This article presents a density-based topology optimization (TO) method for a coupled thermal-fluid problem, in which the Navier-Stokes and heat transport equations are coupled. The two-dimensional ...microchannel heat sink model with fixed solid heat generation plates based on TO method is developed. These devices, such as air-cooled heat sinks, have recently attracted considerable attention in engineering applications of thermal cooling devices. The high-performance and functional diversification cooling devices are obtained by the proposed optimization method in this research. An optimal design problem is formulated as a multi-objective optimization problem, which includes heat resistance, energy dissipation and pressure drop. In the numerical implementation, Helmholtz-type Partial Differential Equation (PDE) based filter and smoothed Heaviside projection filter are utilized to produce discrete solutions, thus solving ill-posedness. Furthermore, TO result of channel layout obtained for a microchannel heat sink design is presented as an example to illustrate the validity of design methodology. Finally, several numerical examples are provided to study the effects of the weighting coefficient changes on the optimal results.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Fiber nonlinear interference (NLI) modeling and monitoring are the key building blocks to support elastic optical networks. In the past, they were normally developed and investigated separately. ...Moreover, the accuracy of the previously proposed methods still needs to be improved for heterogenous dynamic optical networks. In this paper, we present the application of machine learning (ML) in NLI modeling and monitoring. In particular, we first propose to use ML approaches to calibrate the errors of current fiber nonlinearity models. The Gaussian-noise model is used as an illustrative example, and significant improvement is demonstrated with the aid of an artificial neural network. Further, we propose to use ML to combine the modeling and monitoring schemes for a better estimation of NLI variance. Extensive simulations with 2411 links are conducted to evaluate and analyze the performance of various schemes, and the superior performance of the ML-aided combination of modeling and monitoring is demonstrated.
•The novel designs of micromixer were obtained based on topology optimization method.•The mixing quality maximization problem of topology optimization was formulated.•The mixing mechanism for ...non-Newtonian fluid at low Reynolds number was investigated.
Improving the mixing performance is a crucial and widely concerned topic in microfluidic devices for low Reynolds numbers (Re). In this paper, the mixing unit as the design domain in a typical T-shape micromixer considering non-Newtonian fluid effects is investigated using topology optimization. The objective of topology optimization is to maximize the mixing quality under the prescribed pressure drop of the micromixer. Based on the optimized structures obtained by topology optimization, high-fidelity calculations are performed to eliminate the influence of the greyscale problem. For the Newtonian fluid, the optimized structure has better mixing performance than the reference structure with the same pressure drop. For the non-Newtonian fluid, cross-comparison is conducted to obtain the optimized structure. The results show that the mixing qualities of the 25-period mixing unit are 93.90% (Newtonian fluid, Re = 8) and 93.84% (non-Newtonian fluid, Re = 0.24), respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
China publishes 5,052 academic journals in science, technology, and medicine. It
ranks third in terms of the number of publications, behind the United States and
the United Kingdom. In recent years, ...English-language journals have increased
annually in China, but there are only just over 300 English journals published,
accounting for about 6.5% of all published journals, whereas Chinese
journals account for about 93.5%. Using 30 years’ data from the
Chinese science citation database (CSCD), I compiled statistics on the average
number of papers, the average number of references, the language of references,
the distribution of author age, etc. I also analyzed the role of Chinese STM
journals in terms of their academic significance. It is observed that the
average number of journal papers and references per paper has been on the rise
in the past 30 years. English literature accounts for a large proportion of the
references, and the authors are young. The conclusion is that Chinese journals
are important for young scholars to publish their papers, and Chinese scholars
widely use international research results for reference in their research.
Self-assembly of ionic liquids (ILs) in solution has attracted wide attention due to their potential applications in chemical and biological investigations. In this study, the aggregation behavior of ...1-alkyl-3-methylimidazolium alkyl sulfate in aqueous solution was investigated by molecular dynamics simulations. The simulations reveal that interactions between tail groups play a dominant role in stabilizing the vesicle. The permeability of the vesicle was further studied, and the exchange rate of water molecules is determined by the thickness of membrane. Besides thickness, arrangement of alkyl chain of ILs in the vesicle structure influences the permeability. The interdigitated structure of tail groups in the C8mimC12SO4 system decreases the water exchange rate compared with the similar system of C12mimC8SO4. Furthermore, the hydrogen bonding interaction and orientation analysis indicate that the orientation of the imidazolium ring provides the empty positions for water–anion interactions and promotes the water molecules to approach the hydrophobic region. These results suggest that vesicle with excellent permeability properties could be obtained by screening the hydrophilic and hydrophobic of ILs and they might be beneficial for the application in separation and drug delivery process.
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IJS, KILJ, NUK, PNG, UL, UM
Bottom‐up synthesized graphene nanostructures, including 0D graphene quantum dots and 1D graphene nanoribbons, have recently emerged as promising candidates for efficient, green optoelectronic, and ...energy storage applications. The versatility in their molecular structures offers a large and novel library of nanographenes with excellent and adjustable optical, electronic, and catalytic properties. In this minireview, recent progress on the fundamental understanding of the properties of different graphene nanostructures, and their state‐of‐the‐art applications in optoelectronics and energy storage are summarized. The properties of pristine nanographenes, including high emissivity and intriguing blinking effect in graphene quantum dots, superior charge transport properties in graphene nanoribbons, and edge‐specific electrochemistry in various graphene nanostructures, are highlighted. Furthermore, it is shown that emerging nanographene‐2D material‐based van der Waals heterostructures provide an exciting opportunity for efficient green optoelectronics with tunable characteristics. Finally, challenges and opportunities of the field are highlighted by offering guidelines for future combined efforts in the synthesis, assembly, spectroscopic, and electrical studies as well as (nano)fabrication to boost the progress toward advanced device applications.
The recent progress on the fundamental properties of different bottom‐up synthesized nanographenes, and the collective properties upon forming nanographene‐2D material‐based van der Waals heterostructures, toward their state‐of‐the‐art applications in optoelectronics and energy storage is summarized. Forthcoming challenges and opportunities of this emerging field are highlighted, and perspectives in boosting the progress toward advanced device applications are offered.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract Recent advances in NIR triggering upconversion-based photodynamic therapy have led to substantial improvements in upconversion-based nanophotosensitizers. How to obtain the high efficiency ...of singlet oxygen generation under low 980 nm radiation dosage still remains a challenge. A highly efficient nanophotosensitizer, denoted as UCNPs-ZnPc, was constructed for photodynamic therapy, which is based on near infrared (NIR) light upconversion nanoparticle (UCNP) and Zn(II)-phthalocyanine (ZnPc) photosensitizer (PS). The high1 O2 production efficiency came from the enhancement of the 660 nm upconversion emission of NaYF4 :Yb3+ , Er3+ UCNP with 25% Yb3+ doping, covalent assemblage of UCNP and ZnPc which significantly shortened the distance and enhanced the energy transfer between the two. The high1 O2 production led to a secure and efficient PDT treatment, as evidenced by the in vivo test where UCNPs-ZnPc of 50 mg per kg body weight was locally injected into the liver tumor in mice, a low 980 nm radiation dose of 351 J/cm2 (0.39 W/cm2 ) and short irradiation duration of 15 min were sufficient to perform image-guided PDT and caused the liver tumor inhibitory ratio of approximately 80.1%. Histological analysis revealed no pathological changes and inflammatory response in heart, lung, kidney, liver or spleen.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A light field camera can capture light information from various directions within a scene, allowing for the reconstruction of the scene. The light field image inherently contains the depth ...information of the scene, and depth estimations of light field images have become a popular research topic. This paper proposes a depth estimation network of light field images with occlusion awareness. Since light field images contain many views from different viewpoints, identifying the combinations that contribute the most to the depth estimation of the center view is critical to improving the depth estimation accuracy. Current methods typically rely on a fixed set of views, such as vertical, horizontal, and diagonal, which may not be optimal for all scenes. To address this limitation, we propose a novel approach that considers all available views during depth estimation while leveraging an attention mechanism to assign weights to each view dynamically. By inputting all views into the network and employing the attention mechanism, we enable the model to adaptively determine the most informative views for each scene, thus achieving more accurate depth estimation. Furthermore, we introduce a multi-scale feature fusion strategy that amalgamates contextual information and expands the receptive field to enhance the network’s performance in handling challenging scenarios, such as textureless and occluded regions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An efficient synthetic route for the diastereoselective construction of trans‐dihydrobenzofurans via cascade 3,3‐sigmatropic rearrangement/3+2 annulation sequences has been developed. This protocol ...represents a metal‐free transformation of the promising N‐phenoxy amides with terminal alkynes and features mild conditions, good functional group compatibility, and practical synthetic potential.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Plant meristem cells divide and differentiate in a spatially and temporally regulated manner, ultimately giving rise to organs. In this study, we isolated the Arabidopsis jing he sheng 1 (jhs1) ...mutant, which exhibited retarded growth, an abnormal pattern of meristem cell division and differentiation, and morphological defects such as fasciation, an irregular arrangement of siliques, and short roots. We identified JHS1 as a homolog of human and yeast DNA Replication Helicase/Nuclease2, which is known to be involved in DNA replication and damage repair. JHS1 is strongly expressed in the meristem of Arabidopsis. The jhs1 mutant was sensitive to DNA damage stress and had an increased DNA damage response, including increased expression of genes involved in DNA damage repair and cell cycle regulation, and a higher frequency of homologous recombination. In the meristem of the mutant plants, cell cycle progression was delayed at the G2 or late S phase and genes essential for meristem maintenance were misregulated. These results suggest that JHS1 plays an important role in DNA replication and damage repair, meristem maintenance, and development in plants.
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![Metal‐Free [3,3]‐Sigmatropi...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1615-4150/small "Metal‐Free [3,3]‐Sigmatropic Rearrangement/[3+2] Annulation Cascade of N‐Phenoxy Amides with Terminal Alkynes for the Diastereoselective Synthesis of trans‐Dihydrobenzofurans")
