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在Ka波段上全波段参差增益耿效应放大

微纳电子技术 1976年第5期 60-63页

作者： j.g.de koning 李继国

使用参差增益放大方法已经证明了在 Ka 波段上全波段低噪声瞬时放大的可能性。利用对这两级放大器总增益变化的简化分析计算了满足最大允许波纹所需的最小隔离电平。用这个方法,已经得到26.6～39.4千兆赫、10±2.2分贝增益。

关键词：全波段环行器频带反射型高频段低频段频程 Ka 放大器电路

Bayesian model averaging(BMA)for nuclear data evaluation

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Nuclear Science and Techniques 2024年第11期35卷 193-218页

作者： E.Alhassan D.Rochman g.Schnabel A.j.koning SCK CEN(Belgian Nuclear Research Centre) Boeretang 2002400 MolBelgium Laboratory for Reactor Physics and Thermal‑Hydraulics Paul Scherrer Institute5232 VilligenSwitzerland Nuclear Data Section International Atomic Energy Agency(IAEA)ViennaAustria Division of Applied Nuclear Physics Department of Physics and AstronomyUppsala UniversityUppsalaSweden

To ensure agreement between theoretical calculations and experimental data,parameters to selected nuclear physics models are perturbed and fine-tuned in nuclear data *** approach assumes that the chosen set of models accurately represents the‘true’distribution of considered ***,the models are chosen globally,indicating their applicability across the entire energy range of ***,this approach overlooks uncertainties inherent in the models *** this work,we propose that instead of selecting globally a winning model set and proceeding with it as if it was the‘true’model set,we,instead,take a weighted average over multiple models within a Bayesian model averaging(BMA)framework,each weighted by its posterior *** method involves executing a set of TALYS calculations by randomly varying multiple nuclear physics models and their parameters to yield a vector of calculated ***,computed likelihood function values at each incident energy point were then combined with the prior distributions to obtain updated posterior distributions for selected cross sections and the elastic angular *** the cross sections and elastic angular distributions were updated locally on a per-energy-point basis,the approach typically results in discontinuities or“kinks”in the cross section curves,and these were addressed using spline *** proposed BMA method was applied to the evaluation of proton-induced reactions on ^(58)Ni between 1 and 100 *** results demonstrated a favorable comparison with experimental data as well as with the TENDL-2023 evaluation.

关键词： Bayesian model averaging(BMA) Nuclear data Nuclear reaction models Model parameters TALYS code system Covariances

A quark nova in the wake of a core-collapse supernova:a unifying model for long duration gamma-ray bursts and fast radio bursts

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Research in Astronomy and Astrophysics 2020年第2期20卷 119-186页

作者： Rachid Ouyed denis Leahy Nico koning department of Physics and Astronomy University of Calgary

By appealing to a quark nova(QN;the explosive transition of a neutron star to a quark star) in the wake of a core-collapse supernova(CCSN) explosion of a massive star,we develop a unified model for long duration gamma-ray bursts(LgRBs) and fast radio bursts(FRBs).The time delay(years to decades)between the SN and the QN,and the fragmented nature(i.e.,millions of chunks) of the relativistic QN ejecta are key to yielding a robust LgRB *** our model,an LgRB light curve exhibits the interaction of the fragmented QN ejecta with turbulent(i.e.,filamentary and magnetically saturated) SN ejecta which is shaped by its interaction with an underlying pulsar wind nebula(PWN).The afterglow is due to the interaction of the QN chunks,exiting the SN ejecta,with the surrounding *** model can fit BAT/XRT prompt and afterglow light curves simultaneously with their spectra,thus yielding the observed properties of LgRBs(e.g.,the Band function and the X-ray flares).We find that the peak luminositypeak photon energy relationship(i.e.,the Yonetoku law),and the isotropic energy-peak photon energy relationship(i.e.,the Amati law) are not fundamental but ***-like emission in our model results from coherent synchrotron emission(CSE) when the QN chunks interact with non-turbulent weakly magnetized PWN-SN ejecta,where conditions are prone to the Weibel *** field amplification induced by the Weibel instability in the shocked chunk frame sets the bunching length for electrons and pairs to radiate *** resulting emission frequency,luminosity and duration in our model are consistent with FRB *** find a natural unification of high-energy burst phenomena from FRBs(i.e.,those connected to CCSNe) to LgRBs including X-ray flashes(XRFs) and X-ray rich gRBs(XRR-gRBs) as well as superluminous SNe(SLSNe).We find a possible connection between ultra-high energy cosmic rays and FRBs and propose that a QN following a binary neutron star merger can yiel

关键词： stars:neutron stars:quark pulsars:general supernovae:general gamma-ray burst:general fast radio burst:general

Hints of a second explosion(a quark nova) in Cassiopeia A supernova

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Research in Astronomy and Astrophysics 2015年第4期15卷 483-500页

作者： Rachid Ouyed denis Leahy Nico koning department of Physics and Astronomy University of Calgary

We show that the explosive transition of the neutron star （NS） to a quark star （QS）（a Quark Nova） in Cassiopeia A （Cas A） a few days following the supernova （SN） proper can account for several of the puzzling kinematic and nucleosynthetic features that are observed. The observed decoupling between Fe and 44Ti and the lack of Fe emission within 44Ti regions is expected in the QN model owing to the spallation of the inner SN ejecta by relativistic QN neutrons. Our model predicts the 44Ti to be more prominent to the NW of the central compact object （CCO） than in the SE and little of it along the NE-SW jets, in agreement with NuStar observations. Other intriguing features of Cas A are addressed, such as the lack of a pulsar wind nebula and the reported few percent drop in the CCO temperature over a period of 10 yr.

关键词： ISM: individual object (Cassiopeia A) -- ISM: supemova remnants --stars: neutron

SN 2009ip and SN 2010mc as dual-shock Quark-Novae

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Research in Astronomy and Astrophysics 2013年第12期13卷 1463-1470页

作者： Rachid Ouyed Nico koning denis Leahy department of Physics and Astronomy University of Calgary 2500 University Drive NW

In recent years a number of double-humped supernovae （SNe） have been discovered. This is a feature predicted by the dual-shock Quark-Nova （QN） model where an SN explosion is followed （a few days to a few weeks later） by a QN explo- sion. SN 2009ip and SN 2010mc are the best observed examples of double-humped SNe. Here, we show that the dual-shock QN model naturally explains their light curves including the late time emission, which we attribute to the interaction between the mixed SN and QN ejecta and the surrounding circumstellar matter. Our model applies to any star （O-stars, luminous blue variables, Wolf-Rayet stars, etc.） provided that the mass involved in the SN explosion is ~ 20 Mo which provides good conditions for forming a QN.

关键词： circumstellar matter -- stars: evolution -- stars: winds outflows --supernovae: general -- supernovae: individual (SN 2009ip SN 2010mc)

Quark nova model for fast radio bursts

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Research in Astronomy and Astrophysics 2016年第5期16卷 87-98页

作者： Zachary Shand Amir Ouyed Nico koning Rachid Ouyed department of Physics and Astronomy University of Calgary

Fast radio bursts （FRBs） are puzzling, millisecond, energetic radio transients with no discernible source; observations show no counterparts in other frequency bands. The birth of a quark star from a parent neutron star experiencing a quark nova - previously thought undetectable when born in isolation - provides a natural explanation for the emission characteristics of FRBs. The generation of unstable r-process elements in the quark nova ejecta provides millisecond exponential injection of electrons into the surrounding strong magnetic field at the parent neutron star＇s light cylinder via β-decay. This radio synchrotron emission has a total duration of hundreds of milliseconds and matches the observed spectrum while reducing the inferred dispersion measure by approximately 200 cm-3 pc. The model allows indirect measurement of neutron star magnetic fields and periods in addition to providing astronomical measurements of β-decay chains of unstable neutron rich nuclei. Using this model, we can calculate expected FRB average energies （- 1041 erg） and spectral shapes, and provide a theoretical framework for determining distances.

关键词： stars: neutron -- nuclear reactions nucleosynthesis abundances -- radiation mechanisms:general -- radio continuum: general

Scalable jet-Based Fabrication of PEI-Hydrogel Particles for CO_(2) Capture

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Energy & Environmental Materials 2024年第6期7卷 351-358页

作者： jieke jiang Eline van Daatselaar Hylke Wijnja Tessa de koning gans Michel Schellevis Cornelis H.Venner derk W.F.Brilman Claas Willem Visser Engineering Fluid Dynamics group Department of Thermal and Fluid EngineeringFaculty of Engineering TechnologyUniversity of Twente7500AEEnschedeThe Netherlands Sustainable Process Technology Faculty of Science and TechnologyUniversity of Twente7500AEEnschedeThe Netherlands

The capture,regeneration,and conversion of CO_(2) from ambient air and flue gas streams are critical aspects of mitigating global *** sorbents for CO_(2) absorption are very promising as they have high mass transfer areas without energy input and reduce emissions and minimize corrosion as compared to liquid ***,precisely tunable solid CO_(2) sorbents are difficult to ***,we demonstrate the high-throughput production of hydrogel-based CO_(2)-absorbing particles via liquid *** wrapping a liquid jet consisting of an aqueous solution of cross-linkable branched polyethylenimine(PEI)with a layer of suspension containing hydrophobic silica nanoparticles,monodisperse droplets with a silica nanoparticle coating layer was formed in the air.A stable Pickering emulsion containing PEI droplets was obtained after these ejected droplets were collected in a heated oil *** droplets turn into mm-sized particles after thermal curing in the *** diameter,PEI content,and silica content of the particles were systematically varied,and their CO_(2) absorption was measured as a function of *** regeneration of the particles enabled cyclic testing,revealing a CO_(2) absorption capacity of 6.5±0.5 mol kg^(−1)solid PEI in pure CO_(2) environments and 0.7±0.3 mol kg^(−1)solid PEI for direct air *** thousands of particles were produced per second at a rate of around 0.5 kg per hour,with a single *** process can be further scaled by *** complete toolbox for the design,fabrication,testing,and regeneration of functional hydrogel particles provides a powerful route toward novel solid sorbents for regenerative CO_(2) capture.

关键词： CO_(2) capture droplet hydrogel liquid jet particle steam regeneration

Offering Adequate Pedagogical Progression via Mobile Equipments——Experiment of a French Engineering School

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开放教育研究 2006年第1期12卷 59-62页

作者： jean-Luc koning grenoble National Institute of Technology France

Students may enter our 5-year engineering school in France at two levels; first and third year. However, due to their quite different backgrounds (this is especially true for third year students) , we need to provide newcomers with a 6-week training period during which they follow classes in the fields where they particularly feel weak. Unfortunately, depending on the student' s background, this is not always possible to bring him/her to the expected level. Another aspect one needs to mention is that these students may not have the same weaknesses in a given field. However, for economical reasons, those classes follow a uniform program as it is not feasible to provide a customised progression. In this paper we discuss how to redesign a mathematics course so as to offer tailored exercise sequencing. groups of 20 students could then draw their exercises from an intranet database according to their previously completed work, try to solve it by themselves, request additional hints and even ask for some direct help from the teacher. Such a database is currently under development. If it turns out several students stumble against the same difficulty the teacher could show the whole class room how to solve it using the digital projector. This project goes one step further than our initial mobile education project (2003 - 2004 ). Until recently, we had used the equipment in a unique direction, from the instructor toward the students. Here, in this new project we are focusing on the whole loop in order to offer a more adequate (personalized) pedagogical progression ; from the student to the teacher (when the tablet PCs are monitored by the teacher) , and back toward the students (when a direct help is provided by the teacher).

关键词：法国移动学习设备工程院校开放教育教学方法

不确定性规避与新冠肺炎疫情下的股市隐含波动率

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不确定性规避与新冠肺炎疫情下的股市隐含波动率

作者： de koning jEROEN FRANK 上海财经大学

学位级别：硕士

2020年初爆发的新冠肺炎疫情对全球股票市场产生了巨大的冲击,但各国股票市场的波动率却呈现很大的差异。为什么会出现这种情况?或者说,为什么面对同样的冲击,各国股票市场却表现出不同特征的波动?这可能与不同国家的文化差异有关,因为... 详细信息

2020年初爆发的新冠肺炎疫情对全球股票市场产生了巨大的冲击,但各国股票市场的波动率却呈现很大的差异。为什么会出现这种情况?或者说,为什么面对同样的冲击,各国股票市场却表现出不同特征的波动?这可能与不同国家的文化差异有关,因为民族文化的某些特质可以直接影响当地人的行事风格。已有的研究已经证明了这一点,但是所有的研究结论主要涉及股票市场受冲击后的长期表现。那么,短期情况又如何呢?这是本文试图探讨的问题。本论文运用霍夫斯泰德(Hofstede)“不确定性规避”文化维度研究COVID-19大流行期间某国股市的隐含波动率。研究的主要问题是,某国不确定性规避程度是如何影响该国COVID-19大流行期间股市的隐含波动率的?本论文采用十三个国家和地区的每日数据,特别是政府对COVID-19疫情的应对、相应的股市隐含波动率、不确定性规避程度、对外国投资者的投资自由度(考虑到外国潜在投资者的存在有可能扭曲市场的表现)等等。本论文建立模型,运用这些数据进行回归分析,结果表明,COVID-19大流行期间,不确定性规避程度较高的国家,其股票市场的隐含波动率往往也较高,这与某些已有的研究结论是不同的。

关键词： COVID-19疫情文化维度不确定性规避股票市场隐含波动率