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排序方式: 共有99条查询结果,搜索用时 15 毫秒
1.
在很高的温度和适宜的生长条件下,分别采用熔盐籽晶法和高温引上法生长了高质量的YAP、NAB、KTP、LN、BBO、SBN等多元氧化物单晶,它们具有优良的物理化学性能,严格的化学比,固定的组成与结构以及较好的化学均匀性和电子束轰击下的稳定性。广泛地用于激光和非线性光学领域。我们选用这些晶体为原材料研制电子探针定量分析的标准样品。经过测量和标定,这些单晶标样符合中华人民共和国国家标准GB 4930-85(电子探针显微分析标准样品通用技术条件)的规定。含有稀土元素的标样如NAB和YAP能发出绿色荧光,是电子显微术中理想的阴极发光材料。 相似文献
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Yue Sun Aidong Xu Kai Wang Xiufang Zhou Haifeng Guo Xiaojia Han 《Entropy (Basel, Switzerland)》2022,24(7)
One of the biggest challenges for the fault diagnosis research of industrial robots is that the normal data is far more than the fault data; that is, the data is imbalanced. The traditional diagnosis approaches of industrial robots are more biased toward the majority categories, which makes the diagnosis accuracy of the minority categories decrease. To solve the imbalanced problem, the traditional algorithm is improved by using cost-sensitive learning, single-class learning and other approaches. However, these algorithms also have a series of problems. For instance, it is difficult to estimate the true misclassification cost, overfitting, and long computation time. Therefore, a fault diagnosis approach for industrial robots, based on the Multiclass Mahalanobis-Taguchi system (MMTS), is proposed in this article. It can be classified the categories by measuring the deviation degree from the sample to the reference space, which is more suitable for classifying imbalanced data. The accuracy, G-mean and F-measure are used to verify the effectiveness of the proposed approach on an industrial robot platform. The experimental results show that the proposed approach’s accuracy, F-measure and G-mean improves by an average of 20.74%, 12.85% and 21.68%, compared with the other five traditional approaches when the imbalance ratio is 9. With the increase in the imbalance ratio, the proposed approach has better stability than the traditional algorithms. 相似文献
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Huaming?YangEmail author Guanzhou?Qiu Xiangchao?Zhang Aidong?Tang Wuguo?Yang 《Journal of nanoparticle research》2004,6(5):539-542
CdO nanoparticles of 43 nm in crystal size were successfully synthesized by the mechanochemical reaction (CdCl2 + Na2CO3) with NaCl as a diluent and subsequent thermal treatment at 700°C for 2 h. The samples were characterized by differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Effect of calcination temperature on the crystal size of CdO nanoparticles was primarily investigated. The apparent activation energy of CdO nanoparticle formation during thermal treatment was calculated to be 12.2 kJ/mol. 相似文献
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Electrochemical pesticide sensitivity test using acetylcholinesterase biosensor based on colloidal gold nanoparticle modified sol-gel interface 总被引:2,自引:0,他引:2
Based on the change in electrochemical behavior of enzymatic activity induced by pesticide, a novel electrochemical method for investigation of pesticide sensitivity using acetylcholinesterase (AChE) biosensor was developed. The sol-gel-derived silicate network assembling gold nanoparticles (AuNPs-SiSG) provided a biocompatible microenvironment around the enzyme molecule to stabilize its biological activity and prevented them from leaking out of the interface. The composite was characterized using atomic force microscopy and proved to be chemically clean, porous and homogeneous. AuNPs promoted a conductive pathway for electron transfer and improved electrochemical reactions at a lower potential. Typical pesticides such as monocrotophos, methyl parathion and carbaryl were selected for pesticide sensitivity tests. Due to the inhibitions of pesticides, the electrochemical responses of substrate on AChE-sensors decreased greatly. The inhibition curves showed good correspondence with the results by UV spectrophotometry assay. The proposed electrochemical pesticide sensitivity test exhibited high sensitivity, desirable accuracy, low cost and simplified procedures. This method could be developed as a conventional method to select efficient enzyme inhibitors and investigate toxic compounds against to enzyme. 相似文献
7.
Hou Y Jaffrezic-Renault N Martelet C Tlili C Zhang A Pernollet JC Briand L Gomila G Errachid A Samitier J Salvagnac L Torbiéro B Temple-Boyer P 《Langmuir : the ACS journal of surfaces and colloids》2005,21(9):4058-4065
To make ultrathin films for the fabrication of artificial olfactory systems, odorant biosensors, we have investigated mixed Langmuir and Langmuir-Blodgett films of odorant-binding protein/amphiphile. Under optimized experimental conditions (phosphate buffer solution, pH 7.5, OBP-1F concentration of 4 mg L(-1), target pressure 35 mN m(-1)), the mixed monolayer at the air/water interface is very stable and has been efficiently transferred onto gold supports, which were previously functionalized by self-assembled monolayers (SAMs) with 1-octadecanethiol (ODT). Atomic force microscopy and electrochemical impedance spectroscopy were used to characterize mixed Langmuir-Blodgett (LB) films before and after contact with a specific odorant molecule, isoamyl acetate. AFM phase images show a higher contrast after contact with the odorant molecule due to the new structure of the OBP-1F/ODA LB film. Non-Faradaic electrochemical spectroscopy (EIS) is used to quantify the effect of the odorant based on the electrical properties of the OBP-1F/ODA LB film, as its resistance strongly decreases from 1.18 MOmega (before contact) to 25 kOmega (after contact). 相似文献
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对汤岗子热矿泥黑粉中矿物元素进行了分析研究。用微波消解法处理汤岗子热矿泥黑粉样品,采用ICP-MS法对热矿泥黑粉中16种元素进行分析。结果表明,在优化实验条件下,方法的检出限为0.00028~14.66μg/L,相对标准偏差为0.18%~6.20%,回收率为91.5%~108.2%。为探讨汤岗子热矿泥黑粉对人体的保健作用提供了参考数据。 相似文献