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111.
黄泛平原古城“环城湖”与城市防洪减灾 总被引：1，自引：0，他引：1
以黄泛平原为研究背景,以该地城内形态相似的“环城湖”为研究对象,通过对其构成要素、历史成因、演变过程、空间格局等方面的研究,探讨了“环城湖”在黄河洪水与泥沙作用下的生成机制与演变规律.认为:古城“环城湖”是特定自然条件下黄河泛滥引起生态环境改变与古代城市营建模式共同作用的结果,在古城营建过程中承担着泄洪、排涝等防洪减灾功能,并在当今城市建设中仍发挥着重要作用;只有充分了解古城“环城湖”的形成过程与演变机制,才能重新认识和定位“环城湖”的当代价值,从本质上把握古城“环城湖”的特色与精华. 相似文献
112.
Aljaž Škrjanc;Dominik Jankovič;Anton Meden;Matjaž Mazaj;Erik Svensson Grape;Martin Gazvoda;Nataša Zabukovec Logar; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(6):2305258
Zeolitic imidazolate frameworks (ZIFs) are a subclass of metal–organic framework that have attracted considerable attention as potential functional materials due to their high chemical stability and ease of synthesis. ZIFs are usually composed of zinc ions coordinated with imidazole linkers, with some other transition metals, such as Cu(II) and Co(II), also showing potential as ZIF-forming cations. Despite the importance of nickel in catalysis, no Ni-based ZIF with permanent porosity is yet reported. It is found that the presence and arrangement of the carbonyl functional groups on the imidazole linker play a crucial role in completing the preferred octahedral coordination of nickel, revealing a promising platform for the rational design of Ni-based ZIFs for a wide range of catalytic applications. Herein, the synthesis of the first Ni-based ZIFs is reported and their high potential as heterogeneous catalysts for Suzuki–Miyaura cross-coupling C─C bond forming reactions is demonstrated. 相似文献
113.
Blaženka Divjak;Barbi Svetec;Damir Horvat; 《Journal of Computer Assisted Learning》2024,40(6):2616-2632
Sound learning design should be based on the constructive alignment of intended learning outcomes (LOs), teaching and learning activities and formative and summative assessment. Assessment validity strongly relies on its alignment with LOs. Valid and reliable formative assessment can be analysed as a predictor of students' academic performance, but the question is how significant its predictive power is, and what other elements can affect predictions. 相似文献
114.
Yu‐Jung Lin Chun‐Chieh Chen Dang Nguyen Huei‐Rou Su Kun‐Ju Lin Hsin‐Lung Chen Yu‐Jung Hu Po‐Liang Lai Hsing‐Wen Sung 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(23)
Nitric oxide (NO) is a potent tumor‐cell radiosensitizer but it can be readily scavenged by hemoglobin (Hb) in vivo. A biomimetic incubator that can generate and deliver NO in a scavenger (Hb)‐free environment to enhance its radiosensitizing effect to maximize its efficacy in radiotherapy is proposed. This NO incubator comprises a poly(lactic‐co‐glycolic acid) (PLGA) hollow microsphere (HM) that contains an NO donor (NONOate) and a surfactant molecule (sodium caprate, SC) in its aqueous core. In acidic tumorous environments, the PLGA shell of the HM allows the penetration of protons from the outside, activating the hydrolytic cleavage of NONOate, spontaneously generating NO bubbles, which are immediately trapped/stabilized by SC. The SC‐stabilized NO bubbles in the HM are then squeezed through the spaces of its PLGA matrices by the elevated internal pressure. Upon leaving the HM, the entrapped NO molecules may passively diffuse through their SC‐stabilized/protected layer gradually to the tumor site, having a long‐lasting radiosensitizing effect and inhibiting tumor growth. The entire process of NO generation and delivery is conducted in a scavenger (Hb)‐free environment, mimicking the development of young ovoviviparous fish inside their mothers' bodies in the absence of predators before birth. 相似文献
115.
Fuyong Yue Vincenzo Aglieri Riccardo Piccoli Roberto Macaluso Andrea Toma Roberto Morandotti Luca Razzari 《Advanced Materials Technologies》2020,5(5)
The precise determination of the polarization state of light is fundamental for a vast variety of applications in remote sensing, astronomy, optics and terahertz technology, to name just a few. Typically, polarization characterization is performed by using a combination of multiple optical devices such as beam splitters, polarizers, and waveplates. Moreover, to achieve high‐precision, balanced photodetectors and lock‐in amplifiers are employed, thus contributing to increasing system complexity. Here, a technique for polarization rotation measurements with a dynamic range of 180° and a sensitivity of about 10−2 degrees is realized using a properly designed metasurface. Such device generates a vector beam with an azimuthally‐dependent polarization distribution, as a result of the superposition of two vortex beams carrying opposite orbital angular momenta (ℓ = ±30). After propagation through a linear polarizer, the spatial intensity profile of such a beam turns into 60 lobes. By tracking the displacement of only two of these lobes on a camera, the rotation of the input polarization state can be retrieved with high resolution. The proposed approach offers a new route toward the development of compact high‐precision polarimeters and can also be exploited in quantum information processing, optical communications, as well as nonlinear and chiral optics. 相似文献
116.
Computer simulations of animal groups are usually performed via individual‐based modelling, where simulated animals are designed on the level of individuals. With this approach, developers are able to capture behavioural nuances of real animals. However, modelling each individual as its own entity has the downside of having a high computational cost, meaning that individual‐based models are usually not suitable for real‐time simulations of very large groups. A common alternative approach is flow‐based modelling, where the dynamics of animal congregations are designed on the group level. This enables researchers to create real‐time simulations of massive phenomena at the cost of biological authenticity. A novel approach called hybrid modelling tries to mix the best of both worlds—precision of individual‐based models and speed of flow‐based ones. An unknown surrounding hybrid model is the question of their biological authenticity and relevance. In this study, we develop a hybrid model for the simulation of herds of grazing sheep. Through Bayesian data analysis, we show that such an approach can encompass several aspects of real‐world sheep behaviour. Our hybrid model is also extremely efficient, capable of simulating herds of more than 1,000 individuals in real time without resorting to graphics processing unit execution. 相似文献
117.
Binbin Chen Nicolas Gauquelin Daen Jannis Daniel M. Cunha Ufuk Halisdemir Cinthia Piamonteze Jin Hong Lee Jamal Belhadi Felix Eltes Stefan Abel Zoran Jovanović Matjaž Spreitzer Jean Fompeyrine Johan Verbeeck Manuel Bibes Mark Huijben Guus Rijnders Gertjan Koster 《Advanced materials (Deerfield Beach, Fla.)》2020,32(50):2004995
118.
Since the first demonstration of light‐emitting electrochemical cells (LECs) in 1995, much effort has been made to develop this technology for display and lighting. A common LEC generally contains a single emissive layer blended with a salt, which provides mobile ions under a bias. Ions accumulated at electrodes facilitate electrochemical doping such that operation voltage is low even when employing high‐work‐function inert electrodes. The superior properties of simple device architecture, low‐voltage operation, and compatibility with inert metal electrode render LECs suitable for cost‐effective light‐emitting sources. In addition to enormous progress in developing novel emissive materials for LECs, optical engineering has been shown to improve device performance of LECs in an alternative way. Light outcoupling enhancement technologies recycle the trapped light and increase the light output from LECs. Techniques to estimate emission zone position provide a powerful tool to study carrier balance of LECs and to optimize device performance. Spectral tailoring of the output emission from LECs based on microcavity effect and localized surface plasmon resonance of metal nanoparticles improves the intrinsic emission properties of emissive materials by optical means. These reported optical techniques are overviewed in this review. 相似文献
119.
Yang Li Xi Tian Si‐Ping Gao Lin Jing Kerui Li Haitao Yang Fanfan Fu Jim Yang Lee Yong‐Xin Guo John S. Ho Po‐Yen Chen 《Advanced functional materials》2020,30(5)
In the emerging Internet of Things, stretchable antennas can facilitate wireless communication between wearable and mobile electronic devices around the body. The proliferation of wireless devices transmitting near the human body also raises interference and safety concerns that demand stretchable materials capable of shielding electromagnetic interference (EMI). Here, an ultrastretchable conductor is fabricated by depositing a crumple‐textured coating composed of 2D Ti3C2Tx nanosheets (MXene) and single‐walled carbon nanotubes (SWNTs) onto latex, which can be fashioned into high‐performance wearable antennas and EMI shields. The resulting MXene‐SWNT (S‐MXene)/latex devices are able to sustain up to an 800% areal strain and exhibit strain‐insensitive resistance profiles during a 500‐cycle fatigue test. A single layer of stretchable S‐MXene conductors demonstrate a strain‐invariant EMI shielding performance of ≈30 dB up to 800% areal strain, and the shielding performance is further improved to ≈47 and ≈52 dB by stacking 5 and 10 layers of S‐MXene conductors, respectively. Additionally, a stretchable S‐MXene dipole antenna is fabricated, which can be uniaxially stretched to 150% with unaffected reflected power <0.1%. By integrating S‐MXene EMI shields with stretchable S‐MXene antennas, a wearable wireless system is finally demonstrated that provides mechanically stable wireless transmission while attenuating EM absorption by the human body. 相似文献
120.
Alisa Šehić Jelena Vasiljević Andrej Demšar Mirjam Leskovšek Vili Bukošek Jožef Medved Marija Čolović Ivan Jerman Barbara Simončič 《应用聚合物科学杂志》2019,136(5):47007
Polyamide 6 (PA6) composite filament yarns were produced by the simultaneous incorporation of melamine cyanurate (MeCy) with multiwalled carbon nanotubes (CNTs) and carbon black (CB) into a composite matrix in a melt-spinning process. The results show that the simultaneous incorporation of MeCy with CNTs or CB additives provided filaments with a uniform black color. Tensile analysis confirmed that a reinforcing effect was achieved when CB was used, whereas the CNTs induced a reducing effect on the filament tenacity. With regard to the burning behavior, the flame-retardant action of MeCy was preserved in the presence of CB but was significantly hindered when used in combination with CNTs. These results indicate that the mixture of MeCy and CB was much more compatible for the production of reinforced PA6 composite filaments with increased thermal stability and improved flame retardancy over those of the MeCy and CNTs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47007. 相似文献