Catalytic transfer hydrogenation of 7-ketolithocholic acid to ursodeoxycholic acid with Raney nickel

He Tian,Xuejun Cao,Hongbin Zhao 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

Ursodeoxycholic acid was produced by the stereoselective reduction of 7-ketolithocholic acid. This hydrogenation reaction was catalyzed by the T-1 Raney nickel and potassium borohydride was used as hydrogen donor instead of inflammable hydrogen gas. Potassium tert-butoxide was introduced to improve yield of ursodeoxycholic acid from about 70% to a maximum of 94% by inducing the stereoselectivity on hydroxyl group at 40 8C and atmospheric pressure. Reduction reaction conditions such as amount of reactants, temperature and stirring speed were optimized. The whole process is safe and low-cost. Eventually, the product, ursodeoxycholic acid was characterized by IR, 1H NMR and 13C NMR spectra.

Optimal Configuration of Flexible Interconnection Devices for Transferring Photovoltaic Power in Active Distribution Network

Wu Hongbin,He Ye,Lin Xueshan,Bi Rui,Hua Yuting,Sun Ming,Xu Bin 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

With the increasing penetration of distributed photovoltaic in distribution network, it is more difficult to control active distribution network (ADN). A flexible interconnection device (FID) can realize regional interconnection of the ADN through transferring power. However, the influence of installation position and number of FIDs on the ADN varies, it is necessary to analyze its operational planning model. In this study, first, a photovoltaic power and load forecasting model is established, followed by reduction of the typical scenarios. Second, the ADN operational planning model is established according to the line load balance index to analyze the coordination and determine the power transfer value of the FID in different installation positions and numbers for the ADN. Third, the net income index of the distribution network in the entire life cycle is established to analyze the economy of the ADN and determine the optimal FID installation location and quantity. Finally, numerous simulations and comparisons are carried out on the actual example system, and the results show that the FID can effectively transfer the active power, strengthen the ADN power supply level, and solve the problem of power supply imbalance caused by distributed photovoltaic access.

Backstepping method based controller design for third-order truck platoon robust to dynamic uncertainty and external disturbance

Jianbo Feng,Liyang He,Yanxue Wang,Jianwei Yang,Hongbin Ren 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3

The vehicle platoon is subject to dynamic uncertainty and external disturbance, such as air drag and parameter variation in practice, so lack of consideration for those factors can deteriorate control performance. This paper proposes a nonlinear control algorithm based on a novel adaptive backstepping method to cope with the uncertainty and disturbance. The virtual controller in the backstepping method utilizes only the local information of the individual vehicle, rather than the global state information, in the control algorithm design. A third-order vehicle dynamics model was built to incorporate the nonlinearity and the factor of actuation delay. The fuzzy logic system (FLS) is applied to estimate the nonlinearity in vehicle dynamics to facilitate the adaptive control. Five scenarios with different settings were constructed to verify the control performance in the simulation, which indicates the effectiveness and robustness of the controller to dynamic uncertainty and external disturbance.

Study of nano-SiO2 reinforced CO2 foam for anti-gas channeling with a high temperature and high salinity reservoir

Wanli Kang,Haizhuang Jiang,Hongbin Yang,Zhe Li,Bobo Zhou,Yingqi He,Bauyrzhan Sarsenbekuly,Maratbek Gabdullin 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

CO2 flooding has been widely applied in lots of low permeability reservoirs. After extensive CO2 injection,some reservoirs began to show serious gas channeling problems. CO2 foam had been successfully used tosolve gas channeling problems due to its advantages of water selective plugging features (not pluggingoil). In this paper, a novel CO2 foam system was developed for high temperature and high salinity(HTHS)(85 ℃, 60,000 mg/L) aiming at solving the gas channeling in Changqing Oilfield. Taking the foam half-lifeas the evaluation standard, the optimum foam system (0.5 wt% EC-1 + 1 wt% SiO2) for the target reservoirwas determined. The influences of temperature, salinity and pressure on the CO2 foam performance werestudied by high temperature and high pressure(HTHP)method. The ability and mechanism of anti-gaschanneling were studied by experiments of sand packed tube and microscopic displacement,respectively. The results showed that the foam system possessed good foam properties at HTHS withpressure. As the concentration of SiO2 nanoparticles increased, the resistance factor of the foam systemincreased. However, temperature showed an adverse effect on foam stability, the resistance factordecreased with the increase of temperature. The Jamin superposition and emulsion plugging mechanismof foam system was revealed by microscopic displacement experiments.

Rapid visual detection of Mycobacterium avium subsp. paratuberculosis by recombinase polymerase amplification combined with a lateral flow dipstick

Guimin Zhao,Hongmei Wang,Peili Hou,Chengqiang He,Hongbin He 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.2

Paratuberculosis (Johne’s disease) is a chronic debilitating disease of domestic and wild ruminants. However, widespread point-of-care testingis infrequent due to the lack of a robust method. The isothermal recombinase polymerase amplification (RPA) technique has applied for rapiddiagnosis. Herein, RPA combined with a lateral flow dipstick (LFD) assay was developed to estimate DNA from Mycobacterium avium subsp. paratuberculosis. First, analytical specificity and sensitivity of the RPA-nfo primer and probe sets were assessed. The assay successfullydetected M. paratuberculosis DNA in 30 min at 39oC with a detection limit of up to eight copies per reaction, which was equivalent to thatof the real-time quantitative polymerase chain reaction (qPCR) assay. The assay was specific, as it did not amplify genomes from five otherMycobacterium spp. or five pathogenic enteric bacteria. Six hundred-twelve clinical samples (320 fecal and 292 serum) were assessed byRPA-LFD, qPCR, and enzyme-linked immunosorbent assay, respectively. The RPA-LFD assay yielded 100% sensitivity, 97.63% specificity,and 98.44% concordance rate with the qPCR results. This is the first report utilizing an RPA-LFD assay to visualize and rapidly detect M. paratuberculosis. Our results show this assay should be a useful method for the diagnosis of paratuberculosis in resource-constrained settings.

Annexin A2 gene interacting with viral matrix protein to promote bovine ephemeral fever virus release

Lihui Chen,Xingyu Li,Hongmei Wang,Peili Hou,Hongbin He 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.2

Bovine ephemeral fever virus (BEFV) causes bovine ephemeral fever, which can produce considerable economic damage to the cattle industry. However, there is limited experimental evidence regarding the underlying mechanisms of BEFV. Annexin A2 (AnxA2) is a calcium and lipid-conjugated protein that binds phospholipids and the cytoskeleton in a Ca2+-dependent manner, and it participates in various cellular functions, including vesicular trafficking, organization of membrane domains, and virus proliferation. The role of the AnxA2 gene during virus infection has not yet been reported. In this study, we observed that AnxA2 gene expression was up-regulated in BHK-21 cells infected with the virus. Additionally, overexpression of the AnxA2 gene promoted the release of mature virus particles, whereas BEFV replication was remarkably inhibited after reducing AnxA2 gene expression by using the small interfering RNA (siRNA). For viral proteins, overexpression of the Matrix (M) gene promotes the release of mature virus particles. Moreover, the AnxA2 protein interaction with the M protein of BEFV was confirmed by GST pull-down and co-immunoprecipitation assays. Experimental results indicate that the C-terminal domain (268–334 aa) of AxnA2 contributes to this interaction. An additional mechanistic study showed that AnxA2 protein interacts with M protein and mediates the localization of the M protein at the plasma membrane. Furthermore, the absence of the AnxA2-V domain could attenuate the effect of AnxA2 on BEFV replication. These findings can contribute to elucidating the regulation of BEFV replication and may have implications for antiviral strategy development.

Measurement of TOF of fast neutrons with ²³⁸U target

Li, Meng,Guan, Yuanfan,Lu, Chengui,Zhang, Junwei,Yuan, Xiaohua,Duan, Limin,Yang, Herun,Hu, Rongjiang,He, Zhiyong,Wei, Xianglun,Ma, Peng,Gan, Zaiguo,Yang, Chunli,Zhang, Hongbin,Chen, Liang,Qiu, Tianli Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

We developed a Dual-PPACs detector for fast neutron measurements that consists of two sets of PPAC: conventional PPAC and fission PPAC. A²³⁸U(U₃O₈) coating is placed in the fission PPAC's anode, which is used as the neutrons conversion layer. An experiment was performed to measure neutron time-of-flight (TOF) in which ²⁵²Cf spontaneous fission source was used. An excellent time resolution of 164ps has been observed at 6 mbar in isobutene gas. With the excellent time resolution of Dual-PPACs detector, exact neutron energy can be extracted from the timing measurement. The experimental detection efficiency was 1.9 × 10^-7, consistent with the efficiency of 2.5 × 10^-7 given by a Geant4 simulation. Ultimately, the results show that the Dual-PPACs detector is a suitable candidate for measuring fast neutrons in the future CiADS system.