POSTHARVEST BIOLOGY AND TECHNOLOGY
·
2018
·
IF 3.112
Yurong Ma,Qingfeng Ban,Jingying Shi,Tiantian Dong,Cai-Zhong Jiang,Qingguo Wang
The effects of 1-methylcyclopropene (1-MCP) treatment, storage time, and shelf life and temperature on phenolic concentrations and antioxidant activity in apple peel and flesh of ‘Jonagold’ apple ( Malus domestica Borkh) have been investigated. Hyperoside and chlorogenic acid were the most abundant phenolic compounds in the peel and flesh, respectively. The flesh had lower concentrations of individual phenolics, total phenolics, flavonoids and lower antioxidant activity (determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay) than the peel. In addition, the profiles of phenolics as well as the changing patterns of individual phenolics also differed between the peel and the flesh. After long-time storage (180 d), the greatest decrease of concentrations was the concentrations of hyperoside (27 %) in the peel and total phenolics (35 %) in the flesh. Also, during the 90–180 d storage period, hyperoside and rutin in the peel, chlorogenic acid in the flesh, and flavonoids and antioxidant activity decreased in both peel and flesh tissues. Individual phenolics exhibited different stabilities during the early stages after harvest. 1-MCP reduced the reduction in the concentrations of hyperoside in the peel, chlorogenic acid in the flesh, and total phenolics, flavonoids and antioxidant activity in both the peel and flesh tissues during storage and shelf life. However, for quercetin and rutin, the protective effect of 1-MCP was only observed during the shelf life period. Overall, phenolic compounds responded variously to storage, shelf life, shelf temperature and 1-MCP treatment.
研究领域:
食品科学
·
植物生理学
✓ 已验证
产品关联
DOI
高影响因子
DESIGNED MONOMERS AND POLYMERS
·
2019
·
IF 1.528
Meng-Di Chen,Guo Zhang,Shi-Chang Chen,Xian-Ming Zhang,Wen-Xing Chen
In this study, 9-anthracenemethyl methacrylate (AMMA) and styrene (St) as monomers and benzoyl peroxide as an initiator were used to synthesize P(St-co-AMMA), a macromolecule tracer with a fluorescence effect, via free radical copolymerization. A fluorescent online detection device was built on the basis of the principle of fluorescence online detection by using the single-screw extrusion platform of a torque rheometer to explore the effect of the amount of macromolecular tracer and screw speed on the residence time distribution of polystyrene in single-screw extrusion. Fourier transform infrared spectroscopy, 1H-NMR, thermal stability, fluorescence properties, and rheological properties show that the resulting product P(St-co-AMMA) has a degree of thermal stability, fluorescence, and rheological properties similar to polystyrene, so this product can be used to characterize the residence time distribution during single-screw extrusion. The amount of macromolecular tracer P(St-co-AMMA) does not affect the residence time distribution of polystyrene during single-screw extrusion processing, meanwhile, the minimum residence time decreases and the residence time distribution becomes narrow as the screw speed increases, that is, the axial mixing capacity of the single-screw extruder decreases as the screw speed increases.
研究领域:
高分子化学
·
材料科学
·
聚合物加工工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 50
·期 11
·19814-19821
·
IF 5.1
Weichang Li,Danping Chen,Lili Hu,Dongbing He,Shubin Chen,Chunlei Yu,Sen Qian,Zhehao Hua,Gao Tang,Ren Jing,Xinyuan Sun,Minghui Zhang,Shan Liu,Hua Cai,Jifeng Han,Shenghua Yin
The large size (4 cm × 4 cm × 1 cm) Ce 3+ -doped high gadolinium oxyfluoride glass with density of 5.83 g/cm³ was prepared by the melt quench method at 1220 °C. The glass is colorless and transparent over the visible range. The prolonged decay time under 275 nm UV light demonstrates the energy transfer from Gd 3+ ions to Ce 3+ ions. The X-ray excited luminescence spectra (XEL) show the emission peak corresponds to the 5d→4f transitions of Ce 3+ ion. The integral emission intensity of glass was compared with that of bismuth germanate oxide (BGO) crystals. The scintillation property of glass was studied under the γ -ray from 137 Cs source and a clear energy peak was observed with light yield (LY) over 1100 ph/MeV. The scintillation decay time comprises fast and slow components. All results presented in this work indicate the appropriate potential to be high-energy rays detecting material for CEPC .
研究领域:
材料科学
·
核物理探测
·
光学材料
·
高能物理
·
无机非金属材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·Vol. 46
·期 4
·4720-4729
·
IF 3.45
Guojiao Ding,Rujie He,Keqiang Zhang,Min Xia,Chengwei Feng,Daining Fang
Stereolithography based additive manufacturing provides an effective method to fabricate complex-shaped SiC ceramic components. The dispersion and stability of the ceramic slurry are very important for stereolithography. In this study, the dispersion and stability of SiC ceramic slurries were investigated systematically. The effects of resin monomers , dispersants , particle size, solid loading and ball milling time on the dispersion, rheological behavior and stability of SiC ceramic slurries were studied in detail. Finally, an optimal SiC ceramic slurry for stereolithography based additive manufacturing was obtained, and complex-shaped SiC ceramic architectures were fabricated.
研究领域:
材料科学
·
先进制造
·
陶瓷工程
·
高分子材料
·
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
·
环境灾害监测
·
地理信息系统
·
山地灾害防治
·
地球观测
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 73
·46461-46471
·
IF 3.108
Shui Jiang,Jun Wang,Yubing Sun
Chinese pecans (Carya cathayensis) continuously deteriorate during storage because of their high fatty acid contents. In this study, an electronic nose (E-nose) was introduced to characterize Chinese pecans with different storage times. Chemometric methods (principal component analysis (PCA), partial least squares regression (PLSR), and back propagation neural networks (BPNNs)) were employed to analyze E-nose data. For qualitative analysis, PCA could visualize the discrimination between different pecans based on the E-nose data. For quantitative analysis, the results indicated that BPNN models performed better both in predicting storage times and fatty acid contents than the PLSR models. In addition, a multi-target BPNN regression model was built to simultaneously predict the contents of the six main fatty acids, and the results (R2 > 0.95 in calibration sets and R2 > 0.88 in validation sets) were satisfactory. This study provides a potentially viable method for determining the storage times and fatty acid profiles of nut products.
研究领域:
食品科学
·
分析化学
·
农产品贮藏
·
营养化学
·
食品安全
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuqing Sun,Adeel Abbas,Hongxiang Wang,Chang Tan,Zhihao Li,Yujie Zong,Hui Sun,Chunlei Wang,Hongchao Wang
Quaternary Cu 2 MnSnSe 4 alloys with low intrinsic thermal conductivity are identified as promising middle-temperature thermoelectric materials. However, zT is depressed by the poor electrical performance. To overcome this issue, here, a series of Cu 2.1 Mn 0.9 SnSe 4 samples are prepared by ball-milling method which appears as a time-saving technique and lattice strain variation is observed by changing the annealing time ( x = 0, 1, 2, 3, 4 days). The vacancy defects concentration of Cu, with lowest vacancy defects formation energy, is changed with the competition between compression and tension-strain state, consistent with the first principles calculations, which optimizes the carrier transport. As a result, about 4 times increment of the carrier mobility is found. Moreover, the lattice strain of several nanometers is observed with TEM analysis, which scatters phonon strongly. A lowest κ L value of 0.57 W m −1 K −1 at 673 K is obtained for x = 3 sample, which is close to the amorphous limit. The interactive effect of enhanced mobility and strong scattering of phonons, contributing to a record zT ∼ 0.48 at 673 K for x = 3 sample. Lattice strain engineering is an effective tactic to simultaneously optimize the electrical and thermal transport.
研究领域:
材料科学
·
凝聚态物理
·
功能材料
·
能源材料
·
半导体物理
✓ 已验证
DOI
高影响因子
Russian Journal of Physical Chemistry A
·
2024
·Vol. 97
·期 14
·3227-3237
·
IF 0.7
Zheng Yayuan
This paper investigates the kinetics of sodium sulfate crystallization in a stirred bed crystallizer through experimental analysis, focusing on the homogeneous and heterogeneous nucleation mechanisms of the compound. Key nucleation parameters, including tension (γ), critical nucleation radius ( r* ), critical nucleation free energy (Δ G* ), and critical nucleation molecule number ( i* ), are measured under various temperatures and supersaturation ratios, utilizing classical nucleation theory. The results demonstrate that as temperature and supersaturation ratio increase, induction time, critical nucleation free energy, critical nucleation radius, and critical molecule number decrease, while nucleation rate increases. The crystal shape remains relatively constant with changes in temperature and supersaturation ratio, but the average particle size increases with higher supersaturation and temperature. The observed changes in nucleation parameters are consistent with classical nucleation theory. In addition, population balance equations are employed to fit kinetic equations for crystal nucleation and growth rates in a stirred crystallization system. The results show that the growth rate increases with higher supersaturation and stirring rates, while the influence of parameters in the nucleation rate equation suggests that suspension density has the greatest effect, followed by supersaturation ratio and stirring rate.
研究领域:
化学工程
·
材料科学
·
物理化学
·
过程工程
·
晶体工程
✓ 已验证
DOI
高影响因子
PROCEEDINGS OF THE COMBUSTION INSTITUTE
·
2022
·Vol. 39
·期 1
·315-324
·
IF 6.535
Qianjin Lin,Wanxiong Liao,Jia Cheng,Chun Zou,Bin Yang,Wenxiang Xia
Few studies on the low-temperature combustion behavior of MIPK, being a promising fuel additive , have been conducted. In this work, ignition delay times (IDTs) of MIPK were measured in the temperatures ranging between 780–910 K and pressures of 20 and 25 bar using a rapid compression machine (RCM). Oxy-fuel combustion combined with biofuel could remove CO 2 from the atmosphere. The IDTs of MIPK were measured in the temperatures ranging between 1125–1600 K under the O 2 /CO 2 atmosphere at the pressures of 1 and 10 bar using a shock tube . A low to high-temperature MIPK kinetic model (HUST-MIPK model) was proposed, in which the low-temperature sub-model consists of 19 low-temperature reaction classes and was constructed by analogy-based method, the high-temperature sub-model was adapted from the works of Cheng et al.. The predictions of HUST-MIPK model are in good agreement with the present low-temperature IDTs, high-temperature O 2 /CO 2 atmosphere IDTs, and the literature experimental data. The negative temperature coefficient (NTC) behavior was not observed in the temperature range from 790 to 910 K in the present RCM experiments, but was observed for methyl propyl ketone (MPK) and diethyl ketone (DEK) under similar conditions. The low-temperature chemistry of three pentanone isomers (MIPK, MPK, and DEK) was compared using the flux and sensitivity analysis. The comparison of the experimental high-temperature IDTs between O 2 /CO 2 and O 2 /Ar atmospheres indicates the IDTs of MIPK under O 2 /CO 2 atmosphere are longer than those under O 2 /Ar atmosphere at 1 bar, and the effects of CO 2 are almost independent of the pressure. The physical and chemical effects of CO 2 on the ignition were studied in detail.
研究领域:
燃烧化学
·
燃料化学
·
反应动力学
·
能源工程
·
大气环境影响
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Ruichong Chen,Jianqi Qi,Lin Su,Qiwu Shi,Xiaofeng Guo,Di Wu,Tiecheng Lu,Zhijun Liao
In this work, we report a rapid, simple and controllable approach to prepare B 4 C ceramic double-curvature shells by dropping the coating slurry on a molybdenum (Mo) substrate. The B 4 C slurry finally forms a nearly uniform spherical thin shell on the Mo substrates after drainage and curing process. We discovered that the uniformity and the wall thickness of the thin shell structure are controlled by the curing time and the viscosity of the slurry, respectively. This novel fabrication method not only provides an alternative way to prepare B 4 C ceramic double-curvature shells for the potential application as an ICF capsule, but also sheds light on the uniformity control of other ceramic double-curvature thin shells.
研究领域:
材料科学
·
核聚变工程
·
先进陶瓷制备
·
表面涂层技术
·
功能材料
✓ 已验证
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2019
·Vol. 30
·期 11
·2781-2789
·
IF 2.162
Tingjun Zhong,Richard J. Mandle,John W. Goodby,Lanying Zhang,Cuihong Zhang
In this work, the thiol-ene click reaction is employed to fabricate polymer-dispersed liquid crystal (PDLC) films by photoinitiated polymerization. The PDLC films are prepared by systematic variation of key conditions: variety and content of -ene monomer, liquid crystal (LC) content, curing time, and curing light intensity. We find that both the morphologies and electro-optic properties of these films are adjustable. When increasing the length of alkyl main chain of -ene monomers, the driving voltages reduce, but in turn, the contrast ratio decreases. Increasing -ene monomer content raises the driving voltages as well as the response time, and the increase of LC content lowers the driving voltages but has a negative effect on the contrast ratio. The changes to the curing conditions (both curing time and UV light intensity) can be used to modify the driving voltages, response time, and contrast ratios of PDLC films. These comparative studies will elucidate new insights in commercial applications of intelligent PDLC films.
研究领域:
材料科学
·
高分子化学
·
软物质物理
·
光电功能材料
·
智能材料
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Jizhen Zhu,Sixu Wang,Mohsin Raza,Yuan Feng,Jing Li,Yebing Mao,Liang Yu,Yong Qian,Xingcai Lu
Methanol is an attractive oxygenate increasingly used as primary fuel for dual-fuel combustion technology yielding beneficial thermal-efficiency and emissions in modern engines. As such, it is significant to fundamentally understand the autoignition behavior of methanol/diesel mixtures. This study measured the ignition delay times (IDTs) of methanol/diesel blends with different mixing ratios (30%, 50%, 70% methanol by mol.) on a heated shock tube and a heated rapid compression machine at temperatures of 650−1450 K, pressures of 6−20 bar, and equivalence ratios of 0.5, 1.0 and 2.0. The typical two-stage ignition characteristics with the negative temperature coefficient response were observed for dual-fuel mixtures. In general, both the total and first-stage IDTs decrease with the increment of pressure and equivalence ratio as well as diesel proportion in mixtures. The simulation results performed with a published detailed mechanism in conjunction with a tri-component diesel surrogate demonstrate generally good agreement with the experimental data at all test conditions. Moreover, a crossover of IDTs occurs at a higher temperature (~1500 K) for varying equivalence ratios, and experiment and simulation both exhibit a non-linear mixing effect of methanol addition on diesel ignition. Interestingly, simulation results clearly suggest a crossover (~940 K) for mixtures with varying methanol content at an intermediate-temperature, where the IDT of the mixture with a lower methanol ratio becomes longer as the temperature is higher than that of the crossover. Furthermore, brute-force sensitivity analyses assisted with reaction path analysis were conducted to gain deeper insights into the autoignition chemistry of dual-fuel mixtures, especially for the chemical interaction between both fuels during the low-temperature oxidation process . It is found that methanol hardly generates •OH, whereas •OH is mainly produced by the low-temperature reaction pathways of diesel. Thus, •OH is the bridge for both fuels during the ignition process. At the high methanol ratio, the H-abstraction of diesel is mainly via •HO 2 while CH 3 OH consumes a large percentage of •OH. Consequently, the competition between methanol and diesel for •OH radicals inhibits the overall reactivity of reaction network. In addition, the original data reported here lay a foundation for the development and validation of more accurate and robust dual-fuel kinetic schemes.
研究领域:
燃烧化学
·
燃料科学
·
化学动力学
·
内燃机工程
·
替代燃料技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）