14 results on '"Chen, Wenqi"'
Search Results
2. The study on performance and aerodynamics of micro counter-rotating HAWT
- Author
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Chen Wenqi, Wu Yunke, Hong Jie, Li Zhiqiang, and Zhang Zhihong
- Subjects
Maximum power principle ,Rotor (electric) ,Computer science ,020209 energy ,Mechanical Engineering ,Mechanical engineering ,02 engineering and technology ,Building and Construction ,Aerodynamics ,Rotation ,01 natural sciences ,Pollution ,Industrial and Manufacturing Engineering ,law.invention ,Mechanism (engineering) ,General Energy ,law ,Range (aeronautics) ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Counter rotating ,Pitch angle ,Electrical and Electronic Engineering ,010306 general physics ,Civil and Structural Engineering - Abstract
Compared with large HAWT, the power coefficient and economical performance of the micro HAWT are inferior. However, due to flexible deployment, rapid installation, easy-to-use and low cost, it is still necessary to carry out research on micro HAWT to improve their performance. As a structure proven to be able to increase the power coefficient of HAWT effectively, the aerodynamic characteristics of the micro counter-rotating HAWT (CRWT) is studied in detail by experiments and LBM-LES simulation in this paper. Firstly, the results show the micro CRWT can enhance the power coefficient by two schemes. One is that the equal diameter counter rotating rotors with certain pitch angle can achieve a maximum power coefficient in a wider range of speed. The other is to use the vice rotor to enhance the power output of the main rotor, whether the vice rotor is in front rotor or rear, the rotation of the vice rotor can significantly improve power coefficient of the main rotor, so as to enhance the power coefficient of the total system. Then the aerodynamic mechanism of the Vice-Main and Main-Vice rotor schemes is further discussed with LBM-LES result in detail.
- Published
- 2018
3. Propensity score-matched analysis of clinical outcome after enucleation versus regular pancreatectomy in patients with small non-functional pancreatic neuroendocrine tumors
- Author
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Lou Wenhui, Mao Weilin, Lv Yang, Zhang Lei, Han Xu, Kuang Tiantao, Chen Wenqi, Wang Huanyu, Wu Wenchuan, Xue-feng Xu, Jin Dayong, Wang Dansong, and Zhou Wentao
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Adult ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Enucleation ,Neuroendocrine tumors ,Disease-Free Survival ,Metastasis ,03 medical and health sciences ,0302 clinical medicine ,Pancreatectomy ,Postoperative Complications ,medicine ,Humans ,In patient ,Propensity Score ,Pathological ,Aged ,Retrospective Studies ,Hepatology ,business.industry ,Gastroenterology ,Middle Aged ,medicine.disease ,Prognosis ,Surgery ,Pancreatic Neoplasms ,Treatment Outcome ,030220 oncology & carcinogenesis ,Lymphatic Metastasis ,Propensity score matching ,Cohort ,Disease Progression ,030211 gastroenterology & hepatology ,Female ,business ,Follow-Up Studies - Abstract
The effectiveness of enucleation in treatment for low-grade (G1, G2) small (≤2 cm) non-functional pancreatic neuroendocrine tumors (sNF-pNETs) remains controversial. This study investigated short- and long-term outcome of enucleation comparing with regular pancreatectomy in patients with sNF-pNETs.The clinical data of patients with sNF-pNETs who underwent surgery in our hospital from January 2000 to December 2017 were retrospectively collected. Short- and long-term outcomes of two operations were analyzed. The propensity score matching (PSM) was performed to reduce potential selection bias.A total of 123 patients with sNF-pNETs were enrolled with 62 males, 69 G1, and median age was 56.91 ± 10.04 years old. During the follow-up period (mean 87 ± 58.1 months), 9(7.32%) disease progressed (recurrence or metastasis) and 2 died (1.62%), 5-years OS was 100%, 5-years DFS was 91.4%. Both lymph node metastasis (p = 0.117) and pathological grade (p = 0.050) were not prognostic factors for sNF-pNETs. The propensity score-matched cohort comprised 27 patients with enucleation and 44 patients with regular pancreatectomy. Enucleation was noninferior to regular pancreatectomy in terms of DFS, before or after PSM. The surgical duration (P 0.01) and blood loss (P 0.01) significantly decreased in enucleation compared with regular pancreatectomy. The other postoperative complications tended to occur in regular pancreatectomy than in enucleation, but no statistically significant difference (all p 0.05).Enucleation seems to be an effective option for the treatment of sNF-pNETs with a lower total rate of postoperative complications and similar long-term prognosis, compared with regular pancreatectomy.
- Published
- 2019
4. Downregulated expression of RACK1 results in pancreatic cancer growth and metastasis
- Author
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Zhang, Lei, Lv, Yang, Rong, Yefei, Chen, Wenqi, Fang, Yuan, Mao, Weilin, Lou, Wenhui, Jin, Dayong, and Xu, Xuefeng
- Subjects
in vivo ,receptor for activated C kinase 1 ,pancreatic cancer ,NF-κB ,OncoTargets and Therapy ,Original Research - Abstract
Lei Zhang,* Yang Lv,* Yefei Rong,* Wenqi Chen, Yuan Fang, Weilin Mao, Wenhui Lou, Dayong Jin, Xuefeng Xu Department of General Surgery, Zhongshan Hospital, Fudan University, Shanghai, China *These authors contributed equally to this work Background: The expression and function of the Receptor for Activated C Kinase 1 (RACK1) in cancer growth and metastasis are confused in different cancers, especially in pancreatic ductal adenocarcinoma (PDAC). Methods: One-hundred and eighty-two PDAC tissue specimens (95 males and 87 females) including pancreatic cancer tissue and para-carcinoma tissue were collected for analysis between 2005 to 2012. Blood phenotypic parameters using cell count and capillary electrophoresis were investigated. HE staining, real time PCR, Western blot analysis, and soft agar assays were performed to determine the role of RACK1. Purpose: In this study, we aim to determine the specific role of RACK1 in the untility of PDAC. Results: We found that RACK1 expression was significantly lower in pancreatic cancer tissue than in para-carcinoma normal pancreatic tissue both in clinic and mice with pancreatic cancer at the early stage. Our results suggested that RACK1 silence could significantly promote cell growth and metastasis of pancreatic cancer cells. But we found that the overexpression of RACK1 has the opposite effect in vitro. In vivo MIAPaca-2 cells overexpressing RACK1, the results demonstrated lower metastatic ability than MIAPaca-2 cells. RACK1 overexpression could decrease the NF-κB transactivation activity of MIAPaca-2 cells, which was consistent with the inhibitory effect of RACK1 overexpression on the pro-migration and pro-invasive target gene of NF-κB, while which could be increased by RACK1 silence. RACK1 silence also enhanced protein expression of pro-migration and pro-invasive NF-κB target genes, which on the contrary, could be reversed by IκBα. Besides, RACK1 expression was significantly associated with lymph node metastasis, vessels metastasis, invasion of nerves as well as TNM staging. The 3-year survival rate of patients with high RACK1 expression was significantly higher than those patients with low RACK1 expression. However, RACK1 expression was not an independent risk factor for of the long-term postoperative survival of patients with pancreatic cancer. Conclusion: The obtained results in our study suggested that the low expression of RACK1 was associated with cancer cell growth and metastasis in pancreatic cancer through the activation of the NF-κB pathway. RACK1 could be a potential therapeutic drug target to pancreatic cancer and metastasis. Keywords: receptor for activated C kinase 1, pancreatic cancer, NF-κB, in vivo
- Published
- 2019
5. Bimetallic Schiff base complexes for stereoselective polymerisation of racemic-lactide and copolymerisation of racemic-lactide with ε-caprolactone
- Author
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Xuan Pang, Chen Wenqi, Zhiqiang Sun, Jingwei Yang, Ranlong Duan, Shuai Li, Xuesi Chen, and Han Zhang
- Subjects
Steric effects ,Lactide ,Schiff base ,010405 organic chemistry ,Chemistry ,General Chemical Engineering ,General Chemistry ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Monomer ,Polymerization ,Polymer chemistry ,Stereoselectivity ,Bimetallic strip ,Caprolactone - Abstract
Three pairs of bimetallic Schiff base aluminum complexes (1a–6a) with different tetraamine backbone bridging parts and bulky silyl-substituted moieties on salicylidene were synthesized. Using these complexes as catalysts for ring opening polymerisation (ROP) of racemic-lactide (rac-LA), systematical stereoselectivity and kinetic studies on ROP of rac-LA were carried out. The Gibbs free energy difference between homo-propagation and cross-propagation (ΔG≠) calculated by activation entropy and enthalpy showed that bulky substituents at the 3-position enhanced the stereoselectivity. And the kinetic study results indicated that bulkier substituents with more steric hindrance reduced the ROP reactivity. Moreover, these complexes could also be used for copolymerisation of rac-LA and e-caprolactone (e-CL). Copolymers of poly(LA-co-CL) with various monomer ratios were synthesized. Kinetic research on copolymerisation as well as microstructure analysis demonstrated that poly (LA-co-CL) achieved by these complexes were tapered block copolymers.
- Published
- 2016
6. Homogeneously dispersed composites of hydroxyapatite nanorods and poly(lactic acid) and their mechanical properties and crystallization behavior
- Author
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Cheng Ying, Qingting Liu, Ching-Ping Wong, Rong Zhang, Xudong Fu, Yang Liu, Shengfei Hu, Hailong Hu, Chen Wenqi, and Junjun Tan
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chemistry.chemical_classification ,Nanocomposite ,Materials science ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,law.invention ,Nanocrystal ,chemistry ,Mechanics of Materials ,law ,Ultimate tensile strength ,Monolayer ,Ceramics and Composites ,Nanorod ,Crystallization ,Composite material ,0210 nano-technology ,Dispersion (chemistry) - Abstract
Aiming to disperse HA nanocrystals in a polymer matrix homogenously, uniform oil-soluble HA nanorods were synthesized via an oleic acid (OA)-assisted mixed-solvent thermal method, and then poly(lactic acid) (PLA)/HA nanorods nanocomposites were fabricated by using a solution method. The HA nanorods with an OA monolayer on the surface dispersed homogeneously in organic solvents and the dispersion in polymer solution was transparent and colloidally stable. TEM images showed that HA nanorods dispersed as single particles without aggregation in PLA matrix. The elongation at break of the composites increased from 4.24% to 8.79% by adding HA nanorods, whereas the tensile strength and Young's modulus were largely unchanged. HA nanorods accelerated evidently the PLA crystallization rate even at a low HA loading and induced a transition to an ordered crystalline morphology confirmed via non-iso/isothermal crystallization, the spherulitic morphology, calculations and wide-angle X-ray diffraction during heating and cooling cycles.
- Published
- 2020
7. Synergistic effect of PLA–PBAT–PLA tri-block copolymers with two molecular weights as compatibilizers on the mechanical and rheological properties of PLA/PBAT blends
- Author
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Chen Wenqi, Zhiqiang Sun, Jingru Sun, Ranlong Duan, Xuan Pang, Xinchao Bian, Han Zhang, Feng Lidong, Zhang Bao, and Xuesi Chen
- Subjects
Melt viscosity ,Materials science ,Interfacial bonding ,Chemical engineering ,Molecular mass ,Rheology ,General Chemical Engineering ,Polymer chemistry ,Copolymer ,General Chemistry ,Elongation ,Miscibility ,Ring-opening polymerization - Abstract
Two types of polylactide–poly(butylene adipate-co-terephthalate)–polylactide (PLA–PBAT–PLA) tri-block copolymers with different molecular weights (CP1 and CP2) were synthesized as compatibilizers for PLA/PBAT blends. Synergistic effects of CP1 and CP2 on the mechanical and rheological properties of the blends have been studied in detail. The addition of small amounts of CP1 and CP2 remarkably increased the elongation at the break point. 0.5 and 0.5 wt% of CP1 and CP2 led to an increase of elongation by over eightfold. Thermal, morphological and rheological analyses showed that addition of CP1 and CP2 increased the miscibility and interfacial bonding strength between PLA and PBAT, in addition to decreasing the melt viscosity. It was thought that the low-molecular-weight compatibilizer CP1 with high mobility would have a positive effect during the transportation of the high-molecular-weight CP2 from the matrix to the interface. In addition, CP2 played a key role in improving the interaction at the interface.
- Published
- 2015
8. Synthesis, characterization and application of methyl 3,5-disulfo-benzoate dipotassium dihydrate as nucleating agent for poly(L-lactide)
- Author
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Xinchao Bian, Chen Wenqi, Xuesi Chen, Han Zhang, Xuan Pang, and Zhiqiang Sun
- Subjects
chemistry.chemical_classification ,Materials science ,General Chemistry ,Polymer ,Crystal structure ,Triclinic crystal system ,law.invention ,chemistry.chemical_compound ,Sulfonate ,Differential scanning calorimetry ,chemistry ,law ,Polymer chemistry ,Copolymer ,Crystallization ,Mass fraction ,Nuclear chemistry - Abstract
A newly synthesized aromatic sulfonate compound, complex 2 with formula of K2[H3COOC-C6H3(SO3)2]·2H2O(methyl 3,5-disulfo-benzoate dipotassium dihydrate) was synthesized and characterized by elemental analysis, infrared(IR) spectrometry, nuclear magnetic resonance(NMR) and crystal structure measurement. Single-crystal X-ray diffraction(XRD) revealed that complex 2 crystallized in the triclinic system with space group $$P_{\bar 1}$$ . Complex 2 was used as nucleating agent for poly(L-lactide)(PLLA). The crystallization of PLLA with powder of complex 2 was investigated by means of differential scanning calorimetry(DSC) and polarized optical microscopy (POM). The results prove that complex 2 was effective as nucleating agent for PLLA. It could accelerate crystallization by reducing the induction time and increasing the density of nuclei in the crystallization process. The half-time of crystallization(t 0.5) for pure PLLA was about 8 times longer than that of PLLA sample with 1.0%(mass fraction) of complex 2.
- Published
- 2013
9. A quantitative HPLC method for determining lactide content using hydrolytic kinetics
- Author
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Zhantuan Gao, Chen Wenqi, Xinchao Bian, Xuesi Chen, Feng Lidong, and Zhiming Chen
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chemistry.chemical_classification ,Materials science ,Lactide ,Chromatography ,Polymers and Plastics ,Organic Chemistry ,Kinetics ,High-performance liquid chromatography ,chemistry.chemical_compound ,Hydrolysis ,chemistry ,Polylactic acid ,Anhydrous ,Organic chemistry ,Quantitative analysis (chemistry) ,Lactone - Abstract
A new method for quantitative analysis of lactide has been developed by applying chemical kinetics to a HPLC system. The most important advance is its practical approach to the quantification of analytes that are unstable in the HPLC mobile phase. In HPLC analysis, anhydrous mobile phases cannot separate lactide from impurities, and only mixtures of water and organic solvent can achieve effective separation. By selecting conditions for testing and studying the kinetics of lactide hydrolysis, extensive experiments revealed that lactide degradation can be treated as a pseudo-first-order reaction under the given HPLC conditions, and lactide content or purity can be quantitatively determined. This method is practical for measuring the purity of the intermediate lactide in polylactic acid (PLA) production and the lactide content in PLA. When lactide content is high, the relative standard deviation (RSD) of the measurements is
- Published
- 2009
10. Syntheses and crystal structures of (η5-C5H5)3Ln(THF) (Ln = Ce, Er)
- Author
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Zhang Yin, Xia Jusong, Jin Zhongsheng, Lin Guanyang, Wei Gecheng, and Chen Wenqi
- Subjects
Potassium ,Organic Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,Ether ,Crystal structure ,Biochemistry ,Inorganic Chemistry ,Erbium ,chemistry.chemical_compound ,Cerium ,Sodium cyclopentadienide ,Crystallography ,chemistry ,X-ray crystallography ,Materials Chemistry ,Molecule ,Physical and Theoretical Chemistry - Abstract
Brown crystalline tricyclopentadienyl cerium tetrahydrofuranate (THF) complex (eta5-C5H5)3Ce(THF) was prepared by the reaction of (NH4)2Ce(NO3)6 with sodium cyclopentadienide (C5H5Na) in THF at molar ratio of 1:6. ErCl3.4THF reacts with potassium cyclooct
- Published
- 1994
11. Multi-hop Routing for Wireless Network in Underground Mines
- Author
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Chen Wenqi and Xu Zhao
- Subjects
Zone Routing Protocol ,Dynamic Source Routing ,Static routing ,Wi-Fi array ,Computer science ,business.industry ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Wireless Routing Protocol ,Link-state routing protocol ,Multipath routing ,Computer Science::Networking and Internet Architecture ,Hazy Sighted Link State Routing Protocol ,business ,Computer network - Abstract
Multi-hop transmission link constructed by wireless relay nodes is a feasible solution to long range wireless communication in underground mines. In this paper, a fast routing protocol is proposed to guarantee the multi-hop wireless link between the mine rescue robot and operation console. This routing method contains a fast recursive algorithm for neighboring nodes selection and routing data frame’s design. The proposed method is proved competent for establishing a reliable and effective multi-hop wireless channel very fast.
- Published
- 2010
12. China Energy Conservation Investment Corporation
- Author
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Chen Wenqi
- Subjects
Energy conservation ,Market economy ,Renewable Energy, Sustainability and the Environment ,Natural resource economics ,Geography, Planning and Development ,Business ,Management, Monitoring, Policy and Law ,China ,Investment (macroeconomics) ,Corporation ,Energy policy - Published
- 1996
13. The syntheses of the complexes (η5-C5H5)Ln(η8-C8H8)·nTHF and (η5-C9H7)Ln(η8-C8H8)·2THF and the crystal structure determination of (η5-C5H5)Pr(η8-C8H8)·2THF and (η5-C9H7)Pr(η8-C8H8)·2THF
- Author
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Chen Wenqi, Jin Zhongsheng, and Wen Ke
- Subjects
chemistry.chemical_compound ,Crystallography ,Stereochemistry ,Chemistry ,Sandwich compound ,Yield (chemistry) ,X-ray crystallography ,Molecular Medicine ,Molecule ,Crystal structure ,Ring (chemistry) - Abstract
LnCL3 reacts with NaC5H5 and K2C8H8 to yield the complexes (η5-C5H5)Ln(η8-C8H8)·nTHF (Ln = Pr, Nd, n= 2; Ln = Gd, n= 1) and LnCl3 reacts with KC9H7 and K2C8H8 to yield the complexes (η5-C9H7)Ln(η8-C8H8)·2THF (Ln = Pr, Nd; η5-C9H7= indenyl); crystallography reveals (η5-C5H5)Pr(η8-C8H8)·2THF and (η5C9H7)Pr(η8-C8H8)·2THF not to possess the parallel ring sandwich structure.
- Published
- 1991
14. Crystal structure of NdCl3·4THF and its catalytic activity in polymerization of diene
- Author
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Chen Wenqi, Xing Yan, Yang Guang-Di, Jin Zhongsheng, and Fan Yuguo
- Subjects
Diene ,Stereochemistry ,Coordination number ,Crystal structure ,Inorganic Chemistry ,Bond length ,chemistry.chemical_compound ,Crystallography ,Pentagonal bipyramidal molecular geometry ,chemistry ,Polymerization ,X-ray crystallography ,Materials Chemistry ,Physical and Theoretical Chemistry ,Monoclinic crystal system - Abstract
The crystal and molecular structures of NdCl3· 4THF have been determined by the low temperature (−60 °C) X-ray diffraction method. NdCl3·4THF recrystallizes in the monoclinic space group P21/c with unit cell parameters a = 9.404(4), b = 21.591(5), c = 11.751(3) A, β = 111.03(3)°, Z = 4. The final R value is 0.039. Three chlorine atoms and four oxygen atoms from THF are coordinated with the central Nd(III) ion to give a pentagonal bipyramid polyhedron with coordination number 7, the average NdCl bond length is 2.674 A and NO 2.498 A. When combined with aluminum alkyls, NdCl3· 4THF is a highly effective catalyst for the polymerization of dienes. Relationships between complex structures and polymerization activities are discussed and the difference in polymerization activities between NdCl3 and NdCl3·4THF is related to their crystal stabilities.
- Published
- 1987
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