钢的裂纹研究思路及应注意的问题

研究钢的裂纹,要确定裂纹的特征和产生裂纹的影响因素。经过分析,初步确定出裂纹产生的原因,然后采取改进措施,反复实践,直到最终消除裂纹。提出研究钢的裂纹,要注意结合各种专业知识,善于积累现场经验和借鉴他人的工作成果;掌握数理统计及物理检验的方法,提高调查研究的能力等方面的建议。     

某型柴油机增压系统概述

增压技术能提高柴油机功率和改善经济性能,某型柴油机增压技术非常先进,是该公司核心技术之一。本文分析了其增压系统的特点,并介绍了增压器的特殊功能和先进结构。     

木薯发酵制备酒精后剩余残渣的综合利用

木薯发酵制备乙醇会产生大量以淀粉和纤维素为主要成分的残渣。经实验证明,在浓硫酸(60%)、浓硝酸和催化剂共同作用下,经水解-氧化-水解可成功地将木薯渣制备成草酸。实验确定了用木薯渣制备草酸的较优条件,测定了产品的熔点,分析了剩余残渣、废水,结果表明剩余残渣和废水不会对环境造成污染,既为草酸的生产提供了新思路,又为农产品的残渣综合利用找到途径,发展前景广阔。     

The Main Progress of Perovskite Solar Cells in 2020–2021

Perovskite solar cells (PSCs) emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from ...     

Up?Scalable Fabrication of -SnO2 with Multifunctional Interface for High Performance Perovskite Solar Modules

Tin dioxide -(SnO2) has been demonstrated as one of the promising electron transport layers for highefficiency perovskite solar cells (PSCs). However, scalable ...     

脚踝康复受力测量电路的设计

通过分析脚踝康复受力间接测量原理,基于MSP430单片机设计出一种脚踝康复受力测量电路,进行了脚踝康复受力测量实验,实验证明脚踝康复受力测量电路实现踝关节康复力和力矩的间接测量,为踝关节安全康复提供了指导性数据,便于患者自主控制康复强度,提高了康复效果。     

Essential oil composition and antimicrobial activity of Sphallerocarpus gracilis seeds against selected food-related bacteria

Sphallerocarpus gracilis from China is a little-investigated edible and medicinal plant. In the present study, the essential oil composition from S. gracilis seeds was investigated by GC and GC–MS. A total of 34 compounds representing 94.69% of the essential oil were tentatively identified. The main constituents were p-cymene (17.42%), γ-terpinene (25.58%) and α-asarone (33.12%). The antimicrobial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of the essential oil from S. gracilis seeds were evaluated against eight Gram-positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Bacillus megaterium, Bacillus cereus, Bacillus coagulans and Bacillus subtilis), four Gram-negative bacteria (Salmonella enteritidis, Salmonella typhimurium, Klebsiella pneumoniae and Escherichia coli) and one fungus (Aspergillus niger). Results revealed that the essential oil from S. gracilis seeds exhibited significant in vitro antimicrobial property. Among all the tested microorganisms, the essential oil showed the strongest inhibitory effect against K. pneumoniae, whereas no inhibitory effect was found against L. monocytogenes and A. niger. Additionally, scanning electron microscopy (SEM) was used to observe morphological changes of bacteria treated with the essential oil from S. gracilis seeds. SEM observations confirmed the physical damage and considerable morphological alteration to the tested microorganisms treated with the essential oil. The data of this study suggests that the essential oil from S. gracilis seeds has great potential for application as a natural antimicrobial agent to preserve food.     

Improve on/off ratio of organic heterojunction transistors by adopting single-sandwich configuration

Organic heterojunction transistors (OHJTs) based on 5,5′″-bis(naphtha-2-yl)-2,2′:5″,2′″-quaterthiophene (NaT₄)/copper-hexadecafluoro-phthalocyanine (F₁₆CuPc) heterojunction were fabricated in single-sandwich and sandwich configurations, respectively. All the devices operated in depletion-accumulation (normally-on) mode. High field-effect mobility of 0.35 cm²/Vs was obtained for all devices, which was higher than that, 0.20 cm²/Vs of the devices with NaT₄ as active layer. The on/off ratio of 1 × 10⁵ was obtained for OHJTs with single-sandwich configuration, which is three orders of magnitude higher than that of OHJTs with sandwich configuration. Compared with OHJTs with sandwich configuration, the higher on/off ratio was mainly determined by the lower off state current in OHJTs with single-sandwich configuration. In OHJTs with single-sandwich configuration, the well-type shield effect of the source and drain electrodes caused a very narrow empty region in F₁₆CuPc film, which is responsible for the lower off state current.     

Study on Thermal Deformation Behavior and Properties of Vacuum Hot-press Sintered W(50)/Cu-Al_2O_3 Composite

In this work, the tungsten particulate reinforced Al2O3 dispersion strengthened copper base composites were successfully fabricated by using a vacuum hot-press sintering method. With the test temperature varying from 650 to 950 ℃ and the strain rate varying from 0.01 to 5 s-1, the W(50)/Cu-Al2O3 composites were isothermally compressed on a Gleeble-1500D thermal simulator. The true stress-strain curves of the W(50)/Cu-Al2O3 under different test conditions were obtained. The dynamic recrystallization of the W...     

Crystallization and infrared radiation properties of iron ion doped cordierite glass-ceramics

Heterogeneous ion solution is an important method to improve the wanted property of polycrystalline materials. In this paper, for the purpose of infrared radiation property modification, different contents Fe₂O₃ were doped in MgO-Al₂O₃-SiO₂ system glasses. The effects of Fe₂O₃ doping on nucleation mechanism, crystallization behaviors and especially infrared radiation properties of this cordierite-crystalline based glass-ceramics were systematically investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that, the doping of iron ion can promote the phase separation of this magnesium aluminosilicate glass, and therefore change the crystallization mechanism of this glass from surface crystallization to bulk crystallization. The iron ion incorporates into the crystal structure of cordierite by mean of substituting Mg²⁺ in M site. The substitution of Fe³⁺ to Mg²⁺ can form the vacant site of Mg²⁺ cations. For the effects of lattice distortion, impurity and vacancy defects which caused by the incorporation of iron ion, the infrared radiation performance of cordierite based glass-ceramics can be improved effectively.