Food Bioscience
·
2024
·
IF 4.8
Xiaoning Liu,Zekun Xu,Xingxun Liu,Chuangchuang Zhang,Mengting Ma,Zhongquan Sui,Harold Corke
Starch granule surface and channel proteins (GSCP) or starch granule channel proteins (GCP) were respectively removed from waxy and non-waxy rice starches . The effects of α-amylase hydrolysis on the lamellar structure changes of rice starches were examined by small-angle X-ray scattering (SAXS). SAXS revealed that the scattering peaks of hydrolyzed starch granules were broadened. The result was also evidenced by the decreased peak areas ( A ) and increased peak width at half-maximum ( W ). The α-amylase hydrolysis of starches could induce a transformation from a mass to a surface fractal and increase the compactness of starches. Moreover, the thickness of amorphous lamellae ( d a ) decreased and that of crystalline lamellae ( d c ) increased for starches after hydrolysis. Hydrolyzed starches exhibited a higher proportion of short-branch chains (fa) and long-branch chains (fb3) compared to their native form, indicating that α-amylase mainly attacked the long molecular chain of amylopectin with branch points in the amorphous lamellae. Removal of GSCP accelerated and exacerbated the decrease in d a and the increase in d c . Further, GSCP removal brought on the formation of less compact starch during long-time hydrolysis. Overall, the results demonstrated that GSCP removal had significant impacts on structural changes during α-amylase hydrolysis from lamellar to molecular scales.
研究领域:
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Ruiwen Ji,Meng Lei,Cécile Genevois,Wenda Zhang,Xing Ming,Lunhua He,Mathieu Allix,Congling Yin,Xiaojun Kuang,Xianran Xing
Layered materials coupling a two-dimensional strong-bonding layered network with much weaker van der Waals (vdW) interaction between the layers are sought after for the development of nanoelectronics and energy conversion devices. It is important to elucidate the layer stacking rules in these vdW materials and control the thickness of the strong-bonding layers for tuning the nanosheet height during exfoliation and therefore tailor physical properties. Here, we show that the single Bi2O2Se ionic layer in the three-anion vdW semiconductor Bi4O4SeCl2 showing extremely low thermal conductivity can be expanded to higher-order layers forming a homologous series Bi2+2nO2+2nSenX2 (X = Cl, Br) with variable ionic layer thicknesses. Bi4O4SeX2 (n = 1) and Bi6O6Se2X2 (n = 2) were isolated as single-phase materials, while materials with larger layer thicknesses such as Bi8O8Se3Cl2 (n = 3) contain different defect-intergrowth structures at the crystallite scale. The anionic disorder of Se and X within the Bi2O2Se and Bi2O2X2 slabs is a critical factor in the stabilization of Bi2+2nO2+2nSenX2. The ∼50% Se substitution by X anions in the Bi2O2Se slab as related to the weak interlayer interaction can serve as a stabilization criterion of Bi2+2nO2+2nSenX2. All of these materials show similar optical indirect band gaps of ∼1.05 eV, originating from the electronic states in the Bi2O2Se slabs. Pellets prepared from these vdW materials possessed low bulk resistivities (100 Ω·cm) and exceptionally low and tunable thermal conductivities (0.66 W/mK and lower) parallel to the pressing axis of the pellets (heavier the halogen is, lower is the thermal conductivity). The results presented here provide important multiple anion chemistry for tailoring the ionic-bonding network into different thicknesses in the vdW layered structures and therefore their physical properties.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Liwang Liu,Hong Li,Zirui Liu,Ya-Hong Xie
Colloidal quantum dots (QDs) have attracted a great amount of attention for their appealing optoelectronic properties. In this work, the CuInS 2 (CIS)/ZnS core/shell QDs based on 4.3 nm cores with various layers of ZnS shell (0 to 10) were synthesized. With the sequential growth of a ZnS shell over a CIS core, the band alignment of core/shell QDs converts from a type I to quasi-type II structure. This conversion prolongs the carrier lifetime and affects the electron transfer rate ( K et ) and electron transfer efficiency ( η ET ). A comparative study indicates that the photovoltaic performance of CIS based QDSCs can be markedly improved by optimizing the layers of ZnS shell. The highest photo conversion efficiency (PCE) of 2.07% is obtained at optimum ZnS thickness of about 1.55 nm. These results show tuning the thickness of shell to change the band alignment is an effective strategy to manipulate the carriers transportation behaviors and thus affect the PCE of CIS-based optoelectronic devices.
研究领域:
材料科学
·
光电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Bao-Shui Wu,Peng Wang,Shu-Hua Teng
Mesoporous carbon-coated iron oxide (α-Fe 2 O 3 @C) nanoparticles were hydrothermally synthesized by using α-Fe 2 O 3 nanospheres (ca. 50 nm) as the cores and resorcinol as the carbon source of the shells. The formation of the mesoporous carbon coatings was confirmed by means of SEM, TEM , FT-IR, TG, XPS and BET measurements. Moreover, the coating thickness was easily adjusted to be 4, 7 and 10 nm by changing the amount of resorcinol. When used as the anodes for lithium-ion batteries (LIBs), the α-Fe 2 O 3 @C nanoparticles exhibited significantly improved electrochemical properties as compared to pure α-Fe 2 O 3 nanoparticles. With the increase of the coating thickness, the α-Fe 2 O 3 @C electrodes presented an initial increase and subsequent decrease in their cycling stability and rate performance. Especially, the α-Fe 2 O 3 @C-7 nanoparticles displayed a high reversible capacity of 1223 mA h/g at 1 A/g, a good cycling stability retaining 1093 mA h/g at 1 A/g after 100 cycles as well as a remarkable rate performance of 570 mA h/g at 5 A/g. The quantitative kinetic analysis revealed that 58 % of the charge storage was contributed by the capacitive process at 0.5 mV/s. The well-defined core-shell structure and superior electrochemical performance of the α-Fe 2 O 3 @C-7 nanoparticles will make them a promising anode for LIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Membranes
·
2022
·Vol. 12
·期 4
·417
·
IF 4.562
Mengling Zhang,Xiangyang Hu,Lei Peng,Shilin Zhou,Yong Zhou,Shijie Xie,Xiaoxiao Song,Congjie Gao
The realistic resistance zone of water and salt molecules to transport across a TFC-RO membrane is the topmost polyamide nanofilm. The existence of hollow voids in the fully aromatic polyamide (PA) film gives its surface ridge-and-valley morphologies, which confuses the comprehensions of the definition of the PA thickness. The hollow voids, however, neither participate in salt–water separation nor hinder water penetrating. In this paper, the influence of intrinsic thickness (single wall thickness) of the PA layer on water permeability was studied by adjusting the concentration of reacting monomers. It confirms that the true permeation resistance of water molecules originates from the intrinsic thickness portion of the membrane. The experimental results show that the water permeability constant decreases from 3.15 ± 0.02 to 2.74 ± 0.10 L·m−2·h−1·bar−1when the intrinsic thickness of the membrane increases by 9 nm. The defects on the film surface generate when the higher concentration of MPD is matched with the relatively low concentration of TMC. In addition, the role of MPD and TMC in the micro-structure of the PA membrane was discussed, which may provide a new way for the preparation of high permeability and high selectivity composite reverse osmosis membranes.
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Ruoyu Chen,Hongbin An,Jie Zhan,Saisai Li,Aiqin Mao,Haiming Wen
A high entropy carbide (TaNbTiV)C was fabricated via spark plasma sintering of high entropy powders that were prepared using a molten salt method. The as-fabricated high entropy carbide was then investigated for its high-temperature oxidation behavior at 850 °C, under atmospheres with three different oxygen contents (20 vol%, 40 vol%, and 60 vol%). After the high-temperature oxidation process, the main phases observed in all the specimens were incompletely oxidized phase (Nb x Ti 1-x )C y O 2-y and oxides (Nb 0.5 Ta 0.5 ) 2 O 5 , TiO 2 , and Nb 2 O 5 . Importantly, the thickness of the oxide layer initially increased and then decreased as the oxygen content increased. When the oxygen content reached 40 vol%, the ceramic displayed severe oxidation behavior with observed thicker of the oxide layer, as well as numerous pores and cracks in the oxide layer. This work provides new insights into the oxidation behavior of high entropy carbides.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Composites Part C: Open Access
·
2021
·
IF 0
Anthony Chun Yin Yuen,Timothy Bo Yuan Chen,Bo Lin,Wei Yang,Imrana I. Kabir,Ivan Miguel De Cachinho Cordeiro,Andrew E. Whitten,Jitendra Mata,Bin Yu,Hong-Dian Lu,Guan Heng Yeoh
MXene is a class of 2D materials exfoliated from ternary carbide and nitride ceramics. During synthesis, etching and delamination conditions affect the quality, overall crystallinity, defects and surface functionalization of MXene flakes. In this article, the morphological structure of MXene (Ti 3 C 2 ) nanosheets under temperature between 20 °C and 60 °C were investigated with the application of Small-Angle Neutron Scattering (SANS) combined with several complementary techniques, such as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The SANS analysis enabled structural information to be obtained about the Ti 3 C 2 nanosheets, which consists of layers of transition metal carbides in a multilayer lamella morphology. The results showed that a single Ti 3 C 2 layer is approximately 11.4 – 11.8 Å (1.14 – 1.18 nm) in thickness with a 20.3 – 21.5 Å (2.03 – 2.15 nm) interstacking layer gaps. This results in a total thickness of approximately 32 Å (3.2 nm), which was consistent with the model-dependent lamella model analysis. Furthermore, the thickness of the Ti 3 C 2 layer increased by approximately ~2 Å (0.2 nm) when the temperature increased from 20 - 40 to 50 - 60 °C.
研究领域:
材料科学
·
纳米技术
·
物理化学
✓ 已验证
产品关联
DOI
Nanomaterials
·
2022
·Vol. 12
·期 9
·1454
·
IF 5.719
Lufeng Hu,Zhixiang Ye,Dan Wu,Zhaojin Wang,Weigao Wang,Kai Wang,Xiangqian Cui,Ning Wang,Hongyu An,Bobo Li,Bingxi Xiang,Mingxia Qiu
Highly luminescent FAPb0.7Sn0.3Br3nanocrystals with an average photoluminescence (PL) quantum yield of 92% were synthesized by the ligand-assisted reprecipitation method. The 41-nm-thick perovskite film with a smooth surface and strong PL intensity was proven to be a suitable luminescent layer for perovskite light-emitting diodes (PeLEDs). Electrical tests indicate that the double hole-transport layers (HTLs) played an important role in improving the electrical-to-optical conversion efficiency of PeLEDs due to their cascade-like level alignment. The PeLED based on poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,40-(N-(p-butylphenyl))-diphenylamine)] (TFB)/poly(9-vinylcarbazole) (PVK) double HTLs produced a high external quantum efficiency (EQE) of 9%, which was improved by approximately 10.9 and 5.14 times when compared with single HTL PVK or the TFB device, respectively. The enhancement of the hole transmission capacity by TFB/PVK double HTLs was confirmed by the hole-only device and was responsible for the dramatic EQE improvement.Keywords:perovskite light-emitting diode;FAPb0.7Sn0.3Br3film;double hole transport structure;light-emitting layer thickness
研究领域:
材料科学
·
光电设备
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TRIBOLOGY INTERNATIONAL
·
2022
·
IF 5.62
Changbao Liu,Xiaoqiang Fan,Minhao Zhu
For adapting to the working condition of high-speed rail grinding with strong impact and heat, the basalt fibers reinforced grindstones (BFRGs) were prepared. Their performances were evaluated from three aspects, including the mechanical properties of grindstones themselves, grinding behavior and grinding quality. The results show that basalt fibers significantly improve the strength of grindstone, which has reached up to 78.3 MPa increased by 25.5%. The heat effect of BFRGs drops as low as 159 ℃. After grinding, the thickness of white etching layer is reduced to 0.5 µm. The content of basalt fiber at 6.7 wt% in resin can achieve the optimum comprehensive performance, mainly depending on the advantages in blocking effect and rolling bearing of basalt fibers.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Chuang-Tian Zhan,Sheng-Jin He,Wei-Ming Guo,Yuan-Bin Chen,Shi-Kuan Sun,Hua-Tay Lin
Combined with the thickness control of interlayers (∼10 µm and ∼60 µm), SiC nano-powders with Al 2 O 3 -Y 2 O 3 -MgO-CaO additive (NITE-SiC) were used as the joining materials to achieve the low-temperature joining of SiC ceramics. Some residual pores were observed in the interlayer with a thickness of ∼60 µm after joining at 1650 ℃, and the shear strength of SiC joints measured was 39.3 ± 5.5 MPa. Observations showed the fracture of joints occurred at the interlayer. When the thickness of the interlayer decreased to ∼10 µm, no cracks or porosity were observed at the interface region after joining at 1650 ℃. The shear strength of SiC joints increased to 69.5 ± 8.9 MPa, and the fracture originated from the matrix. The results demonstrated using NITE-SiC with Al 2 O 3 -Y 2 O 3 -MgO-CaO additive as the joining layer and reducing the thickness of the interlayer could lower the joining temperature and significantly improve the mechanical strength of joints.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Danting Shi,Tengjing Gong,Rui Wang,Weihua Qing,Senlin Shao
Janus membranes with asymmetric wettability have attracted wide attentions for their robust anti-oil-wetting/fouling abilities in membrane distillation (MD). Compared to traditional surface modification approaches, in this study, we provided a new approach which manipulated surfactant-induced wetting to fabricate Janus membrane with a controllable thickness of the hydrophilic layer. The membranes with 10, 20, and 40 μm of wetted layers were obtained by stopping the wetting induced by 40 mg L −1 Triton X-100 ( J = 25 L m −2 h −1 ) at about 15, 40, and 120 s, respectively. Then, the wetted layers were coated using polydopamine (PDA) to fabricate the Janus membranes. The resulting Janus membranes showed no significant change in porosities or pore size distributions compared with the virgin PVDF membrane. These Janus membranes exhibited low in-air water contact angles (< 50°), high underwater oil contact angles (> 145°), and low adhesion with oil droplets. Therefore, they all showed excellent oil-water separation performance with ∼100% rejection and stable flux. The Janus membranes showed no significant decline in flux, but a trade-off existed between the hydrophilic layer thicknesses and the vapor flux. Utilizing membranes with tunable hydrophilic layer thickness, we elucidated the underlying mechanism of such trade-off in mass transfer. Furthermore, the successful modification of membranes with different coatings and in-situ immobilization of silver nanoparticles indicated that this facile modification method is universal and can be further expanded for multifunctional membrane fabrication.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMISTRY OF MATERIALS
·
2020
·
IF 9.567
Dong Li,Xiaoli Zhang,Muhammad Ramzan,Kai Gu,Yu Chen,Jiatao Zhang,Bingsuo Zou,Haizheng Zhong
Shell thickness control of core/shell quantum dots (QDs) plays an important role in determining their optical properties as well as the corresponding device performance. PbSe-based core/shell QDs are attractive near-infrared (NIR) light emitters for photonic and optoelectronic applications. We herein report the colloidal synthesis of giant shell PbSe-based core/shell QDs through controllable reactions between preformed PbSe QDs and Cd2+ ions in polar solvents. The preformed PbSe QDs experienced cation-exchange reaction in N,N-dimethylformamide (DMF), while they underwent epitaxial growth of CdS shell in dimethyl sulfoxide (DMSO). The cation exchange of preformed PbSe QDs in DMF result in PbSe/CdSe core/shell QDs with similar size (ca. 6.3 nm) but tunable shell thickness from 0.5 to 2.9 nm. In comparison, the epitaxial growth of preformed PbSe QDs in DMSO produce PbSe/CdS core/shell QDs in DMSO with average core size of ∼5.7 nm but tunable shell thickness from 0.5 to 3.1 nm. These resulting PbSe-based core/shell QDs show tunable photoluminescence emission of 1393–1744 nm for PbSe/CdSe core/shell QDs and 1566–1719 nm for PbSe/CdS core/shell QDs. The cation exchange and epitaxial growth reactions of preformed PbSe QDs were further investigated by comparing the interactions between solvents and cation ions through nuclear magnetic resonance (NMR) measurements. The interactions between Cd2+ and DMSO are stronger than that of DMF, while the interactions between Pb2+ and DMSO are weaker than that of DMF. The difference accounts for the reaction transition from cation exchange to epitaxial growth, providing alternative route for fabricating shell controllable PbSe-based core/shell QDs.
研究领域:
材料科学
·
纳米技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）