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Dramatic Difference Between Cu_(20)H_(8)and Cu_(20)H_(9)Clusters in Catalysis

CCS Chemistry 2024年第6期6卷 1581-1590页

作者： chun-yu liu Tong-yu liu Zong-Jie Guan Song Wang yuan-yuan Dong Feng Hu De-en Jiang Quan-Ming Wang Department of Chemistry Engineering Research Center of Advanced Rare Earth Materials(Ministry of Education)Tsinghua UniversityBeijing 100084 Jiangsu Engineering Research Centre for Digital Textile Inkjet Printing Key Laboratory of Eco-Textile Jiangnan UniversityMinistry of EducationWuxiJiangsu 214122 Department of Chemical and Biomolecular Engineering Vanderbilt UniversityNashvilleTennessee 37235 Department of Chemistry Vanderbilt UniversityNashvilleTennessee 37235 College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082 Hefei National Research Center for Physical Sciences at the Microscale School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefeiAnhui 230026

Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in *** synthesized a pair of atomically precise copper clusters that are very close in composition,[Cu_(20)H_(9)(Tf-dpf)_(10)]·BF4(Cu_(20)H_(9))and[Cu_(20)H_(8)(Tf-dpf)_(10)]·(BF_(4))_(2)(Cu_(20)H_(8)),by using a pyridyl-functionalized flexible amidinate ligand,N,N′-di(5-trifluoromethyl-2-pyridyl)*** one-hydride difference in their composition leads to significant variation in geometric and electronic structures and,consequently,distinctly different optical and catalytic ***_(20)H_(8)exhibits 25 times higher catalytic activity than Cu_(20)H_(9)(96.7%vs 3.7%in yield)in the selective hydrogenation of anα,β-unsaturated aldehyde(cinnamaldehyde)to saturated aldehyde(3-phenylpropanal).Electrospray ionization mass spectrometry combined with density functional theory calculations reveal that the greater ease of dissociation of one Tf-dpf ligand compared to Cu_(20)H_(8)is the key to its higher *** work demonstrates a clear case of structure and composition sensitivity in nanocatalysis and that one hydride,out of∼330 atoms in the nanoclusters,can make a huge difference in the catalytic *** insights will be useful in the design and synthesis of atomically precise nanocatalysts.

关键词： copper cluster hydride amidinate ligand structural transformation hydrogenation catalysis

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Fuzzy Shape Control Based on El man Dynamic Recursion Network Prediction Model

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Journal of Iron and Steel Research International 2006年第1期13卷 31-35页

作者： JIA chun-yu liu Hong-min College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China

In the strip rolling process, shape control system possesses the characteristics of nonlinearity, strong coupling, time delay and time variation. Based on self adapting Elman dynamic recursion network prediction model, the fuzzy control method was used to control the shape on four-high cold mill. The simulation results showed that the system can be applied to real time on line control of the shape.

关键词： shape prediction shape control Elman dynamic recursion network parameter self-adjusting fuzzy control

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One-pot Approach to the Conversion of Alcohols into α-Halo-α, β-unsaturated Esters

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Chinese Chemical Letters 2006年第3期17卷 329-332页

作者： Gui Sheng DENG chun yu liu College of Chemistry and Chemical Engineering Hunan Normal University Changsha 410081

The sequential oxidation-Horner-Wadsworth-Emmons reaction of alcohols to prepare α-Halo-α,β-unsaturated esters （halo =F, Cl） with middle to excellent （Z）-selectivity was developed.

关键词： Horner-Wadsworth-Emmons reaction,α-Halo-α,β--unsaturated esters alcohol one-pot approach synthesis.

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A Local Limit Theorem for Solutions of BSDEs with Mao's non-Lipschitz Generator

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 329-336页

作者： yu-chun liu Long Jiang Ying-ying Xu Department of Mathematics China University of Mining and Technology Xuzhou 221116 China School of Mathematics Fudan University Shanghai 200433 China

This paper establishes a local limit theorem for solutions of backward stochastic differential equations with Mao＇s non-Lipschitz generator, which is similar to the limit theorem obtained by [3] under the Lipschitz a... 详细信息

关键词： Backward stochastic differential equation Mao's non-Lipschitz generator local limit theorem

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Enhanced photoluminescence of monolayer MoS_(2)on stepped gold structure

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Chinese Physics B 2022年第8期31卷 639-644页

作者： yu-chun liu Xin Tan Tian-Ci Shen Fu-Xing Gu School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China

Different Mo S_(2)/Au heterostructures can play an important role in tuning the photoluminescence(PL)and optoelectrical properties of monolayer Mo S_(2).Previous studies of PL of Mo S_(2)/Au heterostructures were mainly limited to the PL enhancement by using different Au nanostructures and PL quenching of monolayer Mo S_(2)on flat Au ***,we demonstrate the enhanced excitonic PL emissions of monolayer Mo S_(2)/Au heterostructures on Si/Si O_(2)*** transferring the continuous monolayer Mo S_(2)onto a stepped Au structure consisting of 60-nm and 100-nm Au films,the Mo S_(2)/Au-60 and Mo S_(2)/Au-100 heterostructures exhibit enhanced PL emissions,each with a blue-shifted PL peak in comparison with the Mo S_(2)/Si O_(2).Furthermore,the PL intensity of Mo S_(2)/Au-60 is about twice larger than that of Mo S_(2)/*** different enhanced excitonic PL emissions in Mo S_(2)/Au heterostructures can be attributed to the different charge transfer effects modified by the stepped Au *** work may provide an insight into the excitonic PL and charge transfer effect of Mo S_(2)on Au film and yield novel phenomena in Mo S_(2)/Au heterostructures for further study of PL tuning and optoelectrical properties.

关键词： MoS_(2) stepped gold heterostructures enhanced photoluminescence

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Reproducibility of macular perfusion parameters in non-proliferative diabetic retinopathy patients by two different OCTA sweep modes

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International Journal of Ophthalmology(English edition) 2022年第9期15卷 1483-1487页

作者： Shen Qu Ao Rong yun-Li Niu Xin liu yu-Shan Zhang chun-yu liu Yan-Long Bi Department of Ophthalmology Tongji Hospital Affiliated to Tongji University School of MedicineShanghai 200065China

·AIM:To assess the reproducibility of macular perfusion parameters in non-proliferative diabetic retinopathy(NPDR)patients measured by different examiners and two different sweep modes of optical coherence tomography angiography(OCTA).·METHODS:Ninety-eight(98 eyes)patients with NPDR were included in this *** participates were performed three times using Cirrus OCTA with Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode by two *** macular foveal avascular zone(FAZ)and vessel density(VD)in the superficial retinal layer(SRL)were *** reproducibility of the measurements was evaluated with intraclass correlation coefficients(ICC)and coefficient of variation(CoV).·RESULTS:The intra-mode ICCs of Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode were 0.957 to 0.959 and 0.964 to 0.977,respectively;and the inter-mode ICCs were 0.962 to *** intra-examiner ICCs of macular perfusion parameters were>0.950;and the inter-examiner ICCs were0.928 to *** CoVs were<1.0%.·CONCLUSION:Cirrus OCTA can measure macular perfusion parameters in NPDR patients with excellent *** measurements of FAZ and VD in the SRL determined by Angiography 3×3 mm^(2)and 6×6 mm^(2)sweep mode are highly consistent and both sweep modes are suitable for macular perfusion parameters measurement.

关键词： optical coherence tomography angiography macular per fusion parameters reproducibility non-proliferative diabetic retinopathy

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Forward and Backward Slip Models in MAS Rolling Process and Its On-Line Application

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Journal of Iron and Steel Research International 2007年第4期14卷 15-19页

作者： HU Xian-lei JIAO Zhi-jie HE chun-yu liu Xiang-hua WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

Based on the MAS rolling process in plate mill, the mathematical models of forward and backward slips of the wedges at plate head and tail were derived. According to the new model, the difference between the forward slip of the wedge and that of the normal part of the plate is obviously very small. The deviation is less than 2.5 % in general. Thus, in actual application, the forward slip of normal part of the plate can be used to calculate the length of rolled plate instead of the derived model. The rationality of this simplified method was confirmed with the application in Shougang 3 500 mm plate mill. The test results showed that the wedges of plate head and tail are symmetrical. The plate width deviation is greatly decreased by using the MAS method.

关键词： MAS plate forward slip backforward slip wedge

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The influence of medium on the stability of coordination compounds *** system In(tiron)^--NaClO_4-C_2H_5OH-H_2O

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Chinese Journal of Chemistry 1992年第2期10卷 122-129页

作者： GUO,yu-Hong LIANG,chun-yu liu,Qi-Tao Department of Chemistry,Liaoning University,Shenyang 110036 Department of Chemistry Liaoning University Shenyang 110036

The stability constants of complex anion In(tiron)^-in mixed solvents of ethanol-water with weight percentages of ethanol being 0,5,15,25,35 and 50 have been measured spectrophotometrically at 293 K,using NaClO_4 as supporting electrolyte with ionic strength ranging from 0.1 to 3.3mol·dm^(-3). The thermodynamic stability constants of In(tiron)^-in various mixed solvents have been obtained by a polynomial approximation equation based on Pitzer's *** a comparison,the traditional Debye-Hückel equation has also been used to treat the same *** results show that this polynomial approximate method is obviously superior to the old *** was discovered that there is a linear rela- tion between the thermodynamic stability constants of In(tiron)^-and the mole fraction of organic component in mixed solvents or the reciprocal of dielectric constants of mixed *** medium effect and the standard free energy of transfer,ΔG_(tr)~0,for the coordination reaction:In^(3+)+tiron^(4-)= In(tiron)^-,have also been discussed.

关键词： ab NaClO4-C2H5OH-H2O OH

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Molecular investigation into the transformation of recalcitrant dissolved organic sulfur in refinery sour water during stripping process

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Petroleum Science 2024年第3期21卷 2112-2119页

作者： yu-Guo Li Chen He chun-Mao Chen Fan liu Quan Shi State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China State Key Laboratory of Coal Mining and Clean Utilization Beijing 100013China PetroChina Ningxia Petrochemical Company Yinchuan 750021NingxiaChina

Refinery sour water primarily originates from the tops of towers in various units and coker condensate,and cannot be discharged directly to a wastewater treatment plant due to high levels of chemical oxygen demand(COD)and organic sulfur *** after the recovery of H_(2)S from the sour water by the stripping process,the effluent still contains a high concentration of dissolved organic sulfur(DOS),which can have a huge bad *** chemical composition of dissolved organic matter(DOM)in refinery wastewater has been extensively studied,the investigation of recalcitrant DOS from sour waters remains *** the present study,chemical composition of sour water DOMs(especially DOS)was investigated using fluorescence spectroscopy(excitation-emission matrix,EEM)and mass spectrometry,including gas chromatography-mass spectrometry(GC-MS)and high-resolution Orbitrap *** GC-MS and EEM results showed that volatile and low-aromaticity compounds were effectively removed during the stripping process,while compounds with high hydrophilicity and humification degree were found to be more *** Orbitrap MS results showed that weak-polar oxygenated sulfur compounds were easier to be removed than oxygenated ***,the effluent still contained significant amounts of sulfur-containing compounds with multiple sulfur atoms,particularly in the form of highly unsaturated and aromatic *** Orbitrap MS/MS results of CHOS-containing compounds from the effluent indicate that the sulfur atoms may exist as sulfonates,disulfide bonds,*** the composition and structure of sour water DOS is crucial for the development of effective treatment processes that can target polysulfide compounds and minimize their impact on the environment.

关键词： Molecular transformation Dissolved organic sulfur Stripping process Refinery sourwater Orbitrap MS

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Abdominal paracentesis drainage ameliorates severe acute pancreatitis in rats by regulating the polarization of peritoneal macrophages

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World Journal of Gastroenterology 2018年第45期24卷 5131-5143页

作者： Ruo-Hong liu Yi Wen Hong-yu Sun chun-yu liu yu-Fan Zhang Yi Yang Qi-Lin Huang Jia-Jia Tang Can-Chen Huang Li-Jun Tang PLA Center of General Surgery and Pancreatic Injury and Repair Key Laboratory of Sichuan Province Chengdu Military General HospitalChengdu 610083Sichuan ProvinceChina Third Military Medical University(Army Medical University) Chongqing 400037China Jiaotong Hospital Affiliated with the Sichuan Provincial People’s Hospital Chengdu 611730Sichuan ProvinceChina Department of Ultrasound Chinese Academy of Medical Sciences and Peking Union Medical College HospitalBeijing 100032China

AIM To investigate the role of peritoneal macrophage(PM) polarization in the therapeutic effect of abdominal paracentesis drainage(APD) on severe acute pancreatitis(SAP).METHODS SAP was induced by 5% Na-taurocholate retrograde injection in Sprague-Dawley rats. APD was performed by inserting a drainage tube with a vacuum ball into the lower right abdomen of the rats immediately after the induction of SAP. To verify the effect of APD on macrophages, PMs were isolated and cultured in an environment, with the peritoneal inflammatory environment simulated by the addition of peritoneal lavage in complete RPMI 1640 medium. Hematoxylin and eosin staining was performed. The levels of pancreatitis biomarkers amylase and lipase as well as the levels of inflammatory mediators in the blood and peritoneal lavage were determined. The polarization phenotypes of the PMs were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry, qPCR and immunohistochemical staining. The protein expression in macrophages that had infiltrated the pancreas was determined by Western *** APD treatment significantly reduced the histopathological scores and levels of amylase, lipase, tumor necrosis factor-α and interleukin(IL)-1β, indicating that APD ameliorates the severity of SAP. Importantly, we found that APD treatment polarized PMs towards the M2 phenotype, as evidenced by the reduced number of M1 macrophages and the reduced levels of proinflammatory mediators, such as IL-1β and L-selectin, as well as the increased number of M2 macrophages and increased levels of anti-inflammatory mediators, such as IL-4 and IL-10. Furthermore, in an in vitro study wherein peritoneal lavage from the APD group was added to the cultured PMs to simulate the peritoneal inflammatory environment, PMs also exhibited a dominant M2 phenotype, resulting in a significantly lower level of inflammation. Finally, APD treatment increased the proportion of M2 macrophages and upregulated the e

关键词： Abdominal paracentesis drainage Peritoneal macrophages Polarization Severe acute pancreatitis

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