Search Results (191)

Hyperthermal environments are encountered in many situations, and significant heat stress can exacerbate the fatigue perception of individuals and potentially threaten their safety. Heat acclimation (HA) interventions have many benefits in preventing the risk of incidents. However, whether HA interventions in specific environments can cope with other different hyperthermal environments remains uncertain. In this study, forty-three young male participants were heat-acclimated over 10 days of training on a motorized treadmill in a fixed hyperthermal environment, and they were tested in different hyperthermal environments. Physiological indices (rectal temperature (T_r), heart rate (HR), skin temperature (T_sk), and total sweat loss (M_sl)) and subjective perception (rating of perceived exertion (RPE) and thermal sensation votes (TSVs)) were measured during both the heat stress test (HST) sessions and HA training sessions. The results show that HR and T_sk significantly differed between pre- and post-heat acclimation (p < 0.05 for all) following the acclimation program. However, after heat acclimation training, the reduction in T_r (ΔT_r) was more notable in lower-ET* environments, and M_sl showed distinct changes in different ET* environments. The RPE and TSV decreased after HA interventions, although the difference was not significant. The results indicate that HA can effectively reduce the peak of physiological parameters. However, when subjected to stronger heat stress, the improvement effects of heat acclimation on human responses will be affected. In addition, HA can alleviate physiological thermal strain, thereby reducing the adverse effects on mobility, but it has no effect on the supervisor’s ability to perceive the environment. This study suggests that additional HA training can reduce the risk of activities in high-temperature environments but exhibits different effects under different environmental conditions, indicating that hot acclimation suits have selective effects on the environment. This study provides recommendations for additional HA training before high-temperature activities. Full article

Urban outdoor thermal comfort (OTC) has become an increasingly critical issue under the pressures of urbanization and climate change. Comparative analyses of urban blocks with distinct spatial morphologies are essential for identifying OTC issues and proposing targeted optimization strategies. However, existing studies predominantly rely on microclimate numerical simulations, while comparative assessments of OTC from the human thermal perception perspective remain limited. This study employs the thermal walk method, integrating microclimatic measurements with thermal perception questionnaires, to conduct on-site OTC investigations across three urban blocks with contrasting spatial morphologies—a business district (BD), a residential area (RA), and a historical neighborhood (HN)—in Beijing, a hot summer and cold winter climate city. The results reveal substantial OTC differences among the blocks. However, these differences demonstrated great seasonal and temporal variations. In summer, BD exhibited the best OTC (mTSV = 1.21), while HN performed the worst (mTSV = 1.72). In contrast, BD showed the poorest OTC in winter (mTSV = −1.57), significantly lower than HN (−1.11) and RA (−1.05). This discrepancy was caused by the unique morphology of different blocks. The sky view factor emerged as a more influential factor affecting OTC over building coverage ratio and building height, particularly in RA (r = 0.689, p < 0.01), but its impact varied by block, season, and sunlight conditions. North–South streets generally perform better OTC than East–West streets, being 0.26 units cooler in summer and 0.20 units warmer in winter on the TSV scale. The study highlights the importance of incorporating more applicable physical parameters to optimize OTC in complex urban contexts and offering theoretical support for designing climate adaptive urban spaces. Full article

College student military training is an organized, high-intensity, short-term militarized activity in China; this study aims to explore the differences in thermal perception between different intensities of military training. Questionnaires and microclimate measurements were conducted during summer military training in cold regions, including the Protective and Rescue Training and Assessment (PRTA), Formation Training (FT), the Shooting and Tactical Training and Assessment (STTA), the Route March (RM), and Dagger Practice (DP). The results indicated that (1) there was no significant correlation between the intensity of the activity and votes on thermal perception. The strongest thermal sensations, the lowest comfort, and the lowest thermal acceptability were experienced during FT, with a lower activity intensity. (2) Air temperature (T_a), globe temperature (T_g), relative humidity (RH), mean radiant temperature (T_mrt), and solar radiation (G) had significant effects on the TSV. (3) FT involved the lowest neutral temperatures (NUTCI/NPET), while DP and RM training had the highest NUTCI and NPET values, respectively. The neutral temperature range during military training was narrower compared to that in other aerobic activities. This study reveals, for the first time, the non-traditional correlation between military training intensity and thermal perception, confirming the specificity of thermal sensations in mandatory training and providing a theoretical basis for optimizing military training arrangements and developing thermal protection strategies. Full article

High-Bandwidth Memory (HBM) enables the bandwidth required by modern AI and high-performance computing, yet its three dimensional stack traps heat and amplifies thermo mechanical stress. We first review how conventional solutions such as heat spreaders, microchannels, high density Through-Silicon Vias (TSVs), and Mass Reflow Molded Underfill (MR MUF) underfills lower but do not eliminate the internal thermal resistance that rises sharply beyond 12layer stacks. We then synthesize recent hybrid bonding studies, showing that an optimized Cu pad density, interface characteristic, and mechanical treatments can cut junction-to-junction thermal resistance by between 22.8% and 47%, raise vertical thermal conductivity by up to three times, and shrink the stack height by more than 15%. A meta-analysis identifies design thresholds such as at least 20% Cu coverage that balances heat flow, interfacial stress, and reliability. The review next traces the chain from Coefficient of Thermal Expansion (CTE) mismatch to Cu protrusion, delamination, and warpage and classifies mitigation strategies into (i) material selection including SiCN dielectrics, nano twinned Cu, and polymer composites, (ii) process technologies such as sub-200 °C plasma-activated bonding and Chemical Mechanical Polishing (CMP) anneal co-optimization, and (iii) the structural design, including staggered stack and filleted corners. Integrating these levers suppresses stress hotspots and extends fatigue life in more than 16layer stacks. Finally, we outline a research roadmap combining a multiscale simulation with high layer prototyping to co-optimize thermal, mechanical, and electrical metrics for next-generation 20-layer HBM. Full article

In this paper, a novel through-silicon via (TSV) fabrication strategy based on through-hole structures is proposed for low-cost and low-complexity manufacturing. Compared to conventional TSV fabrication processes, this method significantly simplifies the process flow by employing double-sided liner deposition, double-sided barrier layer/seed layer formation, and double-sided Cu electroplating. This method enhances the TSV stability by eliminating Cu contamination issues during chemical–mechanical polishing (CMP), which are a common challenge in traditional blind via fabrication processes. Additionally, the liner and barrier layer/seed layer achieve a high step coverage exceeding 80%, ensuring excellent conformality and structural integrity. For electroplating, a multi-stage bi-directional electroplating technique is introduced to enable void-free Cu filling in TSVs. The fabricated TSVs exhibit an ultra-low leakage current of 135 fA at 20 V, demonstrating their potential for advancing 3D integration technologies in heterogeneous integration. Full article

Local data about indoor thermal comfort are in short supply, which are always different from the predicted results produced by models shown in previous studies. Shopping malls that consume substantial energy need to save energy, provided that thermal comfort is maintained. Therefore, this research investigated indoor thermal comfort using field measurements and questionnaires in a typical shopping mall in Danyang, China, with a hot summer and cold winter climate in order to explore local demands and energy-saving potential. The findings are as follows: (1) The average air temperature ($T_a$) and operative temperature ($T_{op}$) are 26.7 °C and 26.4 °C, which implies a minor influence from radiation and other factors on $T_a$. Women are more sensitive to changes in outdoor temperature since clothing insulation ($I_{cl}$) varies by gender: 0.31 clo and 0.36 clo for male and female individuals, respectively. (2) The thermal neutral temperature (TNT) derived from the thermal sensation vote (TSV) is 25.26 °C, which is significantly higher than the 21.77 °C obtained from the predicted mean vote (PMV) model. (3) There is a wide range of acceptable temperatures for thermal comfort because the highest temperature was identified by the thermal comfort vote (TCV) at 27.55 °C, followed closely by 27.48 °C, 26.78 °C, and 25.32 °C, which were separately derived from the thermal acceptance vote (TAV), TSV, and predicted percentage of dissatisfied (PPD) people; these were based on an upper limit of the acceptable 80% range. (4) In total, 94.85% of respondents accepted the indoor air quality, although the median concentration of CO₂ was 772 ppm, and the neutral relative humidity level was 70.60%. Meanwhile, there is an important relationship between air quality satisfaction and operative temperature; thus, the temperature (26.93 °C) with peak satisfaction can enhance air quality perception and thermal comfort. (5) The energy savings that can be achieved are 25.77% and 9.12% at most based on acceptable thermal comfort compared with baseline energy consumption at 23 °C and 26 °C, respectively. Full article

Phlox are ornamentals of great decorative value, grown throughout the world for their attractive flowers. Phlox cultivar collections at the Tsitsin Main Botanical Garden and the Botanical Garden of Lomonosov Moscow State University (both Moscow, Russia) were surveyed for virus diseases. Tobacco streak ilarvirus (TSV), beet ringspot nepovirus (BRSV), and BRSV satellite RNA (satRNA) were first detected in phlox when viromes of symptomatic Phlox paniculata plants were studied using high-throughput sequencing. The nearly complete genomes of three TSV and BRSV isolates and two BRSV satRNAs were assembled and characterized. TSV isolates shared 96.9–99.7% nucleotide sequence identity and were 82.2–89.1% identical to their closest relatives from broad bean, dahlia, and echinacea. BRSV isolates were distantly related to each other (83.7–89.3% identity) and were closest to those from oxalis and potato. BRSV satRNAs shared 90.6% identity and were 87.8–94.1% identical to satRNAs associated with tomato black ring virus L and S serotypes. Thus, TSV, BRSV, and BRSV satRNA were for the first time detected in a new natural host P. paniculata in Russia, adding to the list of known phlox viruses and expanding information on the host range, geographic distribution, and genetic diversity of these viruses. Full article

This study aims to optimize indoor thermal environment assessment methods for primary school classrooms in regions with hot summers and cold winters, enhancing air-conditioning management efficiency and accuracy. Given the complexity of Predicted Mean Vote (PMV) calculations and its reduced accuracy under high temperature and humidity, this research explores the use of Thermal Sensation Vote (TSV) as a simpler alternative. Field measurements and subjective assessments were conducted to analyze the relationship between TSV and PMV, leading to a regression model linking predicted TSV (TSV_p) with temperature and humidity. Results indicate that temperature and humidity significantly impact TSV, with regression coefficients of 0.499 and 0.055, respectively. Furthermore, when TSV is ≥1, the proportion of PMV of ≥0.5 remains stable, validating TSV_p as a reliable indicator. Based on these findings, energy-efficient air-conditioning management strategies are proposed, recommending a temperature setting of 28 °C for thermal comfort. This study provides insights into climate control strategies in educational buildings, promoting sustainable development. Full article

The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity of structures, combined with the temperature-dependent and viscoelastic properties of organic materials, make it increasingly difficult to predict the thermo-mechanical behavior of wafer-level Cu-PI RDL structures, posing a severe challenge in warpage prediction. This study models and simulates the thermo-mechanical response during the manufacturing process of Cu-PI RDL at the wafer level. A cross-scale wafer-level equivalent model was constructed using a two-level partitioning method, while the PI material properties were extracted via inverse fitting based on thermal warpage measurements. The warpage prediction results were compared against experimental data using the maximum warpage as the indicator to validate the extracted PI properties, yielding errors under less than 10% at typical process temperatures. The contribution of RDL build-up, wafer backgrinding, chemical mechanical polishing (CMP), and through-silicon via (TSV)/through-glass via (TGV) interposers to the warpage was also analyzed through simulation, providing insight for process risk evaluation. Finally, an artificial neural network was developed to correlate the copper ratios of four RDLs with the wafer warpages for a specific process scenario, demonstrating the potential for wafer-level warpage control through copper ratio regulation in RDLs. Full article

Advanced packaging represents a crucial technological evolution aimed at overcoming limitations posed by Moore’s Law, driving the semiconductor industry from two-dimensional toward three-dimensional integrated structures. The increasing complexity and miniaturization of electronic devices have significantly heightened the challenges associated with failure analysis during process development. The focused ion beam–scanning electron microscope (FIB-SEM), characterized by its high processing precision and exceptional imaging resolution, has emerged as a powerful solution for the fabrication, defect localization, and failure analysis of micro- and nano-scale devices. This paper systematically reviews the innovative applications of FIB-SEM in the research of core issues, such as through-silicon-via (TSV) defects, bond interfacial failures, and redistribution layer (RDL) electromigration. Additionally, the paper discusses multimodal integration strategies combining FIB-SEM with advanced analytical techniques, such as high-resolution three-dimensional X-ray microscopy (XRM), electron backscatter diffraction (EBSD), and spectroscopy. Finally, it provides a perspective on the emerging applications and potential of frontier technologies, such as femtosecond-laser-assisted FIB, in the field of advanced packaging analysis. Full article

Accurately assessing human thermal comfort plays a key role in improving indoor environmental quality and energy efficiency of buildings. Non-invasive thermal comfort recognition has shown great application potential compared with other methods. Based on thermal correlation analysis, human facial temperature recognition and body thermal adaptive action detection are both performed by one binocular infrared camera. The YOLOv5 algorithm is applied to extract facial temperatures of key regions, through which the random forest model is used for thermal comfort recognition. Meanwhile, the Mediapipe tool is used to detect probable thermal adaptive actions, based on which the corresponding thermal comfort level is also assessed. The two results are combined with PMV calculation for multivariate human thermal comfort prediction, and a weighted fusion strategy is designed. Seventeen subjects were invited to participate in experiments for data collection of facial temperatures and thermal adaptive actions in different thermal conditions. Prediction results show that, by using the experiment data, the overall accuracies of the proposed fusion strategy reach 82.86% (7-class thermal sensation voting, TSV) and 94.29% (3-class TSV), which are better than those of facial temperature-based thermal comfort prediction (7-class: 78.57%, 3-class: 90%) and PMV model (7-class: 20.71%, 3-class: 65%). If probable thermal adaptive actions are detected, the accuracy of the proposed fusion model is further improved to 86.8% (7-class) and 100% (3-class). Furthermore, by changing clothing thermal resistance and metabolic level of subjects in experiments, the influence on thermal comfort prediction is investigated. From the results, the proposed strategy still achieves better accuracy compared with other single methods, which shows good robustness and generalization performance in different applications. Full article

This study introduces a methodology for characterizing and modeling the viscosity and specific volume–pressure–temperature (pvT) behavior of sheet molding compound (SMC) materials, based on the use of specialized testing equipment. Conventional rheometers are inadequate for such materials due to the presence of long fibers, necessitating the use of specialized equipment like squeeze flow rheometers and pvT dilatometers. Our findings demonstrate that traditional oscillatoric rheometer measurements underestimate the viscosity of CF-SMCs, highlighting the need for advanced, albeit non-standardized, testing methods. Additionally, we found that standard Tait models failed to capture the temperature-dependent porosity of CF-SMCs at low pressures, whereas models based on thermodynamic state variables (TSVs) provided accurate predictions across a broader range of conditions. The study also addressed the complexities introduced by fiber–flow coupling and the fiber orientation in measuring the viscosity, revealing limitations in conventional modeling approaches. The numerical analysis showed that a power law-based anisotropic viscosity model (PL-IISO) combined with a TSV model offered the best predictive performance in finite volume flow simulations, especially for thick-walled regions. However, the current modeling approaches have limited predictive capabilities for the fiber orientation in thin-walled regions. This research underscores the challenges in accurately modeling CF-SMC materials in terms of the fiber orientation, whereas the compression forces needed from the pressing machine could be predicted accurately within an average error of 6.5% in the squeeze flow experiments. Full article

Through-Silicon-Via (TSV) technology is of crucial importance in the process of defect-free copper filling in vias. In this study, the small molecule 2-mercapto-1-methylimidazole (SN2) is proposed as a new leveler. It enables bottom-up super-filling of blind vias without the need for inhibitors. Atomic force microscopy (AFM), X-ray diffraction (XRD), and XPS were employed to characterize the surface morphology, crystal structure, and adsorption properties of copper crystals in these systems. Meanwhile, by means of electrochemical measurements, the inhibitory effect of the leveler SN2 on copper ion deposition and the synergistic effect between SN2 molecules and other additives were investigated. The LSV test indicated that additive SN2 inhibited copper electrodeposition after being added to the plating solution, and this inhibitory effect enhanced with increasing SN2 concentration. In the actual plating wafer test (1 ASD plating for 1 min, 5 ASD plating for 5 min, and 10 ASD plating for 1 h), the best plating effect was achieved at 3 ppm, which verified the conjecture of the galvanostatic measurements. Moreover, XPS and computer simulations revealed that SN2 could be adsorbed onto the copper surfaces. This work will inspire the discovery of new effective levelers in the future. Full article

With the growing demand for high-performance computing (HPC), artificial intelligence (AI), and data communication and storage, new chip technologies have emerged, following Moore’s Law, over the past few decades. As we enter the post-Moore era, transistor dimensions are approaching their physical limits. Advanced packaging technologies, such as 3D chiplets hetero-integration and co-packaged optics (CPO), have become crucial for further improving system performance. Currently, most solutions rely on silicon-based technologies, which alleviate some challenges but still face issues such as warpage, bumps’ reliability, through-silicon vias’ (TSVs) and redistribution layers’ (RDLs) reliability, and thermal dissipation, etc. Glass, with its superior mechanical, thermal, electrical, and optical properties, is emerging as a promising material to address these challenges, particularly with the development of femtosecond laser technology. This paper discusses the evolution of both conventional and advanced packaging technologies and outlines future directions for design, fabrication, and packaging using glass substrates and femtosecond laser processing. Full article

This study investigates the impact of different noise levels on thermal comfort in outdoor environments. The research was conducted in two university squares in Xi’an, China, exhibiting distinct noise exposures, with twenty volunteers participating in the study. These individuals provided subjective evaluations of thermal comfort through questionnaires while situated in environments with disparate acoustic conditions in conjunction with the documentation of prevailing meteorological circumstances. The analysis yielded three salient findings. Initially, a marked elevation in perceived warmth was noted in environments experiencing higher noise levels, with 35.29% of subjects in the high-noise plaza (HP) reporting feeling warm (TSV = 2), which was 11.76 percentage points higher than in the low-noise plaza (LP). This included a 5.88 percentage point uptick in the frequency of “hot” (TSV = 3) thermal sensations reported in the HP. Furthermore, an intensification of thermal discomfort was observed in noisier settings, with the thermal comfort vote (TCV) in HP encompassing a spectrum from very uncomfortable to neutral and a predominant 90% of TCVs indicating discomfort, 35.29% of which were deemed very uncomfortable. Lastly, the findings suggest that high-decibel noise exposure notably amplifies the perception of heat within a specific high-temperature bandwidth. Beyond this delineated thermal threshold, the influence of noise on thermal sensation substantially diminishes. Full article