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991.
Effects of Oxidation Curing of Polycarbosilane on Dielectric and Microwave Absorption Properties of PDCs‐SiC Ceramics 下载免费PDF全文
Yimin Shi Fa Luo Donghai Ding Feng Wan Wancheng Zhou Dongmei Zhu 《International Journal of Applied Ceramic Technology》2016,13(1):17-22
Polycarbosilane (PCS) was cured by oxidizing at different temperatures and pyrolyzed at 1000°C in vacuum. The dielectric properties of SiC ceramics were studied in X band. The ε′ and ε″ of SiC ceramics derived from oxidation‐curing PCS decreased to 4 and 0.35, respectively, which attribute to the decrease of free carbon content and order. SiC ceramic derived from PCS cured at 180°C showed that reflection loss was lower than ?10 dB in the frequency range from 8.2 to 11.3 GHz and the minimum value was ?26.7 dB at 9.6 GHz, which exhibits a promising prospect as microwave‐absorbing materials. 相似文献
992.
The precise control of active pharmaceutical ingredient(API) crystal nucleation and polymorphism is a key consideration in pharmaceutical manufacturing.In this study,tunable nanoparticles were developed to regulate the nucleation process of coumarin.Magnetic silica nanoparticles with four different functional groups(-NH2,-COOH,-SH,-NCO) were prepared and coated on the substrate for inducing the crystallization of coumarin.Confined melt crystallization and microspacing sublimation crys... 相似文献
993.
Shanshan Ye Dan Luo Lizhen Shi Jianpeng Mou Junpeng Du Dewu Wu Jiangchong Zhou Jianyan Ding Quansheng Wu 《International Journal of Applied Ceramic Technology》2022,19(6):3367-3375
Lithium-containing silicates have been considered as a considerable alternative for luminescent materials. In this study, a novel cyan-emitting phosphor, Na3LiHf2Si3O12: Eu2+, was successfully synthesized via cationic substitution with Na4Hf2Si3O12: Eu2+ as the initial model. The crystal structure, morphology, and luminescence performance of Na4-xLixHf2Si3O12: Eu2+ were investigated in detail. The substitution of Li+ for Na+ site causes a significant blue-shift of the emission band in the range of 550–500 nm and a smaller full width at half maximum. As a result, a cyan phosphor Na3LiHf2Si3O12: Eu2+ that can be effectively excited by near-ultraviolet and high-energy beams is obtained. The mechanism of emission regulation was proposed based on the transformation of crystal structure and luminescence performance. In addition, the thermal quenching and cathodoluminescence behaviors were also studied. The results show that cation substitution is an effective method to design new lithium-containing silicate phosphors. 相似文献
994.
Jiangkun Cao Aaron Reupert Yicong Ding Lothar Wondraczek 《Journal of the American Ceramic Society》2022,105(4):2616-2624
Tuning the optical properties of active species embedded within a glass matrix by modifying the ligand environment is of interest for luminescence-based technologies, for example, in optical sensing, data transmission, or spectral conversion. Here, we discuss a facile synthesis procedure for a glass-crystal composite material comprising of bismuth (Bi)-doped zirconia within an aluminoborate glass phase. The approach offers tunable and broad photoemission characteristics in the visible spectral region from 400 to 750 nm. Incorporation of Bi ions into the crystal phase enhances the photoemission intensity by two orders of magnitude, with an external quantum efficiency of about 29%. At higher ZrO2 dopant concentration, we observe a red-shift of both the excitation and the emission bands to match commodity ultra-violet light emitting diodes as excitation sources. Encapsulation within the aluminoborate glass phase provides advantageous thermal behavior, with the emission intensity remaining at >80 % of its initial value up to a temperature of 400 K. 相似文献
995.
Zhang Zhuoran Liu Tao Qi Zenghua Li Fan Yang Kun Ding Sheng Lin Song Tian Feng 《SILICON》2022,14(16):10521-10534
Silicon - Uncontrolled bleeding is an important cause of traumatic death in wartime and peacetime. Despite the significant advances in hemostatic research, it is still challenging to develop safer... 相似文献
996.
Kangjing Wang Liting Zhao Ting Li Qian Wang Zhongyang Ding Dr. Weifu Dong 《Chembiochem : a European journal of chemical biology》2022,23(4):e202100497
Self-stable precipitation polymerization was used to prepare an enzyme-immobilized microsphere composite. Phosphomannose isomerase (PMI) with His-tag was successfully immobilized on Ni2+ charged pyridine-derived particles. The maximum amount of PMI immobilized on such particles was ∼184 mg/g. Compared with free enzyme, the activity of the immobilized enzymes was significantly improved. In addition, the immobilized enzymes showed a much better thermostability than free enzymes. At the same time, the immobilized enzymes can be reused for multiple reaction cycles. We observed that the enzyme activity did not decrease significantly after six cycles. We conclude that the pyridine-derived particles can be used to selectively immobilize His-tagged enzymes, which can couple the enzyme purification and catalysis steps and improve the efficiency of enzyme-catalyzed industrial processes. 相似文献
997.
Xuelin Zhang Chunqiao Zhou Dr. Yang Yang Hailin Liu Song Wang Dr. Xiaoli Ding Dr. Hu Wang 《ChemMedChem》2022,17(4):e202100517
Small-molecule inhibitors of MDM2 that block the MDM2-p53 protein-protein interaction have been considered as potential therapeutic agents for the treatment of cancer. Here, we identify five highly potent inhibitors of MDM2 (termed as WY 1–5) that display significant inhibitory effects on MDM2-p53 interaction by using a combined strategy of pharmacophore modeling, virtual screening, and molecular docking studies. Among them, WY-5 is the most active MDM2 inhibitor with an IC50 value of 14.1±2.8 nM. Moreover, WY-5 significantly up-regulate the protein level of p53 in SK-Hep-1 cells harboring wild-type p53. In vitro anticancer study reveals that WY-5 markedly inhibits the survival of SK-Hep-1 cells. In vivo anticancer study suggests that WY-5 significantly inhibits the growth of SK-Hep-1 cells-derived xenograft in nude mice, with no observable toxicity. Our results demonstrate that WY-5 may be a promising candidate for the treatment of cancer harboring wild-type p53. 相似文献
998.
Yawen Yang Mengyuan Peng Min Sha Jiaqing Fang Ding Zhang Renming Pan Biao Jiang 《Journal of surfactants and detergents》2022,25(2):205-216
Fluorocarbon surfactants were the main components of aqueous film-forming foam extinguishing agents (AFFF). Unfortunately, the widely used fluorocarbon surfactant perfluorooctane sulfonate (PFOS) was limited due to its toxicity, bioaccumulation and biodegradability. In this paper, an environmentally friendly quaternary ammonium cationic fluorocarbon surfactant with high surface activity and simple synthesis route was reported. The surface performance and aggregation behavior of the mixed solution of this fluorocarbon surfactant and sodium n-octyl sulfate were studied by means of surface tension meter and transmission electron microscope (TEM). The results showed that the synergistic effect of sodium n-octyl sulfate and this fluorocarbon surfactant was significant, and many vesicles could be observed in the mixed solution with the concentration of 0.1 mol/L under TEM. Subsequently, three environmental friendly AFFF formulations (F-1, F-2, F-3) were designed with the mixture of the fluorocarbon surfactant, sodium n-octyl sulfate and lauryl betaine BS-12 as foaming agent. Through its foam performance test, it could be seen that F-3 showed relatively excellent foam performance. The initial foam height h0 was 70 mm, the 25% drainage time was 315 s, the extinguishing time was 28 s, and the burn-back time was 720 s. This kind of fire extinguishing agent had the potential of fire protection application. 相似文献
999.
使用活性炭负载磷钨酸催化剂,对1-癸烯齐聚反应进行研究,考察磷钨酸负载量、催化剂活化温度、活化时间、反应温度、反应压力和反应时间对1-癸烯转化率的影响。确定最佳的工艺条件为:磷钨酸负载质量分数37%,催化剂活化温度200℃,活化时间3 h,反应温度180℃,反应压力0.5 MPa,反应时间4 h。在此条件下,对聚烯烃合成油的物化性能进行研究,结果表明,采用活性炭负载磷钨酸催化剂催化1-癸烯齐聚合成油100℃黏度为4.60 mm2·s-1,黏度指数为126,凝点为-58℃,1-癸烯转化率为83.5%。 相似文献
1000.