检索结果-内蒙古大学图书馆

arXiv 2024年

作者： Zhang, Bo-Wen Qiu, Xi-Yang Ma, Yicheng Hu, Qingmei Fitó-Parera, Aina Kohata, Ikuma Feng, Ya Zheng, Yongjia Zhang, Chiyu Matsuo, Yutaka Wang, YuHuang Chiashi, Shohei Otsuka, Keigo Xiang, Rong Levshov, Dmitry I. Cambré, Sofie Wenseleers, Wim Rotkin, Slava V. Maruyama, Shigeo Department of Mechanical Engineering The University of Tokyo Tokyo113-8656 Japan State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou310027 China Theory and Spectroscopy of Molecules and Materials Department of Physics University of Antwerp Antwerp2610 Belgium Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power Engineering Dalian University of Technology Liaoning 116024 China Department of Chemistry and Biochemistry Chemical Physics Program Maryland Nano Center University of Maryland College ParkMD20742 United States Department of Chemical Systems Engineering Graduate School of Engineering Nagoya University Nagoya464-8603 Japan Institute of Materials Innovation Institutes for Future Society Nagoya University Nagoya464-8603 Japan Theory and Spectroscopy of Molecules and Materials Department of Chemistry University of Antwerp Antwerp2610 Belgium Nanostructured and Organic Optical and Electronic Materials Department of Physics University of Antwerp Antwerp2610 Belgium Materials Research Institute Department of Engineering Science & Mechanics The Pennsylvania State University University ParkPA16802 United States

Carbyne, a one-dimensional (1D) carbon allotrope with alternating triple and single bonds, has the highest known mechanical strength but is unstable to bending, limiting synthesis to short linear chains. Encapsulation within carbon nanotubes (CNTs) stabilizes carbyne, forming confined carbyne (CC), thus enabling further research concerning attractive 1D physics and materials properties of carbyne. While CC has been synthesized in multi-walled CNTs (MWCNTs) using the arc-discharge method and in double-walled CNTs (DWCNTs) via high-temperature high-vacuum (HTHV) method, synthesis in single-walled CNTs (SWCNTs) has been challenging due to their fragility under such conditions. In this work, we report a low-temperature method to synthesize CC inside SWCNTs (CC@SWCNT). By annealing SWCNTs containing ammonium deoxycholate (ADC) at 400°C, ADC is converted into CC without damaging the SWCNTs. Raman spectroscopy revealed a strong CC phonon (CC-mode) peak at 1860–1870 cm-1, much stronger than the SWCNT G-band peak, confirming a high fraction of CC in the resulting material. The Raman mapping result showed the uniformity of the CC-mode signal across the entire film sample, proving the high efficiency of this method in synthesizing CC in every SWCNT of appropriate size. Notably, the CC-mode peaks of CC@SWCNT (above 1860 cm-1) are higher than those reported in previous CC@CNT samples (mostly -1). This is attributed to larger SWCNT diameters (>0.95 nm) used in this study, compared to the typical 0.6–0.8 nm range. Larger diameters result in reduced confinement, allowing carbyne to closely resemble free-standing carbyne while remaining stabilized. This low-temperature synthesis of long-chain, nearly freestanding carbyne within large-diameter SWCNTs offers new opportunities for exploring 1D physics and the unique properties of carbyne for potential applications. © 2024, CC BY-NC-ND.

关键词： Single-walled carbon nanotubes (SWCN)

来源：评论

学校读者我要写书评

暂无评论

Unleashing the Power of Nature: Eco-Friendly Mussel-Byssus-Inspired Pbs/Pbat Fishing Gear for Biodegradation by Marine Microbes

SSRN

引用

SSRN 2023年

作者： Hong, Yuri Yang, Ho-Sung Lee, Min Hee Kim, Sinyang Park, Sung Bae Hwang, Sung Yeon Park, Jeyoung Koo, Jun Mo Oh, Dongyeop Hwang, Dong Soo Gyeongsangbuk-do Pohang37673 Korea Republic of Ulsan44429 Korea Republic of Department of Plant & Environmental New Resources Graduate School of Biotechnology Kyung Hee University Gyeonggi-do 17104 Korea Republic of Department of Chemical and Biomolecular Engineering Sogang University Seoul04107 Korea Republic of Department of Organic Materials Engineering Chungnam National University Daejeon34134 Korea Republic of Department of Polymer Science and Engineering and Program in Environmental and Polymer Engineering Inha University Incheon22212 Korea Republic of

Abstract Abandoned, lost, and discarded fishing gear (ALDFG) poses global challenges for marine ecosystems as they destroy algal forests, the largest oceanic carbon dioxide sinks. Biodegradable polybutylene succinate (PBS), which has a tensile toughness similar to that of nylon, has been suggested as a potential fishing-gear material. However, its slow degradation in the marine environment and limited draping characteristics need to be addressed before it can be used in environmentally friendly fishing gear. Inspired by the mussel byssus, a mussel-thread-like holdfast known for its stiff yet extensible mechanical properties, we developed fishing gear using a mussel-byssus-mimetic fiber (artificial byssus, AB) structure. The AB was composed of poly(butylene adipate-co-butylene terephthalate) (PBAT) fibers with favorable draping characteristics coated with mechanically resilient and PBS, which demonstrated sufficient toughness and draping properties for use in fishing gear. The AB may serve as fishing-gear material capable of mitigating ALDFG issues, given its marine degradability by microbial strains that degrade PBS and PBAT. Furthermore, it could serve as a substrate for ocean afforestation, given the improved settlement and growth of seaweed spores (Pyropia yezoensis) on AB. Overall, AB-based fishing gear is expected to enhance macroalgal forest conservation and expansion, and facilitate marine carbon capture through marine afforestation. © 2023, The Authors. All rights reserved.

关键词： Butenes

来源：评论

学校读者我要写书评

暂无评论

Oxygen-producing composite dressing activated by photothermal and piezoelectric effects for accelerated healing of infected wounds

引用

Chemical engineering Journal 2023年 476卷

作者： Lai, Yen-Han Roy Barman, Snigdha Ganguly, Anindita Pal, Arnab Yu, Jui-Han Chou, Syun-Hong Huang, E-Wen Lin, Zong-Hong Chen, San-Yuan Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Institute of Biomedical Engineering National Tsing Hua University Hsinchu30013 Taiwan Department of Biomedical Engineering National Taiwan University Taipei10617 Taiwan Graduate Institute of Biomedical Science China Medical University Hospital Taichung40400 Taiwan School of Dentistry College of Dental Medicine Kaohsiung Medical University Kaohsiung80708 Taiwan International Intercollegiate Ph.D. Program National Tsing Hua University Hsinchu30013 Taiwan

The process of wound healing is often obstructed by the prevalence of bacterial infection at the wound site. Hence, innovative strategies to alleviate infection is extremely necessary to realize effective wound recovery in a timely manner. Here, we report a self-activated composite dressing consisting of piezoelectric and photothermal functional layers for combating wound infection and provide the desired treatment. The synergistic dressing is functionalized with piezoelectric Poly-L-lactic acid (PLLA) which under the effect of ultrasound irradiation controllably generates reactive oxygen species (ROS) for antibacterial activity, thus facilitating the dressing to inhibit the growth of bacteria at the wound bed. Further, the dressing is modified with calcium peroxide (CaO2) which can effectively convert the generated ROS into molecular oxygen (O2) in presence of catalase enzyme for treating chronic hypoxia in the infected wounds. The sustained generation of O2 by the wound dressing augmented the cell proliferation, migration and tissue regeneration aiding in wound healing. By combining the inherent photothermal activity of reduced graphene oxide (rGO), the synergistic dressing under NIR irradiation enhanced the wound recovery by upregulating the heat shock protein 90 (Hsp90) secretion owing to the heat generation on the wounds. The results obtained demonstrate that the self-triggered multifunctional wound dressing is a promising candidate for clinical treatment of infected wounds with a user-friendly interface. © 2023 Elsevier B.V.

关键词： Ultrasonics

来源：评论

学校读者我要写书评

暂无评论

Interfacial Layer materials with a Truxene Core for Dopant-Free NiOx-Based Inverted Perovskite Solar Cells

引用

Small 2024年第33期20卷 e2310939页

作者： Ramanujam, Rajarathinam Hsu, Hsiang-Lin Shi, Zhong-En Lung, Chien-Yu Lee, Chin-Han Wubie, Gebremariam Zebene Chen, Chih-Ping Sun, Shih-Sheng Institute of Chemistry Academia Sinica Nankang Taipei11529 Taiwan Taiwan International Graduate Program Sustainable Chemical Science and Technology Academia Sinica Nankang Taipei11529 Taiwan Department of Applied Chemistry National Yang Ming Chiao Tung University Hsinchu30050 Taiwan Department of Materials Engineering Ming Chi University of Technology 84 Gunjuan Road Taishan New Taipei City24301 Taiwan College of Engineering and Center for Sustainability and Energy Technologies Chang Gung University Taoyuan33302 Taiwan

Nickel oxide (NiOx) is commonly used as a holetransporting material (HTM) in p-i-n perovskite solar cells. However, the weak chemical interaction between the NiOx and CH3NH3PbI3 (MAPbI3) interface results in poor crystallinity, ineffective hole extraction, and enhanced carrier recombination, which are the leading causes for the limited stability and power conversion efficiency (PCE). Herein, two HTMs, TRUX-D1 (N2,N7,N12-tris(9,9-dimethyl-9H-fluoren-2-yl)-5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-10,15-dihydro-5H-diindeno[1,2-a:1′,2′-c]fluorene-2,7,12-triamine) and TRUX-D2 (5,5,10,10,15,15-hexaheptyl-N2,N7,N12-tris(4-methoxyphenyl)-N2,N7,N12-tris(10-methyl-10H-phenothiazin-3-yl)-10,15-dihydro-5H-diindeno[1,2-a:1′,2′-c]fluorene-2,7,12-triamine), are designed with a rigid planar C3 symmetry truxene core integrated with electron-donating amino groups at peripheral positions. The TRUX-D molecules are employed as effective interfacial layer (IFL) materials between the NiOx and MAPbI3 interface. The incorporation of truxene-based IFLs improves the quality of perovskite crystallinity, minimizes nonradiative recombination, and accelerates charge extraction which has been confirmed by various characterization techniques. As a result, the TRUX-D1 exhibits a maximum PCE of up to 20.8% with an impressive long-term stability. The unencapsulated device retains 98% of their initial performance following 210 days of aging in a glove box and 75.5% for the device after 80 days under ambient air condition with humidity over 40% at 25 °C. © 2024 Wiley-VCH GmbH.

关键词： Passivation

来源：评论

学校读者我要写书评

暂无评论

Transient and elusive intermediate states in self-assembly processes: An overview

Responsive Materials

引用

Responsive materials 2024年第2期2卷

作者： Ziyi Zhang Ze Hu Junfei Xing Quan Li Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing China Materials Science Graduate Program Kent State University Kent Ohio USA Junfei Xing and Quan Li.

The transient and elusive intermediate states are the keys in self-assembly processes, which are common phenomena shaping the structure, properties, and functionalities of assembled materials across many scientific domains. However, the understanding about the intermediate states of self-assembly process is always challenging and limited. In this review, we focus on these states by combining theoretical and experimental approaches. By examining a wide variety of self-assembly systems that span from biological to metal–organic nanostructures, this review uncovers the wealth of intermediate states of self-assembled materials. In addition to combining the current knowledge, it will identify challenges and provide a new insight into the opportunities for future research.

关键词： biotechnology intermediate state materials science nanostructure self-assembly

来源：评论

学校读者我要写书评

暂无评论

Injectable Gelatin-Pectin Hydrogel for Dental Tissue engineering: Enhanced Angiogenesis and Antibacterial Efficacy for Pulpitis Therapy

SSRN

引用

SSRN 2024年

作者： Phan, Chau My Luu, Cuong Hung Murugesan, Mohanapriya Nguyen, Thi-Nhu-Quynh Ha, Nhu-Y Ngoc Ngo, Huong Lan Nguyen, Ngoc-Dan Ho Pan, Zhouyi Phan, V.H. Giang Li, Yi Thambi, Thavasyappan College of Materials and Textile Engineering & Nanotechnology Research Institute Jiaxing University Zhejiang Province Jiaxing314001 China Biomaterials and Nanotechnology Research Group Faculty of Applied Sciences Ton Duc Thang University Ho Chi Minh City Viet Nam School of Environment and Science Griffith University NathanQLD4111 Australia Queensland Micro- and Nanotechnology Centre Griffith University NathanQLD4111 Australia Graduate School of Biotechnology College of Life Sciences Kyung Hee University Gyeonggi do Yongin si17104 Korea Republic of

Pulpitis is inflammation of the dental pulp, often caused by bacterial infection from untreated cavities, leading to pain. The main challenge in treatment is eliminating infection while preserving tooth vitality. This study aimed to address this challenge by developing a hydrogel for convenient insertion into the root canal system, securely attaching to dentin walls. We developed an injectable hydrogel system by chemically cross-linking natural polysaccharide pectin with gelatin (GPG) through reversible Schiff base reaction. The GPG system was then assessed for its ability to encapsulate and release drugs, such as ciprofloxacin (CIP) for infection prevention and deferoxamine (DFO) for promoting blood vessel proliferation and reducing inflammatory reactions. The GPGs absorbed significant amounts of CIP and DFO, enabling sustained release over a ten-day period. When subcutaneously implanted, the GPGs formed stable gel depots, with only 50% of the gels degrading, indicating a sustained biodegradation pattern. Additionally, the GPG system demonstrated excellent antibacterial activity against both gram-negative and gram-positive bacteria. Results from in vitro scratch healing tests and in ovo chorioallantoic membrane chick model tests showed promising biocompatibility and promotion of vascular proliferation by the GPG. This study heralds an innovative frontier in endodontic therapeutics, poised to revolutionize dental pulp regeneration. © 2024, The Authors. All rights reserved.

关键词： Controlled drug delivery

来源：评论

学校读者我要写书评

暂无评论

Affordable, high-resolution bioprinting with embedded concentration gradients

引用

Bioprinting 2021年 21卷

作者： Shen, Edwin M. McCloskey, Kara E. Graduate Program in Biological Engineering and Small-scale Technologies University of California Merced United States Department of Materials Science and Engineering University of California Merced United States

Three-dimensional (3D) bioprinting has brought major innovations to the field in its ability to fabricate cell-laden constructs that closely resemble physiological tissue. Unfortunately, many bioprinters print only one material and at limited resolutions. Improving on the resolutions, functionality, and affordability necessitates attention to both printing techniques and printers. Here, we present our results towards building an affordable, partially open-source bioprinter, ModiPrint, that enables multiple cell-material combination printing with high resolution extrusions (100 μm) of alginate. We also introduce a new technique to improve extrusion resolution in complex geometries. The results show that we were able to maintain viability of human pluripotent stem cells (hiPSCs) after high resolution printing. Lastly, we were able to generate concentration gradients of small molecules or cytokines embedded within hydrogels by combining extrusion and drop-on-demand bioprinting. We expect ModiPrint and the novel techniques in our study will assist other bioprinting researchers. © 2020 The Authors

关键词： Alginate Biomimicry Bioprinting Concentration gradients FRESH Hydrogels ModiPrint Open-source Pluripotent stem cells

来源：评论

学校读者我要写书评

暂无评论

Utilization of ornamental rock waste as a catalytic support for α-MoO₃ in biodiesel production

引用

Scientific reports 2025年第1期15卷 19152页

作者： H B Sales M S Oliveira A L Silva H L Pereira A C F M Costa M C F Alves Laboratory of Ceramic Materials Synthesis (LabSMac) Graduate Program in Materials Science and Engineering (PPGCEMat) Academic Unit of Materials Engineering (UAEMa) Federal University of Campina Grande (UFCG) Rua Aprígio Veloso 882 Bodocongó 58.429-900 Campina Grande PB Brazil. herbet_bezerra@***. Laboratory of Ceramic Materials Synthesis (LabSMac) Graduate Program in Materials Science and Engineering (PPGCEMat) Academic Unit of Materials Engineering (UAEMa) Federal University of Campina Grande (UFCG) Rua Aprígio Veloso 882 Bodocongó 58.429-900 Campina Grande PB Brazil. Laboratory of Inorganic Materials for Environmental Catalysis Research Department of Chemistry (MATIPECA) Graduate Program in Chemistry (PPGQ) DQ State University of Paraíba (UEPB) Rua Baraúnas 351 Universitário 58.429-500 Campina Grande PB Brazil.

This study aimed to explore the use of ornamental stone waste as a support for the α-MoO₃ catalyst to develop efficient and sustainable heterogeneous systems for biodiesel production. The catalysts were characterized using physicochemical techniques including X-ray diffraction with Rietveld refinement, FTIR and Raman spectroscopy, scanning electron microscopy with EDS, transmission electron microscopy, nitrogen adsorption/desorption (BET method), particle size distribution, ammonia temperature-programmed desorption (TPD-NH₃), magnetic measurements, and gas chromatography to analyze simultaneous transesterification/esterification (TES) reactions and quantify methyl and ethyl esters. XRD patterns revealed crystalline phases such as mica-biotite, ferro-tschermakite, albite, quartz, and iron-magnesium silicates-components of the catalytic support-as well as orthorhombic α-MoO₃ phases, also confirmed in the heterogeneous systems. FTIR and Raman analyses showed characteristic vibrational bands, while SEM images displayed irregular agglomerates, corroborated by TEM. Nitrogen adsorption isotherms indicated mesoporous structures with surface areas ranging from 0.615 to 3.87 m²/g. Particle size analysis showed D₅₀ values between 5.02 and 20.00 μm, with total acidity ranging from 77.0 to 245 µmol/g of NH₃. Magnetic tests indicated ferrimagnetic behavior. The catalytic performance confirmed the effectiveness of the waste as a support for α-MoO₃, particularly in the system containing 40% Mo ions (40%σ-MoO₃:Waste), which achieved conversions between 78% and 95%. These findings highlight the environmental and technological potential of the studied catalysts, reinforcing the economic viability and ecological relevance of reusing industrial waste in the sustainable production of biodiesel from waste oils.

关键词： And sustainability Green technology Heterogeneous catalysis Industrial waste MoO₃ Waste oils

来源：评论

学校读者我要写书评

暂无评论

Extraction of Terahertz Wave Parameters that Characterize Woolen Clothes

SSRN

引用

SSRN 2024年

作者： Yoshizumi, Toa Iwasaki, Kazuma Fujii, Sho Kimura, Tsuyoshi Yamamoto, Masaya Manago, Gaku Yu, Jeongsoo Tanabe, Tadao Department of Mechanical Engineering Shibaura Institute of Technology 3-7-5 Toyosu Koto-ku Tokyo135-8548 Japan Faculty of Science Yamagata University 1-4-12 Koshirakawacho Yamagata990-8560 Japan Institute of Biomaterials and Bioengineering Tokyo Medical and Dental University 2-3-10 Kanda-surugadai Chiyoda-ku Tokyo101-0062 Japan Department of Materials Processing Graduate School of Engineering Tohoku University 6-6-02 Aramaki-aza Aoba Aoba-ku Sendai980-8579 Japan Graduate School of International Cultural Studies Tohoku University 41 Kawauchi Aoba-ku Miyagi-ken Sendai9808576 Japan Graduate School of Environmental Studies Tohoku University 468-1 Aramaki Aza Aoba Aoba-ku Miyagi-ken Sendai9808572 Japan

Recycling wool is practical within the recycled fiber market as it is abundant and has a higher value. To reduce the cost of sorting fibers, terahertz waves have been used to extract parameters within the spectral information that are characteristic of wool fiber. Differences due to the specific surface shape (scale shape) and the terahertz measurement area were utilized for the identification. Characteristic features of wool content were observed between 19.4 THz and 19.8 THz by FTIR (Fourier Transform Infrared Spectroscopy) measurements. At 19.5 THz, the reflectance decreased from 2.0 % to 0.85 % as the wool content increased. This is due to the scale shape of the wool surface causing scattering. Samples with more than 80 % wool could be identified by 1.4 % or less reflectance at this frequency. A mathematical expression for a reflectance that decreases as the wool content increases can be successfully expressed as an exponential function. In addition, a correlation between the surface structure of the sample and its anisotropy due to weaving to the polarized terahertz wave was confirmed. Due to the structural characteristics of the sample, there is an anisotropy of 45 º or 90 º which could be identified by a transmittance of 40 %. © 2024, The Authors. All rights reserved.

关键词： Wool

来源：评论

学校读者我要写书评

暂无评论

Effects of sodium alginate-poly(acrylic acid) cross-linked hydrogel beads on soil conditioner in the absence and presence of phosphate and carbonate ions

引用

Case Studies in Chemical and Environmental engineering 2024年 9卷

作者： Hidayat, Endar Sarbani, Nur Maisarah Mohamad Lahiri, Sudip Kumar Samitsu, Sadaki Yonemura, Seiichiro Mitoma, Yoshiharu Harada, Hiroyuki Graduate School of Comprehensive Scientific Research Program in Biological System Sciences Prefectural University of Hiroshima Shobara 727-0023 Japan Department of Life System Science Faculty of Bioresources Science Prefectural University of Hiroshima Shobara 727-0023 Japan Data-driven Polymer Design Group Research Center for Macromolecules and Biomaterials National Institute for Materials Science 1−2−1 Sengen Tsukuba 305-0047 Japan Department of Mechanical & Industrial Engineering University of Toronto Toronto M5S 3G8 ON Canada Faculty of Allied Health Sciences Chettinad Hospital and Research Institute Chettinad Academy of Research and Education Tamil Nadu Kelambakkam 603103 India

Hydrogel beads, composed of polymers, possess the ability to absorb substantial quantities of water simultaneously and gradually release it in dry conditions. In this work, hydrogel beads were synthesized using sodium alginate (S-Alg) and poly (acrylic acid) (P-Acc), either in the absence or presence of phosphate (PO₄ ³⁻) (S-Alg/P-Acc@PO₄ ³⁻) and carbonate (CO₃ ²⁻) anionic ions (S-Alg/P-Acc@CO₃ ²⁻). Subsequently, these beads were crosslinked with Ca²⁺ ions. The scanning electron microscopy (SEM) images demonstrated that the presence of anionic ions has an impact on the structure of the hydrogel beads and enhances porosity expansion while concurrently reducing the concentration of carboxyl (COOH) groups. The hydrogel beads exhibited a great swelling behavior, with S-Alg/P-Acc@CO₃ ²⁻ capable of absorbing up to 73.5 % of water in acidic conditions, but decreased under neutral and basic conditions. Soil water loss (SWL) experiments confirmed the ability of hydrogel beads to retain water in the soil. Additionally, observations of soil characteristics after a 14-day treatment revealed no significant difference in pH and C/N ratio (P-value <0.05). However, soil's available Fe and N–NO₃ ^- significantly reduced (P-value <0.05) while substantially promoting soil N–NH₄ ⁺, available phosphorus (P), cation exchange capacity (CEC), soil organic carbon (SOC), and exchangeable cation (Ca²⁺, K⁺ and Mg²⁺). The presence of hydroxyl (-OH) and –COOH groups was found to be crucial for enhancing soil properties. © 2024 The Authors

关键词： Anionic ions Hydrogel beads Poly (acrylic acid) Sodium alginate Soil characteristics Soil water retention Swelling

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：