Inert Elements Research Articles

Mechanism to improve the reliability of copper wire bonding with palladium-coating of the wire

Pd-coating of Cu (PCC) bond wires has been widely employed to improve the reliability of Cu wire bonding technology for microelectronics. Description of the underlying mechanism, however, is lacking in literature. We provide an interpretation of how the improvement is induced. After an un-biased highly accelerated stress test (uHAST), the most Cu-rich intermetallics (IMC) were Cu3Al2 under the bare Cu bond wire, and predominantly (CuPdx)Al under the PCC wire. The Pd-coating therefore had suppressed the formation of (CuPdx)3Al2. The suppression stemmed from the improvement of the thermodynamic stability of (CuPdx)Al, which also decreased the kinetics of phase transformation toward (CuPdx)3Al2. The cathode/anode area ratio of (CuPdx)Al is lower than that of Cu3Al2. The corrosion rate of (CuPdx)Al therefore becomes lower, and the reliability of the wire bonding increases. Ni behaves thermodynamically quite similar to Pd in the ternary system of Cu wire bonding, and therefore possesses the potential to similarly improve the corrosion resistance. Furthermore, the use of Al wires on Al alloy pads will implement a monometallic system across the bonding interface which can also enhance the corrosion resistance. The underlying correlation between the atomic ratio of (Inert Element)/(Active Element) of the IMC and the corrosion rate of the IMC revealed here is pertinent to the research in other fields including the corrosion of alloys/dealloying and nanoporosity, and the making of functional materials with nanoporosity for applications such as catalysis and advanced energy technologies.

Multiple superionic states in helium–water compounds

Superionic states are phases of matter that can simultaneously exhibit some of the properties of a liquid and of a solid. For example, in superionic ice, hydrogen atoms can move freely while oxygen atoms are fixed in their sublattice. ‘Superionicity’ has attracted much attention in both fundamental science and applications. Helium is the most inert element in nature and it is generally considered to be unreactive. Here, we use ab initio calculations to show that He and H2O can form stable compounds within a large pressure range that can exist even close to ambient pressure. Surprisingly, we find that they can form two previously unknown types of superionic state under high pressure and high temperature. In the first of these phases, the helium atoms exhibit liquid behaviour within a fixed ice-lattice framework. In the second phase, both helium and hydrogen atoms move in a liquid-like fashion within a fixed oxygen sublattice. As the He–O interaction is weaker than the H–O interaction, the helium atoms in these superionic states have larger diffusion coefficients and lower ‘melting’ temperatures than those of hydrogen, although helium is heavier than hydrogen. The insertion of helium atoms substantially decreases the pressure at which superionic states may be formed, compared to those in pure ice. Superionic states of matter simultaneously exhibit some of the properties of a liquid and of a solid. Detailed numerical simulations predict two superionic phases in mixtures of helium and water.

Optimal design and experimental research of vehicle suspension based on a hydraulic electric inerter

As the mechanical dual of a capacitor via the force-current analogy, an inerter has been successfully applied in various fields such as automotive engineering, civil engineering and aerospace engineering. The introduction of an inerter not only allows the use of network synthesis analogy to design mechanical layouts but also opens the door to adopt electrical element impedances to simulate the corresponding mechanical elements. This paper combines both of these ideas and presents a new form of a mechatronic inerter, namely the hydraulic electric inerter (HEI), which consists of a hydraulic piston inerter and a linear motor. On the basis of the HEI device, a bicubic impedance function is considered in the optimal design of a vehicle suspension system employing both mechanical elements and electrical elements. In addition, a methodology for reducing the order of the bicubic impedance function is proposed, and the network is finally realized by utilizing inerter, spring and damper elements. Then, by comparison with a passive suspension, the advantages of the new vehicle ISD (inerter-spring-damper) suspension, called the vehicle HE-ISD (hydraulic electric-inerter spring damper) suspension, are demonstrated by numerical simulations. Finally, a HEI device is designed, and bench tests of the vehicle HE-ISD suspension are carried out. Experimental results indicate that, the vehicle HE-ISD suspension is superior to the passive suspension system, the RMS (root-mean-square) value of the suspension working space is improved by 19.97%, and the RMS value of the dynamic tire load is improved by 10.21%.

An inactive metal supported oxide cathode material with high rate capability for sodium ion batteries

Sodium ion batteries (SIBs) are considered to be one of the most promising large-scale energy storage systems. However, the lack of high-performance cathode materials has challenged its development. Herein, a new P2-type Na0.8Li0.1Mn0.6Ni0.2Cu0.1O2 cathode material is designed and synthesized via coprecipitation method for the first time. As inert elements, Li play the role of structural supporting site in prismatic lattice to reinforce overall crystals, so that the material maintains high structural stability in the process of Na+ intercalation/deintercalation. The charge and discharge tests exhibit that it delivers a reversible capacity of 135.1 mA h g−1 at 0.1C with high retention of 83.1% after 100 cycles. Besides, it still keeps a retention of 81.7% after 400 cycles at 1 A g−1 with initial capacity of 84.7 mA h g−1. The large lattice spacing, monophasic reaction and high sodium diffusivity are the guarantee of excellent electrochemical performance. Therefore, this work is significant for the development of promising new Na ion insertion cathode.

Identification of beneficial mass-included inerter-based vibration suppression configurations

Vibration suppression capabilities of linear passive vibration absorbers, such as traditional tuned mass damper (TMD), and recently proposed inerter-based vibration absorbers, have been studied for multiple mechanical systems. In particular, significant performance advantages have been obtained with a specific device making use of both inerter and mass elements, namely the tuned mass damper inerter (TMDI). However, there are still countless mass-included inerter-based configurations that have not been studied, which can potentially provide more preferred dynamic properties. In this paper, an immittance-function-layout (IFL) is introduced, which can cover a large range of topological connection possibilities with both mass and inerter elements. With the recently proposed structural immittance format, a systematic approach is established to identify the most beneficial IFL type mass-included inerter-based configurations with pre-determined number of each element type. Vibration suppression performance with single-IFL type device and two parallel-connected IFLs (i.e. dual-IFL) type devices are investigated in this paper. Three optimal configurations are identified for mitigating the maximum inter-storey drift of an example 3-storey building model subjected to base excitation. With this 3-storey building model, results show that, for the optimum single-IFL configuration, the performance improvement is 7.3% compared with the optimum TMDI, and with identified beneficial dual-IFL configurations, up to 34.9% performance advantages are obtained. Furthermore, consistent performance gains are shown under real-life earthquake inputs and with a 10-storey building model using identified absorber configurations.

Rational design of an argon-binding superelectrophilic anion

Chemically binding to argon (Ar) at room temperature has remained the privilege of the most reactive electrophiles, all of which are cationic (or even dicationic) in nature. Herein, we report a concept for the rational design of anionic superelectrophiles that are composed of a strong electrophilic center firmly embedded in a negatively charged framework of exceptional stability. To validate our concept, we synthesized the percyano-dodecoborate [B12(CN)12]2-, the electronically most stable dianion ever investigated experimentally. It serves as a precursor for the generation of the monoanion [B12(CN)11]-, which indeed spontaneously binds Ar at 298 K. Our mass spectrometric and spectroscopic studies are accompanied by high-level computational investigations including a bonding analysis of the exceptional B-Ar bond. The detection and characterization of this highly reactive, structurally stable anionic superelectrophile starts another chapter in the metal-free activation of particularly inert compounds and elements.

Structural Design and Inertial Impact Analysis of Vehicle ISD Suspension

This paper concerns the impact of inerter element on the vehicle suspension system. On the basis of the analysis of three simple elements’ networks including one inerter, one spring and one damper, the improved networks are further proposed. A quarter-vehicle model is considered, and the three performance indexes, namely the body acceleration, suspension working space and dynamic tire load are taken into account. With the increase of the inertance value, numerical simulations are carried out and the influences on the performance indexes, the partial frequencies and the dominant frequencies are discussed in detail. Results indicate that the value of the partial frequencies and the dominant frequencies will reduce effectively by increasing the inertance value of the suspension system. At last, two type suspension layouts are analysed by comparing to a passive suspension, and their performance advantages are also validated.

Resonant inerter based vibration absorbers on flexible structures

The paper presents an explicit two-step calibration procedure for tuned inerter based vibration absorbers on flexible structures. It makes use of a local approximate representation of the structural response to the device force, in which the contribution of the non-resonant modes is represented approximately around the resonance frequency by a background flexibility and a background inertia term. The calibration procedure then consists of two steps. The first step calibrates an equivalent vibration absorber including the background terms, and the second step subsequently evaluates the parameters of the actual device by extracting the background flexibility and inertia parameters. The first step represents the classic idealized single degree of freedom representation of the structure, whereas the second step leads to an increase of stiffness, inertia and damping parameters of the actual device due to background flexibility of the structure. The procedure is illustrated in detail for three inerter based vibration absorbers: parallel coupling of damper and stiffness, parallel coupling of damper and inerter, and finally a device with two dampers in parallel with stiffness and inerter elements, respectively. Explicit expressions for the calibration are obtained for each device, and it is demonstrated that the procedure leads to a balanced plateau of amplification around the resonance frequency of the magnitude assumed as the basis for the device parameter calibration.

Dynamic characteristics of multiple inerter based dampers for suppressing harmonically forced oscillations

Based on the ball-screw mechanism, a tuned viscous mass damper (TVMD) has been proposed, which has functions of amplifying physical mass of the system and frequency tuning. Considering the sensitivity of a single TVMD\'s effectiveness to frequency mistuning like that of the conventional tuned mass damper (TMD) and according to the concept of the conventional multiple tuned mass damper (MTMD), in the present paper, multiple tuned mass viscous dampers (MTVMD) consisting of many tuned mass dampers (TVMD) with a uniform distribution of natural frequencies are considered for attenuating undesirable vibration of a structure. The MTVMD is manufactured by keeping the stiffness and damping constant and varying the mass associated with the lead of the ball-screw type inerter element in the damper. The structure is represented by its mode-generalized system in a specific vibration mode controlled using the mode reduced-order method. Modal properties and fundamental characteristics of the MTVMD-structure system are investigated analytically with the parameters, i.e., the frequency band, the average damping ratio, the tuning frequency ratio, the total number of TVMD and the total mass ratio. It is found that there exists an optimum set of the parameters that makes the frequency response curve of the structure flattened with smaller amplitudes in a wider input frequency range. The effectiveness and robustness of the MTVMD are also discussed in comparison with those of the usual single TVMD (STVMD) and the results shows that the MTVMD is more effective and robust with the same level of total mass.

Modeling of combustion synthesis in multilayer gasless system

A combustion model for a flat layered composition has been developed, where chemically active layers alternate with inert metallic layers with high thermal conductivity. The heat exchange between the layers was specified by the conjugate boundary conditions. A numerical study of gasless combustion of a multi-layer system with heat-conjugated layers of two types was performed. Optimal layer sizes and parameters of the layer system were obtained to provide the maximum burning rate of the layer package. The effect of increasing the burning rate was found to be associated with heat recovery and an increase in the effective thermal conductivity of the system. The concentration limits of combustion were determined depending on the volume content of the inert element. Replacing the system of inert layers with that of low-calorie mixture layers leads to a model for synthesis of inorganic materials in the "chemical furnace" mode.

Metal‐Dependent Support Effects of Oxyhydride‐Supported Ru, Fe, Co Catalysts for Ammonia Synthesis

AbstractAmmonia is an attractive energy carrier for the hydrogen economy, given its high hydrogen density and ease of liquefaction. A titanate oxyhydride has recently been demonstrated that can catalyze ammonia synthesis without Ru or Fe metal, despite titanium being regarded as an inert element. Here, the synthesis activity of ammonia is examined when Ru, Fe, and Co particles are supported onto the oxyhydride BaTiO2.5H0.5. The activity of BaTiO2.5H0.5 as support is significantly higher than BaTiO3. For example, the activity for Fe and Co increases by a factor of 70–400, making them more active than Ru/MgO, one conventional Ru catalyst. In terms of mechanism, for Ru, H/D isotope studies show participation of lattice hydride in the catalytic cycle, while kinetic analysis shows reduced H2 poisoning probably due to spillover. For Fe (and Co), the presence of hydride results in significantly lower activation energy and N2 reaction order, likely due to strong electron donation from the oxyhydride. This metal‐dependent support effect is further verified by N2 isotopic exchange experiments. These perovskite‐type oxyhydrides can be easily modified in terms of A‐ and B‐site (A = Ba, B = Ti); the high potential for compositional variation and morphologies will expand the search for efficient catalysts for ammonia synthesis.

L’Arbre Caigut, 2018.

Photographic selection of parts of the work "L'arbre caigut", included in Projecte L (Project L), a set of works from the period 22/02/2017 - 02/22/2018. The deterioration of a plum folded after a storm and the peculiar position it adopts, between two different heights, frozen in a brief temporary period. The body of the tree, reconstructed inside an exhibition, accompanied by elements of its original habitat, and of two nocturnal images, propose a reflexive truce on the presence of inert elements and on the imprecise limits of life.

Old puzzle of incommensurate crystal structure of calaverite AuTe2 and predicted stability of novel AuTe compound

Gold is a very inert element, which forms relatively few compounds. Among them is a unique material-mineral calaverite, [Formula: see text] Besides being the only compound in nature from which one can extract gold on an industrial scale, it is a rare example of a natural mineral with incommensurate crystal structure. Moreover, it is one of few systems based on Au, which become superconducting (at elevated pressure or doped by Pd and Pt). Using ab initio calculations we theoretically explain these unusual phenomena in the picture of negative charge-transfer energy and self-doping, with holes being largely in the Te [Formula: see text] bands. This scenario naturally explains incommensurate crystal structure of [Formula: see text], and it also suggests a possible mechanism of superconductivity. An ab initio evolutionary search for stable compounds in the Au-Te system confirms stability of [Formula: see text] and [Formula: see text] and leads to a prediction of an as yet unknown stable compound AuTe, which until now has not been synthesized.

Boosting performance of lanthanide magnetism perovskite for advanced oxidation through lattice doping with catalytically inert element

ABO3-type perovskite oxides, characterized by high structural flexibility, have found potential applications in many redox processes, including as catalysts for advanced oxidation in wastewater remediation. Here, we demonstrated that by doping the generally believed catalytically inert A-site of LaMnO3 (LMO) perovskite with strontium, the catalytic performance for advanced oxidation is surprisingly boosted. Specifically, La0.4Sr0.6MnO3-δ (LSMO46) was designed which exhibited a high specific activity (0.0608 min−1 m−2) for peroxymonosulfate (PMS) activation, ∼6 times that of LMO and ∼41 times that of reported nanosized MnFe2O4 and Fe/Fe3C. The superior activity was also embodied by low activation energy (44.3 kJ mol−1). Moreover, LSMO46 displayed a lower metal leaching and a better reusability than LMO and Fe/Fe3C and easy catalyst recovery for its magnetic behavior. Such enhanced catalytic activity was attributed to the positively-charged surface (8.3 mV) that favored the adsorption of negatively-charged organics and the presence of a large amount of surface anion defects (oxygen vacancies), created by the doping, that induced the generation of considerable amount of singlet oxygen (1O2) which was demonstrated as the dominant reactive species by selective radical scavenging and EPR trapping. A coupled activation mechanism involving major singlet oxygen and minor free radicals was further proposed for the effective decomposition of organics in LSMO46/PMS system. The findings in this study thus provide us a new strategy for the development of efficient catalysts for advanced oxidation in environmental treatment.

THE DEVICE FOR MEASURING COLOUR

In this paper, the authors propose a device for measuring the color characteristics of light reflected or transmitted through an optical medium. The main element of this device is the measuring transducer, which assigns to each radiation three signals proportional to the color coordinates. Existing devices have many drawbacks, among which low speed, due to the use of inert elements, which makes it impossible to measure rapidly changing light fluxes. In this device, the authors tried to minimize these limitations by using photodiodes and a microcontroller with a built-in ADC and other devices.. Also in this article, a mathematical model of the device is proposed. Attention is paid to psychophysiological perception of color. As a result, we found a device that has a number of advantages over its counterparts, which makes it possible to perform color measurement with higher accuracy.

Electrodeposition of Mg-Based Alloys for Anti-Corrosion and Energy Storage Applications

Magnesium has gained a lot of attention due to its inherent properties such as light-weight with a density of 1.7 g/cm3 and the highest strength to weight ratio. Such unique properties make magnesium a suitable candidate for various applications including vehicles, aerospace projects, construction, energy storage applications and medical implants. One of the crucial issues with the use of magnesium on these applications is the tendency of the material to corrode. This is due to the high chemical activity of magnesium, its standard equilibrium potential of Mg/Mg2+ is -2.4 V vs. NHE. To prevent these problems, there have been reported strategies such as formation of alloys with noble metals or inert elements and the protection of the metal with a coating film.1 From the mentioned solutions, the most suitable solutions to prevent corrosion on magnesium without compromising its properties are the formation of alloys using passive elements such as Al, Ni or Cr and the protection of magnesium with a coating film. 2,3 Based on these two solutions, we propose to use aluminum as the second element for the alloy formation to prevent corrosion of magnesium and to enhance its structural, thermal, and electrical performance. In our study, we’ve been able to produce magnesium alloys by electro-co-deposition which have demonstrated to have a lower corrosion behavior compared to pristine magnesium films. Similarly, magnesium-based materials are gaining interest in energy storage application due to two-electron transfer per a reaction and thus a high volumetric capacity compared to the state-of-art Li-ion batteries. Also, they have shown to be safer than Li since Mg during cycling do not form dendrites.4 Herein, we explore the use of electro-co-deposited Mg-Al alloy as electrodes to construct high energy rechargeable Mg batteries. References (1) Esmaily, M.; Svensson, J. E.; Fajardo, S.; Birbilis, N.; Frankel, G. S.; Virtanen, S.; Arrabal, R.; Thomas, S.; Johansson, L. G. Fundamentals and Advances in Magnesium Alloy Corrosion. Prog. Mater. Sci. 2017, 89, 92–193. (2) Liu, R. L.; Scully, J. R.; Williams, G.; Birbilis, N. Reducing the Corrosion Rate of Magnesium via Microalloying Additions of Group 14 and 15 Elements. Electrochim. Acta 2018, 260, 184–195. (3) Yuwono, J. A.; Birbilis, N.; Liu, R.; Ou, Q.; Bao, Q.; Medhekar, N. V. Aqueous Electrochemical Activity of the Mg Surface: The Role of Group 14 and 15 Microalloying Elements. J. Electrochem. Soc. 2017, 164 (13), C918–C929. (4) Bucur, C. B. Challenges of a Rechargeable Magnesium Battery A Guide to the Viability of This Post Lithium-Ion Battery, 1st editio.; Spinger Briefs in Energy, 2018.

Petrogenesis of South Armorican serpentinized peridotites

Twenty three serpentinite samples collected from five outcrops in south Brittany (Audierne near Quimper, Champtoceaux near Nantes), western France, were studied using optical microscopy, electron microprobe (EMP), inductively-coupled optical emission spectroscopy (ICP-OES), inductively-coupled plasma mass spectrometry (ICP-MS), and laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS). Their bulk-rock major and trace element contents recomputed on an anhydrous basis are broadly characteristic of mantle-derived peridotites, as are the covariation trends of inert elements despite evidence of serpentinization-related remobilization of some fluid-mobile elements (FME; e.g., Ca, La, Ce, Sr, U). One outcrop near Champtoceaux shows fertile lherzolite compositions and chondrite-normalized rare earth element patterns consistent with low (5–7%) degree of mantle partial melting. The other four occurrences are harzburgites displaying higher partial melting degrees (15–25%). Regardless of their degree of fertility, our South Armorican peridotites bear evidence of high-temperature melt/fluid - rock metasomatic interaction yielding an overall enrichment in highly incompatible elements (HIE; Cs, Rb, Ba, Th, U, Pb, La). Hydrous modal metasomatism has been identified in both lherzolites and harzburgites. The lherzolites reacted with HIE-enriched small-volume fluids at P = 1.5–2 Gpa for T > 900 °C that produced a Ti-poor pargasite. The Audierne harzburgites were pervasively refertilized by alkali-rich hydrous melts that precipitated K- and Cr-rich pargasite. Taken as a whole, South Armorican peridotites record a great diversity of protoliths, from supra-subduction zone ophiolites (Audierne) to arc-fore arc provenance.

Improvement of the lateral stability of vehicle suspension incorporating inerter

As a newly proposed two terminals mechanical element, inerter has been successfully applied in vehicle suspension system to improve its vertical vibration isolation performance. The novelty of this paper is to explore the advantages of lateral stability of vehicle suspension by the use of inerter element. A full car model considering the steering condition is built, and the standard fishhook steering input is chosen to test the lateral stability of the suspension system. By considering the ride comfort performance and the rollover resistance performance, three basic suspension layouts incorporating inerter element are optimized by means of genetic algorithm. Constraints of the suspension working space and road holding ability are also taken into account during the optimization. Two steering input condition, namely the sine-steer input and the fishhook steer input are performed to evaluate the vehicle suspension performance. Results show that, the ride comfort and the lateral stability of the vehicle suspension system can be synchronously improved by including the inerter element.

Dispersion transitions and pole-zero characteristics of finite inertially amplified acoustic metamaterials

This work presents a comprehensive analysis of wave dispersion patterns and band gap formation associated with Inertially Amplified Acoustic Metamaterials (IAAM). The findings explain the different mechanisms by which inertial amplification affect wave dispersion in the individual IAAM cell as well as the evolution of such effects in finite configurations of these cells. Derived expressions for acoustic wave dispersion in IAAMs reveal unique features including flat dispersion branches with zero group velocity and a transition from a metamaterial (local resonance) to a phononic behavior that is directly related to the location and magnitude of the inerter elements. Using a closed-form transfer function approach, the translation of such effects to IAAM realizations with a known number of cells is interpreted from the pole-zero distributions of the resultant finite structures. It is also shown that band gaps are not always necessarily enlarged in the presence of inertial amplification. Comparing with benchmark conventional acoustic metamaterials, the conditions leading up to favorable as well as inferior IAAM designs are fully derived. Finally, an alternative resonator-free acoustic metamaterial is presented and shown to exhibit local resonance effects under appropriately tuned conditions.

An inerter-based active vibration isolation system

This paper presents a theoretical study on passive and active vibration isolation schemes using inerter elements in a two degree of freedom (DOF) mechanical system. The aim of the work is to discuss basic capabilities and limitations of the vibration control systems at hand using simple and physically transparent models. Broad frequency band dynamic excitation of the source DOF is assumed. The purpose of the isolator system is to prevent vibration transmission to the receiving DOF. The frequency averaged kinetic energy of the receiving mass is used as the metric for vibration isolation quality. It is shown that the use of inerter in the passive and active vibration isolation schemes considered enhances the isolation effect.