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Erratum to:A Donsker Delta Functional Approach to Optimal Insider Control and Applications to Finance

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Communications in Mathematics and Statistics 2015年第3期3卷 535-540页

作者： Olfa Draouil berntФksendal Department of Mathematics University of Tunis El ManarTunisTunisia Department of Mathematics University of OsloP.O.Box 1053Blindern0316 OsloNorway Norwegian School of Economics(NHH) Helleveien 305045 BergenNorway

Erratum to:***.(2015)3:365-421 DOI 10.1007/s40304-015-0065-y Unfortunately,in the original publication of the article some equations appeared *** corrected equations are given below:•In(1.1)it should be added that the... 详细信息

关键词： assumed Optimal equations

Optimal control with delayed information flow of systems driven by G-Brownian motion

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Probability, Uncertainty and Quantitative Risk 2018年第1期3卷 229-252页

作者： Francesca Biagini Thilo Meyer-Brandis berntØksendal Krzysztof Paczka Department of Mathematics LMU MunichTheresienstraße 3980333 MunichGermany Department of Mathematics University of OsloP.O.Box 1053 BlindernN-0316 OsloNorway Department of Mathematics University of MunichTheresienstraße 3980333 MunichGermany

In this paper,we study strongly robust optimal control problems under volatility *** the G-framework,we adapt the stochastic maximum principle to find necessary and sufficient conditions for the existence of a strongl... 详细信息

关键词： G-Brownian motion optimal control problem stochastic maximum principle

Extreme Value Estimation of Beaufort Sea Ice Dynamics Driven by Global Wind Effects

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China Ocean Engineering 2022年第4期36卷 532-541页

作者： Chana Sinsabvarodom Arvid Næss bernt J.Leira Wei Chai Department of Marine Technology Norwegian University of Science and TechnologyTrondheim 7491Norway Department of Mathematical Sciences Norwegian University of Science and TechnologyTrondheim 7491Norway School of Naval Architecture Ocean and Energy Power EngineeringWuhan University of TechnologyWuhan 430070China

The purpose of the present study is to investigate the extreme values of the ice drift speed,which are also considered in the light of the magnitude of the simultaneous wind *** relationship between wind speed and ice drift speed is *** long-term ice drift data is collected by using local subsurface measurements based on acoustic Doppler current profilers(ADCP)in the Beaufort Sea during the period of ***-looking sonars(ULS)are deployed in order to observe the ice thickness as well as to identify events that correspond to open water *** relationship between the ice drift speed and the wind speed is also *** is found that the magnitude of the average ice drift speed is approximately 2.5%of the wind speed during the winter *** of the extreme values of the ice drift speed is studied by application of the average conditional exceedance rate(ACER)*** is found that the extreme ice drift speed during the ice melt season(*** summer season)is approximately20%-30%higher than that during the ice growth season(*** winter season).The extreme ice drift speed can be effectively estimated based on the 2.5%wind ***,the extreme ice drift speed can be obtained based on the extreme values of 2.5%of the wind speed based on multiplying with an amplification factor which varies in the range from 1.7 to 2.0 during the growth season,corresponding to increasing return periods of 10,25,50 and 100years.

关键词： ice drift extreme wind speed extreme ice-drift speed

Activation of Transition Metal(Fe,Co and Ni)-Oxide Nanoclusters by Nitrogen Defects in Carbon Nanotube for Selective CO_(2) Reduction Reaction

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Energy & Environmental Materials 2023年第1期6卷 253-263页

作者： Yi Cheng Jinfan Chen Chujie Yang Huiping Wang bernt Johannessen Lars Thomsen Martin Saunders Jianping Xiao Shize Yang San Ping Jiang Institute of Environmental Science and Engineering School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083China Institute of Materials China Academy of Engineering PhysicsP.O.Box 9071-12Mianyang 621907China Australian Synchrotron ANSTOClayton Vic.3168Australia Centre for Microscopy Characterization and Analysis(CMCA)The University of Western AustraliaCrawley WA 6009Australia State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Eyring Materials Center Arizona State UniversityTempe AZ 85257USA WA School of Mines:Minerals Energy&Chemical EngineeringCurtin UniversityPerth WA 6102Australia

The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish ***,highly efficient,cheap catalysts are urgently *** metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)***,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)***_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine *** faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 *** in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.

关键词： activation effect electrochemical CO_(2)reduction reaction N defect proton-coupled electron transfer process transition metal oxide nanocluster

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极地船舶结构设计思考

中国舰船研究 2022年第5期17卷 212-219页

作者： bernt J.LEIRA 柴威 Gowtham RADHAKRISNAN 挪威科技大学海洋技术系挪威特隆赫姆7491 武汉理工大学船海与能源动力工程学院湖北武汉430063

冰脊和冰山与极地船体发生碰撞将影响船体结构安全,并决定船体结构设计载荷。船体结构设计应遵循基于风险的设计原则,通常涉及以下极限状态设计准则:1)服务极限状态(SLS);2)最终极限状态(ULS);3)疲劳极限状态(FLS);4)事故极限状态(ALS)... 详细信息

冰脊和冰山与极地船体发生碰撞将影响船体结构安全,并决定船体结构设计载荷。船体结构设计应遵循基于风险的设计原则,通常涉及以下极限状态设计准则:1)服务极限状态(SLS);2)最终极限状态(ULS);3)疲劳极限状态(FLS);4)事故极限状态(ALS)。最终极限状态和事故极限状态对应于发生概率极低的船与冰脊作用以及冰山撞击事件,旨在确保船体结构不会完全损毁。然而,对于较低概率水平的冰载荷分析,需进行较大数据量的工况分析,计算耗时无法承受。为此,引入环境等值轮廓方法,来大幅减少冰载荷分析所需工况数量,并给出设计工况最有可能的冰体参数组合方式。结合最终极限状态和事故极限状态,举例说明这一方法的运用方式。环境等值轮廓方法可为现有极地船舶船体结构设计方法提供有效补充。

关键词：极地船舶船–冰作用环境等值轮廓法船舶结构设计冰载荷

Coupling Effect of Riser on Integrated FPS in Deepwater Area

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China Ocean Engineering 2009年第4期23卷 613-622页

作者：韩志强 bernt J.Leira 李飒 Tianjin Branch China Classification Society Marine Technology Department Norwegian University of Science and Technology Civil Engineering Department Tianjin University

The main challenge in predicting global responses of floating vessels in deepwater and uhra-deepwater areas comes from the system＇s coupled effect, tn this paper, the coupled approach is used to analyze effects of riser on floating system in deepwater. The analysis results show that the coupling effects of risers will mainly affect the low frequency （LF） motions of the system. That is because risers will provide the system with a significant low frequency （LF） damping which will vary with the sea states. Under storm sea state, the excitation term from drag force will govern the response. While under the moderate conditions, the damping effect of risers is more significant. In the practical engineering, the combination effect should be considered by other ways when the risers are omitted from the model.

关键词： riser semi-submersible cow,piing deepmater

Improvement of Wired Drill Pipe Data Quality via Data Validation and Reconciliation

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International Journal of Automation and computing 2018年第5期15卷 625-636页

作者： Dan Sui Olha Sukhoboka bernt Sigve Aadn?y Petroleum Engineering Department University of Stavanger

Wired drill pipe（WDP）technology is one of the most promising data acquisition technologies in today s oil and gas *** the first time it allows sensors to be positioned along the drill string which enables collecting and transmitting valuable data not only from the bottom hole assembly（BHA）,but also along the entire length of the wellbore to the drill *** technology has received industry acceptance as a viable alternative to the typical logging while drilling（LWD）*** more and more WDP applications can be found in the challenging drilling environments around the world,leading to many innovations to the *** most of the data acquired from WDP can be noisy and in some circumstances of very poor *** factors contribute to the poor data *** common sources include mis-calibrated sensors,sensor drifting,errors during data transmission,or some abnormal conditions in the well,*** challenge of improving the data quality has attracted more and more focus from many researchers during the past *** paper has proposed a promising solution to address such challenge by making corrections of the raw WDP data and estimating unmeasurable parameters to reveal downhole *** advanced data processing method,data validation and reconciliation（DVR）has been employed,which makes use of the redundant data from multiple WDP sensors to filter/remove the noise from the measurements and ensures the coherence of all sensors and *** it has the ability to distinguish the accurate measurements from the inaccurate *** addition,the data with improved quality can be used for estimating some crucial parameters in the drilling process which are unmeasurable in the first place,hence provide better model calibrations for integrated well planning and realtime operations.

关键词： Data quality wired drill pipe (WDP) data validation and reconciliation (DVR) drilling models.

Impact of elliptical boreholes on in situ stress estimation from leak-off test data

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Petroleum Science 2018年第4期15卷 794-800页

作者： Hong Xue Han Shunde Yin bernt Sigve Aadnoy Department of Petroleum Engineering University of Wyoming Petroleum Engineering Department University of Stavanger

We developed an inversion technique to determine in situ stresses for elliptical boreholes of arbitrary trajectory. In this approach, borehole geometry, drilling-induced fracture information, and other available leak-off test data were used to construct a mathematical model, which was in turn applied to finding the inverse of an overdetermined system of *** method has been demonstrated by a case study in the Appalachian Basin, USA. The calculated horizontal stresses are in reasonable agreement with the reported regional stress study of the area, although there are no field measurement data of the studied well for direct calibration. The results also indicate that 2% of axis difference in the elliptical borehole geometry can cause a 5% difference in minimum horizontal stress calculation and a 10% difference in maximum horizontal stress calculation.

关键词： Inversion Leak-off test data Elliptical borehole In situ stress

解析光电化学氮还原合成氨中局域电子结构和合金化的协同效应

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Chinese Journal of Catalysis 2023年第2期45卷 141-151页

作者：郑建云吕艳红黄爱彬 bernt Johannessen 曹逊蒋三平王双印湖南大学化学与化工学院化学/生物传感与化学计量国家重点实验室中国湖南长沙410082 湖南第一师范学院物理与化学学院中国湖南长沙410202 中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室中国上海200050 中国科学院大学材料科学与光电子工程中心中国北京100049 澳大利亚同步辐射光源澳大利亚科廷大学西澳矿业学院澳大利亚

氨是氮肥等工业的主要原料,因此氨产量居各种化工产品的首位.目前,90%以上的氨通过传统Haber-Bosch法制得,但该反应需要在高温高压下进行,消耗大量能源,同时排放大量CO_(2).基于此,科研人员致力于寻求一种绿色、高效的合成氨替代方法.其... 详细信息

氨是氮肥等工业的主要原料,因此氨产量居各种化工产品的首位.目前,90%以上的氨通过传统Haber-Bosch法制得,但该反应需要在高温高压下进行,消耗大量能源,同时排放大量CO_(2).基于此,科研人员致力于寻求一种绿色、高效的合成氨替代方法.其中,利用太阳能,通过光电化学氮还原合成氨是最有潜力和竞争力的方法之一,该方法也为有效利用太阳能提供了新途径.目前,虽然光电化学氮还原研究取得了一定进展,但是氨产率和氮转换效率低限制了其经济可行性.这主要归因于四个方面:(1)牢固的氮氮三键使得氮气难以活化;(2)复杂的多步和多电子反应使得动力学迟缓;(3)析氢竞争反应降低了太阳能-氨的转换效率;(4)氮气在水溶液中的溶解度低导致吸附在光电阴极表面的氮气较少.为解决上述问题,本文通过溅射法在B掺杂的p型(100)晶向硅片上共沉积Au,Co和Pd,然后在600℃下和空气中快速退火,制得由助催化剂/保护层/光吸收层组成的层级硅基光电阴极,并用于氮还原合成氨.成分和结构表征结果表明,层级硅基光电阴极由p型硅光吸收层、二氧化硅保护薄层和AuCoPd合金纳米颗粒助催化剂组成,该电极可表示为AuCoPd-CoOx/SiO_(2)/Si,简称ACP电阴极.角分辨X射线光电子能谱和同步辐射X射线吸收光谱结果表明,形成了局域电子结构AuCoPd合金纳米颗粒,并可分析出Au离子和Pd离子在纳米颗粒上的比例和分布.变压光电化学实验结果表明,ACP光电阴极表现出较好的氮还原合成氨性能,在3 MPa下氨产率达到22.2±0.4μg·h^(-1)·cm^(-2),法拉第效率达到22.9%.同时,ACP光电阴极的光电化学氮还原行为遵循勒夏特列(化学平衡移动)原理:随着反应压强增加,氨产率、法拉第效率和起始光电压均随之增大.原位X射线光电子能谱和原位同步辐射X射线吸收光谱结果表明,Au离子和Pd离子为氮还原反应的活性位点,为氮气活化及加氢提供反应场所;同时,揭示了邻近的Pd元素为Au物种上活化的氮气提供了活性质子,促进了氮还原合成氨反应进程.综上,本文为设计高效且稳定的光电阴极并应用于光电化学氮还原反应提供一定的参考.

关键词：光电化学氮固定电子局域结构合金化加压反应协同机理