bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial Reactions in the System of MnTe-H2O
Authors: Zarubina Oksana N. , Mokrousov Gennady M. , Maliy Liubov V.
Published: October 2015

The thermodynamically possible reactions in MnTe-H2O system at room temperature have been studied. The potential–pH diagram has been plotted assuming quasi-equilibrium on interfacial boundary. The possible mechanism of formation and the composition of a surface in dependence on electrode potential and pH have been discussed and the stable conditions for manganese telluride, i.e. the specific area in the diagram (pH from −2 to 14 and potential from −1.5…− 1.1 to −0.9…−0.6 V) have been found. The obtained results may help optimize the conditions for electodeposition of manganese telluride thin films and for liquid chemical etching for the formation of interfacial boundaries.
Hydrothermal Synthesis of Nanocrystalline Titanium Dioxide for Use as a Photoanode of DSSCs
Authors: Kozyukhin Sergey , Sadovnikov Alexey , Presniakov Michael , Baranchikov Alexander , Borilo Lyudmila P. , Kozik Vladimir , Ivanov Vladimir K.
Published: October 2015

Nanocrystalline TiO2powder was synthesized using microwave-assisted hydrothermal treatment of titanium oxysulfate in the presence of NH4F. X-ray powder diffraction analysis and Raman spectroscopy were used to determine phase composition and particle size of obtained titanium dioxide. The studies using methods of TEM and EDX spectroscopy have shown that synthesized TiO2powder is a promising functional material for fabrication of photoanode of dye-sensitized solar cells (DSSCs).
Effectiveness of the Technologies of Titanium Implants Covering
Authors: Petrovskaya Tatiana S. , Vereschagin Vladimir I.
Published: October 2015

The aim of this work is to improve the known methods of forming coatings on titanium implants: anodizing, plasma spraying, and ceramic one. For this purpose we use hydroxyapatite (HA) obtained from biological raw materials by roasting technology that preserves the microstructure of natural HA. The sol-gel method has been used to impart bioactivity to anodic coatings. In addition, criteria for evaluating the effectiveness of the methods for forming coatings, based on analysis of author data and expert opinions, are proposed. The evaluation of the methods used in this paper is presented.
Peat- and Natural Zeolite-Based Solid Composite Modified by Metal Ions for Photodegradation of Dyes in Waters
Authors: Naumova Ludmila B. , Batalova Valentina N. , Alekseenko Kira V.
Published: October 2015

The present research is aimed at tackling the problem of profound degradation of organic pollutants in waters by creating new composite materials with the given functional properties. The work studies the preparation methods and the catalytic activity of natural peat-and zeolite-based composites during photochemical removal of organic dyes from aqueous media. The composites were prepared by chemical modification with polyvalent metal ions - Fe(II,III), Cu(II), Ce(IV), Ti(IV) – in two ways: ion exchange/saturation and Pechini method (polymerizable complex method). It was shown that the obtained composites are efficient catalysts of oxidative photodegradation of Rhodamine C, Rhodamine 6G, brilliant green and eosine in aqueous solutions.
Structure and Sorption Properties of Silica Chemically Modified with Copper Malonate
Authors: Pakhnutova Evgeniya A. , Slizhov Yury G.
Published: October 2015

The sorbent with the grafted layers of malonate copper was obtained on the surface of silica gel Silokhrom S-120 by the method of successive assemblies. Structural, sorption and chromatographic properties of the investigated materials were studied by adsorption of porosimetry, gas chromatography, pH-measurement and Hammett’s method. The sorbent was used for solid phase extraction of organic compounds from aqueous solutions.
Metal-Polymer Sensors for Voltammetric Analysis
Authors: Shelkovnikov Vladimir V. , Anishchenko Mikhail V. , Anishchenko Yuliya V. , Minaev Konstantin M.
Published: October 2015

The way of the graphite electrodes production, modified by polymeric composition, containing nanoparticles of gold or mercury, for determination of metals’ ions by the method of stripping voltammetry is offered. The influence of copolymer’s structure, nature of solvent, concentration of metal-modifier, viscosity of composition, film’s thickness and conditions of its formation on electrochemical and mechanical characteristics of sensor systems was studied. The approbation of electrodes was carried out using the certified techniques with help of the method of stripping voltammetry during determination of zinc, cadmium, lead, copper, mercury, arsenic, selenium.
Nickel-Containing Systems in Reaction of Partial Oxidation of Hydrocarbons
Authors: Galanov Sergey , Sidorova Olga I. , Batyreva Vera A.
Published: October 2015

Nickel dispersion, which provides total catalytically active metal surface, is significant for partial catalytic oxidation of natural gas to obtain high purpose products yield and productivity in syngas. The interaction of reaction medium under high reaction temperatures during 20-25 hours promotes the increase of total square of active Ni component for block catalysts obtained with self-propagating high-temperature synthesis, which allows achieving productivity in syngas 7.1·103cm3(syngas)/cm3(catalyst)·hour. It is observed that for catalyst systems obtained with precipitation, chemical composition of oxide phase influences the particles size of metal nickel. For granular catalysts obtained through precipitation after 25-hour exploitation, average particle size (according to CSR) metal nickel is 3-4.5 times smaller than Ni in catalysts obtained with self-propagating high-temperature synthesis. This allows achieving productivity in syngas 8.1·103cm3/сm3·hour, when there is average temperature decrease over the catalytic layer by ~100°С in comparison with blocks acquired through self-propagating high-temperature synthesis.
Peculiarities of SiO2-MxOy (where М – Mn, Fe, Co, Ni) Thin Films Formation
Authors: Brichkov Anton S. , Brichkova Victoria Y. , Egorova Lidia A. , Kozik Vladimir , Ivanov Vladimir K.
Published: October 2015

The paper studies the formation of thin-film and disperse SiO2-MxOysystems (where M – Mn, Fe, Co, Ni) synthesized with sol-gel technology. The influence of metal salt on tetraethoxysilane hydrolysis and film-forming solution viscosity is considered. Dependence of the film optical properties on their composition was determined.
Progress in the Integration of planar and 3D Coils on LTCC by using photoimageable Inks
Authors: Perrone Rubén , Thust Heiko , Drüe Karl-Heinz
Published: October 2015

This paper presents some results of our investigations in the integration of coils in LTCC using the Fodel® Technology as line patterning technology. Planar as well as 3-D inductors were simulated, manufactured, measured and modeled. The structures were manufactured with different shapes, a line width from 30 μm to 70 μm, a space between turns from 100 μm and 200 μm and diameters of inner turns from 0.5 mm to 2 mm. The smallest and most critical inductors (0.5 mm diameter) were manufactured with vias, whose diameter were about 60 μm. The manufacturing of smaller coils was possible due to the increased resolution of Fodel® thick-film inks also in inner layers in combination with micro vias, which were produced with a multifunctional Laser. Combining these technologies with buried cavities and a symmetric turn arrangement we obtained inductors that can be used in a wider range of frequencies (up to 10 GHz).
Development of LTCC Smart Channels for Integrated Chemical, Temperature, and Flow Sensing
Authors: Ho Clifford K. , Peterson Kenneth A. , McGrath Lucas K. , Turner Timothy S.
Published: October 2015

This paper describes the development of “smart” channels that can be used simultaneously as a fluid channel and as an integrated chemical, temperature, and flow sensor. The uniqueness of this device lies in the fabrication and processing of low-temperature co-fired ceramic (LTCC) materials that act as the common substrate for both the sensors and the channel itself. Devices developed in this study have employed rolled LTCC tubes, but grooves or other channel shapes can be fabricated depending on the application requirements. The chemical transducer is fabricated by depositing a conductive polymer “ink” across a pair of electrodes that acts as a chemical resistor (chemiresistor) within the rolled LTCC tube. Volatile organic compounds passing through the tube are absorbed into the polymers, causing the polymers to reversibly swell and change in electrical resistance. The change in resistance is calibrated to the chemical concentration. Multiple chemiresistors have been integrated into a single smart channel to provide chemical discrimination through the use of different polymers. A heating element is embedded in the rolled tube to maintain a constant temperature in the vicinity of the chemical sensors. Thick-film thermistor lines are printed to monitor the temperature near the chemical sensor and at upstream locations to monitor the incoming ambient flow. The thermistors and heating element are used together as a thermal anemometer to measure the flow rate through the tube. Configurations using both surface-printed and suspended thermistors have been evaluated.
Miniature Multi-electrode Electrochemical Cell in LTCC
Authors: Youngsman John , Marx Brian , Wolter Scott , Glass Jeff , Moll Amy
Published: October 2015

The miniaturization of analytical instruments and packaging of novel sensors is an area that has attracted significant research interest and offers many opportunities for product commercialization. Electrochemical sensors have been used to detect a wide variety of compounds including toxic gases. A miniature electrochemical cell has been designed, constructed, and tested for functionality. The cell will be used in identifying and selecting chemical species in solutions. The cell was constructed of low temperature co-fired ceramic (LTCC) material using gold for the electrodes. Tests performed in sulfuric acid and sea water solutions show that the cell is functioning based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. Miniaturization allows the cell to be deployed as a sensor in many different environments.
LTCC Enzymatic Microreactor
Authors: Malecha Karol , Pijanowska Dorota , Golonka Leszek , Torbicz Wladyslaw
Published: October 2015

A novel three dimensional LTCC (Low Temperature Co-fired Ceramics) based microreactor with immobilized enzyme (urease) is presented in this paper. The microreactor consists of two chambers separated by a threshold. The shape of the chambers was optimized by the Finite Elements Method. The modeling has brought a better understanding of the microflow of chemically modified glass or polymeric beads through the microreactor. The modeling results are verified by the observation of the fluid movement inside the real structure via a top transparent polymer layer. Moreover, immobilization techniques of enzymes on polymeric beads are investigated. Finally, the properties of the LTCC microreactor are compared with the properties of a similar one made in silicon.
Comparison of High-Resolution Patterning Technologies for LTCC Microwave Circuits
Authors: Müller J. , Perrone R. , Drüe K.-H. , Stephan R. , Trabert J. , Hein M. , Schwanke D. , Pohlner J. , Reppe G. , Kulke R. , Uhlig P. , Jacob A.F. , Baras T. , Molke A.
Published: October 2015

Low-temperature co-fired ceramic (LTCC) are widely acknowledged for wide-band and microwave circuits. Within the project consortium KERAMIS, implementation of higher functionality in LTCC substrates is being investigated. Among the applications considered are a 4 × 4 switch matrix [1], voltage-controlled oscillators [2], and amplifiers for multimedia satellite communications working in Ka-band. In order to add more functionality (e.g., filters, couplers) in LTCC, current patterning limits of line width and line separation need to be extended. Four different technologies were considered for higher resolution: a) fine-line printing technology with special screens, b) photo-imageable pastes, c) etching of thick-film conductors (co- and post-fired), and d) thin films on LTCC. Evaluation of patterning technologies is based on a test coupon that was designed and manufactured by the consortium members. The artwork contains lines, line transitions, ring resonators (microstrip and stripline), edge-coupled filters, DC blocking structures, and various lines for DC resistance testing. The smallest gap definition is 50 μm. Two substrate materials, Du Pont tapes 951 and 943, are included in the study. In addition to the main frequency band of interest in the project (17–22 GHz), these structures have been characterized up to 50 GHz. Electrical results are correlated to physical measurements of the structures (line width, spaces, and tolerances) and are evaluated with respect to performance, manufacturability, and yield. Results show excellent performance for screen-printed structures and demonstrated the importance of mask tuning to achieve optimum resolution (under etching etc.).
Kinetic Modeling of LTCC Shrinkage: Effect of Alumina Content
Authors: Eberstein M. , Müller R. , Reinsch S. , Rabe T. , Schiller W.A. , Thiel A. , Deubener J.
Published: October 2015

We studied sintering of LTCC-type glass matrix composites (GMCs) consisting of small glass and alumina particles of equal size. Primarily, crystals act as rigid inclusions, decelerating the densification rate. In later stages, they also dissolve, partially increasing the viscosity. Release of alumina finally induces crystallization of alumosilicates, which enables post-firing stability. To study both effects, two model GMCs were prepared: an α-Al2O3 + barium alumoborosilicate glass (BABS)–GMC, which shows neither significant dissolution nor crystallization, and an α-Al2O3 + calcium alumoborosilicate glass (CABS)–GMC, which dissolves readily and promotes crystallization. The kinetics of shrinkage for both GMC were modeled by utilizing Frenkel theory for the early stage and Mackenzie–Shuttleworth theory for the late stage, assuming that sintering is superimposed by the weighted contributions of triparticle glass–crystal clusters, their random occurrence (ideal mixing), and a shrinkage rate controlled by the GMC effective viscosity. In agreement with modeling, the experimental results showed that the shrinkage rate of BABS–GMC decreases progressively for crystal volume fractions Φ > 0.15. The attainable shrinkage is reduced by up to 8% for Φ = 0.45. For the CABS–GMC with Φ = 0.25, a reduction of Φ to 0.20 was evident due to partial α-Al2O3 dissolution. This effect was found able to increase the sintering temperature by ~50–60 K.
Application of Experimental and Finite Element Modal Analysis in Development of a Novel Solder Joint Inspection Systems
Authors: Zhang Lizheng , Ume I. Charles
Published: October 2015

Inspection of flip chip solder joints has been a crucial process in the electronics manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. New inspection techniques are urgently needed to fill in the gap between available inspection capabilities and industry requirements of low-cost, fast-speed, and highly reliable inspection systems. The laser ultrasound inspection system under development aims to provide a solution that can overcome some of the limitations of current inspection techniques. This research project is based on laser ultrasound and interferometric techniques. A pulsed laser generates ultrasound on the chip's surface, and the entire chip is excited into structural vibration. An interferometer is used to measure the vibration displacement of the chip's surface at several points, and solder joints with different qualities cause different vibration responses. By analyzing the surface vibration responses, defects in solder joints may be detected and/or classified. In this paper, a broadband laser pulse is used for dynamic excitation of the chip before its vibration signature is analyzed. Experimental modal analysis extracts and estimates the modal information (mode frequencies and mode shapes) from raw vibration signals. Multiple-point surface responses are scanned with an interferometer under repeated laser pulse excitation. Spectral estimation on the raw vibration signals gives dominant-mode frequencies. The corresponding vibrational patterns are obtained by reconstructing the scanned grids using the decomposed signals at each mode frequency. Because we are interested only in the transverse vibration on the chip's surface, and because the chip's length and width are much larger than its thickness, it can be modeled as a rectangular plate with pin supports. Modal analysis by finite element modeling is applied to devices with and without defects. The objectives are to identify the differences of mode frequencies and mode shapes between good chips and chips with defects and to identify measurement points that show maximum difference in the presence and absence of defects.
Thick Film Accelerometers in LTCC Technology—Design Optimization, Fabrication, and Characterization
Authors: Neubert Holger , Partsch Uwe , Fleischer Daniel , Gruchow Mathias , Kamusella Alfred , Pham The-Quan
Published: October 2015

Diaphragms and beams for force and pressure sensors, e.g., are state of the art in mechanical elements of MEMS in LTCC technology. These elements sustain small strains and small deformations under load. A number of sensor and actuator applications, however, require movable elements that allow higher deformations while the local strains are still low. Springs, accelerometers, actuators, positioners, and valves are examples of such applications. For an accelerometer we developed an approach fabricate leaf springs, integrated into the LTCC technology. The working principle of the accelerometer is based on a seismic mass disposed on two parallel leaf springs that carry piezoresistors connected such that they form a measuring bridge. In the first design optimization step, we used an FEA model for finding an optimized design meeting our sensitivity requirements, inclusiding resonance frequency. In the second step, we made a tolerance analysis that calculates the probability distributions of functional variables from the probability distributions of the design parameters. This enables the probability of a system failure to be deduced. In a final design step, a design of the ceramic thick film accelerometer was calculated that minimizes the system failure probability. As a result we obtained a design optimized with respect to a set of functional requirements and design tolerances. The results of the computations using the FEA models were compared to results of measurement data acquired from prototypes of the accelerometer.
Silicon on Ceramics—A New Integration Concept for Silicon Devices to LTCC
Authors: Fischer M. , de Torres H. Bartsch , Pawlowski B. , Gade R. , Barth S. , Mach M. , Stubenrauch M. , Hoffmann M. , Müler J.
Published: October 2015

A new integration concept for MEMS-devices to ceramic substrates based on a new bonding technique between nano-scaled black silicon (BSi) and an adapted LTCC substrate is presented. The novel technique allows combining advantages of silicon and ceramic technology whereby a new wafer compound material (silicon on ceramics) and innovative ceramic carrier as well as chip packages become available. The new compound is fabricated by the use of standard technologies (reactive ion etching, lamination, and pressure assisted sintering) without additional materials and devices. A bonding strength up to 1750 N/cm2 and gas tightness are remarkable features of the bond interface. Simultaneously, electrical interconnects between silicon and LTCC can be manufactured during lamination and sintering.
Response Predicting LTCC Firing Shrinkage: A Response Surface Analysis Study
Authors: Girardi Michael , Barner Gregg , Lopez Cristie , Duncan Brent , Zawicki Larry
Published: October 2015

Low temperature cofired ceramic (LTCC) technology is used in a variety of applications including military/space electronics, wireless communication, MEMS, and medical and automotive electronics. The use of LTCC is growing due to the low cost of investment, short development time, good electrical and mechanical properties, high reliability, and flexibility in design integration (i.e., three dimensional microstructures with cavities are possible). The dimensional accuracy of the resulting x/y shrinkage of LTCC substrates is responsible for component assembly problems with a tolerance effect that increases in relation to the substrate size. Response surface analysis was used to predict product shrinkage based on specific process inputs (metal loading, layer count, lamination pressure, and tape thickness) with the ultimate goal to optimize manufacturing outputs (NC files, stencils, and screens) in achieving the final product design the first time. Three regression models were developed for the DuPont 951 tape system with DuPont 5734 gold metallization based on green tape thickness.
IMC Growth Mechanisms of SAC305 Lead-Free Solder on Different Surface Finishes and Their Effects on Solder Joint Reliability of FCBGA Packages
Authors: Kim Sang Ha , Tabuchi Hiroshi , Kakegawa Chika , Park Han
Published: October 2015

Intermetallic compound (IMC) growth behavior of lead-free solder plays an important role in ball grid array (BGA) solder joint reliability for flip chip BGA (FCBGA) packaging applications. The growth mechanism of IMC is reported based on a diffusion model. Thermal treatment such as accelerated thermal cycling (ATC) and isothermal aging exposure also contribute to the growth rate and morphology of lead-free solder IMC. Among the lead-free solder alloys, Sn-3.0wt.%Ag-0.5wt.%Cu (SAC305) solder is a promising substitute for Sn-Pb because of its good mechanical properties and wettability with current surface finishes. After thermal exposure, BGA solder joint reliability is degraded due to IMC formation and growth. In this study, two different thermal treatments, ATC and isothermal aging, and two different pad surface finishes, solder on pad (SOP) and electroless Ni immersion gold (ENIG), are considered in terms of IMC growth rate and mechanical solder joint reliability. An SOP finished interface forms a thin ε-phase Cu3Sn layer and a scallop-like η-phase Cu6Sn5 layer. In contrast, the ENIG finished interface forms a thick (Cu,Ni)6Sn5 IMC layer and prevents overall IMC growth. Different surface finished test vehicles are evaluated in an ATC test in a 0°C to 100°C temperature range and the Ni diffusion layer shows a longer solder joint fatigue lifetime than the nondiffusion barrier interface based on the micro cross-section and dye penetration analysis results. In an isothermal aging test at 100°C and 150°C, the aging temperature and time are valid factors to decide mechanical shock reliability. Interfacial fractures are found in the 100°C aged test vehicle due to easier crack propagation at the interface between the thin Cu3Sn layer and the scallop-like Cu6Sn5 layer based on SEM microstructure analysis results. Finally, this investigation proposes how to improve solder joint reliability and prevent interfacial fracture for SAC305 lead-free application.
A Robust Thin-Film Wafer-Level Packaging Approach for MEMS Devices
Authors: Seetharaman Krishnan , van Velzen Bart , van Wingerden Johannes , van Zadelhoff Hans , Yuan Cadmus , Rietveld Frank , Tak Coen , van Beek Joost , Magnée Peter H.C. , Beijerinck Herman C.W.
Published: October 2015

Micro-electromechanical systems (MEMS) devices are extremely sensitive to their environment, especially at the wafer level, until they are packaged in final form. The harsh back-end (BE) operations that the MEMS devices have to endure include dicing, pick-and-place, wire bonding, and molding. During these processing steps, the MEMS device is exposed to particles and contaminants. Therefore, protection at an early stage is a fundamental requirement.

We describe a silicon nitride thin-film capping, which is processed using a sacrificial layer technique only with front-end technology. This approach is suitable for mass production of MEMS devices, owing to the fact that it is more cost-effective when compared to other approaches such as wafer-to-wafer bonding and die-to-wafer bonding.

A bulk acoustic wave (BAW) resonator that finds application in the radio frequency (RF) front end, for example, in cell phones, is taken as a MEMS vehicle for our work. It is an example of an extremely sensitive MEMS device, because the resonance frequency shifts significantly when additional mass is accidentally deposited on its surface. The thickness of the silicon nitride capping that is required to withstand all the BE steps, in particular transfer molding, is estimated using simple analytical calculations and finite element model (FEM) simulations. The pressure acting on the thin film capping and the thermal load during molding are included in the FEM model. Using this, the minimum thickness required for the capping is determined. We prove that a BAW resonator capped with silicon nitride at the wafer level can be wafer-thinned, diced, wire bonded, and molded without major degradation in performance.
LTCC Based Microfluidic Mass Flow Sensor Concept†
Authors: Zeilmann Christian , Haas Thomas , Backes Andreas , Schmid Ulrich
Published: October 2015

Low temperature cofired ceramics (LTCC) is established as a widespread platform for advanced functional ceramic circuits in many different applications, such as space, aviation, medical, and sensor technology. MLC (multi layer ceramics) based systems allow the integration of passive components, which leads to a high integration level. For microfluidic devices, the integration of 3D structures such as channels and chambers is necessary. Using LTCC will lead to integrating sensor elements due to high reliability, the good ceramic characteristics, and excellent physical properties. To realize 3D micro-channels beyond the laboratory, adequate manufacturing processes are essential. This study proposes the realization of microfluidic channels and shows in which ways these can be realized by a range of newly developed manufacturing methods during the LTCC process. A benchmark of 3D laser structuring and two cold embossing technologies were investigated to show the benefits and also the limits of each technology. The sensor elements, which were directly integrated into the LTCC body, are based on PTC and resistor materials realized in thick film technology. The excellent performance of a microfluidic LTCC system will be shown based on a manufactured demonstrator. The final conclusion is that these established manufacturing and integration methods offer remarkable potential to meet the requirements for future circuit designs, where actual design concepts cannot solve all issues, in particular where harsh environmental conditions occur or a high integration concept is mandatory.
Aerosol Jet Printing of Two Component Thick Film Resistors on LTCC
Authors: Swiecinski K. , Ihle M. , Jurk R. , Dietzen E. , Partsch U. , Eberstein M.
Published: October 2015

Aerosol jet printing is a rather new technology for the deposition of thick film structures offering high line and space resolution. This method offers high potential for miniaturization for thick film structures. The advantages of this technology could be shown with inks carrying a single solid powder (e.g., silver, platinum, ceramic, or glass powder). One of the challenges in printing solid powder mixtures is the differences in the aerodynamic properties of different powders. Those differences result in changes of the mixing ratio within the aerosol jet and therefore poor reproducibility in the finished film.

In this work, thick film resistors consisting of RuO2 with particle size <1 μm as the conducting phase and different glass powders with particle size around 1 μm as the isolating phase were investigated. One glass had a density rather close to RuO2, the other glass significantly lower. Inks were made from RuO2/glass powder mixtures, a solvent, and organic additives. After manufacturing, the inks are printed on LTCC and the microstructures of the dried and the fired films were visualized by FIB preparation and SEM. The resistances as well as the temperature coefficients of the resistors were measured and compared with resistor films with an identical solid composition manufactured by conventional screen printing. The results of the obtained resistors are presented and discussed in terms of powder properties, ink dispersion, and printing parameters.
A 4H-SiC Bipolar Technology for High-Temperature Integrated Circuits
Authors: Lanni L. , Malm B. G. , Zetterling C.-M. , Östling M.
Published: October 2015

A 4H-SiC bipolar technology suitable for high-temperature integrated circuits is tested with two interconnect systems based on aluminum and platinum. Successful operation of low-voltage bipolar transistors and digital integrated circuits based on emitter coupled logic (ECL) is reported from 27°C up to 500°C for both the metallization systems. When operated on −15 V supply voltage, aluminum and platinum interconnect OR-NOR gates showed stable noise margins of about 1 V and asymmetric propagation delays of about 200 and 700 ns in the whole temperature range for both OR and NOR output. The performance of aluminum and platinum interconnects was evaluated by performing accelerated electromigration tests at 300°C with current density of about 1 MA/cm2 on contact chains consisting of 10 integrated resistors. Although in both cases the contact chains failed after less than one hour, different failure mechanisms were observed for the two metallization systems: electromigration for the aluminum system and poor step coverage and via filling for the platinum system.
Causality Verification Using Polynomial Periodic Continuations for Electrical Interconnects
Authors: Barannyk Lyudmyla L. , Aboutaleb Hazem A. , Elshabini Aicha , Barlow Fred
Published: October 2015

We present a method for checking causality of band-limited tabulated frequency responses. The approach is based on Kramers-Krönig relations and construction of periodic polynomial continuations. Kramers-Krönig relations, also known as dispersion relations, represent the fact that real and imaginary parts of a causal function form a Hilbert transform pair. The Hilbert transform is defined on an infinite domain, while, in practice, discrete values of transfer functions that represent high-speed interconnects are available only on a finite frequency interval. Truncating the computational domain or approximating the behavior of the transfer function at infinity causes significant errors at the boundary of the given frequency band. The proposed approach constructs a periodic polynomial continuation of the transfer function that is defined by raw frequency responses on the original frequency interval and by a polynomial in the extended domain, and requires the continuation to be periodic on a wider domain of a finite length and smooth at the boundary. The dispersion relations are computed spectrally using fast Fourier transform and inverse fast Fourier transform routines applied to periodic continuations. The technique does not require the knowledge or approximation of the transfer function behavior at infinity. The method significantly reduces the boundary artifacts that are due to the lack of out-of-band frequency responses, and is capable of detecting small, smooth causality violations. We perform the error analysis of the method and show that its accuracy and sensitivity depend on the smoothness and accuracy of data and a polynomial continuation. The method can be used to verify and enforce causality before the frequency responses are employed for macromodeling. The performance of the method is tested on several analytic and simulated examples.
Variational data assimilation for the optimized ozone initial state and the short-time forecasting
Authors: Park S.-Y. , Kim D.-H. , Lee S.-H. , Lee H. W.
Published: October 2015

Abstract. In this study, we apply the four-dimensional variational (4D-Var) data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation is analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12 h assimilation periods and the 120 observatory sites show a 49.4 % decrease in the root mean squred error (RMSE), and a 59.9 % increase in the index of agreement (IOA). The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE with assimilation vs. that without assimilation are 8 and 13 % for the +24 and +12 h, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential improvement in ozone prediction for both the daytime and night time with application of data assimilation is also presented.
CH4 parameter estimation in CLM4.5bgc using surrogate global optimization
Authors: Müller J. , Paudel R. , Shoemaker C. A. , Woodbury J. , Wang Y. , Mahowald N.
Published: October 2015

Abstract. Over the anthropocene methane has increased dramatically. Wetlands are one of the major sources of methane to the atmosphere, but the role of changes in wetland emissions is not well understood. The Community Land Model (CLM) of the Community Earth System Models contains a module to estimate methane emissions from natural wetlands and rice paddies. Our comparison of CH4 emission observations at 16 sites around the planet reveals, however, that there are large discrepancies between the CLM predictions and the observations. The goal of our study is to adjust the model parameters in order to minimize the root mean squared error (RMSE) between model predictions and observations. These parameters have been selected based on a sensitivity analysis. Because of the cost associated with running the CLM simulation (15 to 30 min on the Yellowstone Supercomputing Facility), only relatively few simulations can be allowed in order to find a near-optimal solution within an acceptable time. Our results indicate that the parameter estimation problem has multiple local minima. Hence, we use a computationally efficient global optimization algorithm that uses a radial basis function (RBF) surrogate model to approximate the objective function. We use the information from the RBF to select parameter values that are most promising with respect to improving the objective function value. We show with pseudo data that our optimization algorithm is able to make excellent progress with respect to decreasing the RMSE. Using the true CH4 emission observations for optimizing the parameters, we are able to significantly reduce the overall RMSE between observations and model predictions by about 50 %. The methane emission predictions of the CLM using the optimized parameters agree better with the observed methane emission data in northern and tropical latitudes. With the optimized parameters, the methane emission predictions are higher in northern latitudes than when the default parameters are used. For the tropics, the optimized parameters lead to lower emission predictions than the default parameters.
Urgenda: een typisch gevalletje rechter, wetgever of politiek?
Authors: van Gestel R.A.J.
Published: October 2015

Urgenda: een typisch gevalletje rechter, wetgever of politiek?

Het vonnis van de Haagse rechtbank in de zaak Urgenda tegen de Staat der Nederlanden heeft wereldwijd de aandacht getrokken. Het bevel van de rechter aan de Staat om meer te doen om de uitstoot van broeikasgassen met 25 procent ten opzichte van 1990 te verminderen heeft zowel lof als kritiek geoogst in de (internationale) media en literatuur. Milieuorganisaties loven de durf van de rechtbank om de Staat via het onrechtmatigedaadsrecht te houden aan internationaal overeengekomen CO2-reductiedoelstellingen. Staatsrechtgeleerden hekelen het vonnis daarentegen omdat de rechter te activistisch zou hebben geopereerd, te veel op de stoel van de wetgever en de politiek zou zijn gaan zitten en onvoldoende rekening houdt met de beleidsvrijheid van de Staat. De vraag is echter of deze kritiek niet uitgaat van een te eenzijdige lezing van het vonnis en van verouderde denkbeelden over de rol van de rechter binnen de trias politica.
Proceedings: Using Stem Cell Therapies to Reestablish Osteogenic Capability for Bone Regeneration
Authors: Littman Neil , Abo Arie
Published: October 2015

The California Institute for Regenerative Medicine (CIRM) has invested approximately $70 million in programs targeting various orthopedic indications, including osteoporosis, bone fracture healing, vertebral compression fractures, and several others. The present article serves to outline the current state of CIRM's more advanced programs, comparing and contrasting them with the current standard of care and several other novel approaches under development.

Significance

This report describes CIRM bone programs that are in contrast to current cell therapy approaches. These projects aim to enhance stem cell activity for bone regeneration.
Interaction of Wnt pathway related variants with type 2 diabetes in a Chinese Han population
Authors: Zhou Jian-Bo , Yang Jin-Kui , Zhang Bao-Hong , Lu Jing
Published: October 2015

Aims.Epistasis from gene set based on the function-related genes may confer to the susceptibility of type 2 diabetes (T2D). The Wnt pathway has been reported to play an important role in the pathogenesis of T2D. Here we applied tag SNPs to explore the association between epistasis among genes from Wnt and T2D in the Han Chinese population.

Methods.Variants of fourteen genes selected from Wnt pathways were performed to analyze epistasis. Gene–gene interactions in case-control samples were identified by generalized multifactor dimensionality reduction (GMDR) method. We performed a case-controlled association analysis on a total of 1,026 individual with T2D and 1,157 controls via tag SNPs in Wnt pathway.

Results.In single-locus analysis, SNPs in four genes were significantly associated with T2D adjusted for multiple testing (rs7903146Cin TCF7L2,p= 3.21∗10−3, OR = 1.39, 95% CI [1.31–1.47], rs12904944GinSMAD3,p= 2.51∗10−3, OR = 1.39, 95% CI [1.31–1.47], rs2273368CinWNT2B,p= 4.46∗10−3, OR = 1.23, 95% CI [1.11–1.32], rs6902123CinPPARD,p= 1.14∗10−2, OR = 1.40, 95% CI [1.32–1.48]). The haplotype TGC constructed byTCF7L2(rs7903146),DKK1(rs2241529) andBTRC(rs4436485) showed a significant association with T2D (OR = 0.750, 95% CI [0.579–0.972],P= 0.03). For epistasis analysis, the optimized combination was the two locus model ofWNT2Brs2273368 andTCF7L2rs7903146, which had the maximum cross-validation consistency. This was 9 out of 10 for the sign test at 0.0107 level. The best combination increased the risk of T2D by 1.47 times (95% CI [1.13–1.91],p= 0.0039).

Conclusions.Epistasis betweenTCF7L2andWNT2Bis associated with the susceptibility of T2D in a Han Chinese population. Our results were compatible with the idea of the complex nature of T2D that would have been missed using conventional tools.
Allocation trade-off under climate warming in experimental amphibian populations
Authors: Gao Xu , Jin Changnan , Camargo Arley , Li Yiming
Published: October 2015

Climate change could either directly or indirectly cause population declines via altered temperature, rainfall regimes, food availability or phenological responses. However few studies have focused on allocation trade-offs between growth and reproduction under marginal resources, such as food scarce that may be caused by climate warming. Such critical changes may have an unpredicted impact on amphibian life-history parameters and even population dynamics. Here, we report an allocation strategy of adult anuran individuals involving a reproductive stage under experimental warming. Using outdoor mesocosm experiments we simulated a warming scenario likely to occur at the end of this century. We examined the effects of temperature (ambient vs. pre-/post-hibernation warming) and food availability (normal vs. low) on reproduction and growth parameters of pond frogs (Pelophylax nigromaculatus). We found that temperature was the major factor influencing reproductive time of female pond frogs, which showed a significant advancing under post-hibernation warming treatment. While feeding rate was the major factor influencing reproductive status of females, clutch size, and variation of body size for females, showed significant positive correlations between feeding rate and reproductive status, clutch size, or variation of body size. Our results suggested that reproduction and body size of amphibians might be modulated by climate warming or food availability variation. We believe this study provides some new evidence on allocation strategies suggesting that amphibians could adjust their reproductive output to cope with climate warming.
Two continents and two names for a Neotropical colletid bee species (Hymenoptera: Colletidae: Neopasiphaeinae):Hoplocolletes ventralis(Friese, 1924)
Authors: Almeida Eduardo A.B. , Quinteiro Fábio B.
Published: October 2015

Neopasiphaeine bees (Apoidea: Colletidae) are known for their Amphinotic distribution in the Australian and Neotropical regions. Affinities between colletid taxa in Australia and South America have been speculated for decades, and have been confirmed by recent phylogenetic hypotheses that indicate a biogeographic scenario compatible with a trans-Antarctic biotic connection during the Paleogene. No neopasiphaeine species occurs on both sides of the Pacific Ocean, but the Neotropical speciesHoplocolletes ventralis(Friese, 1924) was described as an Australian taxon due to an error in the specimen labels. This mistake was recognized by CD Michener 50 years ago. We herein report that the same labeling problem also happened withDasycolletes chalceusFriese, 1924, which remained as a tentatively placed species in the Australian genusLeioproctusuntil now. Moreover,Dasycolletes chalceusis interpreted as a synonym ofHoplocolletes ventralis. We also provide a revised diagnosis forHoplocolletes, describe the male ofH. ventralisin detail for the first time, including a comparative study of its genitalia and associated sterna.
Détresse psychologique chez les professionnels et professionnelles exerçant une profession réglementée : facteurs explicatifs et pistes de réflexion
Authors: Cadieux Nathalie , Marchand Alain
Published: October 2015

Cette étude vise à cerner les conditions de travail expliquant le niveau de détresse psychologique chez les professionnels et professionnelles exerçant une profession réglementée au Canada. Des analyses de régression multiples multiniveaux furent conduites à partir des données longitudinales de l'Enquête nationale sur la santé de la population (ENSP) où les mesures répétées dans le temps (n1 = 1 727) sont nichées dans les individus (n2 = 276). Les résultats tendent à démontrer que seules les heures travaillées contribuent de manière significative à l'expérience de détresse psychologique dans ces professions et que plus la consommation d'alcool augmente, plus l'utilisation des compétences élève le niveau de détresse psychologique.
Ion acceleration and reflection on magnetotail antidipolarization fronts
Authors: Zhou Xu‐Zhi , Pan Dong‐Xiao , Angelopoulos Vassilis , Liu Jiang , Runov Andrei , Li Shan‐Shan , Li Jia‐Zheng , Zong Qiu‐Gang , Fu Sui‐Yan
Published: October 2015

Antidipolarization fronts (ADFs), tailward moving structures in the Earth's magnetotail with sharp decreases in their magnetic Bz component, are thought to be mirror images of earthward propagating dipolarization fronts (DFs) generated on the opposite side of the reconnection site. We use ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun) observations and numerical simulations to study the role of ADFs in accelerating and reflecting ambient plasma sheet ions. In both case and statistical observations before ADF arrival, tailward streaming, energy‐dispersed ions are seen first. After about 1 min, the ion fluxes are enhanced significantly with the peak shifted duskward, and then the peak gradually shifts back to the tailward direction until the ADF arrives. All these signatures are reproduced by our simulation model of ion acceleration and reflection on ADFs. We further examine typical ion trajectories before and after ADF reflection, to understand these seemingly complicated ion signatures as well as their similarities with and differences from the DF preceding signatures.
Vegetation controls on surface heat flux partitioning, and land‐atmosphere coupling
Authors: Williams Ian N. , Torn Margaret S.
Published: October 2015

We provide observational evidence that land‐atmosphere coupling is underestimated by a conventional metric defined by the correlation between soil moisture and surface evaporative fraction (latent heat flux normalized by the sum of sensible and latent heat flux). Land‐atmosphere coupling is 3 times stronger when using leaf area index as a correlate of evaporative fraction instead of soil moisture, in the Southern Great Plains. The role of vegetation was confirmed using adjacent flux measurement sites having identical atmospheric forcing but different vegetation phenology. Transpiration makes the relationship between evaporative fraction and soil moisture nonlinear and gives the appearance of weak coupling when using linear soil moisture metrics. Regions of substantial coupling extend to semiarid and humid continental climates across the United States, in terms of correlations between vegetation metrics and evaporative fraction. The hydrological cycle is more tightly constrained by the land surface than previously inferred from soil moisture.