Catalytic performance of amino acid/phosphotungstic acid as bi-functional heterogeneous catalyst for biodiesel production

Qingyu Zhang,Xiaoling Duan,Siyi Tang,Cunwen Wang,Weiguo Wang,Weiliang Feng,Tielin Wang 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.1

In this study, a series of acid-base bi-functional catalysts were prepared by mixing different amounts of basic amino acids (AAs) and phosphotungstic acid (PTA), which exhibited the excellent performance in catalyzing conversion of oleic acid (OA) for the biodiesel production. The physicochemical properties of the catalysts were characterized and analyzed using modern testing techniques and characterization methods such as XRD, FT-IR, XPS, SEM, TEM, and Hammett titration. The various influence parameters were optimized using the central composite design based the response surface methodology, where the maximum biodiesel yield of 97.0% was achieved at the MeOH/OA molar ratio of 5.9, the catalyst loading of 8%, reaction time of 6 h, and reaction temperature of 65℃. Furthermore, the stability and reusability of the prepared catalyst were also demonstrated. At last, the possible catalytic mechanism of the prepared catalyst was comprehensively described.

Sphere Decoding in Parallel Mode and its Performance

Weiliang Fan,Zhijun Wang,Xinyu Mao 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.11

Sphere decoding is a very powerful algorithm in searching the optimal solution of multiple input and multiple output systems. However, it cannot perform in parallel directly. Sphere decoding can be depicted as searching in a tree. In this paper, we propose a parallel mode of the sphere decoding algorithm. We proposed that the searching tree can be partitioned into several sub-trees. The searching is divided into two stages. In the first stage, the partial Euclidean distances of sub-tree root nodes are calculated. In the second stage, several sub-trees perform their searching simultaneously. The Euclidean distance of the early finished sub-tree helps to reduce the calculation in the later finished sub-trees search. Simulation results sho

Optimal strategy for energy management of DC multi‑microgrids considering power loss

Weiliang Zhang,Hui Zhang,Na Zhi,Hanwei Wang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

DC multi-microgrids (DC MMG) improve power supply efficiency. However, they also increase transmission power loss. To reduce the power loss of the DC MMG, an optimization strategy of energy management with an adaptive distribution coefficient is proposed in this paper. By adjusting the power distribution coefficient of each DC microgrid (DC MG), the power distribution of the DC MMG is optimized to reduce power loss. In addition, to quickly predict changes of the DC MG power, the traditional finite control set model predictive control (FCS-MPC) is improved. The duty cycle of the converter is directly calculated according to the change of the current. Finally, experimental verification and comparison show that the proposed method can minimize the power loss of a DC MMG and speed up the balance of power.

Analysis and research on dynamic characteristics of 3D braided composite two-stage reducer case

Weiliang Zhang,Xupeng Wang,Xiaomin Ji,Xinyao Tang,Fengfeng Liu,Shuwei Liu,Mingjun Liu,Xiao-Long Gao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

Based on the analysis of the movement rule of 3D five-way braided yarn, the 3D five-way braided case model is divided into three parts: base, case bottom plate and case wall. According to the characteristics of each part, the braiding and forming principle of a 3D five-way composite case was analyzed. Under the assumption of ignoring the influence of friction, bearing and other factors on the system, the differential equations of motion of the two-stage gear transmission system with case were established. The two-stage gear transmission system was numerically analyzed by Euler method, and the influence of dimensionless meshing frequency, clearance, case mass and damping on the dynamic characteristics of the transmission system was studied. After that, high and low frequency disturbance was applied to the input case. The research shows that the damping ratio of the composite case increases and the low frequency attenuation is accelerated due to the decrease of the case mass, so the composite case has better shock resistance to low frequency interference.

Dynamics and Optimized Torque Distribution Based Force/position Hybrid Control of a 4-DOF Redundantly Actuated Parallel Robot with Two Point-contact onstraints

Haiying Wen,Ming Cong,Guifei Wang,Wenlong Qin,Weiliang Xu,Zhisheng Zhang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.5

A 4-DOF redundantly actuated parallel robot (RAPR) for jaw movement achieved by adding two pointcontactconstraints (higher-kinematic-pairs, HKPs) is presented. The inverse dynamics and driving force optimizationmodel based on pseudo-inverse method are established. In order to overcome the disequilibrium of drivingforces of the redundant chains caused by inclusion of point-contact constraints, an optimized torque distributionbased force/position hybrid control (OTDFP control) method for trajectory tracking is proposed for this RAPR. Experiments are carried out to evaluate the OTDFP control. Comparison with the conventional position control isperformed, showing that the OTDFP control can reduce torque fluctuation and tracking errors of the RAPR. Thechewing experiment of silicone shows the RAPR is not only able to track mandibular movement, but also able toemulate chewing force and temporomandibular joint (TMJ) force under the OTDFP control.

Review : Purification and Characterization of a Novel Extracellular Thermostable Alkaline Protease from Streptomyces sp. M30

( Yan Xin ),( Zhibin Sun ),( Qiongzhen Chen ),( Jue Wang ),( Yicheng Wang ),( Linfeng Luogong ),( Shuhuan Li ),( Weiliang Dong ),( Zhongli Cui ),( Yan Huang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

A novel alkaline protease from Streptomyces sp. M30, SapHM, was purified by ammonium sulfate precipitation, hydrophobic interaction chromatography, and DEAE-Sepharose chromatography, with a yield of 15.5% and a specific activity of 29,070 U/mg. Tryptic fragments of the purified SapHM were obtained by electrospray ionization quadrupole timeof- flight mass spectrometry. Nucleotide sequence analysis revealed that the gene sapHM contained 1,179 bp, corresponding to 392 amino acids with conserved Asp156, His187, and Ser339 residues of alkaline protease. The first 24 amino acid residues were predicted to be a signal peptide, and the molecular mass of the mature peptide was 37.1 kDa based on amino acid sequences and mass spectrometry. Pure SapHM was optimally active at 80°C in 50 mM glycine-NaOH buffer (pH 9.0), and was broadly stable at 0-50°C and pH 4.0-9.0. The protease relative activity was increased in the presence of Ni2+, Mn2+, and Cu2+ to 112%, 113%, and 147% of control, respectively. Pure SapHM was also activated by dimethylformamide, dimethyl sulfoxide, Tween 80, and urea. The activity of the purified enzyme was completely inhibited by phenylmethylsulfonyl fluoride, indicating that it is a serine-type protease. The Km and Vmax values were estimated to be 35.7 mg/ml, and 5 × 104 U/mg for casein. Substrate specificity analysis showed that SapH was active on casein, bovine serum albumin, and bovine serum fibrin.

Ballistic electronic and thermal conductance of monolayer and bilayer black phosphorus

Zexiang Deng,Huanjun Chen,Zhibing Li,Weiliang Wang 한국물리학회 2017 Current Applied Physics Vol.17 No.2

We performed first principle calculations based on density functional theory and GW approximation with Landauer approach to study ballistic electronic conductance and ballistic thermal conductance of black phosphorus (BP) whose dimensions are smaller than the mean free path of carriers. Ballistic electronic conductance of monolayer BP and bilayer BP with four different stacking styles, and ballistic thermal conductance of monolayer BP were investigated. The electronic transmission value along armchair direction is found to be a little higher than that along zigzag direction near the band gap energy range. Our calculations showed that, the G point hole effective mass along zigzag direction is stackingstyle sensitive, while other G point effective mass is independent of stacking style. We also reported the anisotropic ballistic thermal conductance of monolayer BP: the anisotropic ballistic thermal conductance ratio of zigzag-to-armchair approaches a constant (about 2.0) when the temperature is beyond 200 K. The reasons for these properties were discussed.

Structure-Based Design and Synthesis of C-1- and C-4-Modified Analogs of Zanamivir as Neuraminidase Inhibitors

Feng, Enguang,Shin, Woo-Jin,Zhu, Xuelian,Li, Jian,Ye, Deju,Wang, Jiang,Zheng, Mingyue,Zuo, Jian-Ping,No, Kyoung Tai,Liu, Xian,Zhu, Weiliang,Tang, Wei,Seong, Baik-Lin,Jiang, Hualiang,Liu, Hong American Chemical Society 2013 Journal of medicinal chemistry Vol.56 No.3

<P>In order to exploit the 430-cavity in the active sites of neuraminidases, 22 zanamivir analogs with C-1 and C-4 modification were synthesized, and their inhibitory activities against both group-1 (H5N1, H1N1) and group-2 neuraminidases (H3N2) were determined. Compound <B>9f</B> exerts the most potency, with IC<SUB>50</SUB> value of 0.013, 0.001, and 0.09 μM against H3N2, H5N1, and H1N1, which is similar to that of zanamivir (H3N2 IC<SUB>50</SUB> = 0.0014 μM, H5N1 IC<SUB>50</SUB> = 0.012 μM, H1N1 IC<SUB>50</SUB> = 0.001 μM). Pharmacokinetic studies of compound <B>9f</B> in rats showed a much longer plasma half-life (<I>t</I><SUB>1/2</SUB>) than that of zanamivir following administration (po dose). Molecular modeling provided information about the binding model between the new inhibitors and neuraminidase, with the elongated groups at the C-1-position being projected toward the 430-loop region. This study may represent a novel starting point for the future development of improved antiflu agents.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jmcmar/2013/jmcmar.2013.56.issue-3/jm3009713/production/images/medium/jm-2012-009713_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jm3009713'>ACS Electronic Supporting Info</A></P>

Hypoxia-induced circRNF13 promotes the progression and glycolysis of pancreatic cancer

Zhao Qiuyan,Zhu Zhonglin,Xiao Wenqin,Zong Guanzhao,Wang Chuanyang,Jiang Weiliang,Li Kai,Shen Jie,Guo Xingya,Cui Jianhua,Guo Lihong,Wan Rong 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Pancreatic cancer (PC) is one of the most malignant tumors. Rapid progression and distant metastasis are the main causes of patient death. Hypoxia is a hallmark of multiple cancers and is involved in tumor biology. However, little is known about the roles of circRNAs in glycolysis and hypoxia-mediated progression of PC. Here, the expression pattern of hypoxia-related circRNAs was analyzed using RNA sequencing. A unique circRNA termed circRNF13 was found to be upregulated in PC tissues and may be a potential prognostic indicator. HIF-1α and EIF4A3 are involved in regulating the biogenesis of circRNF13. Furthermore, circRNF13 was validated to exert a stimulative effect on cell proliferation, angiogenesis, invasion and glycolysis. Importantly, we found that circRNF13 promoted PDK3 levels by acting as a miR-654-3p sponge, thus promoting the PC malignant process. Collectively, our results reveal that hypoxia-induced circRNF13 mediated by HIF-1α and EIF4A3 promotes tumor progression and glycolysis in PC, indicating the potential of circRNF13 as a prognostic biomarker and therapeutic target for PC.

Short-duration chemoprophylaxis might reduce incidence of deep vein thrombosis in Asian patients undergoing total knee arthroplasty

Zhang Siyuan,Htet Kway Swar,Tan Xin Yang,Wang Xinyu,Wang Wilson,Chua Weiliang 대한슬관절학회 2020 대한슬관절학회지 Vol.32 No.-

Venous thromboembolism (VTE) is a serious complication that may occur after total knee arthroplasty (TKA), leading to the recommendation of routine chemoprophylaxis by international guidelines. This study aims to determine if short-duration chemoprophylaxis after TKA reduces the incidence of VTE in an Asian population.A retrospective study of 316 patients who underwent unilateral primary TKA between 1 January 2011 and 31 December 2013 was conducted. All patients received mechanical prophylaxis. One hundred seventeen patients (37%) received additional chemoprophylaxis, whereas 199 patients (63%) did not. A Doppler ultrasound (DUS) of both lower limbs was conducted for all patients within 6 days after surgery (median = 3 days) to assess for both proximal and distal DVT. Chemoprophylaxis in the form of enoxaparin (low molecular weight heparin; LMWH), aspirin, or heparin was administered until patients had a normal DUS, for a median duration of 4 days. Patients were followed up clinically for a minimum of 6 months to monitor for delayed or recurrent VTE and at least 2 years for patient-reported outcome measures. Overall, 24 patients (7.59%) developed deep vein thrombosis (DVT): three proximal and 21 distal DVTs. Twenty-three of the 24 patients were asymptomatic. Twenty of 199 patients (10.05%) with only mechanical prophylaxis developed DVT, whereas four of 117 patients (3.42%) with additional chemoprophylaxis developed DVT. Multivariate analysis showed that chemoprophylaxis use was associated with reduced incidence of DVT (odds ratio = 0.19, p value = 0.011). Other factors associated with increased DVT incidence include female gender (odds ratio = 5.45, p value = 0.034), positive history of cancer (odds ratio = 5.14, p value = 0.044), and increased length of stay in hospital (odds ratio = 1.19, p value < 0.001). Our study has shown that despite the low incidence of DVT in Asian patients undergoing TKA, short-duration chemoprophylaxis might be effective in reducing the incidence of DVT. However, most DVTs observed in our study were distal and may be of limited clinical significance. Further studies are needed to investigate the impact of chemoprophylaxis use on the incidence of PE and overall mortality rates among Asian patients.