bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress and image-placement distortions of 200mm low-energy electron projection lithography masks
Authors: Eguchi H. , Susa T. , Sumida T. , Kurosu T. , Yoshii T. , Yotsui K. , Itoh K. , Tamura A. , Engelstad R. L. , Lovell E. G. , Azkorra X. , Mikkelson A. , Chang J. , Janowski S. M.
Published: December 2004

Low-energy electron projection lithography (LEEPL) is a candidate for next generation lithography and thus the 1× LEEPL mask requires a stringent local image placement (IP) error budget. Applying a doping method with silicon-on-insulator substrates, 700-nm-thick membranes were investigated for stress control and in-plane distortion (IPD), which are the main contributors to local IP errors. Stress control results show that at a dopant concentration of 6.74×1019∕cm3, the membrane stress in a 10mm test structure is 8.4MPa. Also stress variation is excellent at 0.3MPa across a 200mm complementary stencil mask on support strut-type LEEPL mask. The IPD results indicate that small membrane window size, low void fraction, as well as low membrane stress is the proper strategy to allow a stencil mask with dense stencil patterns to meet required IPD. Additionally, the local IP errors of large scale integrated 90nm hole pattern were demonstrated.
Towards intersubband quantum box lasers: Electron-beam lithography update
Authors: Tsvid G. , D’Souza M. , Botez D. , Hawkins B. , Khandekar A. , Kuech T. , Zory P.
Published: December 2004

We report on the progress in the patterning and fabrication of the intersubband quantum-box (QB) laser structure. From a patterning point of view our goal is to make 30-nm-diameter SiO2 and/or hydrogen silsesquioxane (HSQ) disks on 60–80nm centers on a GaAs surface to serve as masks for in situ etch and regrowth of QBs. Electron-beam lithography with high-resolution negative resist HSQ was used, and two processes have been investigated. The first process is to pattern HSQ directly on the GaAs surface, while the second one involves putting down an intermediate oxide layer first, followed by the e-beam lithography and the transfer of the pattern into the oxide. Problems were encountered with the e-beam patterning of HSQ directly on the GaAs surface because of the broad scattering from the substrate and not very good adhesion. Excellent patterning was demonstrated when the intermediate oxide layer was present between the GaAs substrate and the HSQ resist.
Fabrication of autocloned photonic crystals by using high-density-plasma chemical vapor deposition
Authors: Chen H. L. , Lee H. F. , Chao W. C. , Hsieh C. I. , Ko F. H. , Chu T. C.
Published: December 2004

The high-density-plasma chemical vapor deposition (HDP-CVD) method was demonstrated as an alternative to radio-frequency (rf) bias sputtering method for fabrication of “autocloned” photonic crystals. We successfully preserved periodic surface corrugation after deposition of multilayer stacks under appropriate chemical vapor deposition conditions. Freedom of the shaping process was increased by simply raising the bias power of the autocloning process, and thus created autocloned structures having a strong modulation of the effective refractive index in the lateral direction. The method allows photonic bands of autocloned photonic crystals to be designed with greater controllability and a simpler fabrication process. Furthermore, the HDP-CVD method has better step-coverage than the sputtering method and can be used to fabricate autocloning structures with small feature-sizes.
Patterning via surface monolayer initiated polymerization: A study of surface initiator photoreaction kinetics
Authors: McCoy Kendra , Hess Dennis W. , Henderson Clifford L. , Tolbert Laren M.
Published: December 2004

Surface monolayer initiated polymerization (SMIP) is a potential method for achieving high resolution patterning of surfaces and materials that could be used as an alternative to conventional lithographic methods based on photoresist thin films. This article reports on the photochemical kinetic rate constants of two candidate azo-type surface bound photoradical initiator molecules. X-ray photoelectron spectroscopy was utilized to monitor the relative concentration of azo initiator on a silicon surface as a function of exposure dose to 248nm radiation. This photochemical decomposition data showed that the photoreaction for both initiators followed first order kinetics with photoreaction rate constants in the range of 4.5×10−3cm2∕mJ to 9.7×10−3cm2∕mJ. The difference in the observed rate constants for the two azo initiators was attributed primarily to differences in their quantum efficiencies. These differences in quantum efficiency were attributed to the size of the nontethered fragment that would be produced from the initiator, with larger fragments producing slower photochemical decomposition kinetics. Thus, photoradical initiators with small non-surface bound fragments are desirable in terms of increasing the photosensitivity of such SMIP processes. For successful positive tone imaging using a SMIP process with photoradical initiators, it was estimated that approximately 99% of the monolayer must be decomposed in order to produce images in the resulting polymer layers. Using this information in conjunction with the photochemical reaction rate constants for the azo initiators, exposure doses on the order of 400mJ∕cm2 and larger would be required for the present initiators.
Miniaturized finger-size electron-beam column with ceramic-type lenses for scanning electron microscopy
Authors: Miyoshi M. , Okumura K. , Awata S. , Okada Y. , Maeda T. , Yamaguchi H. , Amano S.
Published: December 2004

A miniaturized electron-beam column has been developed for portable scanning electron microscope, which has greatly reduced size and weight compared with those of conventional electron-beam column, in order to satisfy the demands of new applications in surface analysis, inspection and metrology, electrical testing. For column miniaturization and high precision lens fabrication, we have constructed a ceramic lens integrated column system, in which all of the electro-optical elements are integrated in one ceramics body. In this trial production, we use a newly developed alumina-based high resistive conductive ceramics for the optimization of this electro-static lens operation. All the lens electrodes are metalized and patterned on the inner surface of the cylindrical high resistivity conductive ceramic whose volume resistivity is 1010Ωcm. As the ceramic lens integrated column used here integrates all the lens electrodes and manufactured in a consecutive process, the mechanical alignment error can be reduced, resulting in the concentricity of 0.7 μm, in whole column fabrication. The initial images demonstrate the basic operation of the ceramic lens integrated column system.
Optimizing the fluid dispensing process for immersion lithography
Authors: Abdo A. , Nellis G. , Wei A. , El-Morsi M. , Engelstad R. , Brueck S. R. J. , Neumann A.
Published: December 2004

The concept behind immersion lithography is the insertion of a high refractive index liquid in the space between the final projection lens of an exposure system and the device wafer to improve the overall resolution of the exposure process. Computational fluid dynamics (CFD) simulations were performed in order to investigate the process of initially filling the lens-wafer gap with immersion fluid. The CFD models were used to investigate the effects of dispense velocity, gap height, and fluid dispense angle on the fill process; specifically on the possibility of air entrainment. The simulations revealed that there is an optimal region in the parameter space of gap height and dispense velocity for which the gap fills completely. Outside of this region, either excessive inertial or surface tension forces cause an undesirable, incomplete filling process. The optimal region was found to shift somewhat based on the fluid dispense angle. Finally, experiments were performed to verify the CFD models. The CFD simulations and the experimental results were in good agreement, both qualitatively with regard to the shape and evolution of the free surface and quantitatively with regard to the velocity of the contact line.
Biological lithography: Improvements in DNA synthesis methods
Authors: Kim C. , Li M. , Rodesch M. , Lowe A. , Richmond K. , Cerrina F.
Published: December 2004

We have recently succeeded in synthesizing long oligonucleotides (90-mers) with high yield. This synthesis requires 360 virtual masks, and thus puts challenges on image placement and local contrast. We have updated our DNA synthesis modeling to Monte Carlo simulation from numerical approach. We also devised a method, called “Inverted Capping,” to remove sequence errors from edge scattering of light, which provides a large error reduction and the possibility of fabrication of higher resolutions. Finally, we have also implemented an image locking method to eliminate image drifts.
Structure quality of high aspect ratio sub-micron polymer structures patterned at the electron storage ring ANKA
Authors: Achenbach S. , Mappes T. , Mohr J.
Published: December 2004

We describe the fabrication of polymer structures with lateral dimensions in the sub-micron regime using hard x rays (λ≈0.4nm) from the electron storage ring ANKA. PMMA and Novolak resists have been analyzed with respect to development rates and contrast. Films with a thickness from 2μmto11μm have been patterned using a high resolution x-ray mask consisting of 2μm thick gold absorbers on a suspended silicon nitride membrane. The fabrication of those sub-micron x-ray lithography structures is confined by the mask absorber sizes of down to 400nm and by the process conditions. The yield of resist structures with aspect ratios of 9 and above is limited by bending of the structures. An intermediate buffer layer of polyimide enhances the resist adhesion and reduces cracking in the microstructures. Diffraction at mask absorber edges biases the resist feature size on the order of tens of nanometers. It may also result in surface attack of periodic resist structures if the proximity gap between mask and resist chosen is too high. Resist surfaces are subject to rounding which can locally diminish the sidewall verticality. PMMA structures have been successfully used as a template for electroplating of 1μm thick gold to demonstrate the fabrication capability of sub-micron scale metal parts.
Imaging capabilities of resist in deep ultraviolet liquid immersion interferometric lithography
Authors: Raub Alex K. , Frauenglass A. , Brueck S. R. J. , Conley Will , Dammel Ralph , Romano Andy , Sato Mitsuru , Hinsberg William
Published: December 2004

Liquid immersion lithography (LIL) extends the resolution of optical lithography to meet industry demands into the next decade. Through the use of exposure media such as purified water (n of 1.44 at 193nm), it is possible to reduce minimum pitches compared with traditional air/vacuum exposures media by a factor of as much as 44%—a full technology node. Beyond this simple observation, there is a good deal of work necessary to fully understand the impact of LIL immersion lithography on a lithography processes. This article addresses the impact of water immersion on the imaging capabilities of different resist formulations. All resists were evaluated by imaging dense line-space structures at a 65-nm half-pitch both in air and with water immersion. Studies of dense 65-nm lines made by immersion imaging in HPLC grade water with controlled variations in resist components were performed. Significant differences were observed and will be discussed.
Controlling imprint distortions in step-and-flash imprint lithography
Authors: Schuetter S. D. , Dicks G. A. , Nellis G. F. , Engelstad R. L. , Lovell E. G.
Published: December 2004

Step-and-Flash Imprint Lithography (S-FIL™) is a one-to-one imprinting process in which features are transferred from a template by lowering it onto a low-viscosity, photocurable, monomer solution that conforms to the template surface and is subsequently cured. The potential exists for both low cost and high throughput, making S-FIL a promising candidate for Next-Generation Lithography. However, there are many challenges that must be overcome in order to ensure the future viability of S-FIL. Mechanical distortion control is one of the principal challenges, and is addressed in this article. During the imprinting process, the viscous flow of the monomer liquid causes a significant pressure elevation within the fluid as it is forced to flow outwards through a small gap. These pressures cause out-of-plane distortions and in-plane distortions (OPD and IPD) of the template, which may be manifested as errors in the replicated pattern. A fluid-structure model was developed to predict the template distortion associated with the imprinting process. The model consists of two parts. The Reynolds Equation Module (REM) is a two-dimensional finite-difference model that solves the Reynolds equation, which describes the laminar flow of an incompressible constant-viscosity fluid through a small gap. The pressure distribution predicted by the REM is applied as a structural load, together with vacuum chucking and gravity, to a finite-element model of the template developed using ANSYS®. This model, called the Structural Distortion Model, calculates the resulting OPD and IPD of the template. The process is iterated in time for a continually decreasing gap height that corresponds to lowering the template. This article presents the details of the fluid-structure model, the results of the analysis at nominal conditions, and a parametric study of the effects of the operating conditions and fluid properties on the template distortion.
Predicting the fluid behavior during the dispensing process for step-and-flash imprint lithography
Authors: Abdo A. , Schuetter S. , Nellis G. , Wei A. , Engelstad R. , Truskett V.
Published: December 2004

In this article, the polymer dispense process in the step-and-flash imprint lithography is investigated with computational fluid dynamics (CFD) models. The dispense process is a function of the fluid properties and the system parameters such as the geometry and the details of the actuation motion. Physical arguments show that this functional dependence can be reduced to two dimensionless numbers: the Weber number which represents the ratio of inertia to surface tension forces, and the capillary number which represents the ratio of viscous to surface tension forces. A parametric study showed that there is a clear optimal regime for the dispensing process in which a single, clearly-defined drop forms. The CFD model was verified experimentally by comparing the predicted fluid dispense behavior with photographs of a dispense process.
Compliant pin chuck for minimizing the effect of backside particles on wafer planarity
Authors: Nimmakayala Pawan Kumar , Sreenivasan S. V.
Published: December 2004

A wafer chuck referred to as the compliant pin chuck (CPC) that can minimize the nonplanarity effect of backside particles on semiconductor wafers is presented in this article. The demand for flatter semiconductor substrates has been increasing as the size of the features that can be transferred onto a wafer surface becomes smaller. There are a number of factors affecting wafer planarity, most of which can be corrected by conventional wafer chucks. However, the problem of backside particles (particles affect a large portion of wafer real estate by causing out-of-plane distortion when they get lodged between a wafer and a wafer chuck) has not been adequately addressed by the current wafer chuck technology. The compliant pin chuck was designed to address this concern and fabricated from silicon using lithography based microfabrication techniques. The chuck consists of an array of microflexure mechanisms that react to the presence of backside particles so as to minimize the nonplanarity caused otherwise. It is also shown through experimental results that the fabricated chuck has a planarity of 120nm (standard deviation −3σ) over an area of 30mm×30mm and is less sensitive to backside particles than a conventional wafer chuck.
Three-dimensional simulation of top down scanning electron microscopy images
Authors: Grella Luca , Lorusso Gian , Lee Paul , Frank Fan , Adler David L.
Published: December 2004

Low voltage scanning electron microscopy (SEM) metrology and inspection are performed by immersing the sample in an electric field; under this condition, when a scanning electron beam images a sample containing insulating features (like oxides and resist), a surface global charge builds up to offset the applied field and a transverse local field will form as a result of the scanning beam. The surface global charge is responsible for the voltage contrast and imaging properties, while local fields degrade image resolution. In this article we describe a simulation approach able to explain the imaging properties of charged surfaces and how resolution is affected by local fields. Using electron ray tracing in the column, the simulation follows both the emitted and primary electron trajectories outside the sample. In addition, Monte Carlo scattering simulation calculates the electron trajectory and charge deposition inside the sample. The resulting charge density is used to calculate the field inside and outside the sample by solving the Poisson equation with the proper boundary conditions. Ray tracing, Monte Carlo scattering simulation; and field equation are then integrated in a self-consistent fashion to form a simulation algorithm capable of explaining SEM imaging and charging. The simulation is applied to a variety of cases regarding both inspection and metrology. The results are compared with experiments. Furthermore a method to calculate surface charging will be given for both insulating surfaces and patterned insulating surfaces on a grounded substrate.
Thermal analysis of diamondlike carbon membrane masks in projection electron-beam lithography
Authors: Babin S. , Butomo V. , Kuzmin I. Yu. , Yamashita H. , Yamabe M.
Published: December 2004

Diamondlike carbon (DLC) membrane masks for high-throughput projection electron-beam lithography have an important advantage over stencil masks: a single mask can be used to print donut-shaped patterns. At a membrane thickness on the order of a few tens of nanometers, thermal problems could occur. The temperature rise of a membrane mask was simulated with various exposure parameters. Membrane and scatterer thickness, resist sensitivity, and pattern coverage were varied. It was found that global temperature rise after exposure of a chip is on the order of 0.005 °C, while temperature rise in a membrane area under exposure reaches 2.54 °C. Simulation results were compared to those on a silicon stencil mask. It was found that the global heating is less on a DLC membrane mask.
Nanoflash device with self-aligned double floating gates using scanning probe lithography and tetramethylammonium hydroxide wet etching
Authors: Sheu J. T. , Chen C. C. , You K. S. , Tsai S. T.
Published: December 2004

We report a self-aligned technology for nanoflash devices with double floating gates using scanning probe lithography (SPL) technology and anisotropic wet etching. On a (110) SOI silicon wafer, along [001] and [111] directions, a silicon nanowire was generated through local oxidation with SPL followed by wet etching with tetramethylammonium hydroxide solution. Silicon nanowires (SiNW) with profiles of sidewall either sloped or vertical were formed after anisotropic etching in the [001] or [111] direction respectively. After deposition of a polysilicon film on the SiNW with low pressure chemical vapor deposition, nanostructures of a nanoflash device with polysilicon double-floating side gates were obtained along the [111] part of SiNW after reactive ion etching spacer etching. The silicon nanowire channel has a width of 20 nm and a height of 200 nm; the width of the self-aligned floating gate is approximately 40 nm. Silicon nitride was deposited to serve as gate dielectric. The top gate and source-drain aluminum pads were defined by photolithography. Electrical properties of such a nanoflash device with double-floating side gates are discussed.
Nanomechanical switch fabrication by focused-ion-beam chemical vapor deposition
Authors: Morita Takahiko , Nakamatsu Ken-ichiro , Kanda Kazuhiro , Haruyama Yuichi , Kondo Kazushige , Hoshino Takayuki , Kaito Takashi , Fujita Jun-ichi , Ichihashi Toshinari , Ishida Masahiko , Ochiai Yukinori , Tajima Tsutomu , Matsui Shinji
Published: December 2004

Focused-ion-beam chemical vapor deposition (FIB-CVD) is an excellent technology to form three-dimensional nanostructures. Various three-dimensional nanostructures such as an inductance, a capacitor, a resistance, and a filter-circuit have been demonstrated by applying FIB-CVD with phenanthrene (C14H10) source gas using a computer-controlled pattern generator (CPG). The electrical resistivity measurement of the free-space-nanowiring was carried out by two terminal electrode method. The resistivity was 1×102Ωcm in the case of using C14H10. To reduce the electrical resistivity, tungsten hexacarbonyl [W(CO)6] is added to C14H10 as a source gas. Increasing content of W(CO)6, the electrical resistivity becomes lower from 1×102to2×10−2Ωcm at room temperature. By using free-space-nanowiring fabrication technology, the world smallest nanomechanical switch composed of a coil and a nanowiring has been fabricated and confirmed the switching operation by applying a voltage.
Reaching for the bottom: The evolution of EIPBN
Authors: Smith Henry I. , Pease R. Fabian
Published: December 2004

The International Conference on Electron, Ion, and Photon Beam Technology and Nanofabrication (EIPBN) had its origins 45years ago in electron-beam welding, but the focus soon shifted to microfabrication techniques. Since the early 1960’s, EIPBN has been the premier conference for reporting innovations in micro- and nanofabrication techniques, with a consistent goal of pushing to finer features and practical applications in research and industry. The conference name has evolved to reflect the changes in technology. With the exception of a few years, when some of the conferences were managed by the Electrochemical Society, the conference has been run by volunteers who are also active researchers. This has been one of its strengths, ensuring annual renewal of objectives and directions. In this article we identify some highlights in the history of EIPBN and suggest a direction for the conference in this era of nanotechnology.
Seismological Constraints on Core Composition from Fe-O-S Liquid Immiscibility
Authors: Helffrich George , Kaneshima Satoshi
Published: December 2004

Earth's core is composed primarily of iron (Fe) with about 10% by weight of lighter elements. The lighter elements are progressively enriched in the liquid outer core as the core cools and the inner core crystallizes. Thermodynamic modeling of Fe-O-S liquids shows that immiscible liquids can exist at outer-core pressures (136 to 330 gigapascals) at temperatures below 5200 kelvin and lead to layering in the outer core if the concentrations of the lighter elements are high enough. We found no evidence for layering in the outer core in the travel times and wave forms of
P
4
KP
seismic waves that reflect internally in the core. The absence of layers therefore constrains outer-core compositions in the Fe-O-S system to be no richer than 6 ± 1 weight % (wt %) O and 2 to 15 wt % S. A single core liquid composition of 10.5 ± 3.5 wt % S and 1.5 ± 1.5 wt % O is compatible with wave speeds and densities throughout the outer core.
Toward a Systems Approach to Understanding Plant Cell Walls
Authors: Somerville Chris , Bauer Stefan , Brininstool Ginger , Facette Michelle , Hamann Thorsten , Milne Jennifer , Osborne Erin , Paredez Alex , Persson Staffan , Raab Ted , Vorwerk Sonja , Youngs Heather
Published: December 2004

One of the defining features of plants is a body plan based on the physical properties of cell walls. Structural analyses of the polysaccharide components, combined with high-resolution imaging, have provided the basis for much of the current understanding of cell walls. The application of genetic methods has begun to provide new insights into how walls are made, how they are controlled, and how they function. However, progress in integrating biophysical, developmental, and genetic information into a useful model will require a system-based approach.
Role of the Kinase MST2 in Suppression of Apoptosis by the Proto-Oncogene Product Raf-1
Authors: O'Neill Eric , Rushworth Linda , Baccarini Manuela , Kolch Walter
Published: December 2004

The ablation of the protein kinase Raf-1 renders cells hypersensitive to apoptosis despite normal regulation of extracellular signal–regulated kinases, which suggests that apoptosis protection is mediated by a distinct pathway. We used proteomic analysis of Raf-1 signaling complexes to show that Raf-1 counteracts apoptosis by suppressing the activation of mammalian sterile 20–like kinase (MST2). Raf-1 prevents dimerization and phosphorylation of the activation loop of MST2 independently of its protein kinase activity. Depletion of MST2 from Raf-1
–/–
mouse or human cells abrogated sensitivity to apoptosis, whereas overexpression of MST2 induced apoptosis. Conversely, depletion of Raf-1 from Raf-1
+/+
mouse or human cells led to MST2 activation and apoptosis. The concomitant depletion of both Raf-1 and MST2 prevented apoptosis.
Reproductive Effort, Molting Latitude, and Feather Color in a Migratory Songbird
Authors: Norris D. Ryan , Marra Peter P. , Montgomerie Robert , Kyser T. Kurt , Ratcliffe Laurene M.
Published: December 2004

Toward the end of the breeding season, migratory songbirds face crucial tradeoffs between the timing of reproduction, molt, and migration. Using stable hydrogen isotopes, we show that male American redstarts investing in high levels of reproduction late in the season adopt a unique strategy of combining molt and migration. Tail feathers molted during migration also reflect less orange-red light, indicating reduced carotenoid concentration. Thus, we show how reproduction in a migratory animal can influence both life history strategies (location of molt) and social signals (feather color) during subsequent periods of the annual cycle.
First-Principles Theory for the H + CH
4
→ H
2
+ CH
3
Reaction
Authors: Wu Tao , Werner Hans-Joachim , Manthe Uwe
Published: December 2004

A full-dimensional quantum dynamics simulation of a hydrogen atom reacting with methane on an accurate ab initio potential energy surface is reported. Based on first-principles theory, thermal rate constants are predicted with an accuracy comparable to (or even exceeding) experimental precision. The theoretical prediction is within the range of the significantly varied experimental rate constants reported by different groups. This level of accuracy has previously been achieved only for smaller, three-or four-atom reactive systems. Comparison with classical transition state theory confirms the importance of quantum mechanical tunneling for the rate constant below 400 kelvin.
Mouse Brain Organization Revealed Through Direct Genome-Scale TF Expression Analysis
Authors: Gray Paul A. , Fu Hui , Luo Ping , Zhao Qing , Yu Jing , Ferrari Annette , Tenzen Toyoaki , Yuk Dong-in , Tsung Eric F. , Cai Zhaohui , Alberta John A. , Cheng Le-ping , Liu Yang , Stenman Jan M. , Valerius M. Todd , Billings Nathan , Kim Haesun A. , Greenberg Michael E. , McMahon Andrew P. , Rowitch David H. , Stiles Charles D. , Ma Qiufu
Published: December 2004

In the developing brain, transcription factors (TFs) direct the formation of a diverse array of neurons and glia. We identifed 1445 putative TFs in the mouse genome. We used in situ hybridization to map the expression of over 1000 of these TFs and TF-coregulator genes in the brains of developing mice. We found that 349 of these genes showed restricted expression patterns that were adequate to describe the anatomical organization of the brain. We provide a comprehensive inventory of murine TFs and their expression patterns in a searchable brain atlas database.
Murder They Wrote
Authors: Posner Richard A.
Published: December 2004

A Cultural History of Causality
Science, Murder Novels, and Systems of Thought.
By Stephen Kern
. Princeton University Press, Princeton, NJ, 2004. 447 pp. $29.95, £18.95. ISBN 0-691-11523-0.

Through a consideration of the treatment of murder in novels, the author explores how our understanding of human behavior has changed since the early 19th century.
Dephosphorylation of the Calcium Pump Coupled to Counterion Occlusion
Authors: Olesen Claus , Sørensen Thomas Lykke-Møller , Nielsen Rikke Christina , Møller Jesper Vuust , Nissen Poul
Published: December 2004

P-type ATPases extract energy by hydrolysis of adenosine triphosphate (ATP) in two steps, formation and breakdown of a covalent phosphoenzyme intermediate. This process drives active transport and countertransport of the cation pumps. We have determined the crystal structure of rabbit sarcoplasmic reticulum Ca
2+
adenosine triphosphatase in complex with aluminum fluoride, which mimics the transition state of hydrolysis of the counterion-bound (protonated) phosphoenzyme. On the basis of structural analysis and biochemical data, we find this form to represent an occluded state of the proton counterions. Hydrolysis is catalyzed by the conserved Thr-Gly-Glu-Ser motif, and it exploits an associative nucleophilic reaction mechanism of the same type as phosphoryl transfer from ATP. On this basis, we propose a general mechanism of occluded transition states of Ca
2+
transport and H
+
countertransport coupled to phosphorylation and dephosphorylation, respectively.
Polymer Network Fabricated by Topochemical Polymerization of Self-assembly Films Composed of a Diacetylene Derivative
Authors: Sasada Kaori , Nishiwaki Yuko , Takeoka Yuko , Rikukawa Masahiro , Sanui Kohei
Published: December 2004

Well-ordered layered structures prepared by the self-assembly method using condensing agents better facilitate the γ-ray polymerization of diacetylene units.
Threonine Transformation under Hydrothermal Conditions
Authors: Shiota Dai , Nakashima Satoru
Published: December 2004

In order to revisit the kinetics of amino acid transformation in the chemical evolution, a series of hydrothermal experiments has been conducted for threonine (Thr) solution. Thr transformed into glycine (Gly) and other products including peptides and polymers at 121 to 160 °C. The Thr → Gly decomposition rate (k1) is different from apparent Thr decreasing rate (k), because of the presence of other side reactions.
Systematic Studies on Redox Behavior of Homonuclear Double-bond Compounds of Heavier Group 15 Elements
Authors: Sasamori Takahiro , Mieda Eiko , Nagahora Noriyoshi , Takeda Nobuhiro , Takagi Nozomi , Nagase Shigeru , Tokitoh Norihiro
Published: December 2004

Electrochemical properties of BbtE=EBbt (E = P, Sb, Bi; Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl) systems have been elucidated based on the measurement of cyclic voltammetry and DFT calculations.
Morphology-controllable Solution Route to PbSe Micrometer-scaled Crystals
Authors: Cui Jianhua , Guo Fan , Liu Xinzheng
Published: December 2004

Lead selenide micrometer-scaled crystals were synthesized via a simple morphology-controllable solution route with the reactions of lead nitrate and sodium selenosulfate in aq sodium hydroxide or ethylenediamine solution. Scanning electron microscopy images showed that cubic and spherical PbSe crystals were obtained by varying alkaline medium and Pb2+/SeSO32− molar ratio. The possible reaction mechanism is discussed.
Dissipative Strukturen fester Katalysatoren
Authors: Lintz Hans‐Günther
Published: December 2004

„Die Dynamik der Vorgänge in technischen Katalysatoren ist bestimmt durch das Zusammenwirken von chemischer Reaktion und Transportvorgängen in meist weiter Entfernung vom thermodynamischen Gleichgewicht. In solchen gleichgewichtsfernen Systemen können Phasen und Strukturen entstehen, die im Gleichgewicht und dessen Umgebung nicht erhalten bleiben und deren mögliche Vielfalt nahezu unbegrenzt ist.”︁

These von L. Riekert anläßlich des Ernest‐Solvay‐Kolloquiums 1986 “Reaktionsablauf an technischen Katalysatoren”.
SEXAFS und NEXAFS. Röntgen‐Absorptionsspektroskopie an Adsorbat‐bedeckten Oberflächen
Authors: Haase Jochen
Published: December 2004

Die Röntgen‐Absorptionsspektroskopie an Oberflächen ist eine Methode zur Bestimmung der lokalen Geometrie adsorbierter Atome und Moleküle und damit eine Methode der „Oberflächen‐Kristallographie”︁. Sie wurde erst durch den Bau leistungsfähiger Synchrotron‐Strahlungsquellen möglich, die ein intensives und über einen weiten Wellenlängenbereich kontinuierliches Strahlungs‐Spektrum liefern [1]. Zuvor wurde die Struktur von Adsorbat‐bedeckten Oberflächen hauptsächlich mit Hilfe der Beugung langsamer Elektronen (Low‐Energy Electron Diffraction, LEED) bestimmt. Die klassische Methode der Kristallstrukturanalyse, die Röntgenbeugung, die bei der Erforschung der atomaren Struktur der Materie so erfolgreich ist, hat für Oberflächenuntersuchungen nur begrenzten Wert.
Das Experiment: Abfallfreie Versuche zur Polymerchemie
Authors: Wiskamp Volker , Hörter Manfred , Köhler Bärbel , Nau Britta
Published: December 2004

Umweltschutzaspekte gewinnen in der Chemie zunehmend an Bedeutung. Daher muß es Ziel einer Chemieausbildung sein, bei den Studierenden möglichst früh ein Bewußtsein für die dringende Notwendigkeit des Umweltschutzes zu wecken.
Mehrfachbindungen zwischen schweren Hauptgruppenelementen?. Von der klassischen π‐Bindung zu strukturchemischem Neuland
Authors: Drieß Matthias
Published: December 2004

Gibt es Mehrfachbindungen unter Beteiligung von Schwefel, Phosphor, Arsen, Antimon, Silicium, Germanium, Zinn und Blei? Eine einfache Frage ‐ nur scheinbar! Um sie zu beantworten, muß der Begriff „Mehrfachbindung”︁ neu überdacht werden.
Chiuz aktuell
Authors: Karger Gerhard
Published: December 2004

Die Fachzeitschrift steckt in der Krise, so hört man allerorten. Stagnierende Budgets bei gleichzeitig steigenden Zeitschriftenpreisen führen dazu, daß so manche Bibliothek gezwungen ist, Abonnements zu kündigen. Das treibt im Gegenzug wiederum die Preise in die Höhe ‐‐ eine fatale Situation, die noch dadurch verschärft wird, daß wegen der immer stärker werdenden Spezialisierung und der Erschließung neuer Forschungsgebiete ein ständiger Zwang zur Gründung neuer Zeitschriften besteht. Mit dem Aufkommen immer leistungsfähigerer Computer und Netzwerke stellt sich nun die Frage: Welche Rolle können die neuen Medien bei der wissenschaftlichen Informationsvermittlung spielen, was wurde bereits erreicht, was ist noch Zukunftsmusik?
Microbore‐HPLC im Kriminallabor
Authors: Hagenmayer Anette , Schlipf Eberhard
Published: December 2004

Die Aufklärung einer versuchten Erpressung demonstriert den Einzug moderner Analysenverfahren in die Kriminalistik und gibt gleichzeitig einen Einblick in die von der Öffentlichkeit kaum wahrgenommene Arbeit der “Kriminalchemiker”.
Kinetik‐Simulationssoftware. Behandlung von kinetischen Gleichungen in Modellen von Polymerisationsreaktionen
Authors: Fresen Ira
Published: December 2004

Die Polymerchemie ist ein bedeutender Teilbereich der Technischen Chemie. Will man die Kinetik von Polymerisationsreaktionen ermitteln, müssen die experimentell gewonnenen Ergebnisse an ein Reaktionsmodell angepaßt werden. Das geschieht mit Simulationsprogrammen wie Predici.
Anionen in der Gasphase
Authors: Kalcher Josef , Janoschek Rudolf
Published: December 2004

Important general structural and energetic characteristics are provided for atomic and molecular anions, before spectroscopic quantities such as electron affinity are defined to characterize stable anions. Prepared in this way one encounters atomic anions in the first scope. After a short prelude with diatomic molecular anions an attempt is made to juxtapose anions of alkanes and silanes and the corresponding olefinic systems. Associated with these species there is the phenomenon of short‐lived resonances on the one hand, while on the other hand the anions can be stabilized by appropriate geometry distortions or substituents. Distonic radical anions, where the radical‐center does not coincide with the charge center, or dipolarly‐bound anions, where the extra electron is very feebly bound, are not very well known hitherto, but have a wide field of application in organic chemistry. The presentation of solvated anions with a special focus on SN2‐reactions completes this area. Only a few examples document the unique double‐Rydherg anions, which are characterized by a pair of electrons bound loosely to a cationic core. The multiply‐charged anions are shown to have a very wide field of application in the sequel. The initial “disappointment” that the well‐known small textbook‐polyanions do not exist in the gas phase is followed by the apothegm “more space for charge separation”. With this key‐ note a wide field for organic (carbonic acids, carbon clusters) as well as inorganic compounds (complexes) is opened.
Projektionsversuche mit dem Diaprojektor
Authors: Mayr Armin , Adelhelm Manfred , Höhn Ernst‐Gerhard
Published: December 2004

A variety of demonstration experiments can be shown to a large audience with a minimum amount of chemicals by using an ordinary slide projector and easily mounted cuvettes. A detailed instruction for assembling the cuvettes is given as m d l as examples for suitable demonstration experiments in general, inorganic, organic and physical chemistry.
Welche Bedeutung haben Theoretische Konzepte in der Chemie?
Authors: Reiher Markus , Netz Paulo A.
Published: December 2004

Wir haben versucht, deutlich zu machen, wie wichtig theoretische Konzepte in der Chemie sind. Dabei gelangen wir zu folgenden Schlußfolgerungen über die Konzepte, die in der Chemie herangezogen werden, um Beobachtungen zu deuten und zu verstehen:

Qualitativ chemische Konzepte sind für ein Verständnis der Chemie unverzichtbar. Eine quantenchemische Berechnung liefert nicht automatisch Verständnis und Einordnung in einen Gesamtzusammenhang.

Erst die vereinfachende Beschreibung chemischer Konzepte ermöglicht eine unmittelbare Diskussion chemischer Fragestellungen.

Die Konzepte sind trotz grundlegender physikalischer Theorien bis zu einem gewissen Grade eigenständig.
Hundert Jahre Aspirin®
Authors: Kuhnert Nikolai
Published: December 2004

The article commemorates the centenary of the protection of the proprietary mine of Aspirin. The early medicinal uses of salicylic acid derivatives in herbal remedies arc summarised as well as the biosynthesis of these derivatives. The history of the synthesis of salicylic acid and of acetyl salicylic acid (ASS) is described in detail as is the discovery of additional therapeutic applications and the basic pharmacology of ASS.
Sur une réaction photochimique entre le soufre et l'arsenic jaune
Authors: Haenny Ch.
Published: December 2004

On trouvera dans cette note la description de la méthode suivie pour la préparation de l'arsenic jaune et une première étude d'une réaction photochimique entre l'arsenic jaune et le soufre dissous dans le sulfure de carbone qui donne lieu à des sulfures insolubles dont les propriétés ne sont ni celles d'un mélange de ces éléments ni exactement celles des sulfures d'arsenic connus jusqu'à maintenant.
Untersuchungen über Prinzipien der genetischen Stoffbildung I Über Bildungsformen des Calciumoxalats
Authors: Kohlschütter V. , Kohlschütter V. , Marti Julia
Published: December 2004

Die Reaktion Ca‥ + Ox″ → CaOx führt im Versuch zu unterschiedlichen, für bestimmte physikalisch‐chemische Bedingungen typischen Formen des Produktes; anderseits entsteht Calciumoxalat als pflanzlicher Ausscheidungskörper durch einen rein anorganisch aufzufassenden, aber doch in organische Vorgänge eingegliederten Prozess ebenfalls in verschiedenen Formen, die für bestimmte Gattungen und Arten oder Organe spezifisch sind. Durch diesen Parallelismus kommt den “Bildungsformen” der Verbindung ein besonderes Interesse zu.
Polymerisation und thermischer Zerfall des Acetylens
Authors: Schaläpfer P. , Brunner M.
Published: December 2004

An Hand einer statischen Versuchsmethodik wurde die jedem Selbstzerfall des Acetylens vorausgehende Polymerisation untersucht, die Polymerisationsgeschwindigkeit bei verschiedenen Temperaturen bestimmt und der Einfluss von Katalysatoren studiert. In Glasgefässen verläuft die Polymerisation unter charakteristischem Druckabfall in homogener Phase und ist wahrscheinlich bimolekular.
Über Komplexbildung von Ferri‐ion mit Acetation in wässriger Lösung
Authors: Treadwell W. D. , Fisch W.
Published: December 2004

Bei der elektrometrischen Titration von Ferrichlorid mit Natriumacetat werden auf 3 Atome Ferri‐eisen 8 Acetatreste verbraucht. Essigsäure stört diese Titration nicht, wohl aber Mineralsäuren, wie Salzsäure. Von dem zugesetzten Acetat enthält die Lösung am Schluss der Titration 2 Mole in Form von freier Essigsäure. Damit ist in sehr einfacher Weise die Existenz des Kations [Fe3(CH3CO2)6(OH)2]·, welches den von Werner und Weinland entdeckten Salzen zugrunde liegt, in der Lösung nachgewiesen.
Über die thermische Dissoziation gasförmiger Benzoësäure in Benzol und Kohlendioxyd
Authors: Moser Wolfgang
Published: December 2004

Es wurde die thermische Dissoziation gasförmiger Benzoesäure in Benzol und Kohlendioxyd untersucht und dabei folgendes festgestellt:

Die Dissoziation wird bei ungefähr 370° merklich; in Glasgefässen ohne Katalysatoren ist jedoch die Geschwindigkeit erst oberhalb 400° bequem messbar.

Neben der Hauptreaktion geht in beschränktem Umfang stets eine Dissoziation in Phenol und Kohlenoxyd einher.

Zusatz von Kohlendioxyd verlangsamt die Umsetzung, Zusatz beider Reaktionsprodukte hat keinen merklichen Einfluss auf die Geschwindigkeit.

Der Umsatz vollzieht sich als Wandreaktion; Vergrösserung der Wandfläche beschleunigt.

Aluminium, Eisen und Zink bewirken neben der Hauptreaktion die Bildung von Diphenyl, Wasserstoff und anderen Produkten.

Wirksame Katalysatoren sind Kupfer nnd Cadmium; in Gegenwart von Kupfer verläuft die Reaktion unter sonst gleichen Umständen rund 9 ma1 schneller, in Gegenwart von Cadmium rund 200 mall schneller.

Die Dissoziation der Benzoesäure verläuft unter allen Umständen praktisch bis ans Ende, d. h. bis zum analytisch vollständigen Verschwinden der Benzoesäure.
Phosphor‐, Stickstoff‐ und Siliciumgehalt der Stärkefraktionen
Authors: Samec M.
Published: December 2004

In der vorliegenden Abhandlung wurde auf einige Widersprüche hingewiesen, welche sich zwischen gewissen Beobachtungen P. Karrer's und denen anderer Forscher bezüglich der Einflüsse von Begleitstoffen auf die Eigenschaften von Stärkelösungen und Stärkekleistern ergeben haben. Der Verfasser hält seine Resultate über die Kausalität zwischen dem Gehalte der Stärkesubstanzen an Phosphorsäure, sowie stickstoffhaltigen Begleitstoffen und typischen Eigenschaften der Stärkelösungen aufrecht.
Über die optische Aktivität von Aluminiumbrenzcatechinat
Authors: Treadwell W. D. , Szabados G. , Haimann E.
Published: December 2004

Es wurde festgestellt, dass das Strychninsalz des Aluminiumbrenzcatechninates aus 2 optischen Antiopoden besteht.
Über die Wirkung des Lichts auf Thallium(I)chlorid in Gegenwart von Ammoniak oder Oxalsäure
Authors: Baur Emil , Renz Carl
Published: December 2004

1. Thallium(I)chlorid mit Ammoniak belichtet liefert Photochlorid und eine Oxydation des Ammoniaks zu Nitrat.
Die elektrochemische Nitrierung des Naphtalins
Authors: Fichter Fr. , Plüss Ernst
Published: December 2004

Eine kritische Nacharbeit der elektrochemischen Nitrierung von Naphtalin nach D. R. P. 100 417 ergibt, dass in der Tat bei mittleren Konzentrationen von Salpetersäure die Elektrolyse einer auf 80° erhitzten Mischung von Naphtalin und Säure die Nitrierung begünstigt. Allein es ist nicht die Konzentrationsteigerung, welche diesen Effekt hervorruft, sondern die Erhöhung der Temperatur an der arbeitenden Anode, wo ein Teil des Naphtalins bis zu den Endstufen oxydiert wird. Denn wenn man die Temperatur bei rein chemischen Nitrierversuchen auf 95–98° steigert, so kann man mit verdünnter wässriger Salpetersäure (D = 1,096) bereits einen Nitrierungsgrad von 89,8%. Diese bisher in der Literatur nicht genügend berücksichtigte Variation der Nitrierung wird am Naphtalin etwas eingehender untersucht.
Zur Kenntnis der Carr‐Price‐Reaktion an Carotinoiden
Authors: v. Euler Beth , Karrer P.
Published: December 2004

Die Carr‐Price‐Reaktionen verschiedener Carotinoide sind von der Reaktionszeit, der Mischungsart usw. verschieden abhängig. Einen gewissen Einfluss scheint ausserdem die Beleuchtung der Apparatur zu haben.
Note sur l'ozonation de l'acide oléique et de l'huile de lin et sur l'évolution des produits de cette ozonation
Authors: Briner E. , Denzler C. , Paillard H.
Published: December 2004

Comme d'autres ozonides étudiés antérieurement, les produits d'ozonation de l'acide oléique et de l'huile de lin subissent une évolution caractérisée par le dégagement d'un mélange gazeux renfermant de fortes proportions d'hydrogène et de méthane et très peu d'oxygène.
Über die Verseifung von Äthylenbromid mit alkoholischem Alkalihydroxyd
Authors: Bernoulli A. L. , Kambli Walter
Published: December 2004

Äthylenbromid wurde verseift:

mit Kaliumcarbonat in verdünnter wässriger Lösung,

mit Kaliumcarbonat in 50‐proz. Äthylalkohol‐Wasser‐Gemisch,

mit Natriumhydroxyd in alkoholischer Lösung.
Cinétique de l'action de l'iode sur les chlorhydrates d'hydrazine et d'hydroxylamine
Authors: Berthoud A. , Porret Daniel
Published: December 2004

La vitesse de l'action de l'iode sur le chlorhydrate d'hydrazine est, dans l'obscurité, proportionnelle à la concentration de ce sel et à celle de l'iode. Elle varie en raison inverse de la concentration des ions H. et de celle des ions I' élevée à une puissance un peu inférieure à 2. Les chlorures, bromures et azotates, à égalité de concentration, ont une même influence retardatrice. Le coefficient thermique est égal à 3,4, entre 20° et 30°. Bhattacharya et Dhar ont trouvé un nombre trop faible, 2,6.
Über das Lichtbrechungsvermögen der Cellulose und ihrer Derivate. 1. Der Einfluss von nativen, nicht‐celluloseartigen Begleitstoffen auf das Lichtbrechungsvermögen von Cellulosefasern
Authors: Kanamaru Kisou
Published: December 2004

I. Bei der Reinigung pflanzlicher Fasern steigt der Brechungsindex nγ in der Faser‐Längsrichtung an, während der Index nα in der Querrichtung sinkt. Die extremsten Werte sind bei Hanf gefunden worden; sie betragen nγ = 1,5964 und nα = 1,5251, woraus sich eine Doppelbrechung 0,0713 ergibt.
Über das Lichtbrechungsvermögen der Cellulose und ihrer Derivate. II. Die Beeinflussungen von Cellulosefasern durch Oxydation und Hydrolyse
Authors: Kanamaru Kisou
Published: December 2004

I. Die zwei Typen von abgebauter Ramie‐Cellulose, Oxy‐ und Hydrocellulose zeigen keinen wesentlichen Unterschied in ihrem Brechungsvermögen. Sie weisen mit zunehmendem Reduktionsvermögen einen typischen Gang ihrer Brechungsindices auf, indem zuerst ngM, bei weiter fortschreitendem Abbau auch nα stark ansteigen.
Zur Kenntnis der flüchtigen Pflanzenstoffe I. Über Atlanton, den Riechstoff der echten Cedernholzöle
Authors: St. Pfau Alexander , Plattner Pl.
Published: December 2004

1. Der Riechstoff des Atlas‐ und Himalaya‐cedernöls ist ein Gemisch von zwei Sesquiterpen‐ketonen C15H22O, die als α‐ und γ‐Atlanton bezeichnet werden.
Addition photochimique du chlore à l'acide cinnamique
Authors: Berthoud A. , Porret Daniel
Published: December 2004

La vitesse d'addition du chlore à l'acide cinnamique, sous l'action de la lumière, suit les mêmes lois que l'addition du brome. Elle est approximativement: indépendante de la concentration de l'acide cinnamique, proportionnelle à la concentration du chlore quand l'absorption est totale et à la puissance 3/2 de cette concentration quand l'absorption de la lumière est faible et enfin proportionnelle à la racine carrée de l'intensité lumineuse. Sur ce dernier point, nos résultats diffèrent de ceux de Basu d'après lesquels la vitesse serait proportionnelle à l'intensité lumineuse.
Vielgliedrige heterocyclische Verbindungen VIII. Zur Kenntnis der hochgliedrigen Mono‐ und Poly‐lȧctonringe
Authors: Stoll M. , Rouvé A.
Published: December 2004

1. Es wurde gezeigt, dass die der Veresterungsreaktion entgegenlaufende Verseifungsreaktion keine messbare Geschwindigkeit besitzt.