The resistive coated sphere in the presence of a point generated wave field

We consider the low‐frequency scattering problem of a point source generated incident field by a small penetrable sphere. The sphere, which is also lossy, contains in its interior a co‐ecentric spherical core on the boundary of which an impedance boundary condition is satisfied. An appropriate modification of the incident wave field allows for the reduction of the solution to the corresponding scattering problem of plane wave incidence, by moving the point source to infinity. For the near field, we obtain the low‐frequency coefficients of the zeroth and the first order. This was done with the help of the corresponding solution for the hard core problem and an appropriate use of linearity with respect to the Robin parameter. In the far field, we derive the leading non‐vanishing terms for the normalized scattering amplitude and the scattering cross‐section, which are both of the second order, as well as for the absorption cross‐section, which is of the zeroth order. The special cases of a lossy or a lossless penetrable sphere, of a resistive sphere, and of a hard sphere are recovered by an appropriate choice of the physical or the geometrical parameters. Copyright © 1999 John Wiley & Sons, Ltd.     

智能高分子材料在智能给药系统中的应用

简要介绍了合成智能高分子材料、半合成智能高分子材料和天然智能高分子材料在智能给药系统中的应用研究进展,并展望了其在智能给药系统中的应用前景.     

The Essential Oil Derived from Perilla frutescens (L.) Britt. Attenuates Imiquimod–Induced Psoriasis-like Skin Lesions in BALB/c Mice

Psoriasis is reported to be a common chronic immune-mediated skin disease characterized by abnormal keratinocytes and cell proliferation. Perilla leaves are rich in essential oils, fatty acids, and flavonoids, which are recognized for their antioxidant and anti-inflammatory effects. In this study, the alleviating effect of essential oil (PO) extracted from Perilla frutescens stems and leaves on imiquimod (IMQ) -induced psoriasis-like lesions in BALB/c mice were investigated. Results showed that PO ameliorated psoriasis-like lesions in vivo, reduced the expression of lymphocyte antigen 6 complex locus G6D (Ly-6G), which is a marker of neutrophil activation, and inhibited the expression of inflammatory factors interleukin 1 (IL-1), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX2). In addition, PO significantly decreased the expression of cytokines such as IL-6, IL-1, interleukin 23 (IL-23), interleukin 17 (IL-17), and nuclear factor kappa-B (NF-κB). Furthermore, the down-regulation of mRNA levels of psoriasis-related pro-inflammatory cytokines, such as IL-17, interleukin 22 (IL-22), IL-23, interferon-α (IFN-α), and Interferon-γ (IFN-γ) was observed with the treatment of PO. All results show a concentration dependence of PO, with low concentrations showing the best results. These results suggest that PO effectively alleviated psoriasis-like skin lesions and down-regulated inflammatory responses, which indicates that PO could potentially be used for further studies on inflammation-related skin diseases such as psoriasis and for the treatment of psoriasis such as psoriasis natural plant essential oil resources.     

Enzyme-induced Fenton reaction coupling oxidation of o-phenylenediamine for sensitive and specific immunoassay

Journal of Solid State Electrochemistry - In this paper, a simple and feasible immunoassay protocol with signal amplification for sensitive determination of alpha fetoprotein (AFP, used as a model)...     

Ni-SiO2催化剂空间限域维度对CH4-CO2重整反应金属抗积碳能力的影响

制备了3种化学组成相同但金属活性位点空间结构不同的Ni-SiO₂催化剂(Ni/SiO₂负载型催化剂、 Ni/SBA-15介孔结构催化剂和Ni@SiO₂核壳结构催化剂), 考察了不同空间限域维度及结构对CH₄-CO₂重整反应活性金属抗积碳机制的影响规律. 结果表明, Ni/SiO₂催化剂无空间限域效应, 抗积碳能力最弱, 表现出最差的稳定性; Ni/SBA-15催化剂存在部分空间限域效应, 抗积碳能力明显提高, 表现出较好的稳定性但是仍有失活; Ni@SiO₂催化剂具有完全几何限域效应, 抗积碳能力最强, 表现出最优的稳定性.     

超亲水超疏油油水分离膜的制备及其性能

超亲水-超疏油油水分离膜是一种过水隔油的特殊分离膜,在处理海洋溢油污染、环境含油废水时具有保持分离膜不被油污染的优势,有十分重要的实际意义。为了掌握近年来超亲水超疏油分离膜的发展动态,本文首先以液体静压力与毛细作用力为基础阐述亲水疏油膜的油水分离机理;然后分类概括超亲水-超疏油金属基底网膜、刺激响应油水分离膜、无基底聚合物膜材料的制备及各项性能的研究新进展;最后总结目前在该领域仍存在的问题并进行展望。     

Guiding mode in elliptical core microstructured polymer optical fiber

A kind of microstructured polymer optical fiber with elliptical core has been fabricated by adopting insitu chemical polymerization technology and the secondary sleeving draw-stretching technique. Microscope photography demonstrates the clear hole-structure retained in the fiber. Though the holes distortion is visible, initial laser experiment indicates that light can be strongly confined in the elliptical core region,and the mode field is split obviously and presents the multi-mode characteristic. Numerical modeling is carried out for the real fiber with the measured parameters, including the external diameter of 150μm, the average holes diameter of 3.3μm, and the averageole spacing of .3μm by using full-vector plane wave method. The guided mode fields of the numerical simulation are consistent with the experiment result.This fiber shows the strong multi-mode and weak birefringence in the visible and near-infrared band, and has possibility for achieving the fiber mode convertors, mode selective couplers and so on.     

氰基化合物非均相加氢制备有机胺的研究进展

介绍了不同结构的氰基化合物加氢还原制备有机胺的研究工作,重点对用非均相催化剂的氰基化合物加氢研究现状进行了综述,指出高性能催化剂的开发仍是今后研究的主要方向。     

Study on Lithium Isotope Enrichment by Band Displacement Process

Based on the equilibrium plate model of the distillation type,a set of theoretical equations has been deduced for the isotope's stationary band,and a new method of calculating the height equivalent to a theoretical plate (HETP) used for isotope enrichment was suggested.Moreover,the quantitative relations between the total enrichment and the experimental parameters (concentration of eluant,flow rate,length of band and displaced distance) were established.The expression of enrichment variation,while approaching the stationary state,was corrected and demonstrated experimentally.By the use of that expression,the semicontinuous isotope enrichment process was successfully estimated     

具有农药活性的微生物源核苷类化合物

微生物天然产物在新农药的研究与开发中占据着重要的地位。核苷作为一类重要的生理活性物质, 具有丰富多样的结构及生物活性。本文对微生物来源的具有农药活性的核苷类化合物进行总结,重点综述了具有农药活性的微生物源嘧啶或嘌呤、核苷及其衍生物及核苷酸类似物等三类微生物源核苷类化合物,分别对其来源、结构多样性、农药活性及杀虫、杀菌及抗病毒作用机制进行了概括, 以期对新型农用抗生素的开发及新农药创制提供一些有益的借鉴。