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91.
Wang Wencheng Yuan Xiaohui Wu Xiaojin Dong Yihua 《Multimedia Tools and Applications》2020,79(37-38):27185-27203
Multimedia Tools and Applications - As the key parameter of dehazing algorithms, airlight value directly affect the calculation accuracy of sky region, and any deviation will lead to the chromatic... 相似文献
92.
Yifeng Xu Bingkun Hu Jining Liu Kai Tao Ranran Wang Yang Ren Xiaofeng Zhao Jijin Xu Xuefeng Song 《Journal of the American Ceramic Society》2020,103(2):1281-1292
Microcystins (MCs) is a harmful toxin generated by blue-green algae in water, which has seriously threatened the ecological safety of water and human body. It is urgent to develop new catalysts and techniques for the degradation of MCs. A feasible electrostatic self-assembly method was carried out to synthesize BiVO4/g-C3N4 heterojunction photocatalyst with highly efficient photocatalytic ability, where BiVO4 nanoplates with exposed {010} facets anchored to the g-C3N4 ultrathin nanosheets. The morphology and microstructure of the heterojunction photocatalysts were identified by XRD, SEM, TEM, XPS, and BET. The g-C3N4 nanosheets have huge surface area over 200 m2/g and abundant mesoporous ranging from 2-20 nm, which provides tremendous contact area for BiVO4 nanoplates. Meanwhile, the introduction of BiVO4 led to red-shift of the absorption spectrum of photocatalyst, which was characterized by UV-vis diffuse reflection spectroscopy (DRS). Compared with pure BiVO4 and g-C3N4, the BiVO4/g-C3N4 heterojunction shows a drastically enhanced photocatalytic activity in degradation of microcystin-LR (MC-LR) in water. The MC-LR could be removed within 15 minutes under the optimal ratio of BiVO4/g-C3N4. The outstanding performance of the photocatalyst is attributed to synergetic effect of interface Z-scheme heterojunction and high active facets {010} of BiVO4 nanoplates, which provides an efficient transfer pathway to separate photoinduced carriers meanwhile endows the photocatalysts with strong redox ability. 相似文献
93.
Yong Liu Kangzhuang Chen Fengbo Dong Shuai Peng Yongjie Cui Chenyu Zhang Keqing Han Muhuo Yu Hui Zhang 《Ceramics International》2018,44(9):10199-10203
In this paper, polyborosilazane precursor was synthesied from HMDZ, HSiCl3, BCl3 and CH3NH2 using a multistep method. By controlling the storage conditions, parts of the polyborosilazane fibers were hydrolyzed. FT-IR, NMR, XRD, TEM and monofilament tensile strength test were employed to study the effects of hydrolysis of precursor on the structures and properties of polymer-derived SiBN ceramic fibers. FT-IR and NMR results indicate that Si-N group in PBSZ reacts with H2O to form Si-O-Si group. After pyrolysis reaction at 1400℃, Si-O-Si group will finally transformed into highly ordered cristobalite and β-quartz, resulting in formation of the wrinkled surface of the obtained SiBN ceramic fiber. The strip-like defects on fiber surface, according to monofilament tensile strength test, had a significant effect on mechanical property of the obtained SiBN ceramic fiber and caused no increase in fiber tensile strength of hydrolytic polyborosilazane fiber before and after pyrolytic process. 相似文献
94.
Ningning Fu Jiaxing Li Ming Wang Lili Ren Youqing Luo 《International journal of molecular sciences》2020,21(22)
An obligate mutualistic relationship exists between the fungus Amylostereum areolatum and woodwasp Sirex noctilio. The fungus digests lignin in the host pine, providing essential nutrients for the growing woodwasp larvae. However, the functional properties of this symbiosis are poorly described. In this study, we identified, cloned, and characterized 14 laccase genes from A. areolatum. These genes encoded proteins of 508 to 529 amino acids and contained three typical copper-oxidase domains, necessary to confer laccase activity. Besides, we performed molecular docking and dynamics simulation of the laccase proteins in complex with lignin compounds (monomers, dimers, trimers, and tetramers). AaLac2, AaLac3, AaLac6, AaLac8, and AaLac10 were found that had low binding energies with all lignin model compounds tested and three of them could maintain stability when binding to these compounds. Among these complexes, amino acid residues ALA, GLN, LEU, PHE, PRO, and SER were commonly present. Our study reveals the molecular basis of A. areolatum laccases interacting with lignin, which is essential for understanding how the fungus provides nutrients to S. noctilio. These findings might also provide guidance for the control of S. noctilio by informing the design of enzyme mutants that could reduce the efficiency of lignin degradation. 相似文献
95.
以壳聚糖为碳源和氮源,采用预碳化处理和KOH活化两步法制备了壳聚糖多孔碳材料,考察了活化剂KOH用量对电极材料形貌、结构以及电容性能的影响。结果表明:当KOH与预碳化壳聚糖质量比为0.6∶1时,制备的多孔碳材料KOH-CTS-0.6具有最优的电化学性能。KOH-CTS-0.6具有大比表面积(1 348 m~2·g~(-1)),含有丰富的N、O元素(2.9%N和7.4%O)。在电流密度为0.5 A·g~(-1)时,KOH-CTS-0.6的比电容为235.2 F·g~(-1),显示出优秀的倍率能力;在电流密度为10 A·g~(-1)的大电流时,其比电容依然高达178.6 F·g~(-1)。此外,该材料还具有良好的循环稳定性,500次循环后比电容保持率为94%。 相似文献
96.
Shuncheng Liu Kejian Wang Zhongfeng Zhang Yueqing Ren Lanlan Chen Xiaojie Sun Wenbin Liang 《Polymer Engineering and Science》2020,60(10):2640-2652
Three kinds of ethylene-octene copolymers (POE) were melt-blended with high-density polyethylene (PE-HD) in different proportions. Detailed characterizations were conducted to analyze their structural differences of POE and its effects in toughening PE-HD. The higher molecular weight POE can improve the toughness of PE-HD. 60:40 PE-HD/POE is elongated to break up to 700% while impact strength is 84.7 kJ/m2 at −30°C, which is 21-fold of PE-HD. In the brittle to ductile transition (BDT) during impact, the fracture mechanism changes from the crazing mode to the shear yield-plastic deformation mode. The BDT temperature decreases as the POE molecular weight and its content increase. The interface strength in tension is estimated to access their effects. The Boltzmann-type models were successfully extended to describe the typical S-shaped curves in BDT of notched impact strength vs POE content or temperature. The supplementary decay model is suggested for the attenuation in toughening. Transition map in impact is proposed to select the use range of composition (c ) and temperature (T ) for high toughness. The curves are converted into 3D graph of T -c -impact strength for illustrating their coupling-separate effects, and further into the contour map of impact strength in T -c space for finding their partial equivalence. 相似文献
97.
Although Mg alloy attracts great attention for engineering applications because of high specific strength and low density, low corrosion resistance limits its extensive use. In this study, Mg–Al–Zn–Mn alloy was treated via a laser cladding process to generate a dense and compact laser cladding layer with solid metallurgical bonding on the substrate for improving corrosion resistance, effectively hindering the corrosion pervasion into Mg alloy. The corrosion current density declined from 103 μA/cm2 for Mg alloy to 13 μA/cm2 for the laser cladding layer in NaCl aqueous solution. Moreover, the laser cladding layer was slightly corroded in comparison with Mg alloy in NaCl aqueous solution. Besides, the microhardness of the cladding layer reached a mean value of 170.5 HV, 3.1 times of Mg alloy (56.8 HV) due to the in situ formation of hardening intermetallic phases. Wear resistance of laser cladding layer was also obviously improved. These results demonstrated that the laser cladding layer obviously enhanced anticorrosion property of Mg alloy for engineering applications. 相似文献
98.
Yingli Li Shaoying Zhang Yu Dong 《International Journal of Food Science & Technology》2021,56(1):115-125
Ethylene continues to be a major factor influencing quality of European pears during storage. Although research has been done on the effect of pre-harvest 1-methylcyclopropene (1-MCP) on physiological characteristics in pears, a full understanding of cultivar response and antioxidant metabolism remains elusive. Spraying 1-MCP on ‘Bartlett’ and ‘d’Anjou’ pears was studied with respect to physiology, storage and eating quality, disorders, and antioxidant properties at two harvest date (H1 and H2) during storage and ripening. Treatment with 1-MCP extended the harvest window of ‘Bartlett’ and ‘d’Anjou’ pears 3 and 4 days, respectively, without reducing storage or eating quality. Treatment with 1-MCP reduced ethylene production (EPR) and respiration rates (RR), maintained fruit firmness and green colour during storage and retarded development of desirable melting texture in both cultivars. Additionally, 1-MCP lowered the incidence of disorders by alleviating membrane lipid peroxidation, retaining high total flavonoids (TF) and antioxidant capacity, and enhancing superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in both cultivars. Overall, pre-harvest 1-MCP applications could extend storage time of ‘Bartlett’ and ‘d’Anjou’ pears to 5 and 6 months, respectively, at −1.1 ± 0.5 °C, by reducing ethylene synthesis and enhancing antioxidant metabolism. 相似文献
99.
Li Wei Ren Yinghui Li Chenfang Li Zhipeng Li Maojun 《The International Journal of Advanced Manufacturing Technology》2020,106(3):921-935
The International Journal of Advanced Manufacturing Technology - The wear of micro-grinding tools less than 1 mm in diameter is crucial for achieving acceptable surface quality and accurate... 相似文献
100.
为了提高综采工作面端头超前应力区顶板稳定性,降低顶板支护费用,对8309工作面端头应力区提出了耦合让均压支护技术,控制了端头应力区顶板下沉、破碎现象,可降低支护成本费用320元/m。 相似文献