Stuffed MO layer as a diffusion barrier in metallizations for high temperature electronics

Auger electron spectroscopy was employed to characterize the diffusion barrier properties of molybdenum in the CrSi2/Mo/Au metallization system. The barrier action of Mo was demonstrated to persist even after 2000 hours annealing time at 300 C in a nitrogen ambient. At 340 C annealing temperature, however, rapid interdiffusion was observed to have occurred between the various metal layers after only 261 hours. The presence of controlled amounts of oxygen in the Mo layer is believed to be responsible for suppressing the short circuit interdiffusion between the thin film layers. Above 340 C, its is believed that the increase in the oxygen mobility led to deterioration of its stuffing action, resulting in the rapid interdiffusion of the thin film layers along grain boundaries

Gauging the Relationship Between Contextual Growth and Structural Neglect

Population and land use out-migrations from urban to peripheral areas can result in non-functional, unmaintained historic structures which deteriorate to the point where removal is cheaper than removal – or demolition by neglect. The increasing rate of neglected historic structures is a growing concern. There is a need for research investigating connections between urban growth management and its effect on neglect. This paper applies Newman\u27s (2013) conceptual model of measuring neglect to Geographic Information Systems, comparing rates of neglect in historic Doylestown, Quakertown, and Bristol boroughs in Pennsylvania, USA utilizing different amounts of peripheral agricultural preservation. Comparisons are made examining descriptive statistics on existing conditions, a Polychoric correlation evaluating relationships between drivers of neglect, and a cross-comparative GIS spatial analysis. Results indicate as amounts of peripheral preserved farmlands increase, neglect can be lowered

Insulin modulates the frequency of Ca2+ oscillations in mouse pancreatic islets

Pancreatic islets can adapt to oscillatory glucose to produce synchronous insulin pulses. Can islets adapt to other oscillatory stimuli, specifically insulin? To answer this question, we stimulated islets with pulses of exogenous insulin and measured their Ca2+ oscillations. We observed that sufficiently high insulin (>500 nM) with an optimal pulse period (similar to 4 min) could make islets to produce synchronous Ca2+ oscillations. Glucose and insulin, which are key stimulatory factors of islets, modulate islet Ca2+ oscillations differently. Glucose increases the active-to-silent ratio of phases, whereas insulin increases the period of the oscillation. To examine the dual modulation, we adopted a phase oscillator model that incorporated the phase and frequency modulations. This mathematical model showed that out-of-phase oscillations of glucose and insulin were more effective at synchronizing islet Ca2+ oscillations than in-phase stimuli. This finding suggests that a phase shift in glucose and insulin oscillations can enhance inter-islet synchronization.111Ysciescopu

Firm-level Political Risk and Corporate R&D Investment

I examine how firms make R&D investment decisions during periods of political uncertainty. To minimize stickiness and overly generalized assumptions, I employ quarterly data. I find that firms invest more in R&D when facing high levels of political risk. The results suggest that this positive relationship between political risk and R&D investment is more pronounced for competitive and politically sensitive firms. Additionally, the positive association is evident among firms with higher growth opportunities and more liquid assets. The results are robust to the test for correlation, addressing endogeneity, and alternative proxies adopted for the variables of interest. Overall, the findings of this study support the strategic growth option theory, which suggests that firms follow a preemptive strategy during periods of high uncertainty

Diffusion Adversarial Representation Learning for Self-supervised Vessel Segmentation

Vessel segmentation in medical images is one of the important tasks in the diagnosis of vascular diseases and therapy planning. Although learning-based segmentation approaches have been extensively studied, a large amount of ground-truth labels are required in supervised methods and confusing background structures make neural networks hard to segment vessels in an unsupervised manner. To address this, here we introduce a novel diffusion adversarial representation learning (DARL) model that leverages a denoising diffusion probabilistic model with adversarial learning, and apply it to vessel segmentation. In particular, for self-supervised vessel segmentation, DARL learns the background signal using a diffusion module, which lets a generation module effectively provide vessel representations. Also, by adversarial learning based on the proposed switchable spatially-adaptive denormalization, our model estimates synthetic fake vessel images as well as vessel segmentation masks, which further makes the model capture vessel-relevant semantic information. Once the proposed model is trained, the model generates segmentation masks in a single step and can be applied to general vascular structure segmentation of coronary angiography and retinal images. Experimental results on various datasets show that our method significantly outperforms existing unsupervised and self-supervised vessel segmentation methods.Comment: Accepted at ICLR 202

A more rigorous mathematical model for capillary imbibition of CO2 in shale gas formations

Amathematical model was derived in this study to reveal the mechanism of CO2 imbibition in shale formations considering the combined effects of capillary force and viscous force in concave curved triangle pore channels surrounded by different solid materials with different wettability. The model reveals that CO2 imbibition depth is proportional to the square root of CO2 soaking time, square root of the pore size determined by grain size, square root of interfacial tension and cosine of contact angle, and inversely proportional to the square root of CO2 viscosity. Up to three solid wall materials with different contact angles can be considered in the model. Using the average contact angle for the three materials over-estimates the imbibition distance. CO2 imbibition is faster in concave curved triangle pores than in equivalent circular-shaped pores. The dimensionless geometry correction factor is less than unity (α = 0.81). The newly developed imbibition model can be used for predicting the maximum time of imbibition between parallel fractures in multi-fractured shale formations.Document Type: Original articleCited as: Zhang, J., Guo, B., Amponsah, V. N. B. A more rigorous mathematical model for capillary imbibition of CO2 in shale gas formations. Capillarity, 2025, 14(3): 63-71. https://doi.org/10.46690/capi.2025.03.0

Gauging the Relationship between Contextual Growth and Structural Neglect

Population and land use out-migrations from urban to peripheral areas can result in non-functional, unmaintained historic structures which deteriorate to the point where removal is cheaper than removal – or demolition by neglect. The increasing rate of neglected historic structures is a growing concern. There is a need for research investigating connections between urban growth management and its effect on neglect. This paper applies Newman’s (2013) conceptual model of measuring neglect to Geographic Information Systems, comparing rates of neglect in historic Doylestown, Quakertown, and Bristol boroughs in Pennsylvania, USA utilizing different amounts of peripheral agricultural preservation. Comparisons are made examining descriptive statistics on existing conditions, a Polychoric correlation evaluating relationships between drivers of neglect, and a cross-comparative GIS spatial analysis. Results indicate as amounts of peripheral preserved farmlands increase, neglect can be lowered