bluuebunny/crossref_metadata_2025 huggingface dataset:
Elliptical-ring magnetic arrays fabricated using zone-plate-array lithography
Authors: Jung Wonjoon , Castaño F. J. , Ross C. A. , Menon Rajesh , Patel Amil , Moon Euclid E. , Smith Henry I.
Published: December 2004

Zone-plate-array lithography and lift-off processing were employed to fabricate large arrays of elliptical-ring thin film magnets with widths of 600nm and above. An undercut profile was created using WiDE™ antireflection coating spun underneath a PFI-88 resist layer. The process allowed for up to 60-nm-thick sputtered magnetic multilayered structures. The magnetic properties of the elliptical ring arrays clearly show that the shape anisotropy induced by the ellipticity of the ring creates different magnetization reversal depending on the applied field direction. Magnetic force microscopy shows that the rings display magnetic states characteristic of ring structures, as well as sharp transitions between them. A fabrication process to produce magnetic memory prototypes based on these elliptical rings is presented.
Self-inspection of IC pattern defects
Authors: Feng Hanying , Ye Jun , Pease R. Fabian W.
Published: December 2004

At various steps of IC manufacturing, defects need to be inspected to ensure process integrity. In this article, we describe a new methodology for defect inspection: defect self-inspection, i.e., defect detection based on a captured optical image itself without comparing to a reference image, where the reference image is a database image or an optical image from another die. Through intuitive understanding of human intelligence in detecting defects, we propose a systematic methodology of self-inspection based on pattern code space and code vectors. We describe the general methodology and present its implementations for two common types of defects as specific examples: detection of edge intrusion and protrusion (also known as mouse-bite) and detection of particle or contamination (also known as pinhole/pin-dot).
Large-area patterning for photonic crystals via coherent diffraction lithography
Authors: Zanke Christel , Qi Minghao , Smith Henry I.
Published: December 2004

A new method for lithographically patterning a large-area hexagonal lattice of circular holes is proposed, which is particularly suitable for the fabrication of 2D and 3D photonic crystals (PhC). The method, which we call coherent diffraction lithography (CDL), is based on the interference of beams diffracted from a mask containing a periodic pattern, often referred to as the Talbot effect. We demonstrate the replication of large-area hexagonal lattices using CDL, and investigate the most critical parameters of this technique.
Inspection of templates for imprint lithography
Authors: Hess Harald F. , Pettibone Don , Adler David , Bertsche Kirk , Nordquist Kevin J. , Mancini David P. , Dauksher William J. , Resnick Douglas J.
Published: December 2004

Masks of any next generation lithography (NGL), such as imprint lithography, must eventually achieve and maintain the very low defect counts of current production masks. This requires typically fewer than 10 or even no defects over the entire field. We describe an inspection methodology and how it can be applied to the imprint template. Special test patterns etched onto the template enable both a die to die comparison, to find nuisance defects, and also calibration of sensitivity to different types of preprogrammed defects. A state of the art deep ultraviolet photomask inspection system (KLA-Tencor model 526) can detect these rare events with about 70nm threshold for imprint masks with reflection mode contrast. Initial scans are made at various stages of the imprint process: the newly processed mask, after dicing, and after several imprints. The scans show mostly isolated point defects at a density of ∼10–100permm2. This is an encouraging start for a new NGL, and reductions are expected from better processes, equipment, and handling. In the future viable mask inspection at the 45–22nm node will be very demanding for these 1× masks and will require sensitivities approaching 10–20nm defect size. To this end, special masks suitable for electron (e)-beam inspection are being made and show good contrast and immunity to e-beam charging.
Duo-mold imprinting of three-dimensional polymeric structures
Authors: Kong Y. P. , Low H. Y. , Pang S. W. , Yee A. F.
Published: December 2004

We present a new method of imprinting three dimensional (3D) polymeric micro- and nanostructures using a duo-mold process. In this method, two patterned Si molds are surface treated to have different surface energies. A polymer solution is spin-coated onto one of the molds, forming a planarized thin film on the mold. The two molds are pressed together at an appropriate temperature and pressure and then released. The patterned thin film adhering to one of the molds is then pressed onto a substrate at an appropriate temperature and pressure to form supported 3D structures. Alternatively, the patterned thin film on the mold may be released to form freestanding 3D structures. A key success factor in this process is the silane-based surface treatments to enable the patterning of the thin polymer film and final release from the mold to form 3D structures. We demonstrate various polymethyl methacrylate 3D structures with combinations of grating, circular-, and square-patterned molds. The duo-mold process is a potentially low-cost and high-throughput method to fabricate 3D polymeric micro- and nanostructures.
Surface flatness of polycrystalline copper after argon ion etching followed by annealing
Authors: Hino T. , Taguchi T. , Yamauchi Y. , Hirohata Y. , Nishikawa M.
Published: December 2004

Oblique injection of argon ions with energy of 1 keV was conducted for etching of polycrystalline copper. The surface became rough owing to the formation of blisters. The average diameter and height of blisters was approximately 150 and 20–30 nm, respectively. The polycrystalline copper irradiated by argon ions was annealed to rupture the blisters. The retained argon desorbed in the temperature range from 500 to 800 K. The height of blisters significantly reduced to 10–15 nm although the diameter and surface density of blisters roughly remained the same.
Annealing temperature stability of Ir and Ni-based Ohmic contacts on AlGaN∕GaN high electron mobility transistors
Authors: Kang B. S. , Kim S. , La Roche J. R. , Ren F. , Fitch R. C. , Gillespie J. K. , Moser N. , Jenkins T. , Sewell J. , Via D. , Crespo A. , Dabiran A. M. , Chow P. P. , Osinsky A. , Pearton S. J.
Published: December 2004

Ti ∕ Al ∕ Ir ∕ Au Ohmic contacts on AlGaN∕GaN high electron mobility transistors (HEMTs) show promising electrical performance, with lower specific contact resistance than obtained with the more conventional Ti∕Al∕Ni∕Au metallization. HEMTs with both types of metallization have been measured up to 550°C. We find that the dc performance of devices with Ir-based contacts is significantly better at each temperature up to this maximum value, with higher transconductance (gm), saturated drain-source current (IDSS), and more stable threshold voltage (Vth). These contacts look very promising for HEMT power amplifier applications involving high temperature operation.
Mold deformation in nanoimprint lithography
Authors: Lazzarino F. , Gourgon C. , Schiavone P. , Perret C.
Published: December 2004

In nanoimprint lithography (NIL), one of the key points to be addressed is the printing uniformity on large area. During the process, the silicon mold undergoes significant mechanical stress of different kinds (tension, compression, flexion, and torsion). These stresses are function of the mold design and appear under the concurrent influence of both the applied pressure on the backside of the mold and an opposite force due to the polymer viscoelastic behavior. This translates into non-negligible deformations within patterned or unpatterned zones. This is a major issue because it causes nonuniformity of the printing, mold pattern break and degradation of the polymer surface. In this article, we demonstrate that during the imprint process mold deformations really occur at the local scale of the patterns but also at a larger scale.
Nanoscopic templates using self-assembled cylindrical diblock copolymers for patterned media
Authors: Yang XiaoMin , Xiao Shuaigang , Liu Chao , Pelhos Kalman , Minor Kevin
Published: December 2004

We demonstrated a process to create nanoscopic templates for the nanofabrication of patterned media using thin films of diblock copolymers. The self-assembled monolayers (SAMs) technique is used as a means to chemically modify the topographically confined trench surfaces to manipulate the wetting behavior of cylindrical diblock copolymers and perpendicularly oriented cylindrical poly (styrene-block-methyl methacrylate) (PS-b-PMMA) copolymers are obtained. Through optimizing the annealing conditions, long-range ordering in trenches is achieved after annealing at 170°C for about 24h. The ordering is strongly dependent on the line-edge-roughness (LER) of the trenches and the number of defects in the copolymer films inside the trenches. Efforts to decrease the various defects in the copolymer films and improve the trench LER are still in progress. With our approach, a negative phase 20nm nanoporous SiO2 template and a positive phase 20nm Ta nanodot template based on the self-assembled cylindrical PS-b-PMMA block copolymers are feasible for following pattern transfer to make patterned media.
Assembly and electrical characterization of DNA-wrapped carbon nanotube devices
Authors: Talin A. A. , Dentinger P. M. , Jones F. E. , Pathak S. , Hunter L. , Léonard F. , Morales A. M.
Published: December 2004

In this article we report on the electrical characteristics of single wall carbon nanotubes (SWCNTs) wrapped with single-stranded deoxyribonucleic acid (ssDNA). We fabricate these devices using a solution-based method whereby SWCNTs are dispersed in aqueous solution using 20-mer ssDNA, and are placed across pairs of Au electrodes using alternating current dielectrophoresis (ACDEP). In addition to current voltage characteristics, we evaluate our devices using scanning electron microscopy and atomic force microscopy. We find that ACDEP with ssDNA based suspensions results in individual SWCNTs bridging metal electrodes, free of carbon debris, while similar devices prepared using the Triton X-100 surfactant yield nanotube bundles, and frequently have carbon debris attached to the nanotubes. Furthermore, the presence of ssDNA around the nanotubes does not appear to appreciably affect the overall electrical characteristics of the devices. In addition to comparing the properties of several devices prepared on nominally clean Au electrodes, we also investigate the effects of self-assembled monolayers of C14H29-SH alkyl thiol and benzyl mercaptan on the adhesion and electrical transport across the metal/SWCNT/metal devices.
Electron-beam SAFIER™ process and its application for magnetic thin-film heads
Authors: Yang XiaoMin , Gentile Harold , Eckert Andrew , Brankovic Stanko R.
Published: December 2004

We have coupled the SAFIER™ (shrink assist film for enhanced resolution) process with electron-beam lithography for the fabrication of the write top pole structures for thin-film heads. The SAFIER™ process is designed to physically shrink trench patterns and contact holes with very little deterioration of the resist profile. In this article, we will present the experimental results of the SAFIER™ process for the fabrication of the write top pole. We investigate the SAFIER™ process concerning several key processing issues, including shrink resolution capability, repetition of the SAFIER™ process, shrink-sensitive baking conditions, resist sidewall profile, and line edge roughness (LER) after shrinking of the trench. The experimental results show that this process not only shrinks the size of resist trenches and contact holes, but also improves LER and critical dimension variation. We demonstrate the capability of printing top pole structures with pole widths of sub-20nm in a 0.30-μm-thick resist (aspect ratio>15:1), and electroplated top pole structures of 50nm in a 0.50-μm-thick resist (aspect ratio=10:1).
Effect of the deposition temperature on temperature coefficient of resistance in CuNi thin film resistors
Authors: Hur Sung-Gi , Kim Dong-Jin , Kang Byoung-Don , Yoon Soon-Gil
Published: December 2004

A constantan composition of Cu54Ni46 showing an near zero TCR value was obtained using a Ni power of 100W and a Cu power of 50W by dc magnetron cosputtering. The grain size increases and resistivity of the films decreases with increasing deposition temperature. The crystallinity of the films definitely influences the TCR value, which is an important parameter in resistor devices. The films deposited at 100°C exhibited a near zero TCR value of approximately 5ppm∕°C and the positive TCR values increased with increasing deposition temperature. The films deposited above 100°C do not exhibit irreversibility of the resistance with increasing deposition temperature.
Fatigue life of a microcantilever beam in bending
Authors: Hocheng H. , Kao K. S. , Fang W.
Published: December 2004

The fatigue behavior of a microcantilever beam loaded by various magnetic forces is investigated. The MEMS fabrication techniques, such as exposure, lithography, etching, etc., are applied to construct the micro structures on a silicon wafer. FEM and SEM are employed to study the relations between fractographies, stresses, and strains. The experimental results indicate that the deformation, stress and strain increase as the magnetic force increases, while the fatigue cycle time decreases with the load. The fatigue life lies in the range of 1–5×107cycles at 12–15MPa produced by the magnetic flux. Fracture occurs at the location of the maximum stress as predicted by an analytical approach.
Fabrication of a surface acoustic wave-based correlator using step-and-flash imprint lithography
Authors: Cardinale G. F. , Skinner J. L. , Talin A. A. , Brocato R. W. , Palmer D. W. , Mancini D. P. , Dauksher W. J. , Gehoski K. , Le N. , Nordquist K. J. , Resnick D. J.
Published: December 2004

We report the surface acoustic wave (SAW) correlator devices fabricated using nanoimprint lithography. Using step-and-flash imprint lithography (S-FIL), we produced SAW correlator devices on 100mm diameter z-cut LiNbO3 devices and an aluminum metal etch process. On the same chip layout, we fabricated SAW filters and compared both the filters and correlators to similar devices fabricated using electron-beam lithography (EBL). Both S-FIL- and EBL-patterned correlators and SAW filters were analyzed using a bit-error rate tester to generate the signal and a parametric signal analyzer to evaluate the output. The NIL filters had an average center frequency of 2.38GHz with a standard deviation of 10MHz. The measured insertion loss averaged −31dB. In comparison, SAW filters fabricated using EBL exhibited a center frequency of 2.39GHz and a standard deviation of 100kHz. Based on our preliminary results, we believe that S-FIL is an efficient and entirely viable fabrication method to produce quality SAW filters and correlators.
Lithographically directed self-assembly of nanostructures
Authors: Liddle J. Alexander , Cui Yi , Alivisatos Paul
Published: December 2004

The combination of lithography and self-assembly provides a powerful means of organizing solution-synthesized nanostructures for a wide variety of applications. We have developed a fluidic assembly method that relies on the local pinning of a moving liquid contact line by lithographically produced topographic features to concentrate nanoparticles at those features. The final stages of the assembly process are controlled first by long-range immersion capillary forces and then by the short-range electrostatic and van der Waals interactions. We have successfully assembled nanoparticles from 50to2nm in size using this technique and have also demonstrated the controlled positioning of more complex nanotetrapod structures. We have used this process to assemble Au nanoparticles into prepatterned electrode structures and have performed preliminary electrical characterization of the devices so formed. The fluidic assembly method is capable of very high yield, in terms of positioning nanostructures at each lithographically defined location, and of excellent specificity, with essentially no particle deposition between features.
Fabrication of photonic crystal waveguides composed of a square lattice of dielectric rods
Authors: Assefa Solomon , Petrich G. S. , Kolodziejski L. A. , Mondol M. K. , Smith H. I.
Published: December 2004

The use of a negative resist, hydrogen silsesquioxane (HSQ), combined with electron-beam lithography, was found to greatly simplify the fabrication of photonic crystal structures having submicron-sized features. Two methods of fabrication were compared for the creation of photonic crystals; in this example, the structures were composed of a square lattice of dielectric rods. One method utilized positive resist PMMA, whereas another method used a negative resist HSQ. The process sequence using PMMA required a lift-off step and a hard mask in order to convert the hole-patterned PMMA into high-aspect-ratio dielectric rods through reactive ion etching. Alternatively, the electron-beam exposure and development of HSQ resist resulted in the formation of SiO2-like posts which then served as a hard mask for subsequent etches. The use of HSQ eliminated the need for the SiO2 deposition and nickel lift-off, thereby reducing the required number of steps in the process sequence and greatly simplified the fabrication.
Nanostructures produced by ultraviolet laser irradiation of silicon. II. Nanoprotrusions and nanoparticles
Authors: Guan Y. F. , Pedraza A. J. , Fowlkes J. D. , Joy D. A.
Published: December 2004

Two-dimensional ordered nanoprotrusion arrays were produced at silicon surface substrates by nanosecond ultraviolet laser irradiation using a Lloyd’s mirror set up. These protrusions are 40 to 70nm high and have a diameter of ∼60 to 100nm at their base, and in many cases display a regular rectangular lattice. Their origin and evolution were studied using scanning electron microscopy and atomic force microscopy. Nanoprotrusions originate from a subjacent laser-induced periodic surface structure upon continuing irradiation, under the same processing conditions that produced these ripples. Their evolution is discussed in terms of fingering instabilities of melted silicon consistent with a gradient of surface tension due to a temperature gradient. The temperature gradient is produced by the same mechanism responsible for the ripple formation. At slightly higher laser fluences, nanoparticles were observed to form using a single beam of nonpolarized laser light. The nanoparticles also span a linear ordered array, with line spacing that conforms to the grating equation. Their formation mechanism has been described previously as a result of ablation and redeposition, and thus is widely different from the formation of nanoprotrusions. The differences and similarities of nanoprotrusions and nanoparticles, and their connection with nanoripples, were studied in detail. In particular, when the ripple structure was still seen, nanoprotrusions were observed to form on ripple crests while nanoparticles were located in ripple valleys. Nanoprotrusions remained stable under a 2h thermal annealing at 1073K. By contrast, the aligned nanoparticle arrays became disordered as a result of a 2h anneal at a temperature as low as 423K, as nanoparticles moved on the surface.
Three-dimensional and multimaterial microfabrication using focused-ion-beam chemical-vapor deposition and its application to processing nerve electrodes
Authors: Hoshino T. , Kawamori M. , Suzuki T. , Matsui S. , Mabuchi K.
Published: December 2004

One of the ways to interface electrodes to neurons is a regenerative electrode. The electrode is between the two cut end of a nerve. The cut nerve fiber regenerates through a metalized hold electrode in a two-dimensional (2D) planar of regenerative electrode. As this type of electrode has advantages enabling both the recording of signals of a single nerve fiber and the stimulation of a single nerve fiber, attempts have been made to develop it using traditional 2D microfabrication techniques. However, these traditional 2D techniques have made it difficult to process such electrodes, in particular, electrical wires that have a high density and an integrated structure. In this study, we developed a novel microfabrication method that enables three-dimensional (3D) micro/nanostructures to be fabricated that are made of several kinds of materials with focused-ion-beam chemical-vapor deposition (FIB-CVD). To demonstrate the feasibility of this technique, we designed and fabricated a modified type of regenerative nerve electrode composed of a number of microtubes, each of which worked as both the guide for nerve regeneration and the electrode channel. The 3D structures with this method were fabricated by depositing either diamondlike carbon (DLC, nonconductor) or tungsten (conductor) using a scanning 30keV Ga+ ion beam in an atmosphere of phenanthrene (C14H10) or tungsten hexacarbonyl (W(CO)6). The prototype for the electrode was fabricated with the following process. First, tungsten pillars, which worked as the electrical wiring, were deposited on the substrate by scanning the FIB in W(CO)6 gas. Next, carbon microtubes, which were used to guide the regenerated nerve fiber(s), were built up to be attached to each of the tungsten pillars by depositing DLC with a scanning FIB in C14H10 gas. These carbon microtubes (CMTs) were designed to be curved and to be spread so that they did not contact other wiring pillars, and they were gathered into one at both ends. Our FIB-CVD method made it possible to fabricate complicated 3D structures such as regenerative nerve electrodes made of several kinds of materials.
Immersion lithography: New opportunities for semiconductor manufacturing
Authors: Gil Darío , Brunner Timothy A. , Fonseca Carlos , Seong Nakgeuon , Streefkerk Bob , Wagner Christian , Stavenga Marco
Published: December 2004

Immersion lithography has recently emerged as the preferred lithography solution for manufacturing the next generation of semiconductor devices (likely to address the 65, 45, and possibly the 32nm nodes). Full-field immersion scanners operating at λ=193nm with de-ionized water as the immersion fluid have been recently demonstrated. In this article we report imaging results from the AT1150i prototype, a 0.75 numerical-aperture full-field scanner from ASML. We experimentally confirm the depth-of-focus improvements that immersion enables, and explore the implications of this gain for semiconductor manufacturing. This article also highlights the challenges the technology faces before it can be successfully introduced for semiconductor manufacturing. We pay particular attention to defects, in the form of particles, bubbles, and other processing residues, and highlight evaporation as a key mechanism underpinning these challenges.
Dynamic self-inspection of integrated circuit pattern defects
Authors: Feng Hanying , Ye Jun , Pease R. Fabian W.
Published: December 2004

At various steps of integrated circuit manufacturing, defects need to be inspected to ensure process integrity. Based on the observation that good patterns usually repeat many times while defective patterns are different from others, we here propose an inspection methodology called dynamic self-inspection (DSI). We present a generic and systematic algorithm of DSI based on relative characteristic code space and code vectors. We also present a few specific examples of its implementations, using Euclidian distance between edge traces as relative characteristics.
Initial lithography results from the digital electrostatic e-beam array lithography concept
Authors: Baylor L. R. , Gardner W. L. , Yang X. , Kasica R. J. , Guillorn M. A. , Blalock B. , Cui H. , Hensley D. K. , Islam S. , Lowndes D. H. , Melechko A. V. , Merkulov V. I. , Joy D. C. , Rack P. D. , Simpson M. L. , Thomas D. K.
Published: December 2004

The Digital Electrostatically focused e-beam Array direct-write Lithography (DEAL) concept is currently under development at Oak Ridge National Laboratory (ORNL). This concept incorporates a digitally addressable field-emission array (DAFEA) built into a logic and control integrated circuit to function as the write head for an e-beam lithography tool. The electrostatic focusing is integrated on the DAFEA and consists of additional grids lithographically aligned above the emitters and extraction grid, each separated by a dielectric (nominally low-temperature SiO2) layer. Prototypes of the DAFEA have been fabricated and used to test the focusing of the electron beams and to pattern lines in PMMA resist. First lithography tests have used electron energies of 500 eV to pattern lines less than 1 μm wide at a working distance of 500 μm which extrapolates to <300nm at the nominal DEAL design working distance of 100 μm. Aspects of the DEAL lithography testing and further development are discussed.
Full MEMS monolithic microcolumn for wafer-level arrayal
Authors: Kim Hak , Han Changho , Kim Jinkwang , Kim Hoseob , Chun Kukjin
Published: December 2004

Recently, an advanced microcolumn concept for improved throughput was proposed. However, due to the complexity of the approach, the miniaturization was limited. In addition, microcolumns must run under ultrahigh vacuum conditions in order to obtain stable electron emission at the field-emission tip. Both signal and power lines need to be connected through the ultrahigh vacuum chamber. Therefore, increases in the number of microcolumn arrays necessitate more wiring from the external control unit to the internal units, and the number of wires can become prohibitive. To solve this problem, a new concept, exploiting the possibility of an arrayed microcolumn which uses microelectromechanical systems (MEMS) technology has been developed. This paper describes a monolithic (3×3 arrayed) microcolumn, which consists of a cold field-emission tip, an input lens, an einzel lens, and novel deflectors for multiple-arrayed microcolumns. We also describe its fabrication process, which relies on improved microfabrication and MEMS technology, most notably multiwafer anodic bonding techniques and copper electroplating for the double metallization process. This paper describes an electro-optical analysis and an optimization using an equivalent circuit and a newly proposed simulation tool. We focus on the production possibilities for microcolumns constructed using MEMS technology. The emission current of the fabricated tungsten and molybdenum cold field-emission tip was several microamperes for an applied gate voltage of 100V. The probe current, which was measured in the sample grid of the wafer stage, was about 1nA. The amount of electron-beam deflection was proportional to the applied voltage at the deflector, and operated at about 1μm∕V.
Stability of functional polymers after plasticizer-assisted imprint lithography
Authors: Reano R. M. , Kong Y. P. , Low H. Y. , Tan L. , Wang F. , Pang S. W. , Yee A. F.
Published: December 2004

Poly(3,4-ethylenedioxythiophene) (PEDOT) and chitosan structures on Si, patterned by plasticizer-assisted imprint lithography (PAIL), are examined under a variety of imprinting conditions. The stabilities of pattern dimension and chemical functionality of these polymers are presented. Thermal annealing for 5min at 80°C is found to be an effective method to stabilize imprinted PEDOT patterns. Biofunctionality in chitosan as a function of imprint temperature and pressure is examined through fluorescence spectroscopy. The accessibility of the amine group of chitosan is observed to decrease for imprint temperatures above 80°C, whereas the chemical functionality is not affected by pressure up to 1MPa. Fluorescence spectra of the chitosan are observed to be strong functions of exposure time to O2 plasma.
Conductive nanostructure fabrication by focused ion beam direct-writing of silver nanoparticles
Authors: Kong David S. , Varsanik Jonathan S. , Griffith Saul , Jacobson Joseph M.
Published: December 2004

A focused ion beam has been used to directly pattern thin films of organometallic silver nanoparticles down to a resolution of 100nm. The unexposed regions were washed in hexane leaving the desired pattern, and subsequent annealing formed conductive, metallic features. Multiple-layer structures were also fabricated by spin-coating and exposing additional films of silver nanoparticles on top of already patterned structures. The sensitivity of the nanoparticles to 30keVGa+ ions was measured to be approximately 5μC∕cm2. Using this technique test structures were fabricated in two and three dimensions with resistivities as low as 288μΩcm and 13μΩcm for single- and multiple-layer structures, respectively, as compared to a value of 1.589μΩcm for bulk silver. To our knowledge, this is the highest demonstrated throughput for any electron or ion beam direct-write process utilizing metal-organic precursors.
Reversible nanochemical conversion
Authors: Sugimura Hiroyuki , Lee Sun-Hyung , Saito Nagahiro , Takai Osamu
Published: December 2004

Local chemical conversion of an organic surface that consists of a surface-confined monolayer is demonstrated in a reversible manner based on electrochemical reactions induced beneath a conductive probe tip of an atomic force microscope. The monolayer was prepared by a self-assembling technique from the precursor, p-aminophenyltrimethoxysilane. The chemical state of this self-assembled monolayer was regulated by probe-tip scanning with a bias voltage applied between the tip and substrate. With a positive substrate bias scanning, the monolayer surface was oxidized to be nitroso-terminated. With a negative bias scanning, this monolayer could be amino-terminated. These oxidation and reduction processes could be reversibly repeated.
Ultraviolet-induced damage in fluorocarbon plasma and its reduction by pulse-time-modulated plasma in charge coupled device image sensor wafer processes
Authors: Okigawa Mitsuru , Ishikawa Yasushi , Ichihashi Yoshinari , Samukawa Seiji
Published: December 2004

Highly sensitive charge coupled device (CCD) image sensors present a number of serious problems, such as increased dark current and interface states induced by plasma etching processes. In particular, irradiation with ultraviolet (UV) photons (200 to 310 nm) generates this damage. UV absorption at the Si∕SiO2 interface may contribute to increasing the density of the interface states. To solve this problem we investigated optimum fluorocarbon gas chemistries and the effect of pulse-time-modulated (TM) plasma. We found that selecting appropriate gas chemistries and using TM plasma drastically reduced the dark current in CCDs.
Distributions of Microbial Activities in Deep Subseafloor Sediments
Authors: D'Hondt Steven , Jørgensen Bo Barker , Miller D. Jay , Batzke Anja , Blake Ruth , Cragg Barry A. , Cypionka Heribert , Dickens Gerald R. , Ferdelman Timothy , Hinrichs Kai-Uwe , Holm Nils G. , Mitterer Richard , Spivack Arthur , Wang Guizhi , Bekins Barbara , Engelen Bert , Ford Kathryn , Gettemy Glen , Rutherford Scott D. , Sass Henrik , Skilbeck C. Gregory , Aiello Ivano W. , Guèrin Gilles , House Christopher H. , Inagaki Fumio , Meister Patrick , Naehr Thomas , Niitsuma Sachiko , Parkes R. John , Schippers Axel , Smith David C. , Teske Andreas , Wiegel Juergen , Padilla Christian Naranjo , Acosta Juana Luz Solis
Published: December 2004

Diverse microbial communities and numerous energy-yielding activities occur in deeply buried sediments of the eastern Pacific Ocean. Distributions of metabolic activities often deviate from the standard model. Rates of activities, cell concentrations, and populations of cultured bacteria vary consistently from one subseafloor environment to another. Net rates of major activities principally rely on electron acceptors and electron donors from the photosynthetic surface world. At open-ocean sites, nitrate and oxygen are supplied to the deepest sedimentary communities through the underlying basaltic aquifer. In turn, these sedimentary communities may supply dissolved electron donors and nutrients to the underlying crustal biosphere.
Use of Logic Relationships to Decipher Protein Network Organization
Authors: Bowers Peter M. , Cokus Shawn J. , Eisenberg David , Yeates Todd O.
Published: December 2004

A major focus of genome research is to decipher the networks of molecular interactions that underlie cellular function. We describe a computational approach for identifying detailed relationships between proteins on the basis of genomic data. Logic analysis of phylogenetic profiles identifies triplets of proteins whose presence or absence obey certain logic relationships. For example, protein C may be present in a genome only if proteins A and B are both present. The method reveals many previously unidentified higher order relationships. These relationships illustrate the complexities that arise in cellular networks because of branching and alternate pathways, and they also facilitate assignment of cellular functions to uncharacterized proteins.
ß-Arrestin 2 Regulates Zebrafish Development Through the Hedgehog Signaling Pathway
Authors: Wilbanks Alyson M. , Fralish Gregory B. , Kirby Margaret L. , Barak Larry S. , Li Yin-Xiong , Caron Marc G.
Published: December 2004

β-arrestins are multifunctional proteins that act as scaffolds and transducers of intracellular signals from heptahelical transmembrane-spanning receptors (7TMR). Hedgehog (Hh) signaling, which uses the putative 7TMR, Smoothened, is established as a fundamental pathway in development, and unregulated Hh signaling is associated with certain malignancies. Here, we show that the functional knockdown of β-arrestin 2 in zebrafish embryos recapitulates the many phenotypes of Hh pathway mutants. Expression of wild-type β-arrestin 2, or constitutive activation of the Hh pathway downstream of Smoothened, rescues the phenotypes caused by β-arrestin 2 deficiency. These results suggest that a functional interaction between β-arrestin 2 and Smoothened may be critical to regulate Hh signaling in zebrafish development.
Cumulative Sperm Whale Bone Damage and the Bends
Authors: Moore Michael J. , Early Greg A.
Published: December 2004

Diving mosasaurs, plesiosaurs, and humans develop dysbaric osteonecrosis from end-artery nitrogen embolism ("the bends") in certain bones. Sixteen sperm whales from calves to large adults showed a size-related development of osteonecrosis in chevron and rib bone articulations, deltoid crests, and nasal bones. Occurrence in animals from the Pacific and Atlantic oceans over 111 years made a pathophysiological diagnosis of dysbarism most likely. Decompression avoidance therefore may constrain diving behavior. This suggests why some deep-diving mammals show periodic shallow-depth activity and why gas emboli are found in animals driven to surface precipitously by acoustic stressors such as mid-frequency sonar systems.
Reduced Competition and Altered Feeding Behavior Among Marine Snails After a Mass Extinction
Authors: Dietl Gregory P. , Herbert Gregory S. , Vermeij Geerat J.
Published: December 2004

Extinction may alter competitive interactions among surviving species, affecting their subsequent recovery and evolution, but these processes remain poorly understood. Analysis of predation traces produced by shell-drilling muricid snails on bivalve prey reveals that species interactions were substantially different before and after a Plio-Pleistocene mass extinction in the western Atlantic. Muricids edge- and wall-drilled their prey in the Pliocene, but Pleistocene and Recent snails attacked prey only through the shell wall. Experiments with living animals suggest that intense competition induces muricid snails to attack shell edges. Pliocene predators, therefore, probably competed for resources more intensely than their post-extinction counterparts.
POLARIZATION OBSERVABLES OF THE γd→πNN REACTION IN THE Δ(1232)-RESONANCE REGION
Authors: DARWISH EED M.
Published: December 2004

Polarization observables of the three charge states of the pion for the γd→π NN reaction with polarized photon beam and/or oriented deuteron target are evaluated over the whole Δ(1232)-resonance region adopting a nonrelativistic model based on time-ordered perturbation theory. Results for the π-meson spectra, linear photon asymmetry, vector and tensor target asymmetries are presented. Particular attention is given, for the first time, to double polarization asymmetries for which we present results for [Formula: see text] and [Formula: see text]. We find that all other double polarization asymmetries of photon and deuteron targets vanish.
PROJECTION OPERATOR TREATMENT FOR SUB-COULOMB WIDTHS
Authors: KHAN SOHAIL A.
Published: December 2004

An exact expression using the projection operator method to extract widths and spectroscopic factors is derived. It is applied to sub-Coulomb resonances as they occur in α-decay. A number of α-decaying nuclei are investigated. The widths and spectroscopic factors extracted using the proposed expression are found to be in excellent agreement with those obtained by other methods. Earlier equations of the projection operator for widths and spectroscopic factors would give unrealistic results in this region.
DEFORMATION PROJECTED RMF CALCULATION FOR Cr AND Fe NUCLEI IN THE HYBRID DERIVATIVE COUPLING MODEL
Authors: MITRA PARNA , GANGOPADHYAY G.
Published: December 2004

The ground state properties of even mass Cr and Fe isotopes are studied using the generalized hybrid derivative coupling model. The energy surface of each isotope is plotted as a function of the mass quadrupole moment. The neutron numbers N=20 and N=40 are seen to remain magic numbers but N=28 and 50 are predicted to be non-magic. The neutron number N=70 turns out to be a magic number according to the present calculation. In all the isotopes studied the calculated binding energy values are less than those obtained from experiment while the deformation is in better agreement.
PRODUCTION OF LIGHT ANTINUCLEI IN HEAVY-ION COLLISIONS
Authors: IOFFE B. L. , SHUSHPANOV I. A. , ZYABLYUK K. N.
Published: December 2004

The antideuteron and antihelium-3 production rates in high-energy heavy-ion collisions are calculated in the framework of fusion mechanism. It is supposed that [Formula: see text] participating in the fusion are moving in the mean field of other fireball constituents. It is demonstrated that at high energies, where many pions are present in the fireball, the number of produced [Formula: see text] and [Formula: see text] is determined by the balance between created and disintegrated (mainly in collisions with pions) [Formula: see text] and [Formula: see text]. The explicit formulae for coalescence parameters are presented and compared with the data.
EIKONAL PHENOMENOLOGY FOR HEAVY-ION SCATTERING AT INTERMEDIATE ENERGIES
Authors: AHMAD I. , ALVI M. A.
Published: December 2004

Working within the framework of the Coulomb modified Glauber model and the optical limit approximation, we propose a phenomenological method of analysis for heavy-ion elastic scattering data at intermediate energies. Instead of using the commonly employed Gaussian approximation for the input NN amplitude that is deficient in some respects at low intermediate energies, we evaluate it in terms of a three parameter phenomenological NN phase shift function. The application of the method to some 12 C -nucleus and 16 O -nucleus systems shows that a very good description of the elastic scattering data at several energies can be obtained in this way. In particular, the 12 C –12 C elastic scattering data at 200 MeV/nucleon is very well reproduced. We also calculate the effective NN potential using the phenomenological NN phase shift function by the method of inversion. The calculated potential shows the expected behavior and is found to vary smoothly with energy.
Hydrothermal Synthesis of Single-crystal β-AgVO3 Nanowires and Ribbon-like Nanowires
Authors: Liu Yi , Zhang Yuanguang , Hu Yonghua , Qian Yitai
Published: December 2004

This paper describes for the first time a routine hydrothermal approach to the large-scale synthesis of one-dimensional (1-D) monoclinic β-AgVO3 nanowires and ribbon-like nanowires. The whole process was actualized without the aid of any templates or surfactants. Some factors that affect the shape of 1-D β-AgVO3 nanomaterials were briefly discussed.
Designing a New Kind of Capsule Catalyst and Its Application for Direct Synthesis of Middle Isoparaffins from Synthesis Gas
Authors: He Jingjiang , Xu Bolian , Yoneyama Yoshiharu , Nishiyama Norikazu , Tsubaki Noritatsu
Published: December 2004

A catalyst in the form of capsule catalyst was prepared by coating HZSM5 membrane on a preshaped Co/SiO2 catalyst pellet. The capsule catalyst with HZSM5 membrane exhibited excellent selectivity for light hydrocarbon synthesis, especially for isoparaffin synthesis from syngas (CO + H2). Long chain hydrocarbon formation was totally suppressed by the zeolite membrane. The modification of membrane and core catalyst significantly improved the catalytic properties of these new kinds of capsule catalysts.
Facile Preparation of Helical Ladder-type Polymers with Fused Phenoxathiine Rings
Authors: Iwasaki Tomokazu , Tsukahara Yoshiaki , Nishide Hiroyuki
Published: December 2004

Poly(3-chiral methylsulfinyl-1,2-phenyleneoxide) was synthesized, and the regioselective intramolecular ring-closing of the pendant sulfoxide on the polymer formed the corresponding helical ladder structure comprising of a fused phenoxathiine ring. The CD of the ladder polymer gave a Cotton effect which was caused by the chirality of the pendant group.
Die Chemie des Zellulären Strahlentodes
Authors: Schulte‐Frohlinde Dietrich
Published: December 2004

Auf der Grundlage der Chemie der Desoxyribonucleinsäure (DNA) in wäßriger Lösung und auf der Basis physikalisch‐biologischer Untersuchungen an lebenden Zellen kann heute ein Bild von den chemischen Reaktionen in der Zelle entworfen werden, die nach der Einwirkung energiereicher Strahlung ablaufen und zur Zelldeaktivierung (zum Zelltod) führen können. Weniger wissen wir über die chemischen Vorgänge bei der Entstehung von Mutationen und von Krebs. Ein weiteres Fortschreiten auf dem hier beschriebenen Weg sollte aber auch diese brennenden Fragen einer Antwort näher bringen.
Parfüme, Salben und Schminken im Altertum
Authors: Pászthory Emmerich
Published: December 2004

„Ein Schüttopfer spendete ich auf dem Gipfel des Berges:

Sieben und abermals sieben Räuchergefäße stellte ich hin, in ihre Schalen schüttete ich Süßrohr,Zedernholz und Myrte

Die Götter rochen den wohlgefälligen Duft,

Die Götter scharten wie Fliegn sich um die Opferer.”︁.
Schweinfurter Grün – das brillante Gift
Authors: Andreas Holger
Published: December 2004

Die Geschichte des Schweinfurter Grüns hat gezeigt, wie lange es dauerte, bis man die biochemischen Ursachen zunächst nicht erklärbarer Krankheiten erkannte. Man muß dabei bedenken, daß die organischen Arsenverbindungen erheblich giftiger sind als Arsenik (Arsentrioxid) und deshalb schon in wesentlich geringerer Konzentration wirksam sind. So konnten Erkrankungen in Wohnräumen auftreten, auch wenn mit den damaligen analytischen Mitteln Arsen in der Zimmerluft nicht immer nachgewiesen werden konnte. Auch Leiß sich die Bildung gasförmiger Arsenverbindungen in der Mitte des 19. Jahrhunderts chemisch nicht erklären und daher ein Zusammenhang zwischen den mit arsenhaltigen Farben gestrichenen oder tapezierten Wohnräumen und den Erkrankungen nicht herleiten, obwohl die medizinischen Befunde eindeutig dafür sprachen. Immerhin hat es 50 Jahre gedauert, bis man von den ersten Befunden zum endgültigen Verbot arsenhaltiger Pigmente für Tapeten und lnnenanstriche gelangte.
Gymnestrogenin, ein neues Pentahydroxytriterpen aus den Blättern von Gymnema sylvestre R. BR. Glykoside und Aglykone, 309. Mitteilung
Authors: Stöcklin W.
Published: December 2004

The structure of gymnestrogenin, a new triterpene from the leaves of Gymnema sylvestre R. Br. (Asclepiadaceae), is proposed to be that of 3β, 16β, 21β, 23, 28‐pentahydroxy‐olean‐12‐ene.
Stoffwechselprodukte von Mikroorganismen. 67. Mitteilung [1]. Die Struktur des Granaticins und des Granaticins B. 2. Teil: Die Kristallstruktur des Tri‐O‐acetyl‐O‐jodacetyl‐granaticins
Authors: Brufani M. , Dobler M.
Published: December 2004

The crystal structure of tri‐O‐acetyl‐O‐iodoacetyl‐granaticin has been determined by X‐ray analysis of threedimensional diffractometer intensity data. The crystals are orthorhombic, a = 17.85, b = 14.90, c = 11.26 Å, Z = 4, space group P212121. The molecular structure was established by the heavy atom method and refined by full‐matrix least‐squares analysis. The molecular constitution and configuration is given by formula II. The chirality was determined by the use of anomalous dispersion effects.
Stoffwechselprodukte von Mikroorganismen. 69. Mitteilung [1]. Über das Venturicidin B, das Botrycidin und die Zuckerbausteine der Venturicidine A und B
Authors: Brufani M. , Keller‐Schierlein W. , Löffler W. , Mansperger I. , Zähner H.
Published: December 2004

The known antibiotic Venturicidin A and two new antifungal compounds, Venturicidin B and Botrycidin, have been isolated from a strain of Streptomyces aureofaciens DUGGAR. Venturicidin B gave on methanolysis the methyl glycoside of 2‐deoxy‐D‐rhamnose, Venturicidin A the corresponding 3‐O‐carbamate.
CdO auf Cadmiumanoden in Alkalihydroxidlösungen??
Authors: Huber K. , Stucki S.
Published: December 2004

Anodic films formed potentiostatically in 1M NaOH on Cadmium electrodes were examined by means of electron diffraction under carefully controlled conditions. Glancing incidence electron diffraction indicates the presence of Cd(OH)2 on the electrolyte side of the film and of CdO on the metal side. Transmission electron diffraction of thin isolated films indicates only Cd(OH)2 in films formed below the Flade‐potential of the CdO electrode, but CdO along with Cd(OH)2 above the Flade‐potential. In these films selected area diffraction reveals spots consisting exclusively of a very thin oxid layer.
Epoxide von Cardenoliden und Cardenolidglykosiden Partialsynthetische Versuche in der Reihe der Herzgifte. 1. Mitteilung
Authors: Sawlewicz Ludwika , Linde Horst H. A. , Meyer Kuno
Published: December 2004

Die Partialsynthese der isomeren 4,5‐Epoxide des Canarigenins, des 3‐O‐[β‐D‐Digitoxopyranosido]‐4,5α‐epoxy‐canarigenins sowie der isomeren 14,15‐Epoxide des 14‐Anhydrodigitoxins und des 14,15β‐Epoxids des 14‐Anhydrodigoxins werden beschrieben.
Isolierung und Strukturaufklärung von Ovalicin
Authors: Sigg H. P. , Weber H. P.
Published: December 2004

The structure of ovalicin, a metabolite of the fungus Pseudeurotium ovalis with immunosuppressive activity, has been determined to be 11.
Eine neue Version der Epoxyketon → Alkinon‐Fragmentierung: Thermischer Zerfall der Hydrazone aus α,β‐Epoxycarbonyl‐verbindungen und N‐Amino‐aziridinen. Vorläufige Mitteilung
Authors: Felix Dorothee , Schreiber J. , Piers K. , Horn U. , Eschenmoser A.
Published: December 2004

A new version of the epoxyketone → alkynone fragmentation is described. Hydrazones derived from cyclic α,β‐epoxy‐ketones and N‐amino‐aziridines decompose thermally into molecular nitrogen, an olefinic fragment and an acetylenic carbonyl compound (compare scheme 1). The reaction of phenylglyoxal with N‐amino‐phenyl‐aziridine at room temperature produces styrene and diazo‐acetophenone in high yield (compare scheme 3).