IONICS
·
2022
·Vol. 29
·期 2
·505-518
·
IF 2.961
Yang Dongping,Xiong Deping,Feng Zuyong,Wen Kunhua,Wu Kaidan,He Miao,Feng Yefeng
Sn-based materials receive a lot of attention because of their high theoretical specific capacity, acceptable price, and good electrical conductivity. However, Sn-based materials have a large volume expansion in the circulation process, leading to the rapid decay of capacity. According to the ion diffusion time formula: t = L2/2D, where L is the diffusion length or the particle size, and D is the diffusion constant of the ions and the electrons. It can be seen that reducing the particle size can significantly improve the multiplier performance of the material. At present, the main methods for preparing nano-sized metal/carbon composites are the high-energy ball grinding method, hydrothermal method, calcined metal, and organic matter precursor. In this paper, sodium alginate was used as a precursor system for the Fe-doped Sn @3D carbon composite material, which was applied to the lithium-ion battery anode to obtain excellent electrochemical performance (1133.5 mAhg −1 after 200 cycles at 0.2 Ag −1 ). The increase in the specific surface area of Fe-doped Sn @3D carbon also increases the charge transfer efficiency and further improves the multiplier performance of the electrode. Meanwhile, the nano-size and structure can better buffer the volume expansion and protect the structure of the electrode.
研究领域:
材料科学
·
电化学
·
纳米材料
·
能源存储
·
功能材料
·
复合材料
✓ 已验证
DOI
高影响因子
Landslides
·
2019
·Vol. 16
·期 7
·1313-1324
·
IF 4.252
Yang Wentao,Wang Yunqi,Sun Shao,Wang Yujie,Ma Chao
Detecting slope movement before landslides occur in mountain regions is crucial for disaster reduction. In October 2018, a gigantic landslide occurred on the Jinsha River, causing dammed-lake breach flood 500 km downstream. In this work, we used 25 Sentinel-2 images from November 2015 to August 2018 to explore the capability of this high temporal resolution optical images in detecting slope movement before the Jinsha River landslide. Normalized difference vegetation index (NDVI) was calculated to composite temporal profiles using all Sentinel-2 images. With this NDVI time series, unsupervised K-means classifier was applied to initially classify the study area and find the best thresholds for automatically extracting landslide scars in the image series. These extracted landslide scars were validated using interpreted results from two high spatial resolution images of similar dates in 2015 (user’s accuracy 89.7%, producer’s accuracy 83.6%) and 2018 (user’s accuracy 90.8%, producer’s accuracy 74.9%). After validation, extracted landslide scars of different years were counted and displayed in an RGB composite image to highlight slope movement. In addition, monotonous decrease/increase of NDVI was also observed, indicating continuous expansion of landslide scarps and movement of landslide head along the slope on the landslide surface. This work demonstrated the capability of Sentinel-2 time series images to capture slope movement with short revisit time at low cost. By incorporating other environmental information (such as elevation), this proposed method has the potential to consistently map pre-landslide slope movements over a large region.
研究领域:
遥感地质学
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环境灾害监测
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地理信息系统
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山地灾害防治
·
地球观测
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DOI
高影响因子
IONICS
·
2016
·Vol. 22
·期 8
·1343-1351
·
IF 2.119
Li Qi-Ling,Xu Wang-Qiong,Bai Hong-Li,Guo Jun-Ming,Su Chang-Wei
ZnO-coated LiMn 2 O 4 cathode materials were prepared by a combustion method using glucose as fuel. The phase structures, size of particles, morphology, and electrochemical performance of pristine and ZnO-coated LiMn 2 O 4 powders are studied in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge test, and X-ray photoelectron spectroscopy (XPS). XRD patterns indicated that surface-modified ZnO have no obvious effect on the bulk structure of the LiMn 2 O 4 . TEM and XPS proved ZnO formation on the surface of the LiMn 2 O 4 particles. Galvanostatic charge/discharge test and rate performance showed that the ZnO coating could improve the capacity and cycling performance of LiMn 2 O 4 . The 2 wt% ZnO-coated LiMn 2 O 4 sample exhibited an initial discharge capacity of 112.8 mAh g −1 with a capacity retention of 84.1 % after 500 cycles at 0.5 C. Besides, a good rate capability at different current densities from 0.5 to 5.0 C can be acquired. CV and EIS measurements showed that the ZnO coating effectively reduced the impacts of polarization and charge transfer resistance upon cycling.
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
纳米材料
✓ 已验证
DOI
高影响因子
Science China-Materials
·
2018
·Vol. 61
·期 7
·1001-1006
·
IF 4.318
Zhang Guo-Qiang,Ou Wei,Xu Yang-Sen
氢能源是未来最理想的清洁能源, 可以利用太阳能和光催化材料分解水获得. 开发廉价、 资源丰富、 环境友好的光催化材料, 成为近年来能源和环境领域的研究热点. 基于此, 我们报道了一种新型有机光催化材料-不含金属的荧光素超分子纳米片, 其在可见光下显示出高效的光催化分解水产氢活性, 产氢速率接近341 μmol g −1 h −1 , 在420±10 nm的波段下表观量子效率达到1.2%. 这是荧光素超分子晶体首次被报道并应用于可见光下分解水产氢, 这一发现丰富了有机和超分子光催化剂的种类.
研究领域:
光催化
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能源材料
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超分子化学
·
清洁能源
·
光化学
✓ 已验证
DOI
高影响因子
Early Childhood Education Journal
·
2024
·
IF 2.3
Li Hui,He Huihua,Luo Wenwei,Li Hui
Early childhood digital pedagogy (ECDP) has been widely implemented and studied, but the empirical evidence has not been systematically reviewed. This scoping review aimed to synthesize the existing studies to understand the practices and profiles of ECDP and the redefined roles of teacher, child, and technology. Thirty-eight studies on ECDP published from January 2010 to October 2024 were collected from three academic databases: EBSCO, Web of Science, and ProQuest. Synthesis of the findings of these studies revealed that: Firstly, digital technologies increasingly hold transformative potential for instructional practices at the level of modification and redefinition based on the SAMR framework. Secondly, play-based, project-based, problem-based, and co-operative and collaborative pedagogy with constructivist tendencies are the trademarks of ECDP. Lastly, in pedagogical interactions, teachers, children, and digital technologies each play diverse roles. This review study sheds some light on the practical characteristics of ECDP, which can inspire the effective designs and implementation of ECDP in the future.
研究领域:
教育学
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学前教育
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教育技术
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数字化学习
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教学设计
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发展心理学
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课程与教学论
·
学习科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2023
·Vol. 58
·期 17
·7456-7468
·
IF 4.5
Zhang Ning,Wang Zongliang,Zeng Yuqi,Guo Yueming,Wang Liqiang,Liu Jianguo,Wang Yu,Zhang Peibiao
Preformed three-dimensional scaffolds with insufficient mechanical properties, poor surgical performance, and morphological mismatch to defects with irregular shape have shown drawbacks in animal evaluations and clinical applications. This motivates the development of novel injectable systems to ideally fill bone defects, allowing in situ solidification within the host tissues while retaining high initial mechanical strength and appropriate porosity. In this study, an in situ forming scaffold with time-dependent pore formation inspired by the metamorphosis of a butterfly was fabricated by incorporating gelatin microspheres (GMs) into a poly(lactic-co-glycolic acid) (PLGA)-based injectable implant. After optimizing solvent, molecular weight and solution concentration of PLGA matrix, the injectable mixture could be easily injected into both aqueous solution and random-shaped grooves while in situ solidified instantaneously. The injectability enabled an in situ morphological match within an irregular bone defect, providing high initial strength in the early period. The toughness of the injectable implant also allowed them to be easily bent into a ring without breaking. Time-dependent pore formation was accomplished by gradual degradation of GMs, generating appropriate space for tissue ingrowth in the scaffold. It is expected that the injectable in situ forming implant would aid the bone healing process by maintaining initial mechanical support and creating a spatiotemporally evolutionary microstructure during bone tissue regeneration.
研究领域:
生物材料学
·
组织工程
·
骨科学
·
再生医学
·
高分子科学
·
药物递送系统
✓ 已验证
DOI
高影响因子
IONICS
·
2022
·Vol. 28
·期 8
·3655-3659
·
IF 2.961
Zuo Zhaoyang,Dong Sanfeng,Meng Dongrong
Although the lithium-sulfur batteries have high specific capacity and energy density, it is still a challenge to achieve the wide commercial applications due to the severe polysulfide migration and poor electronic conductivity of the element sulfur. To this context, we developed porous carbon/MnO 2 (PCMO) composites as sulfur host materials to increase the adsorption ability between the PCMO host and polysulfide. The MnO 2 particles embedded on the porous carbon severe as active sites to effectively adsorb and catalyze the polysulfide, therefore improving the redox kinetics and reducing shuttle effect. More importantly, the porous structure of the carbon can provide pathways for the lithium-ion diffusion, which accelerates the ion transport through the electrode. Owing to these merits, the as-prepared PCMO/S cathode exhibits high capacity, stable cycle performance and excellent rate capability.
研究领域:
储能
·
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Eye and Vision
·
2021
·Vol. 8
·期 1
·9
·
IF 3.257
Wang Junjie,Lopes Bernardo T.,Li Hechen,Vinciguerra Riccardo,Cao Si,Wu Songan,Zhu Rong,Wang Qinmei,Zheng Xiaobo,Bao Fangjun,Elsheikh Ahmed
Background Corneal refractive surgery has become reliable for correcting refractive errors, but it can induce unintended ocular changes that alter refractive outcomes. This study is to evaluate the unintended changes in ocular biometric parameters over a 6-month follow-up period after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). Methods 156 consecutive myopic patients scheduled for FS-LASIK and SMILE were included in this study. Central corneal thickness (CCT), mean curvature of the corneal posterior surface (K pm ), internal anterior chamber depth (IACD) and the length from corneal endothelium to retina (ER) were evaluated before and after surgery over a 6-month period. Results Both the FS-LASIK and SMILE groups (closely matched at the pre-surgery stage) experienced flatter K pm , shallower IACD and decreased ER 1 week post-surgery ( P < 0.01), and these changes were larger in FS-LASIK than in SMILE group. During the 1 week to 6 months follow up period, K pm , IACD and ER remained stable unlike CCT which increased significantly ( P < 0.05), more in the FS-LASIK group. Conclusions During the follow up, the posterior corneal surface became flatter and shifted posteriorly, the anterior chamber depth and the length from the corneal endothelium to retina decreased significantly compared with the pre-surgery stage. These unintended changes in ocular biometric parameters were greater in patients undergoing FS-LASIK than SMILE. The changes present clear challenges for IOL power calculations and should be considered to avoid affecting the outcome of cataract surgery.
研究领域:
眼科学
·
屈光手术
·
生物测量
·
临床研究
✓ 已验证
DOI
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2014
·Vol. 174
·期 6
·2236-2244
·
IF 1.687
Dai Yong,Shao Rong,Qi Gang,Ding Bin-Bin
In this study, it was the first report that the Brevibacterium lutescens CCZU12-1 was employed as a sulfur removing bacteria. Using dibenzothiophene (DBT) as the sole sulfur source, B. lutescens could selectively degrade DBT into 2-hydroxybiphenyl (2-HBP) via the “4S” pathway. In the basal salt medium (BSM) supplemented with 0.25 mM DBT and 0.5 g/L Tween-80, high desulfurization rate (100 %) was obtained by growth cells after 60 h. Furthermore, the n -octane–water (10:90, v / v ) biphasic system was built for the biodesulfurization by resting cells. Moreover, a combination of magnetic nano Fe 3 O 4 particles with calcium alginate immobilization was used for enhancing biodesulfurization. In this n -octane–water biphasic system, immobilized B. lutescens cells could be reused for not less than four times. Therefore, B. lutescens CCZU12-1 shows high potential in the biodesulfurization.
研究领域:
生物脱硫
·
环境生物技术
·
微生物技术
·
石油生物炼制
·
应用微生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 6
·5925-5933
·
IF 1.798
Peng Linghui,Guo Ronghui,Lan Jianwu,Jiang Shouxiang,Wang Xiang,Li Chao,Li Juan
Silver nanoparticles were synthesized on bamboo pulp fabric with pretreatment of plasma under microwave radiation. The silver nanoparticles coated bamboo pulp fabrics were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis and X-ray diffraction. Color characteristics and contact angles of silver coated bamboo pulp fabrics were evaluated. Adhesive strength of silver nanoparticles on bamboo pulp fabrics without and with pretreatment of plasma was investigated. Compared with silver nanoparticles coated bamboo pulp fabric without pretreatment of plasma, more silver nanoparticles are coated on the bamboo pulp fabric with pretreatment of plasma. Bamboo pulp fabrics are evenly covered with silver nanoparticles with pretreatment of plasma. In addition, influences of distance between the plasma source and the fabric and treating time on deposition amounts of silver nanoparticles were investigated. Color strength values decrease and increase with the rise of distance and treatment time, respectively. The silver nanoparticles coated bamboo pulp fabric pretreatment of plasma has excellent UV protection, good fastness to laundering and hydrophobicity.
研究领域:
材料科学
·
纳米技术
·
纺织工程
·
表面化学
✓ 已验证
DOI
高影响因子
Early Childhood Education Journal
·
2011
·Vol. 39
·期 5
·313-321
·
IF 0
Mattix April A.,Crawford Patricia A.
Approximately 1.4 million school-aged children entered their families through adoption. As such, adoption represents a real and complex social issue with which young children—adopted or not—can grapple. Adoption picturebooks provide a medium by which children can explore this complicated concept. This manuscript analyzes a standard library collection of adoption picturebooks to explore the salient themes that arise throughout this body of children’s literature. Four major, yet overlapping themes emerged: the adopted child as “precious”, the search for identity, the pursuit of adoption, and the need to establish a sense of belonging. This study shows that the themes located within this subset of children’s literature are broad, fluid and often intricately woven together; a complexity that is mirrored through the same qualities in life. Through adoption picturebooks, children are provided with a terrain in which to explore the conceptual components that frame their identities and are presented with a space to examine the realities of adoption.
研究领域:
儿童文学
·
教育中的社会问题
·
发展心理学
✓ 已验证
DOI
CHEMISTRY AND TECHNOLOGY OF FUELS AND OILS
·
2025
·
IF 0.7
Chen Keyou,Luo Zhifeng,Zhou Quan,Yan Chaozong,Fu Haoran,Wang Qihai,He Jie
Fracturing fluid is the “blood“ of reservoir reconstruction technology. Single-well myriad square fluid and thousand square sand have become the main methods of volume fracturing in uncon-ventional oil and gas horizontal wells. With the gradual exploitation of oil and gas fields to the deep, higher performance requirements have been put forward for fracturing fluid. In this paper, nano- TiO 2 was modified by vinyltrimethoxysilane, and a new type of nanocomposite polymer (PTAS) was synthesized by aqueous solution polymerization of modified nano-TiO 2 with acrylamide (AM), acrylic acid (AA) and 2-acrylamide-2-methylpropylsulfonic acid (AMPS). The synthesis conditions such as monomer ratio, polymerization temperature, polymerization time, and initiator dosage were optimized by using the viscosity of the base solution as an index. The structure and properties of PTAS were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The experimental results showed that the nano-TiO 2 was successfully modified by vinyltrimethoxysilane, and the modified nano- TiO 2 was successfully attached to the polymer molecular chain. The performance evaluation results of PTAS showed that compared with the polymer without nano-TiO 2 P(AM-AA-AMPS), the salt resistance, sand carrying, temperature resistance, shear resistance, and gel breaking properties of PTAS were improved, This is due to the additional modified nano-TiO 2 , which enhances the polymer network structure and improves its structural stability, so that the polymer can maintain good thickening behavior performance while reducing the molecular weight, reducing the residue content after gel breaking, and reducing its damage to the formation. PTAS has a good potential for application in hydraulic fracturing.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）