“钢-铅”粘接结构非接触无损检测技术的研究

针对4层"钢-铅-钢-铅"的粘接结构,分别采用红外热像法、激光超声成像法和中子照相法等进行非接触检测,并对其优势和劣势进行了分析。研究结果表明:红外热像法能实现"钢-铅"粘接结构的非接触检测,但检测时加载的强烈热信号降低了缺陷信号的信噪比,使图像清晰度及大小的准确定量受到影响,需改进电磁热激励线圈的设计,并采用仿真建模分析解决上述问题;激光超声成像法能有效检测出2层粘接结构中准2以上的脱粘缺陷,但对于多层粘接结构需通过更加复杂有效的缺陷特征信号分析和提取方法等达到目的;中子照相法在检测"钢-铅"结构中的EP(环氧树脂)胶粘剂分布方面具有特殊优势,能检测出4层"钢-铅"粘接结构中准1的脱粘缺陷,是一种较理想的检测方法。     

TS-3000总硫分析仪的科学使用管理与保养维护的探讨

根据几年对TS-3000总硫分析仪使用管理的经验,文章对TS-3000总硫分析仪的科学管理使用与保养维护进行了阐述,使TS-3000总硫分析仪在使用、保养、维护工作中探索出针对该仪器科学系统的管理模式,确保该仪器长周期在良好的稳定的状态下运行,保证重点分析项目顺利进行。该仪器的使用和管理可用于同类仪器中借鉴。     

锅炉设备碱性腐蚀原因分析及水处理工艺改进

锅炉的碱性腐蚀经常被人们所忽视,但其造成的后果往往是非常严重的,轻则造成爆管导致停产,重则会威胁到操作人员的人身安全。传统的锅炉水处理方法虽然价格低廉,但其存在先天的不足,在一定条件下无法阻止碱性腐蚀的发生。而近些年逐渐产生的锅炉水处理工艺及与其配套的有机锅炉水处理药剂则全方面改进了传统锅炉水处理方法的不足,并在现场应用中收到了良好的效果。     

Fractal approach for modeling the morphology evolution of olefin polymerization with heterogeneous catalysts

Fractal theory and methodology were used to investigate the morphology of titanium–magnesium‐supported polyethylene catalysts and their relevant polymer particles. Through an analysis of the submicrostructures using scanning electron microscopy images, the surface fractal dimensions of the related particles were estimated with the box‐counting method. With consideration given to the fact that the growth process of a polymer is an evolving fractal process, which is controlled on the one hand by the initial conditions, including the initial fractal dimensions of the catalysts and the initial reaction conditions, and on the other hand by the previous morphology characteristics of the system, a novel polymerization fractal growth model was constructed. The simulation results showed good agreement with the experiment data. Moreover, the morphology evolution with the prepolymerization technique was predicted, and it was suggested that the duration of polymerization was 10–30 min. It was proven that the use of the surface fractal dimension as an important parameter describing the surface morphologies of the particles, either of catalysts or polymers, was real and effective. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1463–1470, 2003     

Caffeic Acid Phenethyl Ester Suppresses Proliferation and Survival of TW2.6 Human Oral Cancer Cells via Inhibition of Akt Signaling

Caffeic acid phenethyl ester (CAPE) is a bioactive component extracted from honeybee hive propolis. Our observations indicated that CAPE treatment suppressed cell proliferation and colony formation of TW2.6 human oral squamous cell carcinoma (OSCC) cells dose-dependently. CAPE treatment decreased G1 phase cell population, increased G2/M phase cell population, and induced apoptosis in TW2.6 cells. Treatment with CAPE decreased protein abundance of Akt, Akt1, Akt2, Akt3, phospho-Akt Ser473, phospho-Akt Thr 308, GSK3β, FOXO1, FOXO3a, phospho-FOXO1 Thr24, phospho-FoxO3a Thr32, NF-κB, phospho-NF-κB Ser536, Rb, phospho-Rb Ser807/811, Skp2, and cyclin D1, but increased cell cycle inhibitor p27^Kip. Overexpression of Akt1 or Akt2 in TW2.6 cells rescued growth inhibition caused by CAPE treatment. Co-treating TW2.6 cells with CAPE and 5-fluorouracil, a commonly used chemotherapeutic drug for oral cancers, exhibited additive cell proliferation inhibition. Our study suggested that administration of CAPE is a potential adjuvant therapy for patients with OSCC oral cancer.     

十二烷基苯磺酸钠改性牡蛎壳粉对铅离子的吸附性能研究

本实验为经十二烷基苯磺酸钠改性的牡蛎壳粉对重金属铅离子吸附性能的研究,采用二甲酚橙显色剂法、紫外分光光度法测定重金属铅离子的浓度,考察了pH值、吸附时间、吸附温度、改性牡蛎壳粉添加量与铅离子初始浓度这五个因素对实验的影响.并在单因素实验的基础上,通过正交实验,结果表明,当50 mL铅离子初始浓度为100 mg/L时,吸...     

Recent advances in nanofiltration,reverse osmosis membranes and their applications in biomedical separation field

In the face of human society’s great requirements for health industry, and the much stricter safety and quality standards in the biomedical industry, the demand for advanced membrane separation technologies continues to rapidly grow in the world. Nanofiltration(NF) and reverse osmosis(RO) as the highefficient, low energy consumption, and environmental friendly membrane separation techniques, show great promise in the application of biomedical separation field. The chemical compositions, microstr...     

Construction of Carbon Nitride Based Intramolecular D–A System for Effective Photocatalytic Reduction of CO2

Catalysis Letters - Photocatalytic technology provides a new strategy for mitigating energy crisis. The development of photocatalytic materials with high efficiency and stable visible light...     

In vivo Structure-Activity Relationship of Dihydromethysticin in Reducing Nicotine-Derived Nitrosamine Ketone (NNK)-Induced Lung DNA Damage against Lung Carcinogenesis in A/J Mice

Lung cancer is the leading cause of cancer-related deaths and chemoprevention should be developed. We recently identified dihydromethysticin (DHM) as a promising candidate to prevent NNK-induced lung tumorigenesis. To probe its mechanisms and facilitate its future translation, we investigated the structure-activity relationship of DHM on NNK-induced DNA damage in A/J mice. Twenty DHM analogs were designed and synthesized. Their activity in reducing NNK-induced DNA damage in the target lung tissues was evaluated. The unnatural enantiomer of DHM was identified to be more potent than the natural enantiomer. The methylenedioxy functional moiety did not tolerate modifications while the other functional groups (the lactone ring and the ethyl linker) accommodated various modifications. Importantly, analogs of high structural similarity to DHM with distinct efficacy in reducing NNK-induced DNA damage have been identified. They will serve as chemical probes to elucidate the mechanisms of DHM in blocking NNK-induced lung carcinogenesis.