독일의 지방자치와 매스미디어

Jepsen-Foge, Dieter Center for Local Autonomy Hanyang University 1997 지방자치와 지역언론의 역할 Vol.- No.1

세계적으로 사고하라 그러나 지방적으로 행동하라 : 이것은 우리 시민들이 정치에 기대하는 것이다. 세계를 주시하라 그러나 지방의 뿌리와 관계를 유지하라 ' 이것은 우리 독자, 청취자, 비평가들이 미 디어에게 요구할 수 있는 것이다. 독일에서 유명한 여론조사기관 (Allensbach)이 사람들에게 그들이 항상 읽고 있는 일간신문의 분 야를 질문하였을 때 응답자의 84%가 그들의 도시나 지역에 관한 지방기사라고 응답하였고, 그 다음으로 58%가 독일의 정치뉴스나 기사라고 응답하였다. 반면 씬%가 세계의 정치뉴스나 기사라고 응 답하였다. 그리고 그 다음으로 광고, 일상기사, 사설, 편집자에 대한 기고, 스포츠기사, 경제 그리고 문화순으로 나타났다.

Local Autonomy and Mass Media

Jepsen-Foge, Dieter Center for Local Autonomy Hanyang University 1997 지방자치와 지역언론의 역할 Vol.- No.1

[TED 브레인] 브레인 TED 추천 강연

메리 루 젭슨(Mary Lou Jepsen),댄 나이츠(Dan Knights) 한국뇌과학연구원 2018 브레인 Vol.73 No.-

Are Drop-Impact Phenomena Described by Rayleigh-Taylor or Kelvin-Helmholtz Theory?

Yoon, Sam S.,Jepsen, Richard A.,James, Scott C.,Liu, Jie,Aguilar, Guillermo Taylor Francis 2009 Drying technology Vol.27 No.3

<P> Drop impact, spreading, fingering, and snap-off are important inmany engineering applications such as spray drying, industrial painting, environmentally friendly combustion, inkjet printing, materials processing, fire suppression, and pharmaceutical coating. Controlling drop-impact instability is crucial to designing optimized systems for the aforementioned applications. Classical Rayleigh-Taylor (RT) theory has been widely used to analyze fingering where instabilities at the leading edge of the toroidal ring form fingers that may ultimately snap off to form small droplets. In this study, we demonstrate the inapplicability of RT theory, in particular because it fails to explain the stable regimes observed under conditions of low air density and the instabilities observed when a drop impacts a pool of equal-density fluid. Specifically, finger instability decreases with decreasing air density, whereas the RT theory suggests that instability should remain unchanged. Moreover, experiments show that fingers form upon impact of a dyed water drop with a water pool, whereas the RT theory predicts noinstability when the densities of the two interacting fluids are equal. Experimental evidence is instead consistent with instability predictions made using the shear-driven Kelvin-Helmholtz theory.</P>

Experimental investigation on splashing and nonlinear fingerlike instability of large water drops

Yoon, S.S.,Jepsen, R.A.,Nissen, M.R.,O’Hern, T.J. Academic Press 2007 Journal of Fluids and Structures Vol.23 No.1

<P><B>Abstract</B></P><P>The fluid physics of the splashing and spreading of a large-scale water drop is experimentally observed and investigated. New phenomena of drop impact that differ from the conventional Rayleigh–Taylor instability theory are reported. Our experimental data shows good agreement with previous work at low Weber number but the number of fingers or instabilities begins to deviate from the R–T equation of Allen at high Weber numbers. Also observed were multiple waves (or rings) on the spreading liquid surface induced from pressure bouncing (or pulsation) within the impacting liquid. The first ring is transformed into a radially ejecting spray whose initial speed is accelerated to a velocity of 4–5 times that of the impacting drop. This first ring is said to be “splashing,” and its structure is somewhat chaotic and turbulent, similar to a columnar liquid jet surrounded by neighboring gas jets at relatively high impact speed. At lower impact speeds, splashing occurs as a crown-shaped cylindrical sheet. A second spreading ring is observed that transforms into fingers in the circumferential direction during spreading. At higher Weber number, the spreading of a third ring follows that of the second. This third ring, induced by the pressure pulsation, overruns and has fewer fingers than the second, which is still in a transitional spreading stage. Several important relationships between the drop impact speed, the spray ejection speed of the first ring, and the number of fingers of the second and third rings are presented, based on data acquired during a set of drop impact experiments. Issues related to the traditional use of the R–T instability are also addressed.</P>

Modeling the Influence of Gas Pressure on Droplet Impact Using a Coupled Gas/liquid Boundary Element Method

Park, Hong-Bok,Yoon, Sam S.,Jepsen Richard A.,Heister Stephen D. The Institute for Liquid Atomization and Spray Sys 2006 한국액체미립화학회지 Vol.11 No.2

An inviscid axisymmetric model capable of predicting droplet bouncing and the detailed pre-impact motion, influenced by the ambient pressure, has been developed using boundary element method (BEM). Because most droplet impact simulations of previous studies assumed that a droplet was already in contact with the impacting substrate at the simulation start, the previous simulations could not accurately describe the effect of the gas compressed between a failing droplet and the impacting substrate. To properly account for the surrounding gas effect, an effect is made to release a droplet from a certain height. High gas pressures are computationally observed in the region between the droplet and the impact surface at instances just prior to impact. The current simulation shows that the droplet retains its spherical shape when the surface tension energy is dominant over the dissipative energy. When increasing the Weber number, the droplet surface structure is highly deformed due to the appearance of the capillary waves and, consequently, a pyramidal surface structure is formed; this phenomenon was verified with our experiment. Parametric studies using our model include the pre-impact behavior which varies as a function of the Weber number and the surrounding gas pressure.

Electronic and superconducting properties of the binary carbide La2C3

김준성,Reinhard K. Kremer,Ove Jepsen,Arndt Simon 한국물리학회 2006 Current Applied Physics Vol.6 No.5

We have studied the electronic structure and investigated the synthesis conditions to optimize the superconducting properties ofthe binary carbide La2C3. From the electronic structure calculation based on two dierent reported crystal structure determinations,the Fermi level (EF) is found to be located near a local minimum of the density of state (DOS) and the DOS atEFvaries with a slightchange of the structural parameters. These results are consistent with the fact that the superconducting properties of La2C3 are sen-sitive to the preparation conditions and the annealing procedure. By a careful control of the C deciency we have improved thesuperconducting properties and prepare samples showing a sharp superconducting transition ofTc = 13.213.3 K. Critical elds,Hc2 (T), estimated from resistivity and susceptibility measurement are considerably higher than reported previously.

Disorder induced polymorphic transitions in the high hydrogen density compound Sr(BH₄)₂(NH₃BH₃)₂

Jørgensen, Mathias,Lee, Young-Su,Bjerring, Morten,Jepsen, Lars H.,Akbey, Ü,mit,Cho, Young Whan,Jensen, Torben R. The Royal Society of Chemistry 2018 Dalton Transactions Vol.47 No.46

<P>The new compound Sr(BH4)2(NH3BH3)2 has been synthesized and characterized with <I>in situ</I> powder X-ray diffraction and fast (28 or 60 kHz) magic angle spinning <SUP>1</SUP>H, <SUP>11</SUP>B and <SUP>15</SUP>N NMR and structurally optimized with density functional theory calculations. This investigation reveals complex structural rearrangements for this compound as a function of temperature. A room temperature orthorhombic polymorph, α-Sr(BH4)2(NH3BH3)2, with the space group symmetry <I>Pbca</I>, has been determined with a layered structure of alternating ammonia borane and Sr(BH4)2, partially stabilized by dihydrogen bonding. Surprisingly the crystal symmetry is lowered upon heating, as evidenced both by <I>in situ</I> synchrotron powder X-ray diffraction and <SUP>11</SUP>B MAS NMR data, resulting in an intermediate polymorph, β′-Sr(BH4)2(NH3BH3)2, present from ∼65 to 115 °C. β-Sr(BH4)2(NH3BH3)2, a sub structure of the β′-polymorph showing higher symmetry with the space group symmetry <I>Aba</I>2, forms upon further heating. <I>Ab initio</I> molecular dynamics simulations show that the ammonia borane molecule can dynamically alternate between a bidentate and a tridentate coordination to Sr at finite temperature. The dynamic properties of the ammonia borane molecule in the solid state are suggested to cause the observed structural complexity. Based on simultaneous thermogravimetric analysis, differential scanning calorimetry and mass spectrometry, the decomposition of the compound was investigated showing a stabilization of ammonia borane in the structure relative to other metal borohydride ammonia boranes and neat ammonia borane.</P>

Early Responders to Liraglutide 3.0 mg as Adjunct to Diet+Exercise from the SCALE Maintenance Trial

( Louis Aronne ),( Boris Stevenin ),( Cecilie Jepsen ),( Sean Wharton Pharmd ),( Yousun Ha ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1

Aims: The SCALE Maintenance trial randomized adults with obesity (BMI>30 kg/m2) or overweight (BMI>27 kg/m2) + comorbidities who lost >5% of initial body weight (BW) during a 4-12 week low calorie diet (1200-1400 kcal/day) run-in period (mean weight loss [WL]: 6.0%) prior to randomization to liraglutide 3.0 mg or placebo as an adjunct to diet and exercise Methods: This post-hoc analysis of SCALE Maintenance compared outcomes in liraglutide 3.0 mg early responders vs. early non-responders (definition: ERs vs. ENRs; >4% vs. < 4% WL at week 16 post-randomization). Efficacy outcomes are observed means or proportions for those completing 56 weeks treatment. The safety analysis set is used for adverse events (AEs). Results: Mean characteristics at randomization (n=212) for liraglutide 3.0 mg were: 46 years old, 84% female, BMI 36 kg/m2. Of those completing 56 weeks treatment, (n=159); 118 (74.2%) were ERs to liraglutide 3.0 mg and 41 (25.8%) ENRs. At week 56, mean WL was -9.2% in ERs vs. +0.3% in ENRs in addition to run-in WL. 89.8% of ERs maintained run-in weight loss (or lost further weight) during 56 weeks vs. 41.5% of ENRs. The percentage of those who regained all run-in WL by week 56 was 0.0% for ERs vs. 14.6%, 0.0% and 0.0% for ENRs. Percentage achieving >5%, >10% or >15% WL at week 56 was 66.9%, 43.2% and 18.6% for ERs vs. 14.6%, 0.0% and 0.0% for ENRs. ERs had greater change in mean waist circumferrence: -7.3cm vs. +0.3cm in ENRs. Serious AEs were 4.4% vs. 0.0% and GI AEs 78.1% vs. 60.4% for ERs vs. ENRs, respectively Conclusions: Among those who completed 56 weeks treatment on liraglutide 3.0 mg. a greater additional WL of -9.2% was observed for ERs vs. +0.3% for ENRs, with a similar proportion experiencing AEs.

Experimental Splash Studies of Monodisperse Sprays Impacting Variously Shaped Surfaces

Yoon, Sam S.,Kim, Ho Y.,Lee, Dongjo,Kim, Namsoo,Jepsen, Richard A.,James, Scott C. Taylor Francis 2009 Drying technology Vol.27 No.2

<P> Despite numerous studies of the drop impact phenomena, studies of the fundamental mechanisms of how the splash corona and subsequent necking yield splashed droplets, not to mention characteristics of these splashed droplets, remain a subject of great interest. Here, we consider a simple question: After impact, what are the characteristics of splashed droplets? Spatial variations in the fraction of splashed liquid, Sauter mean diameter, and drop-size distribution for water and diesel impacting onto variously shaped rods are reported. Liquid drops of nearly uniform size are continuously injected onto a 2-mm-diameter aluminum cylindrical rod at velocities of up to 17 m/s. The impact face of the rod is flat with angles from &thgr; = 0 to 60° or it has a concave, convex, or conical shape. The experimental results indicate that diesel breaks up more easily than water due to its low surface tension. However, due to increased energy loss through viscous dissipation during drop collapse and spreading, dispersion of diesel drops upon and after impact is less energetic than that of water since diesel droplets do not travel as fast or as far as water droplets. During corona formation, stretching and necking of diesel drops before their snap-off are particularly evident due to diesel's high viscosity. Size distribution of splashed diesel droplets is more uniform than that of water near the impact region and water is more uniform further away.</P>