360 research outputs found
Cellulose-starch hybrid films plasticized by aqueous ZnCl2 solution
Starch and cellulose are two typical natural polymers from plants that have similar chemical structures. The blending of these two biopolymers for materials development is an interesting topic, although how their molecular interactions could influence the conformation and properties of the resultant materials has not been studied extensively. Herein, the rheological properties of cellulose/starch/ZnCl2 solutions were studied, and the structures and properties of cellulose-starch hybrid films were characterized. The rheological study shows that compared with starch (containing mostly amylose), cellulose contributed more to the solution’s viscosity and has a stronger shear-thinning behavior. A comparison between the experimental and calculated zero-shear-rate viscosities indicates that compact complexes (interfacial interactions) formed between cellulose and starch with ≤50 wt % cellulose content, whereas a loose structure (phase separation) existed with ≥70 wt % cellulose content. For starch-rich hybrid films prepared by compression molding, less than 7 wt % of cellulose was found to improve the mechanical properties despite the reduced crystallinity of the starch; for cellulose-rich hybrid films, a higher content of starch reduced the material properties, although the chemical interactions were not apparently influenced. It is concluded that the mechanical properties of biopolymer films were mainly affected by the structural conformation, as indicated by the rheological results. View Full-Tex
Exploring crowd persistent dynamism from pedestrian crossing perspective: An empirical study
Crowd studies have gained increasing relevance due to the recurring incidents
of crowd crush accidents. In addressing the issue of the crowd's persistent
dynamism, this paper explored the macroscopic and microscopic features of
pedestrians crossing in static and dynamic contexts, employing a series of
systematic experiments. Firstly, empirical evidence has confirmed the existence
of crowd's persistent dynamism. Subsequently, the research delves into two
aspects, qualitative and quantitative, to address the following questions:(1)
Cross pedestrians tend to avoid high-density areas when crossing static crowds
and particularly evade pedestrians in front to avoid deceleration, thus
inducing the formation of cross-channels, a self-organization phenomenon.(2) In
dynamic crowds, when pedestrian suffers spatial constrained, two patterns
emerge: decelerate or detour. Research results indicate the differences in
pedestrian crossing behaviors between static and dynamic crowds, such as the
formation of crossing channels, backward detours, and spiral turning. However,
the strategy of pedestrian crossing remains consistent: utilizing detours to
overcome spatial constraints. Finally, the empirical results of this study
address the final question: pedestrians detouring causes crowds' persistent
collective dynamism. These findings contribute to an enhanced understanding of
pedestrian dynamics in extreme conditions and provide empirical support for
research on individual movement patterns and crowd behavior prediction.Comment: 31pages, 17figure
Solid fat content and bakery characteristics of interesterified beef tallow-palm mid fraction based margarines
Palm mid fraction (PMF) was interesterified with edible beef tallow (BT) catalyzed using sodium methoxide to investigate the effects on the solid fat content (SFC) of these palmitic rich plastic fats. Interesterified blends crystallize more slowly than BT. Conversely, the crystallization rates of PMF-BT-based interesterification (IE) products were compared with the starting mixture and IE products prepared with non-PMF triglycerides. The SFC PMF-based IE products increased significantly at temperatures between 25 and 40 °C. The SFC profiles became smoother and the products had potential to serve as base oils for preparing specialty fats with a wider range of plasticity. Further exploration of triacylglycerol (TAG) compositional changes revealed that PMF interesterified products had greater saturated/saturated/saturated (S/S/S)-type TAGs compared with soybean oil interesterified products. Moreover, in subsequent evaluations of BT-PMF-based IE fats as a margarine replacement effects in a baked cake model system showed that the material was a suitable functional oil base with acceptable aeration properties and plasticity during baking. Therefore, it is a potential alternative to IE-BT based and traditional IE-BT-palm oil based margarines. The physical-characteristics of bakery products prepared with this fat exhibited improved cake volume with fine structure and clear lifting properties, which affirmed the potential for its application in bakery fats
The Effect of Surface Treatments on Zirconia Bond Strength and Durability
To evaluate the effects of airborne particle abrasion (APA) combined with MDP-containing
resin cement, a glass-ceramic spray deposition (GCSD) method on the shear bond strengths (SBSs) and
durability of 3 mol% yttrium oxide-stabilized zirconia ceramic (3Y-TZP) compared with lithium disilicate glass ceramics (LDGC). 3Y-TZP disks were randomly treated as follows: for Group APA+MDP,
3Y-TZP was abrased using 50 µm Al2O3 particles under 0.1 Mpa and bonded with MDP-containing
resin cement; for Group GCSD, 3Y-TZP was treated with the GCSD method, etched by 5% HF for
90 s, silanized and bonded with resin cement without MDP. Group LDGC was bonded as the Group
GCSD. X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy
(ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy
dispersive X-ray detector (EDX) were used to analyze the surface chemical and micro-morphological
changes of the ceramics before bonding. The bonded ceramic specimens were randomly divided into
subgroups, and the SBSs were determined before and after 10,000 thermocycling. The SBSs were
analyzed with a one-way ANOVA analysis. Failure modes were determined with optical microscopy
and SEM. The XRD, ATR-FTIR and XPS results identified the formation of lithium disilicate and
zirconium silicate on 3Y-TZP after GCSD. The SEM micrographs revealed that 3Y-TZP surfaces
were roughened by APA, while 3Y-TZP with GCSD and LDGC surfaces could be etched by HF to
be porous. The APA treatment combined with MDP-containing resin cement produced the high
immediate zirconia shear bond strengths (SBSs: 37.41 ± 13.51 Mpa) that was similar to the SBSs of
the LDGC (34.87 ± 11.02 Mpa, p > 0.05), but, after thermocycling, the former dramatically decreased
(24.00 ± 6.86 Mpa, maximum reduction by 35.85%) and the latter exhibited the highest SBSs
(30.72 ± 7.97 Mpa, minimum reduction by 11.9%). The 3Y-TZP with GCSD treatment displayed
the lower zirconia SBSs before thermocycling (27.03 ± 9.76 Mpa, p < 0.05), but it was similar to the
3Y-TZP treated with APA and MDP containing resin cement after thermocycling (21.84 ± 7.03 vs.
24.00 ± 6.86 Mpa, p > 0.05). The APA combined with MDP-containing resin cement could achieve
the high immediate zirconia SBSs of those of the LDGC, but it decreased significantly after thermocycling. The GCSD technique could yield the immediate zirconia SBSs similar to those of LDGC
before thermocycling, and long-term zirconia SBSs were similar to those of 3Y-TZP treated with APA
followed by MDP-containing resin cement after thermocycling. Hence, the GCSD technique could
enrich zirconia surface treatments and is an alternative to zirconia surface pretreatment for 3Y-TZP
bond durability
Two-Stage Hybrid Supervision Framework for Fast, Low-resource, and Accurate Organ and Pan-cancer Segmentation in Abdomen CT
Abdominal organ and tumour segmentation has many important clinical
applications, such as organ quantification, surgical planning, and disease
diagnosis. However, manual assessment is inherently subjective with
considerable inter- and intra-expert variability. In the paper, we propose a
hybrid supervised framework, StMt, that integrates self-training and mean
teacher for the segmentation of abdominal organs and tumors using partially
labeled and unlabeled data. We introduce a two-stage segmentation pipeline and
whole-volume-based input strategy to maximize segmentation accuracy while
meeting the requirements of inference time and GPU memory usage. Experiments on
the validation set of FLARE2023 demonstrate that our method achieves excellent
segmentation performance as well as fast and low-resource model inference. Our
method achieved an average DSC score of 89.79\% and 45.55 \% for the organs and
lesions on the validation set and the average running time and area under GPU
memory-time cure are 11.25s and 9627.82MB, respectively
“准官员”的晋升机制:来自中国央企的证据
Using political mobility data for 189 leaders from China’s central state-owned enterprise (CSOEs) in 2008-2011, for the first time this paper investigates the mechanism of political turnover for leaders as quasi-government officers in CSOEs. We find that: (1) the likelihood of promotion of these leaders increases with their economic performance measured as growth rate of operating revenue, while the likelihood of demotion decreases with their economic performance; (2) these leaders with CCP central committee member have higher probability of promotion than their counterpart; (3) these leaders with Ph.D. degree have higher probability of promotion than their counterpart; (4) compared to growth rate of operating revenue, growth rate of maintaining and increasing the value of state capital has no significant effect on promotion; (5) the compensation linked to position in CSOEs has no impact on leaders’ promotion, which indicates that leaders in CSOEs look more likely government officials rather than professional managers
“准官员”的晋升机制:来自中国央企的证据
Using political mobility data for 189 leaders from China’s central state-owned enterprise (CSOEs) in 2008-2011, for the first time this paper investigates the mechanism of political turnover for leaders as quasi-government officers in CSOEs. We find that: (1) the likelihood of promotion of these leaders increases with their economic performance measured as growth rate of operating revenue, while the likelihood of demotion decreases with their economic performance; (2) these leaders with CCP central committee member have higher probability of promotion than their counterpart; (3) these leaders with Ph.D. degree have higher probability of promotion than their counterpart; (4) compared to growth rate of operating revenue, growth rate of maintaining and increasing the value of state capital has no significant effect on promotion; (5) the compensation linked to position in CSOEs has no impact on leaders’ promotion, which indicates that leaders in CSOEs look more likely government officials rather than professional managers
PHTrans: Parallelly Aggregating Global and Local Representations for Medical Image Segmentation
The success of Transformer in computer vision has attracted increasing
attention in the medical imaging community. Especially for medical image
segmentation, many excellent hybrid architectures based on convolutional neural
networks (CNNs) and Transformer have been presented and achieve impressive
performance. However, most of these methods, which embed modular Transformer
into CNNs, struggle to reach their full potential. In this paper, we propose a
novel hybrid architecture for medical image segmentation called PHTrans, which
parallelly hybridizes Transformer and CNN in main building blocks to produce
hierarchical representations from global and local features and adaptively
aggregate them, aiming to fully exploit their strengths to obtain better
segmentation performance. Specifically, PHTrans follows the U-shaped
encoder-decoder design and introduces the parallel hybird module in deep
stages, where convolution blocks and the modified 3D Swin Transformer learn
local features and global dependencies separately, then a sequence-to-volume
operation unifies the dimensions of the outputs to achieve feature aggregation.
Extensive experimental results on both Multi-Atlas Labeling Beyond the Cranial
Vault and Automated Cardiac Diagnosis Challeng datasets corroborate its
effectiveness, consistently outperforming state-of-the-art methods. The code is
available at: https://github.com/lseventeen/PHTrans.Comment: 10 pages, 3 figure
Electrolyte Strategies Facilitating Anion‐Derived Solid‐Electrolyte Interphases for Aqueous Zinc–Metal Batteries
Rechargeable aqueous zinc–metal batteries (AZBs) are a promising complimentary technology to the existing lithium-ion batteries and the re-emerging lithium–metal batteries to satisfy the increasing demands on energy storage. Despite considerable progress achieved in the past years, the fundamental understanding of the solid-electrolyte interphase (SEI) formation and how its composition influences the SEI properties are limited. This review highlights the functionalities of anion-tuned SEI on the reversibility of zinc–metal anode, with a specific emphasis on new structural insights obtained through advanced characterizations and computational techniques. Recent efforts in terms of key variables that govern the interfacial behaviors to improve the long-term stability of zinc anode, i.e., Coulombic efficiency, plating morphology, dendrite formation, and side-reactions, are comprehensively reviewed. Lastly, the remaining challenges and future perspectives are presented, providing insights into the rational design of practical high-performance AZBs
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