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901.
Ayman Abdulhadi Althuwayb Fazirulhisyam Hashim Jiun Terng Liew Imran Khan Jeong Woo Lee Emmanuel Ampoma Affum Abdeldjalil Ouahabi Sébastien Jacques 《计算机、材料和连续体(英文)》2021,69(1):679-694
With the rapid development of the mobile internet and the internet of things (IoT), the fifth generation (5G) mobile communication system is seeing explosive growth in data traffic. In addition, low-frequency spectrum resources are becoming increasingly scarce and there is now an urgent need to switch to higher frequency bands. Millimeter wave (mmWave) technology has several outstanding features—it is one of the most well-known 5G technologies and has the capacity to fulfil many of the requirements of future wireless networks. Importantly, it has an abundant resource spectrum, which can significantly increase the communication rate of a mobile communication system. As such, it is now considered a key technology for future mobile communications. MmWave communication technology also has a more open network architecture; it can deliver varied services and be applied in many scenarios. By contrast, traditional, all-digital precoding systems have the drawbacks of high computational complexity and higher power consumption. This paper examines the implementation of a new hybrid precoding system that significantly reduces both calculational complexity and energy consumption. The primary idea is to generate several sub-channels with equal gain by dividing the channel by the geometric mean decomposition (GMD). In this process, the objective function of the spectral efficiency is derived, then the basic tracking principle and least square (LS) techniques are deployed to design the proposed hybrid precoding. Simulation results show that the proposed algorithm significantly improves system performance and reduces computational complexity by more than 45% compared to traditional algorithms. 相似文献
902.
Hathaichanok Phuengkham Long Ren Il Woo Shin Yong Taik Lim 《Advanced materials (Deerfield Beach, Fla.)》2019,31(34)
Cancer immunotherapies that harness the body's immune system to combat tumors have received extensive attention and become mainstream strategies for treating cancer. Despite promising results, some problems remain, such as the limited patient response rate and the emergence of severe immune‐related adverse effects. For most patients, the therapeutic efficacy of cancer immunotherapy is mainly limited by the immunosuppressive tumor microenvironment (TME). To overcome such obstacles in the TME, the immunomodulation of immunosuppressive factors and therapeutic immune cells (e.g., T cells and antigen‐presenting cells) should be carefully designed and evaluated. Nanoengineered synthetic immune niches have emerged as highly customizable platforms with a potent capability for reprogramming the immunosuppressive TME. Here, recent developments in nano‐biomaterials that are rationally designed to modulate the immunosuppressive TME in a spatiotemporal manner for enhanced cancer immunotherapy which are rationally designed to modulate the immunosuppressive TME in a spatiotemporal manner for enhanced cancer immunotherapy are highlighted. 相似文献
903.
Kyeong Tae Kang Jeongmin Park Dongseok Suh Woo Seok Choi 《Advanced materials (Deerfield Beach, Fla.)》2019,31(34)
The marriage between a 2D layered material (2DLM) and a complex transition metal oxide (TMO) results in a variety of physical and chemical phenomena that cannot be achieved in either material alone. Interesting recent discoveries in systems such as graphene/SrTiO3, graphene/LaAlO3/SrTiO3, graphene/ferroelectric oxide, MoS2/SrTiO3, and FeSe/SrTiO3 heterostructures include voltage scaling in field‐effect transistors, charge state coupling across an interface, quantum conductance probing of the electrochemical activity, novel memory functions based on charge traps, and greatly enhanced superconductivity. In this context, various properties and functionalities appearing in numerous different 2DLM/TMO heterostructure systems are reviewed. The results imply that the multidimensional heterostructure approach based on the disparate material systems leads to an entirely new platform for the study of condensed matter physics and materials science. The heterostructures are also highly relevant technologically as each constituent material is a promising candidate for next‐generation optoelectronic devices. 相似文献
904.
Yang Wang Wei Chen Lei Wang Bao Tu Tian Chen Bin Liu Kun Yang Chang Woo Koh Xianhe Zhang Huiliang Sun Guocong Chen Xiyuan Feng Han Young Woo Aleksandra B. Djurii Zhubing He Xugang Guo 《Advanced materials (Deerfield Beach, Fla.)》2019,31(35)
Hole‐transporting materials (HTMs) play a critical role in realizing efficient and stable perovskite solar cells (PVSCs). Considering their capability of enabling PVSCs with good device reproducibility and long‐term stability, high‐performance dopant‐free small‐molecule HTMs (SM‐HTMs) are greatly desired. However, such dopant‐free SM‐HTMs are highly elusive, limiting the current record efficiencies of inverted PVSCs to around 19%. Here, two novel donor–acceptor‐type SM‐HTMs (MPA‐BTI and MPA‐BTTI) are devised, which synergistically integrate several design principles for high‐performance HTMs, and exhibit comparable optoelectronic properties but distinct molecular configuration and film properties. Consequently, the dopant‐free MPA‐BTTI‐based inverted PVSCs achieve a remarkable efficiency of 21.17% with negligible hysteresis and superior thermal stability and long‐term stability under illumination, which breaks the long‐time standing bottleneck in the development of dopant‐free SM‐HTMs for highly efficient inverted PVSCs. Such a breakthrough is attributed to the well‐aligned energy levels, appropriate hole mobility, and most importantly, the excellent film morphology of the MPA‐BTTI. The results underscore the effectiveness of the design tactics, providing a new avenue for developing high‐performance dopant‐free SM‐HTMs in PVSCs. 相似文献
905.
Soyeon Yoon Minjun Seo In Soo Kim Kwangyeol Lee Kyoungja Woo 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(7):2206311
Poor stability of CsPbBr3 perovskite nanocrystals (NCs) to moisture/heat/light has significantly limited their application as a green phosphor, despite their outstanding luminescent properties. Here, a remarkably stable CsPbBr3 NCs−silica composite phosphor functionalized with surface phenyl molecules (CsPbBr3−SiO2Ph) is synthesized by controlling low-temperature hydrolysis and condensation reaction of perhydropolysilazane in the presence of CsPbBr3 NCs followed by phenyl-functionalization. Through the process, CsPbBr3 NCs are confined in a compact silica matrix, which is impermeable to H2O. The synthesis strategy is extended to a classical red quantum dot, CdZnSeS@ZnS NCs, to fabricate a white light emitting diode (WLED) consisting of CsPbBr3−SiO2Ph and CdZnSeS@ZnS−SiO2Ph phosphor and silicone resin packaged on a commercial blue InGaN chip with luminous efficacy (LE) of 9.36 lm W−1. The WLED undergoes enhancements in both green and red photoluminescence over time to achieve a highly efficient performance of 38.80 lm W−1. More importantly, the WLED exhibits unprecedented operational stability of LE/LE0 = 94% after 101 h-operation at 20 mA (2.56 V). The ultra-high operational stability and efficient performance are mainly attributed to thermal curing and aging through which grain growth occurs as well as deactivation of defect states by permeated atmospheric O2. 相似文献
906.
Gyudong Lee Woo Hyeon Jeong Beomjoo Kim Sungwoong Jeon Andrew M. Smith Jongcheol Seo Kengo Suzuki Jin-young Kim Hyunki Lee Hongsoo Choi Dae Sung Chung Jongmin Choi Hyosung Choi Sung Jun Lim 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(36):2301161
CdxHg1−xSe/HgS/CdyZn1−yS core/multi-shell quantum dots (QDs) exhibiting bright tissue-penetrating shortwave infrared (SWIR; 1000–1700 nm) photoluminescence (PL) are engineered. The new structure consists of a quasi-type-II CdxHg1−xSe/HgS core/inner shell domain creating luminescent bandgap tunable across SWIR window and a wide-bandgap CdyZn1−yS outer shell boosting the PL quantum yield (QY). This compositional sequence also facilitates uniform and coherent shell growth by minimizing interfacial lattice mismatches, resulting in high QYs in both organic (40–80%) and aqueous (20–70%) solvents with maximum QYs of 87 and 73%, respectively, which are comparable to those of brightest visible-to-near infrared QDs. Moreover, they maintain bright PL in a photocurable resin (QY 40%, peak wavelength ≈ 1300 nm), enabling the fabrication of SWIR-luminescent composites of diverse morphology and concentration. These composites are used to localize controlled amounts of SWIR QDs inside artificial (Intralipid) and porcine tissues and quantitatively evaluate the applicability as luminescent probes for deep-tissue imaging. 相似文献
907.
Seung Gyo Jeong Jihyun Kim Taewon Min Sehwan Song Jin Young Oh Woo-suk Noh Sungkyun Park Tuson Park Jong Mok Ok Jaekwang Lee Woo Seok Choi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(41):2303176
The magnetic anisotropy of low-dimensional Mott systems exhibits unexpected magnetotransport behavior useful for spin-based quantum electronics. Yet, the anisotropy of natural materials is inherently determined by the crystal structure, highly limiting its engineering. The magnetic anisotropy modulation near a digitized dimensional Mott boundary in artificial superlattices composed of a correlated magnetic monolayer SrRuO3 and nonmagnetic SrTiO3, is demonstrated. The magnetic anisotropy is initially engineered by modulating the interlayer coupling strength between the magnetic monolayers. Interestingly, when the interlayer coupling strength is maximized, a nearly degenerate state is realized, in which the anisotropic magnetotransport is strongly influenced by both the thermal and magnetic energy scales. The results offer a new digitized control for magnetic anisotropy in low-dimensional Mott systems, inspiring promising integration of Mottronics and spintronics. 相似文献
908.
Jihun Kim Jun Sung Jang Seung Wook Shin Hyeonghun Park Woo-Lim Jeong Seung-Hyun Mun Jung-Hong Min Jiyoung Ma Jaeyeong Heo Dong Seon Lee Jung-Je Woo Jin Hyeok Kim Hyeong-Jin Kim 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(22):2370156
Herein, a novel combination of Mg- and Ga-co-doped ZnO (MGZO)/Li-doped graphene oxide (LGO) transparent electrode (TE)/electron-transporting layer (ETL) has been applied for the first time in Cu2ZnSn(S,Se)4 (CZTSSe) thin-film solar cells (TFSCs). MGZO has a wide optical spectrum with high transmittance compared to that with conventional Al-doped ZnO (AZO), enabling additional photon harvesting, and has a low electrical resistance that increases electron collection rate. These excellent optoelectronic properties significantly improved the short-circuit current density and fill factor of the TFSCs. Additionally, the solution-processable alternative LGO ETL prevented plasma-induced damage to chemical bath deposited cadmium sulfide (CdS) buffer, thereby enabling the maintenance of high-quality junctions using a thin CdS buffer layer (≈30 nm). Interfacial engineering with LGO improved the Voc of the CZTSSe TFSCs from 466 to 502 mV. Furthermore, the tunable work function obtained through Li doping generated a more favorable band offset in CdS/LGO/MGZO interfaces, thereby, improving the electron collection. The MGZO/LGO TE/ETL combination achieved a power conversion efficiency of 10.67%, which is considerably higher than that of conventional AZO/intrinsic ZnO (8.33%). 相似文献
909.
Sun Geun Yoon YoungJun Yang Huding Jin Won Hyung Lee Ahrum Sohn Sang‐Woo Kim Junwoo Park Youn Sang Kim 《Advanced materials (Deerfield Beach, Fla.)》2019,31(3)
Aqueous ion–solid interfacial interactions at an electric double layer (EDL) are studied in various research fields. However, details of the interactions at the EDL are still not fully understood due to complexity induced from the specific conditions of the solid and liquid parts. Several technical tools for ion–solid interfacial probing are experimentally and practically proposed, but they still show limitations in applicability due to the complicated measurements. Recently, an energy conversion device based on ion dynamics (called ionovoltaic device) was also introduced as another monitoring tool for the EDL, showing applicability as a novel probing method for interfacial interactions. Herein, a monitoring technique for specific ion adsorption (Cu2+ and Pb2+ in the range of 5 × 10?6–1000 × 10?6m ) in the solid–liquid interface based on the ionovoltaic device is newly demonstrated. The specific ion adsorption and the corresponding interfacial potentials profiles are also investigated to elucidate a working mechanism of the device. The results give the insight of molecular‐level ion adsorption through macroscopic water‐motion‐induced electricity generation. The simple and cost‐effective detection of the device provides an innovative route for monitoring specific adsorption and expandability as a monitoring tool for various solid–liquid interfacial phenomena that are unrevealed. 相似文献
910.
Yong Cheol Shin Jung Bok Lee Dae‐Hyun Kim Taeyoung Kim Grant Alexander Young Min Shin Ju Young Park Sewoom Baek Jeong‐Kee Yoon Yong Jae Lee Gyeung Mi Seon Mi Hee Lee Mi‐Lan Kang Woo Soon Jang Jong‐Chul Park Ho‐Wook Jun YongTae Kim Hak‐Joon Sung 《Advanced materials (Deerfield Beach, Fla.)》2019,31(41)
Inserting a graft into vessels with different diameters frequently causes severe damage to the host vessels. Poor flow patency is an unresolved issue in grafts, particularly those with diameters less than 6 mm, because of vessel occlusion caused by disturbed blood flow following fast clotting. Herein, successful patency in the deployment of an ≈2 mm diameter graft into a porcine vessel is reported. A new library of property‐tunable shape‐memory polymers that prevent vessel damage by expanding the graft diameter circumferentially upon implantation is presented. The polymers undergo seven consecutive cycles of strain energy‐preserved shape programming. Moreover, the new graft tube, which features a diffuser shape, minimizes disturbed flow formation and prevents thrombosis because its surface is coated with nitric‐oxide‐releasing peptides. Improved patency in a porcine vessel for 18 d is demonstrated while occlusive vascular remodeling occurs. These insights will help advance vascular graft design. 相似文献