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Thickening progression mechanism of silica fume-oil well cement composite system at high temperatures

Petroleum Science 2024年第4期21卷 2793-2805页

作者： Hang Zhang Miao-Miao Hu Peng-Peng Li Guo-Qing Liu Qing-Lu Chang Jie Cao ming Liu Wen-Hua Xu Xiu-jian Xia Jin-Tang Guo School of Chemical Engineering and Technology Tianjin University Zhejiang Institute of Tianjin University Haihe Laboratory of Sustainable Chemical Transformations CNPC Engineering Technology R&D Company Limited

This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C) in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering. Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C, but when temperature reached above130.C, it would aggravate the bulging degree of thickening curves and significantly extend the thickening time, meanwhile causing the abnormal “temperature-based thickening time reversal” and“dosage-based thickening time reversal” phenomena in the range of 130-160.C and 170-180.C respectively. At 130-160.C, the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH) crystal. The introduced silica fume would be attracted to the cement minerals' surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier” to hinder further hydration of the inner cement minerals. This “adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the “temperature-based thickening time reversal” phenomenon. At 170-180.C, the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated, thus the “temperature-based thickening time reversal” vanished and the “dosage-based thickening time reversal” was presented.

关键词： Silica fume Oil well cement Thickening time reversal Pozzolanic reaction Adsorptive barrier CH and C−S−H

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袁世凯“逼迫清帝退位”说献疑

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史学集刊 2024年第1期 4-25页

作者：尚小明北京大学历史学系北京100871

辛亥鼎革时期的袁世凯并没有在理念上经历从君主立宪到民主共和的转变。出于维系多民族国家统一、社会安定及自身利益考虑,袁氏实际上是想造成虚君共和。他首先坚持以十九信条为宗旨,力图主导国民会议之组织,以防唐绍仪和伍廷芳会谈所... 详细信息

辛亥鼎革时期的袁世凯并没有在理念上经历从君主立宪到民主共和的转变。出于维系多民族国家统一、社会安定及自身利益考虑,袁氏实际上是想造成虚君共和。他首先坚持以十九信条为宗旨,力图主导国民会议之组织,以防唐绍仪和伍廷芳会谈所定国民会议方案造成民主共和结果。接着因南京临时政府建立及国民会议商谈走进死胡同,他又意图由清廷授权其组织临时政府,以取消南京临时政府。为此他采取了模棱两可的策略,一方面劝导清廷“速定大计”,改建共和,使南方以为清帝将要退位,另一方面在预拟的相关诏书中竭力避用“退位”一类字眼,并试图将由其“全权组织临时政府”写入诏书。在遭到满蒙亲贵和革命党两方反对后,袁氏转而依靠段祺瑞等北洋将领联衔电奏,要求“立定共和政体,以巩皇位而定大局”,仍未放弃清帝。在得到与南方协商皇室优待条件的授权以后,袁氏奉旨反复拒绝将“逊位”二字写入诏书,主张改用“辞政”。因南方坚决反对虚君共和,袁氏才不得不于最后时刻经清廷授权,同意南方的提议,以“辞位”替代“逊位”。一系列史实证明,所谓袁氏“逼迫清帝退位”的说法是不能成立的。这种观点实际上放大了袁氏对推翻帝制和建立共和的贡献,而真正要逼迫清帝退位的,其实是革命党人和那些转向民主共和的立宪派人士。

关键词：辛亥南北议和袁世凯虚君共和民主共和段祺瑞清帝退位诏书

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Simultaneously Improved Curing,Mechanical,Antioxidative Properties and Reduced ZnO Loading of Silica Filled NR Composites by Incorporation of Low-cost Crude Carbon Dots via Conventional Melt-milling Method

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Chinese Journal of Polymer Science 2024年第6期42卷 815-825页

作者： Chao-Ying Sun Hai-Jun Ji Li-Wei Li Hui Yang Xiao-Peng An Yi-Ping Chen ming-jian Han Can jiang Li-Qun Zhang Peng Yu Run-Guo Wang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China School of Materials Science and Engineering Wuhan Institute of TechnologyWuhan430205China

Rubbers or elastomers play an important role in hi-tech technology and civilian daily life because of their unique and strategical ***,the rubber additives are essential components for rubbers’practical ***,developing novel multifunctional additives has attracted increasing research *** this work,low-cost crude carbon dots(CCDs)were used as multifunctional additives for natural rubber/silica system(without any additional modification)through industrial compatible melt-mixing *** results revealed that the CCDs could disperse well in the NR/silica system,and they could not only endow the rubber compound with excellent anti-aging capability due to CCDs’radical scavenging activity because of their plenty of nitrogen-containing species,but also improve the curing rate and mechanical performance of the rubber ***,the CCDs could reduce the rolling resistance of the rubber composites(tanδvalue at 7%strain of the rubber composite could be decreased by 34%),which is promising for the application of energy-saving tire ***,the addition of CCDs could effectively reduce the ZnO dosage by at least 40%in the rubber composite without deteriorating its ***,this work provides valuable guidance to develop novel cheap yet effective additives for the elastomer.

关键词： Natural rubber Crude carbon dots Antioxidant ZnO reduction Vulcanization

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Recent advances in structural modification on graphitic carbon nitride(g-C_(3)N_(4))-based photocatalysts for high-efficiency photocatalytic H_(2)O_(2)production

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Nano Research Energy 2024年第1期3卷 101-151页

作者： Feng ming Yap Grayson Zhi Sheng Ling Brenden Jing Su jian Yiing Loh Wee-Jun Ong School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia Center of Excellence for NaNo Energy&Catalysis Technology(CONNECT) Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Gulei Innovation Institute Xiamen UniversityZhangzhou 363200China Shenzhen Research Institute of Xiamen University Shenzhen 518057China

To date,extensively high demand for hydrogen peroxide(H_(2)O_(2))has been predominantly supplied by the anthraquinone process for several worldwide applications,encompassing wastewater treatment,environmental remediation,and chemical ***,the compacted manufacturing,massive energy input and the release of tremendous wastes have restricted commercialization *** to mitigate such issues,the photocatalytic H_(2)O_(2)production by utilizing g-C_(3)N_(4)catalysts has endowed a greener,sustainable and promising alternative,considering that it involves water and oxygen as reactants in the present of sunlight as energy ***,we have manifested a comprehensive overview of the research progress for g-C_(3)N_(4)-based semiconductors for photocatalytic H_(2)O_(2)*** review has systematically elucidated state-of-the-art development of different modifications on g-C_(3)N_(4)to unravel the fundamental mechanism of H_(2)O_(2)evolution via oxygen reduction reaction(ORR)and water oxidation reaction(WOR).In addition,the contribution made by vacancy introduction,doping,heterogenization,and co-catalyst passivation with respect to photoefficiency enhancement have been ***,the current challenges and perspective of future development directions on photocatalytic H_(2)O_(2)production have also been *** such,g-C_(3)N_(4)stands as the next step toward advancement in the configuration and modulation of high-efficiency photocatalysts.

关键词： photocatalysis g-C_(3)N_(4) H_(2)O_(2)production structural modification

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Neosophoflavonoids A–C, A class of highly oxidized hybrid flavonoids from Sophora flavescens with antidiabetic effects

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Chinese Chemical Letters 2024年第10期35卷 295-298页

作者： Xu Zhang jiang Li Kai-Zhou Lu Ya-Nan Yang jian-Shuang jiang Xiang Yuan Zi-ming Feng Fei Ye Pei-Cheng Zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and PekingUnionMedical CollegeBeijing100050China

Three highly oxidized hybrid flavonoids neosophoflavonoids A–C(1,2a,and 2b)were isolated from the roots of Sophora *** A possesses a unique highly oxidized heptacyclic6/6/6/6/6/6/5 *** B and C are isomers and share the same highly oxidized hexacyclic 6/6/6/6/6/6 *** planar structures were elucidated from 1D/2D nuclear magnetic resonance(NMR),ultraviolet spectroscopy(UV),infrared spectroscopy(IR),and high resolution electrospray ionization mass spectroscopy(HRESIMS)*** absolute configurations were determined by thorough GIAO13C NMR(DP4+)calculation protocol and electronic circular dichroism(ECD)calculation *** plausible biosynthetic routes for the compounds were also *** compounds exhibited significant protein tyrosine phosphatase-1B(PTP1B)inhibitory activity with half maximal inhibitory concentration(IC_(5)0)values 3.94±0.01,0.38±0.13,and 0.70±0.01μmol/L,*** addition,compared to a positive control fenofibrate(Feno)at 20μmol/L,compounds 2a and 2b exhibited stronger inhibitory effects on lipid accumulation in the oleic acid(OA)-induced cell model at 5 and 10μmol/L.

关键词： Sophora flavescens Highly oxidized hybrid flavonoids Neosophoflavonoids A-C PTP1B inhibition Lipid accumulation inhibition

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A potential giant gallium deposit hosted in the tailing dam of the Fankou Zn-Pb deposit in northern Guangdong Province, South China

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China Geology 2024年第1期7卷 157-160页

作者： Peng-peng Yu Zhao-bin Hu Yi Zheng Lan-xuan Guo Shi-yuan Ouyang Gui-qiang Yuan shang-zhou Chen Cheng-ming Wang Xi Chen School of Earth Sciences and Geological Engineering Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Lab of Geological Process and Mineral Resources Survey Sun Yat-sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519000China Zhongjin Lingnan Nonfemet Co. LtdShenzhen 518000China

*** The Fankou giant zinc(Zn)-lead(Pb)deposit in Guangdong Province is well-known for its huge reserves of over 10 Mt(million ton)Zn+Pb metals and high ore-grade with Zn+Pb exceeding 15%(Guangdong Fankou Deposit Investigation Group,1980;Zhu XY et al.,2017).After 60 years of exploration and exploitation,the deposit has accumulated millions of tons of *** interesting question is that what components are hosted in these tailings,and whether some key and critical metals such as gallium and germanium are extremely enriched and worth further comprehensive *** motivated us to conduct an integrated set of field investigation,sampling,major-trace element analyses and reserve assessments about the Fankou *** this contribution,we discover that the tailings contain a variety of metal elements such as zinc,lead and gallium with comprehensive utilization *** data can act as a scientific guidance for further exploration and utilization of the Fankou tailings,and aid to enhance the utilization efficiency of the key mineral resource in *** study also provide demonstration for future green mine construction in China.

关键词： deposit comprehensive Guangdong

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The Bright Single Pulse Emission from PSR B1133+16

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Research in Astronomy and Astrophysics 2024年第4期24卷 253-261页

作者： Jun Tan Zhi-Gang Wen Zhen Wang Xue-Feng Duan Hong-Guang Wang Na Wang Vishal Gajjar jian-Ping Yuan Rai Yuen Wen-ming Yan jian-Ling Chen Wei Han Hui Wang Cheng-Bing Lyu Ai-Jun Dong Maths and Information Technology School Yuncheng UniversityYuncheng 044000China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Space Science Laboratory University of CaliforniaBerkeley 94710USA Department of Physics and Electronic Engineering Yuncheng UniversityYuncheng 044000China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China

We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio *** time resolution data(61μs)were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr.A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse ***,no giant pulse-like emission with a relative pulse energy larger than 10 and extremely short duration was detected,indicating that these bright pulses cannot be categorized as giant pulse *** majority of these bright pulses are concentrated in pulse phases at both the leading and trailing windows of the average pulse profile,with an occurrence ratio of approximately *** pulse energy distribution for all individual pulses can be described by a combination of two Gaussian components and a cutoff power-law with an index of α=-*** updated nulling fraction of 15.35%±0.45% was determined from the energy *** emission of individual pulses follows a log-normal distribution in peak flux density *** is imperative that regular phase drifting in bright pulse sequence is identified in both the leading and trailing components for the first *** physical mechanisms are discussed in detail to provide insights into these observations.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(PSR B1133+16) methods:observational methods:data analysis

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Bioinspired polysaccharide-based nanocomposite membranes with robust wet mechanical properties for guided bone regeneration

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National Science Review 2024年第3期11卷 215-226页

作者： jian-Hong Xiao Zhen-Bang Zhang JiaHao Li Si-ming Chen Huai-Ling Gao YinXiu Liao Lu Chen ZiShuo Wang YiFan Lu YuanZhen Hou HengAn Wu DuoHong Zou Shu-Hong Yu Department of Chemistry New Cornerstone Science Laboratory Institute of Biomimetic Materials&Chemistry Anhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&Chemistry Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of China Department of Dental Implant Center Stomatologic Hospital and College Key Laboratory of Oral Diseases Research of Anhui Province Anhui Medical University CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Department of Oral Surgery College of Stomatology National Clinical Research Center for Oral DiseasesShanghai Key Laboratory of Stomatology Shanghai Research Institute of Stomatology Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Institute of Innovative Materials(I2M) Department of Chemistry Department of Materials Science and Engineering Southern University of Science and Technology

Polysaccharide-based membranes with excellent mechanical properties are highly desired. However, severe mechanical deterioration under wet conditions limits their biomedical applications. Here, inspired by the structural heterogeneity of strong yet hydrated biological materials, we propose a strategy based on heterogeneous crosslink-and-hydration（HCH） of a molecule/nano dual-scale network to fabricate polysaccharide-based nanocomposites with robust wet mechanical properties. The heterogeneity lies in that the crosslink-and-hydration occurs in the molecule-network while the stress-bearing nanofiber-network remains unaffected. As one demonstration, a membrane assembled by bacterial cellulose nanofiber-network and Ca2+-crosslinked and hydrated sodium alginate molecule-network is designed. Studies show that the crosslinked-and-hydrated molecule-network restricts water invasion and boosts stress transfer of the nanofiber-network by serving as interfibrous bridge. Overall, the molecule-network makes the membrane hydrated and flexible; the nanofiber-network as stress-bearing component provides strength and *** HCH dual-scale network featuring a cooperative effect stimulates the design of advanced biomaterials applied under wet conditions such as guided bone regeneration membranes.

关键词： bioinspiration heterogeneous crosslink-and-hydration dual-scale network nanocomposite membrane wet mechanical properties guided bone regeneration

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Metabolic landscape of head and neck squamous cell carcinoma informs a novel kynurenine/Siglec-15 axis in immune escape

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Cancer Communications 2024年第6期44卷 670-694页

作者： Xin-Yu Zhang jian-Bo Shi Shu-Fang Jin Rui-Jie Wang ming-Yu Li Zhi-Yuan Zhang Xi Yang Hai-Long Ma Department of Oral Maxillofacial-Head and Neck Oncology Shanghai Ninth People’s HospitalCollege of StomatologyShanghai Jiao Tong University School of MedicineShanghaiP.R.China National Clinical Research Center for Oral Diseases ShanghaiP.R.China shanghai Key Laboratory of Stomatology&shanghai Research Institute of Stomatology ShanghaiP.R.China Department of Second Dental Center Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineCollege of StomatologyShanghai Jiao Tong UniversityShanghaiP.R.China

Background:Metabolic reprograming and immune escape are two hallmarksof ***,how metabolic disorders drive immune escape in head andneck squamous cell carcinoma(HNSCC)remains ***,the aim ofthe present study was to investigate the metabolic landscape of HNSCC and itsmechanism of driving immune ***:Analysis of paired tumor tissues and adjacent normal tissues from69 HNSCC patients was performed using liquid/gas chromatography-mass spectrometry and *** tumor-promoting function of kynurenine(Kyn)was explored in vitro and in *** downstream target of Kyn wasinvestigated in CD8^(+)T *** regulation of CD8+T cells was investigatedafter Siglec-15 overexpression in *** engineering nanoparticle was establishedto deliver Siglec-15 small interfering RNA(siS15),and its association withimmunotherapy response were *** association between Siglec-15and CD8^(+)programmed cell death 1(PD-1)^(+)T cells was analyzed in a HNSCCpatient ***:A total of 178 metabolites showed significant dysregulation in HNSCC,including carbohydrates,lipids and lipid-like molecules,and amino *** these,amino acid metabolism was the most significantly altered,especiallyKyn,which promoted tumor proliferation and *** addition,most immune checkpoint molecules were upregulated in Kyn-high patientsbased on ***,tumor-derived Kyn was transferredinto CD8^(+)T cells and induced T cell functional exhaustion,and blockingKyn transporters restored its killing *** to the results,mechanistically,Kyn transcriptionally regulated the expression of Siglec-15 via arylhydrocarbon receptor(AhR),and overexpression of Siglec-15 promoted immuneescape by suppressing T cell infiltration and *** AhR in vivoreduced Kyn-mediated Siglec-15 expression and promoted intratumoral CD8^(+)Tcell infiltration and killing ***,a NH_(2)-modified mesoporous silicananoparticle was des

关键词： head and neck squamous cell carcinoma kynurenine Siglec-15 T cell exhaustion untargeted metabolomics

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Molecular solid solution of lanthanide-titanium-oxo clusters with enhanced photocatalytic hydrogen evolution

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Science China Chemistry 2024年第2期67卷 529-535页

作者： Rong Chen Chao-Long Chen Hui Zhang Zi-Han Wang Fu-Li Sun ming-Hao Du Gui-Lin Zhuang Cheng Wang La-Sheng Long Lan-Sun Zheng Xiang-jian Kong Collaborative Innovation Centre of Chemistry for Energy Materials State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China College of Chemical Engineering Zhejiang University of TechnologyHangzhou310032China

Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely ***,a series of colorless lanthanide-titanium-oxo clusters Ln_(2)Ti_4(μ_(2)-O)_(2)(μ_(3)-O)_4(Piv)_(10)(THF)_(2)(Ln_(2)Ti_4,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)_(3) and titanium *** light yellow crystal of cluster solid solutions Eu_(2)Ti_(4-x)Cd_(x),containing a mixture of Eu_(2)Ti_4 and Eu_(2)Ti_(3)Cd,was obtained by in situ doping Cd^(2+) and S^(2–).Eu_(2)Ti_(3.92)Cd_(0.08) displays efficient photocatalytic hydrogen evolution activity without a co-catalyst,which is up to 2.6 times that of Eu_(2)Ti_*** time-resolved transient absorption spectroscopy and spin-polarized density functional calculations showed that the enhanced photocatalytic performance of Eu_(2)Ti_(4-x)Cd_(x) can be attributed to the narrower HOMO-LUMO gap and lower LUMO position than that of Eu_(2)Ti_*** studyprovides an in situ doping method to realize the simple preparation of cluster solid solution.

关键词： molecular solid solution lanthanide-titanium-oxo clusters photocatalytic hydrogen evolution

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