Temperature Cycling Experiments Research Articles

<italic> In Situ</italic> Interconnect Failure Prediction Using Canaries

A physics-of-failure-based canary approach for early identification of solder interconnect failures has been developed. The canary is composed of a resistance path formed by a near-zero ohm ceramic chip resistor soldered to pads designed to produce failure earlier than standard pad resistors, which are the target structures. The time to failure of the canary can be adjusted by adjusting the printed wiring board pad dimensions and, hence, the solder interconnect area. The developed canary approach is demonstrated through temperature cycling of the resistors. The pad width of a standard resistor is reduced by 80%, thereby reducing the interconnect life. The results from the temperature cycling experiment prove that the developed canary approach provides advanced warning of failures of the standard pad resistors. The FEA results suggest that there is a 78% increase in the strain range in the canary resistor, as compared with the standard resistor. The Engelmaier model, a physics-of-failure-based model for solder interconnect life estimation under thermal cycling, is modified to take the solder interconnect area into account. The model provides time to failure estimates for the canary and target structures. A comparison of the results from the Engelmaier model and temperature cycling experiment shows that the model provides a good estimate of time to failure of standard resistors and a conservative estimate of time to failure of the canary resistors.

Spin-glass-like dynamics of ferromagnetic clusters in La0.75Ba0.25CoO3

We report a magnetization study of the compound La0.75Ba0.25CoO3 where the Ba2+ doping is just above the critical limit for percolation of ferromagnetic clusters. The field cooled and zero-field cooled (ZFC) magnetization exhibit thermomagnetic irreversibility and the ac susceptibility shows a frequency dependent peak at the ferromagnetic ordering temperature (TC ≈ 203 K) of the clusters. These features indicate the presence of a non-equilibrium state below TC. For the non-equilibrium state, the dynamic scaling of the imaginary part of the ac susceptibility and the static scaling of the nonlinear susceptibility clearly establish a spin-glass-like cooperative freezing of ferromagnetic clusters at 200.9(2) K. The assertion of the occurrence of spin-glass-like freezing of ferromagnetic clusters is further substantiated by ZFC ageing and memory experiments. We also observe certain dynamical features which are not present in a typical spin glass, such as: the initial magnetization after ZFC ageing first increases and then decreases with the waiting time; and there is an imperfect recovery of relaxation in negative temperature cycling experiments. This imperfect recovery transforms to perfect recovery for concurrent field cycling. Our analysis suggests that these additional dynamical features have their origin in the inter-cluster exchange interaction and cluster size distribution. The inter-cluster exchange interaction above the magnetic percolation level gives a superferromagnetic state in some granular thin films, but our results show the absence of a typical superferromagnetic-like state in La0.75Ba0.25CoO3.

Fabricating optical fibre-top cantilevers for temperature sensing

In this paper, we propose techniques to fabricate micro-cantilevers onto the end of standard single mode optical fibres using a combination of picosecond laser machining and focused ion beam milling techniques and demonstrate their use as temperature sensors. Using this approach the cantilever can be pre-aligned with the core of the fibre during fabrication, therefore offering a stable and straightforward means of optically addressing the cantilever. The cantilever is designed to measure deflection over a range of 10 µm using a simple readout technique. A phase recovery algorithm is employed to reduce the interrogation error to around 2–3 nm. Finally, a temperature cycling experiment demonstrates that the cantilever could be used as a temperature sensor from room temperature to 500 °C with an average rms temperature error from 20 °C to 500 °C of ∼±1.4 °C.

Modification of Crystal Shape through Deep Temperature Cycling

The evolution of particle shape is an important consideration in many industrial crystallizations. This article describes the design of temperature-cycling experiments (between alternating positive and negative supersaturations) to substantially change crystal shape with only a small number of cycles. The growth and dissolution of monosodium glutamate crystals of varying shapes were monitored using in-process attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), focused beam reflectance measurement (FBRM), particle vision and measurement (PVM), and off-line optical microscopy. The growth and dissolution kinetics were estimated in a multidimensional population balance model based on solute concentration and crystal dimension measurements. This model fitted the experimental data with a limited number of parameters of small uncertainty. In addition, with the estimated kinetic parameters, the model predicted the crystal size and shape distribution in a different temperature-cycling e...

Preparation and properties studies of paraffin/high density polyethylene composites and phase-change coatings

The form-stable paraffin/high density polyethylene (HDPE) composites and phase-change coatings were prepared and characterized in this study. The paraffin acts as thermal absorbing material and HDPE serves as the supporting material, which provides structural strength and prevents the leakage of melted paraffin. Scanning electronic microscope (SEM) showed that the paraffin is dispersed uniformly into porous network of HDPE. Differential scanning calorimeter (DSC) determined the melting temperature and heat storage capacity of the composite piece to be 49.6°C and 150.88kJ/kg, respectively. Moreover, results indicated that the composite pieces showed better thermal stability than composite powders after 6 temperature cycling experiments. The phase-change coatings with 40wt% composites as functional filler showed good adhesion strength and shock resistance, and could decrease the surface temperature obviously comparing with nude Al alloy plates.

Simple feed-through for coupling optical fibres into high pressure and temperature systems

A best practice guide for assembling and testing a simple and inexpensive system feeding an optical fibre into a high pressure and temperature environment is presented. A standard Swagelok-type connector is tested together with different ferrule materials and a PEEK capillary tube as feed-through. The system proved to seal an optical fibre during several pressure and temperature cycling experiments up to 500 bar and 180 °C.

Generation of Accelerated Stability Experiment Profile of Inertial Platform Based on Finite Element

The residual stress generated in the manufacturing process of inertial platform causes the drift of inertial platform parameters in long-term storage condition. However, the existing temperature cycling experiment could not meet the increased repeatability technical requirements of inertial platform parameters. In order to solve this problem, in this paper, firstly the Unigraphics (UG) software and the interface compatibility of ANSYS software are used to establish the inertial platform finite element model. Secondly, the residual stress is loaded into finite element model by ANSYS function editor in the form of surface loads to analyze the efficiency. And then, the generation based on ANSYS simulation inertial platform to accelerate the stability of experiment profile is achieved by the application of the analysis method of orthogonal experimental design and ANSYS thermal-structural coupling. The optimum accelerated stability experiment profile is determined finally, which realizes the rapid, effective release of inertial platform residual stress. The research methodology and conclusion of this paper have great theoretical and practical significance to the production technology of inertial platform.

Temperature-Dependent Competition between Adsorption and Aggregation of a Cellulose Ether—Simultaneous Use of Optical and Acoustical Techniques for Investigating Surface Properties

Adsorption of the temperature-responsive polymer hydroxypropylmethylcellulose (HPMC) from an aqueous solution onto hydrophobized silica was followed well above the bulk instability temperature (T(2)) in temperature cycle experiments. Two complementary techniques, QCM-D and ellipsometry, were utilized simultaneously to probe the same substrate immersed in polymer solution. The interfacial processes were correlated with changes in polymer aggregation and viscosity of polymer solutions, as monitored by light scattering and rheological measurements. The simultaneous use of ellipsometry and QCM-D, and the possibility to follow layer properties up to 80 °C, well above the T(2) temperature, are both novel developments. A moderate increase in adsorbed amount with temperature was found below T(2), whereas a significant increase in the adsorbed mass and changes in layer properties were observed around the T(2) temperature where the bulk viscosity increases significantly. Thus, there is a clear correlation between transition temperatures in the adsorbed layer and in bulk solution, and we discuss this in relation to a newly proposed model that considers competition between aggregation and adsorption/deposition. A much larger temperature response above the T(2) temperature was found for adsorbed layers of HPMC than for layers of methyl cellulose. Possible reasons for this are discussed.

Evaluation of the physical annealing strategy for simulated annealing: A function-based analysis in the landscape paradigm

The effectiveness of the actual annealing strategy in finite-time optimization by simulated annealing (SA) is analyzed by focusing on the search function of the relaxation dynamics observed in the multimodal landscape of the cost function. The rate-cycling experiment, which was introduced in the previous study [M. Hasegawa, Phys. Rev. E 83, 036708 (2011)] to examine the role of the relaxation dynamics in optimization, and the temperature-cycling experiment, which was developed for a laboratory experiment on relaxation-related phenomena, are conducted on two types of random traveling salesman problems (TSPs). In each experiment, the SA search starting from a quenched solution is performed systematically under a nonmonotonic temperature control used in the actual heat treatment of metals and glasses. The results show that, as in the previous monotonic cooling from a random solution, the optimizing ability is enhanced by allocating a lot of time to the search performed near an effective intermediate temperature irrespective of the annealing technique. In this productive phase, the relaxation dynamics successfully function as an optimizer and the relevant characteristics analogous to the stabilization phenomenon and the acceleration of relaxation, which are observed in glass-forming materials, play favorable roles in the present optimization. This nonmonotonic approach also has the advantage of a wider operation range of the effective relaxation dynamics, and in conclusion, the actual annealing strategy is useful and more workable than the conventional slow-cooling strategy, at least for the present TSPs. Further discussion is given of an illuminating aspect of computational physics analysis in the optimization algorithm research.

Anomalous phase separation in La0.225Pr0.4Ca0.375MnO3: consequence of temperature and magnetic-field cycles

The evolutions of electronic phase separation in manganites La0.225Pr0.4Ca0.375MnO3 are studied by the specific temperature and magnetic-field cycling experiments. It is found that the electronic phase separation state at low temperature can be tuned substantially by temperature and/or magnetic-field cycles. Surprisingly, the initial more ferromagnetic metallic (FMM) nuclei can impede the growth of these nuclei during the cooling process. It implies that there must coexist more than two phases which take part in the complex first-order phase transitions, and the charge-disordered insulating phase is possible, one of the parent phases transiting into the FMM phase at low temperature. In addition, the accommodation strain is suggested to control the nucleation and growth of FMM domains.

Magnetic order, aging, and spin frustration in a percolating spin system, LiNi0.8Co0.1Mn0.1O2

Structural and magnetic properties of the Li layered oxide, LiNi0.8Co0.1Mn0.1O2, have been studied by means of x-ray diffraction, dc magnetization, ac linear, and nonlinear susceptibility as well as by magnetic aging and temperature cycling experiments. A percolating spin system interacting via antiferromagnetic and ferromagnetic superexchange interactions of different strength induce a ferrimagnetic quasilong-range order with a transition temperature Tc≈70 K, a Weiss temperature of −25 K and an effective magnetic moment of 2.07 μB. On cooling below Tc the two-dimensional (2D) triangular lattice built up of edge-sharing metal oxide octahedras first exhibits a 2D spin glass like behavior followed by complete spin frustration in three dimensions below 30 K. The findings correlate well with expectations for a ferrimagnetic reentrant cluster glass system as well as with predictions of the percolating cluster model.

IR thermography and FEM simulation analysis of on-chip temperature during thermal-cycling power-metal reliability testing using in situ heated structures

A calibrated system for power metal reliability analysis in smart power technology chips is presented. This system is mainly designed for temperature evaluation during temperature-cycling experiments. Infrared camera measurements under single shot high energy pulses are correlated with electro-thermal finite element simulation and failure analysis. A special test structure, containing poly-silicon heaters, is used to produce thermal stress. The location of a hot spot agrees well with the position of degraded power metal.

Phenomenological theory of nonergodic phenomena in dipole- and spin-glasses

The path-dependent magnetizations (polarizations) and susceptibilities in dipole- and spin-glasses are described analytically for the standard protocols of temperature and field variations using the phenomenological Landau-type description of multiple metastable states in the nonergodic phases. The immediate manifestation of metastable states’ multiplicity as staircases of magnetizations (polarizations) curves in the temperature cycling experiments is explained and described. The obtained results are in a reasonable qualitative agreement with the existing experimental data.

Shape memory and martensite deformation response ofNi2MnGa

The purpose of this paper is twofold: to establish the magnitudeof detwinning stress levels of non-modulated martensite inNi53Mn25Ga22 as a function of heat treatments utilizing single crystals, and to study the shapememory strains from constant-load temperature cycling experiments for agedand unaged conditions. The maximum transformation strains of 5.2% areconsistent with the theoretical predictions based on energy minimization theory.The results exhibit a remarkable narrowing of the thermal hysteresis (as low as2 °C) with increasing applied stress and a considerable two-way shape memory effect. Usingmicroscopy, it is shown that aging produces a finer martensitic plate structurewith an accompanying increase in detwinning stress compared to the unagedcase.

Aging, rejuvenation, and memory effects in the domain state of Sr0.75Ba0.25Nb2O6

The dielectric susceptibility of strontium–barium niobate, Sr0.75Ba0.25Nb2 O 6, reveals strong hole-like aging behaviour in its ferroelectric state. The isothermal evolution of the linear susceptibility satisfactorily follows a stretched exponential law. After aging the sample at a selected temperature both rejuvenation and memory effects are observed in temperature cycle experiments. They seem to indicate cluster glass-like properties of the domain state involved.

Highly stable persistent spectral hole burning in Eu3+ ions doped oxy-fluoride glasses of 30CaF2–10Al2O3–60B2O3

High temperature persistent spectral hole burning up to room temperature has been observed in Eu3+ ions doped oxy-fluoride glasses with a composition of 30CaF2–10Al2O3–60B2O3 (mol%) melted in a reducing atmosphere. The hole stability was studied through light-induced hole refilling and temperature cycling experiments. The burned holes survive thermal cycling to 300K due to a high barrier height of 0.69eV in the sample.

A method for screening the temperature dependence of three-dimensional crystal formation

Temperature is an important parameter controlling protein crystal growth. A new temperature-screening system (Thermo-screen) is described consisting of a gradient thermocycler fitted with a special crystallization-plate adapter onto which a 192-well sitting-drop crystallization plate can be mounted (temperature range 277-372 K; maximum temperature gradient 20 K; interval precision 0.3 K). The system allows 16 different conditions to be monitored simultaneously over a range of 12 temperatures and is well suited to conduct wide (approximately 20 K) and fine (approximately 3 K) temperature-optimization screens. It can potentially aid in the determination of temperature phase diagrams and run more complex temperature-cycling experiments for seeding and crystal growth.

Laser-Driven Microsecond Temperature Cycles Analyzed by Fluorescence Polarization Microscopy

We demonstrate a novel technique to achieve fast thermal cycles of a small sample (a few femtoliters). Modulating a continuous near-infrared laser focused on a metal film, we can drive the local temperature from 130 to 300 K and back, within a few microseconds. By fluorescence microscopy of dyes in a thin glycerol film, we record images of the hot spot, calibrate its temperature, and follow its variations in real time. The temperature dependence of fluorescence anisotropy, due to photophysics and rotational diffusion, gives a steady-state temperature calibration between 200 and 350 K. From 200 to 220 K, we monitor temperature more accurately by fluorescence autocorrelation, a probe for rotational diffusion. Time-resolved measurements of fluorescence anisotropy give heating and cooling times of a few microseconds, short enough to supercool pure water. We designed our method to repeatedly cycle a single (bio)molecule between ambient and cryostat temperatures with microsecond time resolution. Successive measurements of a structurally relevant variable will decompose a dynamical process into structural snapshots. Such temperature-cycle experiments, which combine a high time resolution with long observation times, can thus be expected to yield new insights into complex processes such as protein folding.

Edwards-Anderson spin glasses undergo simple cumulative aging

We study and discuss rejuvenation and memory (numerical) experiments in Ising and Heisenberg three and four dimensional spin glasses. We introduce a quantitative procedure to analyze the results of temperature cycling experiments. We also run, compare, and discuss ``twin'' couples of experiments. We find that in our systems aging is always cumulative in nature, and rejuvenation and memory effects are also cumulative: they are very different from the ones observed in experiments on spin glass materials.

Nonequilibrium dynamics of spin glasses: Examination of the ghost domain scenario

Extensive experimental and numerical studies of the non-equilibrium dynamics of spin glasses subjected to temperature or bond perturbations have been performed to investigate chaos and memory effects in selected spin glass systems. Temperature shift and cycling experiments were performed on the strongly anisotropic Ising-like system {\ising} and the weakly anisotropic Heisenberg-like system {\AgMn}, while bond shift and cycling simulations were carried out on a 4 dimensional Ising Edwards-Anderson spin glass. These spin glass systems display qualitatively the same characteristic features and the observed memory phenomena are found to be consistent with predictions from the ghost domain scenario of the droplet scaling model.