대학교 아시아연구소 2009 아시아연구 Vol.- No.5

南宋時에 地方士人들은 적극적으로 대형교량의 건설과 重修활동에 참여하였다. 이들은 직접적으로 資金을 내어 參與하든지 아니면 社會에 影響力을 발휘하는 방식으로 參與하기도 하였다. 南宋時期다수의 士人들은 公益事業의 主體로써 참여하였는데, 政府施政能力의 萎縮이 士人로 하여금 地方의 橋樑건설과 重修활동에 참여할 수 있는 空間을 제공하였다. “富”에 대한 社會的觀念의 비평은 士人들의 橋樑건설과 重修참여에 輿論의 支持를 제공하였고, 佛教徒또한 士人이 橋樑건설과 重修활동에 참여하는 것을 모범으로 간주하였다. 士人이 橋樑修建에 참여함으로써 士人이 地方事務에 평소 관심을 가지고 있음을 보여주었다. 士人은 橋樑修建等의 活動에 참여함으로써 지방 輿論으로부터 好評을 받았을 뿐만 아니라, 社會事務에 대한 某種의 解釋과 支配權도 갖게 되었다. 이것은 새로운 基層社會勢力成長의 標誌라 할 수 있겠다. During the Southern Song Dynasty,Intellectual started to actively participate in large-scale bridge construction activities,and to participate in two ways of capital and social impact to exert their influence. The growing in strength of Intellectual groups provided the main of undertaking public welfare. The shrinking of government's administrative capability provided the space for Intellectual to participate in bridge construction activities. Social concepts of "the rich" were criticized provided public opinion support for Intellectual participating in bridge construction. Buddhists Set an example for Intellectual to participate in the activities of a bridge construction. Intellectual involved in the construction of the bridge reflects the Intellectual 's concern for local affairs. Through participation in activities such as bridge construction Intellectual received favorable public opinion, but also accessed to a certain extent of the interpretation of Social Affairs dominance. This had become a sign of new growth of grass-roots social forces.

Active Damping Stability Control Method Based on Voltage Compensation for IPMSM Drives with Small DC-Link Capacitor

Song Jian,Song Wen-Xiang,Liu Zhan-Jun,Ma Shao-Cai 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

Aiming at the unstable phenomena such as high DC-link voltage ripple that occur in the interior permanent magnet synchronous motor drive system of the small DC-link capacitor when the rotor speed is high or the load power is large, this paper proposes an active damping control method based on voltage compensation. The method starts from the mathematical model of the driving system, based on the characteristic equation of the driving system, and according to the Rouse stability criterion, the driving system is stabilized by applying a virtual resistance to change the coefficient of the characteristic equation. The proposed method only needs a bandpass filter to extract the DC-link voltage ripple, which is then compensated to the motor stator voltage axis by the damping coefficient. In order to obtain high damping performance, considering the time constant and the delay of the control loop, the theoretical design basis for a reasonable value of the damping coefficient is given, and the influence of the proposed method on the performance of the drive system is evaluated. Simulation and experimental results verify the effectiveness of the proposed method.

Improvement of electrical characteristics of InGaZnO thin film transistors by using HMDSO/O2 plasma deposited SiOCH buffer layer

Liu Chang,Qin Houyun,Liu Yiming,Wei Song,Wang Hongbo,Zhao Yi 한국물리학회 2021 Current Applied Physics Vol.21 No.-

In this work, we present the performance improved InGaZnO thin film transistors by inserting low temperature processed 10 nm thick SiOCH buffer layers between SiNx insulator and InGaZnO channel layer. The influences of oxygen flow rate during the deposition of SiOCH buffer layer have been intensively investigated. Basing on the analysis of hall effect measurement and Fourier transform infrared spectrum, the SiOCH buffer layer can effectively increase the carrier concentration of the channel layer by the hydrogen doping due to re-sputtering and diffusion effect. The InGaZnO thin film transistor with buffer layer exhibits an enhanced performance with mobility of 13.09 cm2/vs, threshold voltage of 0.55 V and Ion/Ioff over 106.

A Recommendation Method basing on Synthetic Strategy for Agricultural Science and Technology Information

Song Jinling,Huang Liming,Gao Yan,Liu Aiyong,Liu Haibin 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.5

To ameliorate the limitations of traditional collaborative filtering technologies and enhance the recommendation quality of agricultural science and technology information, a collaborative filtering recommendation method based on synthetic strategy is proposed. Firstly, filter the user set and user-item rating matrix according to the location of target user, which can solve the regional problem. Then, predict ratings of items according to the similarity of users or item content, which can relax the impact of the sparse rating. In addition, add the rating time to the user-item rating matrix to distinguish the timeliness of the user preference, and add user preference shifting in the similarity formula as a factor which can express the similarity of users or item content better. Our method can not only guarantee the recommended information is local and suit to current season of agricultural production, but also ensure the recommending precision under sparse rating data.

Research on the Relationship Between Serum Levels of Inflammatory Cytokines and Non-small Cell Lung Cancer

Song, Xiao-Yun,Zhou, Shi-Jie,Xiao, Ning,Li, Yun-Song,Zhen, De-Zhi,Su, Chong-Yu,Liu, Zhi-Dong Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Aims: This study was conducted to evaluate the levels of TNF-${\alpha}$, IL-6, IL-8 and VEGF in serum of patients with non- small cell lung cancer, for assessing their possible diagnostic and prognostic roles. Methods: We enrolled 48 patients newly diagnosed with non-small cell lung cancer and 40 healthy controls. TNF- ${\alpha}$, IL-6 and IL-8 levels were measured in the serum of all the subjects with specific radioimmunoassay kits, while EGF was analyzed by sandwich enzyme immunoassay techniques. Results: A statistically significant difference was observed between lung cancer patients and the control group regarding the values of TNF-${\alpha}$, IL-6, IL-8 and VEGF in serum. Moreover, TNF-${\alpha}$, IL-8 and VEGF levels were higher in patients with advanced stages compared to early stages. In addition, higher serum levels of TNF-${\alpha}$, IL-6, IL-8 and VEGF were found in smokers than in non-smokers, both in patients and controls. Conclusion: Serum levels of TNF-${\alpha}$, IL-6, IL-8 and VEGF were all elevated in lung cancer patients, suggesting that inflammatory cytokines could be jointly used as a screening tool. Though TNF-${\alpha}$, IL-8 and VEGF levels were related to advanced disease, long-term survival studies of NSCLC patients should be performed to confirm whether they can act as biomarkers of advanced disease. In addition, smoking would be an important contributor to the processes of inflammation and lung cancer.

Geochemical and S isotopic studies of pollutant evolution in groundwater after acid in situ leaching in a uranium mine area in Xinjiang

Liu Zhenzhong,Tan Kaixuan,Li Chunguang,Li Yongmei,Zhang Chong,Song Jing,Liu Longcheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ34S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%–48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.

Effects of Three Feeding Systems on Production Performance, Rumen Fermentation and Rumen Digesta Particle Structure of Beef Cattle

Liu, Y.F.,Sun, F.F.,Wan, F.C.,Zhao, H.B.,Liu, X.M.,You, W.,Cheng, H.J.,Liu, G.F.,Tan, X.W.,Song, E.L. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.5

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight ($575{\pm}10kg$) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate). The results showed that the average daily gain was significantly higher in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). Consumption per kg weight gain of concentrate, silage, and combined net energy (NEmf) were significantly decreased when cattle received TMR, unlike when they received SI1 and SI2 (p<0.05), indicating that the feed efficiency of TMR was the highest. Blood urea nitrogen (BUN) was significantly decreased when cattle received TMR compared with that in cattle receiving SI1 (p<0.05), whereas there was no difference compared with that in cattle receiving SI2. Ammonia nitrogen concentration was significantly lower in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). The rumen area of cattle that received TMR was significantly larger than that of cattle receiving SI1 (p<0.05), but there was no difference compared with that of cattle receiving SI2. Although there was no significant difference among the three feeding systems in rumen digesta particle distribution, the TMR group trended to have fewer large- and medium-sized particles and more small-sized particles than those in the SI1 and SI2 groups. In conclusion, cattle with dietary TMR showed increased weight gain and ruminal development and decreased BUN. This indicated that TMR feeding was more conducive toward improving the production performance and rumen fermentation of beef cattle.