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聚羧酸系减水剂作为助磨剂使用的构效关系研究

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建筑材料学报 2022年第1期25卷 54-60页

作者：杨海静孙振平 plank johann 水亮亮董耀武同济大学先进土木工程材料教育部重点实验室上海201804 同济大学材料科学与工程学院上海201804 慕尼黑工业大学化学系德国加兴85747 上海市政工程设计研究总院(集团)有限公司上海200092 武汉优城科技有限公司湖北武汉430000

采用甲基烯丙基聚氧乙烯醚(HPEG)为大单体合成一系列具有不同酸醚比、侧链长度及相对分子质量的聚羧酸系减水剂(PCE)作为水泥助磨剂,研究了PCE分子结构对其助磨性能的影响.结果表明:PCE的助磨效果随着酸醚比的增大而增强,当酸醚比超过... 详细信息

采用甲基烯丙基聚氧乙烯醚(HPEG)为大单体合成一系列具有不同酸醚比、侧链长度及相对分子质量的聚羧酸系减水剂(PCE)作为水泥助磨剂,研究了PCE分子结构对其助磨性能的影响.结果表明:PCE的助磨效果随着酸醚比的增大而增强,当酸醚比超过一定范围后,助磨效果有所减弱;具有短侧链及低相对分子质量的PCE具有更好的助磨效果;PCE磨制水泥的标准稠度用水量降低,16 h抗压强度降低,28 d抗压强度没有损失.

关键词：水泥助磨剂聚羧酸系减水剂分子结构粉磨效率

水化水泥颗粒表面超塑化剂吸附层分布模型(英文)

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建筑材料学报 2007年第1期10卷 7-13页

作者： johann plank Panagiotis Chatziagorastou Christian Hirsch Institute for Inorganic Chemistry Munich University of TechnologyGarching 85747Germany

制备了钙矾石(AFt)、单硫型硫铝酸钙(AFm)和钾长石类单矿物,并研究了三聚氰胺磺酸盐甲醛缩聚物(PMS)、β-萘磺酸盐甲醛缩合物(BNS)及聚羧酸盐(PC)等几种化学成分不同的超塑化剂在其早期水化颗粒表面上的吸附行为.研究发现,zeta电位是决... 详细信息

制备了钙矾石(AFt)、单硫型硫铝酸钙(AFm)和钾长石类单矿物,并研究了三聚氰胺磺酸盐甲醛缩聚物(PMS)、β-萘磺酸盐甲醛缩合物(BNS)及聚羧酸盐(PC)等几种化学成分不同的超塑化剂在其早期水化颗粒表面上的吸附行为.研究发现,zeta电位是决定水泥颗粒表面对超塑化剂吸附量的关键因素.以溶液沉淀析出法人工合成的AFt具有较高的正zeta电位,能吸附大量带负电荷的超塑化剂,AFm仅带少量正电荷,其吸附超塑化剂相对较少,钾长石、氢氧钙石和石膏的zeta电位几乎为零或负值,因而基本不吸附超塑化剂.根据实验结果,笔者认为水化水泥颗粒用马赛克结构表示为最佳,而超塑化剂主要吸附在AF表面上.

关键词：水泥超塑化剂吸附钙矾石(A Ft) 单硫型硫铝酸钙(AFm) 钾长石 zeta电位

Recent Developments in Dry Mortar Technology in Europe

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Recent Developments in Dry Mortar Technology in Europe

2006第二届中国国际建筑干混砂浆生产应用技术研讨会

作者： johann plank Chair for Construction Chemicals Institute for Inorganic Chemistry Prof.Dr.

＜正＞*** Over the last years,the global dry-mix mortar production is increasing very fast and is approaching a volume of 100 *** *** growth is mainly generated in countries such as *** Europe, Russia,Dubai and China ...

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欧洲干混砂浆技术发展趋势

欧洲干混砂浆技术发展趋势

首届全国商品砂浆学术会议

作者： johann plank 慕尼黑技术大学

1 引言20世纪60年代之前,欧洲的砂浆无一例外都是在施工现场拌制的,即将原料如胶凝材料(水泥、石灰、石膏)和砂子运送到施工现场,再由人工小批量拌合使用。这种技术存在两大缺点。第一,由于原料质量差、施工现场储存环境不良以及混合比...

1 引言20世纪60年代之前,欧洲的砂浆无一例外都是在施工现场拌制的,即将原料如胶凝材料(水泥、石灰、石膏)和砂子运送到施工现场,再由人工小批量拌合使用。这种技术存在两大缺点。第一,由于原料质量差、施工现场储存环境不良以及混合比例不精确,砂浆质量的波动较大,且没有任何质量控制。无论砂浆的质量是否达到要求,其质量都取决于施工工人的操作技能。第二,现场搅拌和手工操作需要更多的工人来参与完成。

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当今欧洲混凝土外加剂的研究进展

当今欧洲混凝土外加剂的研究进展

作者： johann plank 赵霄龙薛庆刘岩德国慕尼黑大学无机化学系建筑化学品研究所中国建筑科学研究院中国建筑科学研究院中国建筑科学研究院

＜正＞很早以前人们就已经发现,在建筑材料中使用外加剂可以提高其性能。例如,在古罗马,人们把蛋白质作为石膏的缓凝组分,把干血作引气剂使用。当今建筑工程中使用的外加剂则可以起缓凝、速凝、塑化、增黏、抗离析、保水、减缩、消泡、...

＜正＞很早以前人们就已经发现,在建筑材料中使用外加剂可以提高其性能。例如,在古罗马,人们把蛋白质作为石膏的缓凝组分,把干血作引气剂使用。当今建筑工程中使用的外加剂则可以起缓凝、速凝、塑化、增黏、抗离析、保水、减缩、消泡、防水、纤维增强等作用。

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性能优越的混合金属氢氧化物-膨润土钻井液

国外油田工程 2001年第8期17卷 34-35,57页

作者： johann plank 高光军中国石油天然气集团公司工程技术研究院

钻井液对油气井钻探和隧道开凿的成功至关重要 ,用含有悬浮膨润土颗粒的混合金属氢氧化物 (MMH)配制的钻井液具有优越的剪切稀释流变特性 ,特别适用于油气田钻井和施工钻孔。本文从MMH的形成、化学结构、稠化效应及作用方式模型等多方... 详细信息

钻井液对油气井钻探和隧道开凿的成功至关重要 ,用含有悬浮膨润土颗粒的混合金属氢氧化物 (MMH)配制的钻井液具有优越的剪切稀释流变特性 ,特别适用于油气田钻井和施工钻孔。本文从MMH的形成、化学结构、稠化效应及作用方式模型等多方面对其特性进行了解释 ,并举例说明其成功的应用。

关键词：钻井液剪切稀释流变性显微图三维网络模型

Rescue from complications after pancreaticoduodenectomies at a low-volume Caribbean center:Value of tailored peri-pancreatectomy protocols

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World Journal of Gastrointestinal Surgery 2024年第3期16卷 681-688页

作者： Shamir O Cawich Elijah Dixon Parul J Shukla Shailesh V Shrikhande Rahul R Deshpande Fawwaz Mohammed Neil W Pearce Wesley Francis Shaneeta Johnson johann Bujhawan Department of Surgery University of the West IndiesSt Augustine 000000Trinidad and Tobago Department of Surgery Faculty of MedicineUniversity of CalgaryCalgaryAlberta T2N2T9Canada Department of Surgery Weill Cornell Medical CollegeNew YorkNY 10065United States Department of Surgical Oncology Tata Memorial CenterHomi Bhabha National UniversityMumbai 400012India Department of Surgery Manchester Royal InfirmaryManchester M139WLUnited Kingdom University Surgical Unit Southampton General HospitalSouthampton SO166YDUnited Kingdom Department of Surgery University of the West IndiesNassau N-1184Bahamas Department of Surgery Morehouse School of MedicineAtlantaGA 30310United States Department of Surgery General Hospital in Port of SpainPort of Spain 000000Trinidad and Tobago

BACKGROUND Pancreaticoduodenectomy(PD)is a technically complex operation,with a re-latively high risk for *** ability to rescue patients from post-PD complications is as a recognized quality *** protocols were instituted at our low volume facility in the year *** To document the rate of rescue from post-PD complications with tailored protocols in place as a measure of *** A retrospective audit was performed to collect data from patients who experienced major post-PD complications at a low volume pancreatic surgery unit in Trinidad and Tobago between January 1,2013 and June 30,***-dardized definitions from the International Study Group of Pancreatic Surgery were used to define post-PD complications,and the modified Clavien-Dindo classification was used to classify post-PD *** Over the study period,113 patients at a mean age of 57.5 years(standard deviation[SD]±9.23;range:30-90;median:56)underwent PDs at this *** complications were recorded in 33(29.2%)patients at a mean age of 53.8 years(SD:±7.9).Twenty-nine(87.9%)patients who experienced major morbidity were salvaged after aggre-ssive treatment of their ***(3.5%)died from bleeding pseudoaneurysm(1),septic shock secondary to a bile leak(1),anastomotic leak(1),and myocardial infarction(1).There was a significantly greater salvage rate in patients with American Society of Anesthesiologists scores≤2(93.3%vs 25%;P=0.0024).CONCLUSION This paper adds to the growing body of evidence that volume alone should not be used as a marker of quality for patients requiring *** low volumes at our facility,we demonstrated that 87.9%of patients were rescued from major *** attributed this to several factors including development of rescue protocols,the competence of the pancreatic surgery teams and continuous,and adaptive learning by the entire institution,cul-minating in the development of tailored peri-pancreatectomy protoc

关键词： Pancreas Complication Rescue Failure Morbidity Mortality Pancreaticoduodenectomy

General Solutions of First-Order Algebraic ODEs in Simple Constant Extensions

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系统科学与复杂性学报:英文版 2023年第4期36卷 1769-1788页

作者： MITTERAMSKOGLER johann Josef WINKLER Franz Research Institute for Symbolic Computation(RISC) Johannes Kepler Universität LinzA-4040 LinzAustria

If a first-order algebraic ODE is defined over a certain differential field,then the most elementary solution class,in which one can hope to find a general solution,is given by the adjunction of a single arbitrary constant to this *** of this type give rise to a particular kind of generic point—a rational parametrization—of an algebraic curve which is associated in a natural way to the ODE’s defining *** for the opposite direction,we show that a suitable rational parametrization of the associated curve can be extended to a general solution of the ODE if and only if one can find a certain automorphism of the solution *** automorphisms are determined by linear rational functions,i.e.,Möbius *** properties of rational parametrizations,in combination with the particular shape of such automorphisms,lead to a number of necessary conditions on the existence of general solutions in this solution ***,the desired linear rational function can be determined by solving a comparatively simple differential system over the ODE’s field of *** results hold for arbitrary differential fields of characteristic zero.

关键词： Algebraic curve algebraic differential equation general solution Möbius transformation rational parametrization

Bare-throated spurfowl(Pternistis spp.)males across Africa impress females with bright throat colours during courtship

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Avian Research 2023年第3期14卷 416-424页

作者： johann H.van Niekerk Department of Environmental Sciences College of Agriculture and Environmental SciencesUniversity of South AfricaP.O.Box 392Pretoria0003South Africa

The role of bare body parts in sexual signalling in birds has received relatively little attention.I describe how the bare-throated spurfowl males saturate the colours of their throats to attract *** the 23 Afrotropical spurfowl species,the bare-throated subgroup includes Yellow-necked Spurfowl(Pternistis leucosceptus),Rednecked Spurfowl(***),Grey-breasted Spurfowl(***) and Swainson’s Spurfowl(***).The rest of the species include fully feathered throated *** colour intensity of bare throats was scored using an extensive online digital photographic archive encompassing the four species across the year’s *** throat(n=836) was assigned to one of four colour-intensity categories to explore the relationship between colour intensities,breeding cycles,and environmental *** for Swainson’s Spurfowl male saturation of throat colours correlated with monthly rainfall,which peaks one or two months before egg ***’s Spurfowl peaks during egg ***-necked Spurfowl has the largest bare ***-throated spurfowl males perform an elevated courtship display posture above the female to feature their throat *** such displays occur in feather-throated *** with low throat colour saturation harbour more ectoparasites on their bare throats than birds with saturated *** Red-necked Spurfowls have significantly larger bare throats than *** primary function of bare throats probably assists in thermoregulation,particularly in arid *** bare throat may have evolved a secondary role in ***-necked,Red-necked,and Greybreasted Spurfowls use their saturated throat colours as ornaments to court females during the breeding *** female throat colours(unsaturated) may discourage male interlopers and predation during egg *** appears to be carotenoid-food *** different colours among the bare-throated species may serve as prezygotic mechani

关键词： Bare-throated spurfowls Breeding Colour saturation Ornaments Pternistis spp. Sexual size dimorphism