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排序方式: 共有1962条查询结果,搜索用时 343 毫秒
51.
Dr. Vibe B. Jakobsen Dr. Elzbieta Trzop Dr. Laurence C. Gavin Emiel Dobbelaar Dr. Shalinee Chikara Dr. Xiaxin Ding Dr. Kane Esien Dr. Helge Müller-Bunz Dr. Solveig Felton Dr. Vivien S. Zapf Prof. Eric Collet Prof. Michael A. Carpenter Prof. Grace G. Morgan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13407-13414
Domain wall motion is detected for the first time during the transition to a ferroelastic and spin state ordered phase of a spin crossover complex. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy (RUS) revealed two distinct symmetry-breaking phase transitions in the mononuclear Mn3+ compound [Mn(3,5-diBr-sal2(323))]BPh4, 1. The first at 250 K, involves the space group change Cc→Pc and is thermodynamically continuous, while the second, Pc→P1 at 85 K, is discontinuous and related to spin crossover and spin state ordering. Stress-induced domain wall mobility was interpreted on the basis of a steep increase in acoustic loss immediately below the the Pc-P1 transition 相似文献
52.
Inulae Flos, the flower of Inula britannica L., is used as a dietary supplement, beverage, and medicine in East Asia. In this study, we evaluated the gastroprotective effects of Inulae Flos extract (IFE) against gastric mucosal lesions induced by hydrochloric acid (HCl)/ethanol in rats and explored its potential mechanisms by measuring antioxidant enzyme activity, mucus secretion, and prostaglandin E2 (PGE2) levels. Pretreatment with IFE at doses of 100 and 300 mg/kg significantly inhibited gastric lesions in HCl/ethanol-treated rats. IFE increased the activities of superoxide dismutase and catalase and the levels of glutathione and PGE2 in gastric tissues. The administration of IFE also significantly increased the gastric wall mucus contents in HCl/ethanol-induced gastric lesions. These findings suggest that IFE has gastroprotective effects against HCl/ethanol-induced gastric lesions and exerts these effects through increased antioxidant levels and gastric mucus secretion. Inulae Flos may be a promising agent for the prevention and treatment of gastritis and gastric ulcers. 相似文献
53.
Jorge E. Navarro-Baez Luz María Martínez Jorge Welti-Chanes Gnesis V. Buitimea-Cantúa Zamantha Escobedo-Avellaneda 《Molecules (Basel, Switzerland)》2022,27(5)
Phenolic compounds from fruits and vegetables have shown antioxidant, anticancer, anti-inflammatory, among other beneficial properties for human health. All these benefits have motivated multiple studies about preserving, extracting, and even increasing the concentration of these compounds in foods. A diverse group of vegetable products treated with High Hydrostatic Pressure (HHP) at different pressure and time have shown higher phenolic content than their untreated counterparts. The increments have been associated with an improvement in their extraction from cellular tissues and even with the activation of the biosynthetic pathway for their production. The application of HHP from 500 to 600 MPa, has been shown to cause cell wall disruption facilitating the release of phenolic compounds from cell compartments. HPP treatments ranging from 15 to 100 MPa during 10–20 min at room temperature have produced changes in phenolic biosynthesis with increments up to 155%. This review analyzes the use of HHP as a method to increase the phenolic content in vegetable systems. Phenolic content changes are associated with either an immediate stress response, with a consequent improvement in their extraction from cellular tissues, or a late stress response that activates the biosynthetic pathways of phenolics in plants. 相似文献
54.
Man Duan Dongmei Han Nan Gao Wenbin Shen Kun Chang Xinyu Wang Jianshi Du 《Molecules (Basel, Switzerland)》2022,27(5)
Porous organic polymers have an open architecture, excellent stability, and tunable structural components, revealing great application potential in the field of fluorescence imaging, but this part of the research is still in its infancy. In this study, we aimed to tailor the physical and chemical characteristics of indocyanine green using sulfonic acid groups and conjugated fragments, and prepared amino-grafted porous polymers. The resulting material had excellent solvent and thermal stability, and possessed a relatively large pore structure with a size of 3.4 nm. Based on the synergistic effect of electrostatic bonding and π–π interactions, the fluorescent chromogenic agent, indocyanine green, was tightly incorporated into the pore cavity of POP solids through a one-step immersion method. Accordingly, the fluorescent chromogenic POP demonstrated excellent imaging capabilities in biological experiments. This preparation of fluorescent chromogenic porous organic polymer illustrates a promising application of POP-based solids in both fluorescence imaging and biomedicine applications. 相似文献
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红外热成像技术在建筑工程领域具有十分广阔的应用前景。采用H2640型红外热像仪和NS9200 Report Generator分析软件对利用红外热成像技术检测外墙空鼓时的影响因素进行了归纳和分析。通过探讨天气、拍摄角度和图片分析软件对检测结果的影响,提出了拍摄红外图像的最佳时间,确定了最佳拍摄角度;对图片分析软件的误判因素和level&span的范围标定等进行了分析,并提出了相应的处理措施。 相似文献
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激光对抗技术是近年发展起来的一门新兴学科.在信息化战争中得到了广泛应用。在作战中它可有效地对抗红外制导武器、激光制导武器和光电控制系统的威胁。研究分析了舰艇在海战中实施激光对抗的四种方法。 相似文献
59.
轻钢龙骨薄板墙(简称轻板隔墙)的隔声性能由于其构造的复杂性,没有简单公式可以预计其隔声量。在大量实验结果的基础上,利用人工神经网络对一些常见的轻板墙组合构造进行计权隔声量(RW)的预计。根据相关分析和主成份分析的结果,选用板材面密度、墙体总厚度、腔内吸声层厚度、龙骨型式和垫层等因子作为网络的输入变量,由此进行隔声性能的预计,可达到较满意的结果。 相似文献
60.
In this work, a hybrid numerical approach to predict the vibrational responses of planar structures excited by a turbulent boundary layer is presented. The approach combines an uncorrelated wall plane wave technique with the finite element method. The wall pressure field induced by a turbulent boundary layer is obtained as a set of uncorrelated wall pressure plane waves. The amplitude of these plane waves are determined from the cross spectrum density function of the wall pressure field given either by empirical models from literature or from experimental data. The response of the planar structure subject to a turbulent boundary layer excitation is then obtained from an ensemble average of the different realizations. The numerical technique is computationally efficient as it rapidly converges using a small number of realizations. To demonstrate the method, the vibrational responses of two panels with simply supported or clamped boundary conditions and excited by a turbulent flow are considered. In the case study comprising a plate with simply supported boundary conditions, an analytical solution is employed for verification of the method. For both cases studies, numerical results from the hybrid approach are compared with experimental data measured in two different anechoic wind tunnels. 相似文献