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Recent advances in the microfluidic generation of shape-controllable hydrogel microparticles and their applications

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Green Chemical Engineering 2024年第1期5卷 16-30页

作者： Yingzhe liu zhuo chen Jianhong Xu The State Key Lab of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing100084China

Hydrogel microparticles,generally accepted as significant green materials,have been widely used in chemical,biological,and biomedical fields owing to their excellent biocompatibility,biodegradability,and *** these,non-spherical hydrogel microparticles with diverse shape anisotropy have great potential in applications such as drug delivery,cellular interaction,micromotors,*** from their shapes,their functionalities in such fields cannot be satisfied by the typical spherical ***,microfluidics with precise control and domination of fluids at microflow sizes has emerged as a powerful method for synthesizing shape-controllable hydrogel microparticles with good monodispersity and unique *** this review,we tried to provide an overview of the production of non-spherical microparticles composed of green hydrogel materials,emphasizing the microfluidic ***,a brief introduction to their current applications is also presented.

关键词： Microfluidics Hydrogel Microparticles Non-spherical Anisotropic Green materials

Simulation study on cuttings transport of the backreaming operation for long horizontal section wells

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Petroleum Science 2024年第2期21卷 1149-1170页

作者： Yu-Fei chen Hui Zhang Wen-Xin Wu Jun Li Yong Ouyang Zong-Yu Lu De-Xin Ma Yong-Chuan Wu Jun-Bo liu Ke-Rou liu zhuo-Xin Dong china university of Petroleum(beijing) Beijing102249China beijing normal university at Zhuhai Experimental and Practical Education Innovation CenterZhuhai519087GuangdongChina Oil&Gas Technology Research Institute of Petrochina Changqing Oilfield Company Xi'an710016ShaanxiChina Petrochina Xinjiang Oilfield Company Karamay834002XinjiangChina china Oilfield Services Ltd. Tianjin300459China

The backreaming operation plays a significant role in safe drilling for horizontal wellbores, while it may cause severe stuck pipe accidents. To lower the risk of the stuck pipe in backreaming operations, the mechanism of cuttings transport needs to be carefully investigated. In this research, a transient cuttings transport with multiple flow patterns model is developed to predict the evolution of cuttings transported in the annulus while backreaming. The established model can provide predictions of the distribution of cuttings bed along the wellbore considering the bulldozer effect caused by large-size drilling tools(LSDTs). The sensitivity analyses of the size of LSDTs, and backreaming operating parameters are conducted in Section 4. And a new theory is proposed to explain the mechanism of cuttings transport in the backreaming operation, in which both the bit and LSDTs have the “cleaning effect” and “plugging effect”.The results demonstrate that the cuttings bed in annuli is in a state of dynamic equilibrium, but the overall trend and the distribution pattern are obvious. First, larger diameters and longer drilling tools could lead to a higher risk of the stuck pipe. Second, we find that it is not the case that the higher flow rate is always better for hole cleaning, so three flow-rate intervals are discussed separately under the given conditions. When the “dangerous flow rate”(35 L/s in Case 4),the higher the flow rate, the better the cleaning effect of cuttings beds. Third, an interval of tripping velocity called “dangerous velocity” is proposed, in which the cuttings bed accumulation near the LSDTs is more serious than

关键词： Backreaming Stuck pipe Hole cleaning Transient solid transport Multiple flow patterns

From the Green's Function in Tight-Binding Representation to Interatomic Many-body Potentials

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Journal of Materials Science & Technology 1999年第4期15卷 315-319页

作者： Shaojun liu(department of physics, beijing normal university, beijing 100875, china)Xiaobo WEI(department of Physics, liuzhou College of Education, liuzhou 545005, china)Zhaodou chen Jun CAI and Benkun MA(department of Physics, beijing normal university, department of Physics Beijing Normal University Beijing 100875 China department of Physics Liuzhou College of Education Liuzhou 545005 China

In this paper, we deduce the analytical form of many-body interatomic potentials based on the Green's function in tight-binding representation. The many-body potentials are expressed as the functions of the hopping integrals which are the physical origin of cohesion of atoms. For thesimple case of s-valent system, the inversion of the many-body potentials are discussed in detail by using the lattice inversion method.

关键词： Rev Li chen From the Green’s Function in Tight-Binding Representation to Interatomic Many-body Potentials body

Stable hydrogen-bonded organic frameworks and their photo-and electro-responses

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Nano Research 2024年第8期17卷 7675-7699页

作者： Ying Hou Xin-Song Huang Sheng-Hao Gong chen liu Yangyang liu Tian-Fu liu State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China university of Chinese Academy of Sciences Beijing 100049China department of Chemistry and Biochemistry California State UniversityLos AngelesCalifornia 90032USA College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China

Hydrogen-bonded organic frameworks(HOFs)are a recent class of porous materials that have garnered considerable research interest owing to their distinctive *** can be constructed through judicious selection of H-bonding motifs,which are further enforced by other weak intermolecular interactions such asπ–πstacking,van der Waals forces,and framework *** advantage of these interactions,we can expand the functional field of HOFs by introducing active ***,researchers have made substantial advancements in using HOFs for chemical sensing,catalysis,proton conduction,biological applications,and *** low bonding energy of H-bonds allows for precise control over the concentration of ligands in solvents,forming diverse HOF *** varied structures offer significant advantages for producing HOFs with photo-responsive and electro-responsive ***,the presence of H-bonds in HOFs results in their inherent lower stability compared to metal-organic frameworks(MOFs)and covalent-organic frameworks(COFs)formed via coordination and covalent bonds,*** a result,the pursuit of stable and innovative HOF materials with novel functional sites remains an ongoing *** review provides an overview of recent research progress in the development of new strategies for stable HOF synthesis and applications of HOFs with stimuli-responsive *** first classified all synthetic methods reported to date and discussed the stable HOFs synthesized,as well as their unique properties and *** addition,we summarized the applications of HOFs utilizing their synergistic responses to external stimuli,including photo,electrical,pressure,and chemical *** systematically reviewed stable HOF synthesis and applications,which may lead to a deeper understanding of the structure–activity relationship for these materials and guide future HOF design.

关键词： stable hydrogen-bonded organic frameworks(HOFs) photo-response electro-response photoelectric synergistic response

Enhancing the deep-red/near-infrared fluorescence of higher rylene diimides via the chalcogen-annulation strategy

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Science china Chemistry 2024年第4期67卷 1324-1333页

作者： Kai chen Xiao chen Ke Hu Yilun Zhao Yujian liu Guogang liu Jinquan chen Wei Jiang Zhigang Shuai Da-Hui Qu Zhaohui Wang Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CenterFrontiers Science Center for Materiobiology and Dynamic ChemistryInstitute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China Key Laboratory of Organic Optoelectronics and Molecular Engineering Department of ChemistryTsinghua UniversityBeijing 100084China State Key Laboratory of Precision Spectroscopy East China Normal University500 Dongchuan RoadShanghai 200241China

Deep-red/near-infrared fluorescence is highly suitable for bioimaging owing to its ability to deeply penetrate tissues,organs,and live ***,developing organic fluorophores with high deep-red/near-infrared fluorescence quantum yield(Φ_(FL))and fluorescent brightness remain a significant challenge owing to the energy gap ***,we developed a straightforward and effective chalcogen-annulation strategy by introducing O,S and Se into the bay region of TDI and QDI fluorophores,realizing the increase ofΦFLand fluorescent brightness up to 10 *** our best knowledge,this study potentially stands as the pioneering instance showcasing the anti-heavy-atom effect of chalcogens,and the absoluteΦFL(93%)and fluorescent brightness(128,200 cm^(-1)mol^(-1)L)of Se-TDI is among top deep-red/near-infrared organic fluorophores currently *** femtosecond transient absorption(fs-TA)measurements show the absence of obvious changes of the excited state lifetime after the introduction of chalcogens in TDI and QDI fluorophores,indicating that intersystem crossing(ISC)can be neglected in TDI and QDI *** calculations further reveal the chalcogen-annulation strategy increase the radiative rates and reduce the reorganization energy of several accepting modes at the ground state in TDI fluorophores,leading to the suppression of internal conversion(IC)*** chalcogen-annulation strategy,which effectively increases the Φ_(FL)and restricts the IC processes,while remaining unaffected by the heavy-atom effect,offers novel insights and theoretical support for the design and synthesis of deep-red/near-infrared organic fluorophores with high Φ_(FL)and fluorescent brightness.

关键词： π-extended rylene diimides chalcogen-annulation strategy deep-red/near-infrared fluorescence

Optimal geometrical configuration and oxidation state of cobalt cations in spinel oxides to promote the performance of Li-O_(2) battery

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Nano Research 2024年第1期17卷 221-227页

作者： Yu Zhang Shuting Zhang Mengwei Yuan Yufeng Li Rong liu Caiyun Nan chen chen Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China X-ray diffraction Lab Analytical and Testing CenterBeijing Normal UniversityBeijing 100875China

Co_(3)O_(4) is considered as one of promising cathode catalysts for lithium oxygen(Li-O_(2))batteries,which contains both tetrahedral Co^(2+)sites(Co^(2+)Td)and octahedral Co^(3+)sites(Co^(3+)Oh).It is important to reveal the effect of optimal geometric configuration and oxidation state of cobalt ion in Co_(3)O_(4) to improve the performance of Li-O_(2) ***,through regulating the synthesis process,Co^(2+)and Co^(3+)sites in Co_(3)O_(4) were replaced with Zn and Al atoms to form materials with a unique Co *** Li-O_(2) batteries based on ZnCo_(2)O_(4) showed longer cycle life than that of CoAl_(2)O_(4),suggesting that in Co_(3)O_(4),the Co^(3+)Oh site is a relatively better geometric configuration than Co^(2+)Td site for Li-O_(2) *** calculations revealed that Co^(3+)Oh sites provide higher catalysis activity,regulating the adsorption energy of the intermediate LiO_(2) and accelerating the kinetics of the reaction in batteries,which further leads to the change of the morphology of the discharge product and ultimately improves the electrochemical performance of the batteries.

关键词： lithium oxygen(Li-O_(2))batteries geometrical configuration oxidation state lithium peroxide

Existence of unbiased estimate of regression parameters in simple linear EV models

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Science china mathematics 2005年第7期48卷 915-928页

作者： liu Jixue & chen Xiru department of Statistics and Finance, university of Science and Technology of china, Hefei 230026, china department of mathematics, Graduate School of Chinese Academy of Sciences, beijing 100049, china department of Statistics and Finance University of Science and Technology of China Hefei 230026 China department of mathematics Graduate School Chinese Academy of Sciences Beijing 100049 China

It is well known that for one-dimensional normal EV regression model X = x+ u,Y =α+βx+e, where x, u, e are mutually independent normal variables and Eu=Ee=0, the regression parameters a and β are not identifiable without some restriction imposed on the parameters. This paper discusses the problem of existence of unbiased estimate for a and β under some restrictions commonly used in practice. It is proved that the unbiased estimate does not exist under many such restrictions. We also point out one important case in which the unbiased estimates of a and β exist, and the form of the MVUE of a and β are also given.

关键词： EV regression model unbiased estimate identiflability.

Advancements of Macrophages Involvement in Pathological Progression of Colitis-Associated Colorectal Cancer and Associated Pharmacological Interventions

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Chinese Journal of Integrative Medicine 2024年第6期30卷 565-576页

作者： KE Jun-yu SONG Jin-bin LI Long HE Zhen-fan HUANG zhuo-jian liu Zheng-lin chen Gui-rong WANG Hai-yan WEN Su-ru ZHOU Heng-li MA Hui-lin DU Qun WU Yong-qiang LI Yan-wu chen Xin-lin School of Basic Medical Sciences Guangzhou University of Chinese MedicineGuangzhou510006China department of Surgery II Gaozhou Hospital of Traditional Chinese Medicine Affiliated to Guangzhou University of Chinese MedicineGaozhou525200China Science and Technology Innovation Center Guangzhou University of Chinese MedicineGuangzhou510405China The First Clinical Medical College of Guangzhou university of Traditional Chinese Medicine Guangzhou510405China

Intestinal macrophages play crucial roles in both intestinal inflammation and immune homeostasis. They can adopt two distinct phenotypes, primarily determined by environmental cues. These phenotypes encompass the classically activated pro-inflammatory M1 phenotype, as well as the alternatively activated anti-inflammatory M2 phenotype. In regular conditions, intestinal macrophages serve to shield the gut from inflammatory harm. However, when a combination of genetic and environmental elements influences the polarization of these macrophages, it can result in an M1/M2 macrophage activation imbalance, subsequently leading to a loss of control over intestinal inflammation. This shift transforms normal inflammatory responses into pathological damage within the intestines. In patients with ulcerative colitis-associated colorectal cancer (UC-CRC), disorders related to intestinal inflammation are closely correlated with an imbalance in the polarization of intestinal M1/M2 macrophages. Therefore, reinstating the equilibrium in M1/M2 macrophage polarization could potentially serve as an effective approach to the prevention and treatment of UC-CRC. This paper aims to scrutinize the clinical evidence regarding Chinese medicine (CM) in the treatment of UC-CRC, the pivotal role of macrophage polarization in UC-CRC pathogenesis, and the potential mechanisms through which CM regulates macrophage polarization to address UC-CRC. Our objective is to offer fresh perspectives for clinical application, fundamental research, and pharmaceutical advancement in UC-CRC.

关键词： macrophage ulcerative colitis colon cancer Chinese medicine

Atmospheric oxidation capacity and O_(3) formation in a coastal city of southeast china:Results from simulation based on four-season observation

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Journal of Environmental Sciences 2024年第2期136卷 68-80页

作者： Gaojie chen Taotao liu Jinsheng chen Lingling Xu Baoye Hu chen Yang Xiaolong Fan Mengren Li Youwei Hong Xiaoting Ji Jinfang chen Fuwang Zhang Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Key Lab of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China university of Chinese Academy of Sciences Beijing 100049China Minnan normal university Zhangzhou 363000China College of Harbour and Coastal Engineering Jimei UniversityXiamen 361021China Environmental Monitoring Center of Fujian Fuzhou 350013China

The pollution of atmospheric ozone in china shows an obvious upward trend in the past ***,the studies on the atmospheric oxidation capacity and O_(3)formation in four seasons in the southeastern coastal region of china with the rapid urbanization remain ***,a four-season field observation was carried out in a coastal city of southeast china,using an observation-based model combining with the Master Chemical Mechanism,to explore the atmospheric oxidation capacity(AOC),radical chemistry,O_(3)formation pathways and *** results showed that the average net O_(3)production rate(14.55 ppbv/hr)in summer was the strongest,but the average O_(3)concentrations in autumn was *** AOC and ROx levels presented an obvious seasonal pattern with the maximum value in summer,while the OH reactivity in winter was the highest with an average value of 22.75 sec^(-1).The OH reactivity was dominated by oxygenated VOCs(OVOCs)(30.6%-42.8%),CO(23.2%-26.8%),NO_(2)(13.6%-22.0%),and alkenes(8.4%-12.5%)in different *** photolysis dominated OH primary source on daytime in winter,while in other seasons,HONO photolysis in the morning and ozone photolysis in the afternoon contributed *** analysis indicated that O_(3)production was controlled by VOCs in spring,autumn and winter,but a VOC-limited and NOx-limited regime in summer,and alkene and aromatic species were the major controlling factors to O_(3)***,the study characterized the atmospheric oxidation capacity and elucidated the controlling factors for O_(3)production in the coastal area with the rapid urbanization in china.

关键词： Atmospheric oxidation capacity Radical chemistry Ozone production Sensitivity analysis