The National Synchrotron Radiation Research Center is a 1.5 GeV third-generation synchrotron at the Hsinchu Science Park in East District, Hsinchu City, Taiwan as the agency under the Ministry of Science and Technology of the Republic of China.There are twenty-six operational beamlines and four under construction; the NSRRC also operate two beamlines at SPring-8 in Japan. They cover a wide range of functionality, from IR microscopy to X-ray lithography. Wikipedia.
Lee M.-T.,National Synchrotron Radiation Research Center |
Lee M.-T.,National Central University |
Sun T.-L.,Rice University |
Hung W.-C.,Republic of China Military Academy |
Huang H.W.,Rice University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013
Melittin is a prototype of the ubiquitous antimicrobial peptides that induce pores in membranes. It is commonly used as a molecular device for membrane permeabilization. Even at concentrations in the nanomolar range, melittin can induce transient pores that allow transmembrane conduction of atomic ions but not leakage of glucose or larger molecules. At micromolar concentrations, melittin induces stable pores allowing transmembrane leakage of molecules up to tens of kilodaltons, corresponding to its antimicrobial activities. Despite extensive studies, aspects of the molecular mechanism for pore formation remain unclear. To clarify the mechanism, one must know the states of the melittin-bound membrane before and after the process. By correlating experiments using giant unilamellar vesicleswith those of peptide-lipidmultilayers, we found that melittin bound on the vesicle translocated and redistributed to both sides of the membrane before the formation of stable pores. Furthermore, stable pores are formed only above a critical peptide-to-lipid ratio. The initial states for transient and stable pores are different, which implies different mechanisms at low and high peptide concentrations. To determine the lipidic structure of the pore, the pores in peptide-lipid multilayers were induced to form a lattice and examined by anomalous X-ray diffraction. The electron density distribution of lipid labels shows that the pore is formed by merging of two interfaces through a hole. The molecular property of melittin is such that it adsorbs strongly to the bilayer interface. Pore formation can be viewed as the bilayer adopting a lipid configuration to accommodate its excessive interfacial area.
Bahou M.,National Chiao Tung University |
Wu Y.-J.,National Synchrotron Radiation Research Center |
Lee Y.-P.,National Chiao Tung University
Angewandte Chemie - International Edition | Year: 2014
Large protonated polycyclic aromatic hydrocarbons (H+PAHs) are possible carriers of unidentified infrared (UIR) emission bands from interstellar objects, but the characterization of infrared (IR) spectra of large H+PAHs in the laboratory is challenging. IR absorption spectra of protonated coronene (1-C24H13 +) and mono-hydrogenated coronene (1-C24H13 .), which were produced upon electron bombardment of parahydrogen containing a small proportion of coronene (C24H12) during matrix deposition, were recorded. The spectra are of a much higher resolution than those obtained by IR multiphoton dissociation by Dopfer and co-workers. The IR spectra of protonated pyrene and coronene collectively appear to have the required chromophores for features of the UIR bands, and the spectral shifts on an increase in the number of benzenoid rings point in the correct direction towards the positions of the UIR bands. Larger protonated peri-condensed PAHs might thus be key species among the carriers of UIR bands. Protonated pyrene and coronene collectively appear to have the required chromophores for the unidentified infrared (UIR) emission bands from interstellar objects, and the spectral shifts on an increase in the number of aromatic rings point in the correct direction towards the positions of the UIR bands. Larger protonated peri-condensed polycyclic aromatic hydrocarbons might thus be important species among the carriers of UIR bands. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Chen W.-T.,National Taiwan University |
Sheu H.-S.,National Synchrotron Radiation Research Center |
Liu R.-S.,National Taiwan University |
Attfield J.P.,University of Edinburgh
Journal of the American Chemical Society | Year: 2012
Red or yellow phosphors excited by a blue light-emitting diode are an efficient source of white light for everyday applications. Many solid oxides and nitrides, particularly silicon nitride-based materials such as M 2Si 5N 8 and MSi 2O 2N 2 (M = Ca, Sr, Ba), CaAlSiN 3, and SiAlON, are useful phosphor hosts with good thermal stabilities. Both oxide/nitride and various cation substitutions are commonly used to shift the emission spectrum and optimize luminescent properties, but the underlying mechanisms are not always clear. Here we show that size-mismatch between host and dopant cations tunes photoluminescence shifts systematically in M 1.95Eu 0.05Si 5-xAl xN 8-xO x lattices, leading to a red shift when the M = Ba and Sr host cations are larger than the Eu 2+ dopant, but a blue shift when the M = Ca host is smaller. Size-mismatch tuning of thermal quenching is also observed. A local anion clustering mechanism in which Eu 2+ gains excess nitride coordination in the M = Ba and Sr structures, but excess oxide in the Ca analogues, is proposed for these mismatch effects. This mechanism is predicted to be general to oxynitride materials and will be useful in tuning optical and other properties that are sensitive to local coordination environments. © 2012 American Chemical Society.
Lee S.-H.,National Synchrotron Radiation Research Center
Physical Chemistry Chemical Physics | Year: 2010
We investigated the photodissociation dynamics of tetrahydrofuran (c-C 4H8O) at 193.3 nm in a molecular-beam apparatus using photofragment-translational spectroscopy and direct vacuum-ultraviolet (VUV) photoionization. Five dissociation channels leading to products with m/z ratios appropriate for CH2CH2CH2 + H2CO, CH2CHCH2 + CH2OH, H + CH2CH 2 + CH2CHO, CH2CH2 + CH3 + HCO and CH2CH2 + CH2CO + H2 were identified; their branching ratios were determined to be 0.40, 0.25, 0.04 0.29 and 0.02, respectively. Secondary dissociations from nascent products CH 2CH2CH2CHO to CH2CH2 + CH2CHO and from CH2CH2O to CH3 + HCO and likely to CH2CO + H2 were observed. We measured distributions of product kinetic energy, average kinetic-energy release, and fractions in translation for each dissociation channel. The formation of CH 2CHCH2 + CH2OH indicates that hydrogen migration occurs before complete fragmentation. All photofragments have nearly isotropic angular distributions, with β values less than 0.05. The photodissociation of tetrahydrofuran into five channels is proposed to proceed mainly on the ground state potential-energy surface following ring opening and efficient internal conversions. © the Owner Societies.
National Synchrotron Radiation Research Center | Date: 2013-11-18
An apparatus for generating a pulsed magnetic field includes an insulating body, an electrical conductor positioned on the insulating body, and a ferromagnetic body having a hollow portion, wherein the insulating body and the electrical conductor are positioned in the hollow portion. In some embodiments of the present disclosure, the electrical conductor has at least one gap separating the electrical conductor into at least two parts, thereby allowing a current to flow through the at least two parts in parallel to generate a magnetic field in the insulating body.
National Synchrotron Radiation Research Center | Date: 2015-03-25
An X-ray mask structure (10) includes a unibody support substrate (11) having at least one thinned portion (21) surrounded by a wall portion (25), a top layer (15B) disposed on the at least one thinned portion of the support substrate, and a plurality of X-ray absorber patterns (35) disposed on the top layer over the at least one thinned portion. The top layer and the at least one thinned portion form a laminated membrane, wherein the at least one thinned portion and the wall portion provide mechanical support for the top layer, and the laminated membrane provides mechanical support for the plurality of X-ray absorber patterns.
National Synchrotron Radiation Research Center | Date: 2013-11-15
An X-ray mask structure includes a unibody support substrate having at least one thinned portion surrounded by a wall portion, a top layer disposed on the at least one thinned portion of the support substrate, and a plurality of X-ray absorber patterns disposed on the top layer over the at least one thinned portion. The top layer and the at least one thinned portion form a laminated membrane, wherein the at least one thinned portion and the wall portion provide mechanical support for the top layer, and the laminated membrane provides mechanical support for the plurality of X-ray absorber patterns.
National Synchrotron Radiation Research Center | Date: 2011-03-17
The present invention discloses a package structure of an inkjet-printhead chip. The structure includes: a nozzle structure of a print element including an ink chamber layer, a nozzle base layer on the ink chamber layer, and a nozzle layer on the nozzle base layer, wherein a plurality of nozzle through holes are set in the nozzle layer and pass through an ink chamber of the ink chamber layer; a flexible substrate set on the nozzle layer, wherein there is at least an opening set in the flexible substrate to expose those nozzle through holes; and a chip set under the ink chamber layer. Besides, the present package method is to utilize the micro-manufacturing process to form the nozzle structure of a print element and the tape automatic bonding process to bond the flexible substrate on the nozzle layer and the chip under the ink chamber layer.
National Synchrotron Radiation Research Center | Date: 2014-04-29
A relief valve assembly includes a relief valve, a hollow shell disposed on the relief valve so as to form a relieving chamber, and a cap mounted to the hollow shell and closing off a distal end of the relief valve to an external environment. The hollow shell has a distal aperture and a proximal aperture, and the distal end of the relief valve is inserted into the hollow shell through the proximal aperture and protrudes through the distal aperture. The relief valve includes a relief port forming a fluid flow path between a valve chamber of the relief valve and the relieving chamber, and the hollow shell extends past the relief port along a longitudinal axis of the relief valve. The relief valve includes a slide member configured to move in response to an over-pressure condition, and a fluid vents from the valve chamber to the relieving chamber through the relief port.
National Synchrotron Radiation Research Center | Date: 2015-04-10
An electrochemical capacitor includes a positive electrode, a negative electrode disposed proximally to the positive electrode, and a non-aqueous electrolyte, wherein the positive electrode and the negative electrode are immersed in the non-aqueous electrolyte, and a case is presented in the energy storage system to accommodate the non-aqueous electrolyte, the positive electrode, and the negative electrode. The positive electrode has a porous matrix having a plurality of micrometer sized pores and nanostructured metal oxides, wherein the porous matrix is a 3-dimensional (3D) mesoporous metal or a 3D open-structured carbonaceous material, and the nanostructured metal oxides are coated inside the plurality of pores of the porous matrix. The non-aqueous electrolyte includes organic compounds having at least one acylamino group and lithium salts characterized as LiX, wherein Li is lithium and X comprises SCN^(); the organic compounds are cyclic compounds; and the cyclic compounds comprise 2-oxazolidinone, ethyleneurea, or the combination thereof.