Hybrid R-Fe-B/R-Co Magnets with Improved Thermal Stability

Shen, Yi; Higgins, A.; Chen, C.; Liu, S.

doi:10.21236/ada519522

Cited by 6 publications

(10 citation statements)

References 4 publications

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“…However, observations show that the case of GRB 080319B is rare. Most prompt optical flux is consistent with or below the low-energy extension of gamma-rays; 104 3. The gamma-ray lightcurve of GRB 080319B is much more variable than the optical lightcurve.…”

Section: A Breakthrough: Fast Cooling Synchrotron Radiation In a Decamentioning

confidence: 86%

Gamma-Ray Burst Prompt Emission

Zhang

2014

Int. J. Mod. Phys. D

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The origin of gamma-ray burst (GRB) prompt emission, bursts of γ-rays lasting from shorter than one second to thousands of seconds, remains not fully understood after more than 40 years of observations. The uncertainties lie in several open questions in the GRB physics, including jet composition, energy dissipation mechanism, particle acceleration mechanism, and radiation mechanism. Recent broad-band observations of prompt emission with Fermi sharpen the debates in these areas, which stimulated intense theoretical investigations invoking very different ideas. I will review these debates, and argue that the current data suggest the following picture: A quasi-thermal spectral component originating from the photosphere of the relativistic ejecta has been detected in some GRBs. Even though in some cases (e.g. GRB 090902B) this component dominates the spectrum, in most GRBs, this component either forms a sub-dominant "shoulder" spectral component in the low energy spectral regime of the more dominant "Band" component, or is not detectable at all. The main "Band" spectral component likely originates from the optically thin region due to synchrotron radiation. The diverse magnetization in the GRB central engine is likely the origin of the observed diverse prompt emission properties among bursts.

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Section: A Breakthrough: Fast Cooling Synchrotron Radiation In a Decamentioning

confidence: 86%

Gamma-Ray Burst Prompt Emission

Zhang

2014

Int. J. Mod. Phys. D

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“…[ 23,27,28 ] Techniques described by Shen et al and Conix were used to synthesize SA and CPH prepolymers and a melt polycondensation reaction was carried out to synthesize 20:80 CPH:SA and 20:80 CPTEG:CPH copolymers. [ 23,29,30 ] Purity, chemical structure, and molecular weight of the polymers were determined using 1 H NMR spectroscopy on a Varian VXR 300 MHz spectrometer. The 20:80 CPH:SA copolymer had a molecular weight of 13.5 kDa, while the 20:80 CPTEG:CPH copolymer had a molecular weight of 7.5 kDa, which is consistent with previous work.…”

Section: Monomer and Polymer Synthesismentioning

confidence: 99%

Nanoparticle Chemistry and Functionalization Differentially Regulates Dendritic Cell–Nanoparticle Interactions and Triggers Dendritic Cell Maturation

Goodman

Ramirez

Boggiatto

et al. 2014

Part & Part Syst Charact

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Biodegradable polyanhydride nanoparticles have been used as vaccine adjuvants and delivery vehicles. Upon parenteral administration, the surface characteristics of these nanoparticles may be modified by serum protein adsorption, likely affecting how the particles interact with antigen presenting cells. These studies investigated the role of the differential adsorption of serum proteins onto carbohydrate‐functionalized and non‐functionalized polyanhydride nanoparticles of different chemistries on interactions with dendritic cells (DCs). Di‐mannose (a carboxymethyl‐modified disaccharide of 1,2‐α‐linked‐d‐mannopyranoside) or glycolic acid was covalently linked to nanoparticles synthesized using copolymers of 1,6‐bis(p‐carboxyphenoxy)hexane (CPH) and sebacic acid (SA) and 1,8‐bis(p‐carboxyphenoxy)‐3,6‐dioxaoctane (CPTEG) and CPH. Serum protein adsorption to CPH:SA nanoparticles enhanced particle internalization, but did not enhance uptake of CPTEG:CPH nanoparticles. When DCs were cultured with nanoparticles, the surface expression of MHC II, CD86, and CD206 was enhanced and mediated by both polymer chemistry and functionalization. Cytokine secretion by DCs was differentially modulated by both polymer chemistry and functionalization. The amount and profile of serum proteins adsorbed indicated that polymer hydrophobicity and functionalization enhanced protein adsorption. Overall polymer chemistry, functionalization, and serum protein adsorption influenced nanoparticle interactions with DCs and elucidating the complex relationships between these parameters and dendritic cell maturation will enable rational design of targeted vaccines and immunotherapies.

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“…The distance of the GRB emission region from the central engine (R GRB ) has been poorly constrained. If prompt optical data are observed, one may apply the constraint on the synchrotron self-absorption frequency (ν a ) to constrain R GRB (Shen & Zhang 2009). One needs to assume that the optical and γ-ray emission are from essentially the same radius in order to pose such a constraint.…”

Section: Emission Radiusmentioning

confidence: 99%

“…GRB 080928, Rossi et al 2011). Prompt optical observations can also be used to constrain the self-absorption frequency ν a (Shen & Zhang 2009), but, so far, no GRB has been observed clearly with more than two break energies in the prompt spectrum. Meanwhile, early time observations in the optical band provide a greater chance to detect reverse shock emission which has only been observed for a few bursts since the first detection in GRB 990123 (Akerlof et al 1999).…”

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confidence: 99%

Panchromatic Observations of the Textbook GRB 110205a: Constraining Physical Mechanisms of Prompt Emission and Afterglow

Zheng

Shen

Sakamoto

et al. 2012

ApJ

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We present a comprehensive analysis of a bright, long duration (T 90 ∼ 257 s) GRB 110205A at redshift z = 2.22. The optical prompt emission was detected by Swif t/UVOT, ROTSE-IIIb and BOOTES telescopes when the GRB was still radiating in the γ-ray band, with optical lightcurve showing correlation with γ-ray data. Nearly 200 s of observations were obtained simultaneously from optical, Xray to γ-ray (1 eV -5 MeV), which makes it one of the exceptional cases to study the broadband spectral energy distribution during the prompt emission phase. In particular, we clearly identify, for the first time, an interesting two-break energy spectrum, roughly consistent with the standard synchrotron emission model in the fast cooling regime. Shortly after prompt emission (∼ 1100 s), 14.0) optical emission hump with very steep rise (α ∼ 5.5) was observed which we interpret as the the reverse shock emission. It is the first time that the rising phase of a reverse shock component has been closely observed. The full optical and X-ray afterglow lightcurves can be interpreted within the standard reverse shock (RS) + forward shock (FS) model. In general, the high quality prompt and afterglow data allow us to apply the standard fireball model to extract valuable information including the radiation mechanism (synchrotron), radius of prompt emission (R GRB ∼ 3 × 10 13 cm), initial Lorentz factor of the outflow (Γ 0 ∼ 250), the composition of the ejecta (mildly magnetized), as well as the collimation angle and the total energy budget.

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Hybrid R-Fe-B/R-Co Magnets with Improved Thermal Stability

Cited by 6 publications

References 4 publications

Gamma-Ray Burst Prompt Emission

Gamma-Ray Burst Prompt Emission

Nanoparticle Chemistry and Functionalization Differentially Regulates Dendritic Cell–Nanoparticle Interactions and Triggers Dendritic Cell Maturation

Panchromatic Observations of the Textbook GRB 110205a: Constraining Physical Mechanisms of Prompt Emission and Afterglow

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