Activation cross-sections of deuteron induced nuclear reactions on manganese up to 40 MeV

In the frame of a systematic study on activation cross-sections of deuteron induced reactions experimental excitation functions on ⁵⁵Mn were measured with the activation method using the stacked foil irradiation technique up to 40 MeV. By using high resolution γ-ray spectrometry, cross-section data for the production of ^56,54,52Mn and ⁵¹Cr were determined. Comparison with the earlier published data and with the results predicted by the ALICE-IPPE and EMPIRE-II theoretical codes - improved for more reliable calculations for d-induced reactions - and with data in the TENDL 2010 libraries are also included. Thick target yields were calculated from a fit to our experimental excitation curves and implications for practical applications in industrial (Thin Layer Activation) accelerator technology are discussed.     

Proton elastic scattering differential cross-sections for C

Carbon depth profiling presents a strong analytical challenge for all the major ion beam analysis (IBA) techniques, with elastic backscattering spectroscopy (EBS) being widely implemented. In the past, the ¹²C(p,p)¹²C reaction has been successfully evaluated for proton beam energies up to 4.5 MeV. Currently, an attempt is being made to extend this evaluation to higher energies, namely up to E_p,lab = 7 MeV. There is a certain lack of available and/or coherent datasets in literature for these relatively high proton beam energies at backward angles, suitable for IBA. Moreover, the few existing datasets are in certain cases discrepant. Thus, in the present work, the differential cross-section of proton elastic scattering on carbon were measured between 140°and 170°, in steps of 10°, for the proton beam energy range between 2.7 and 7 MeV. The experimental results obtained, along with data from literature, were evaluated applying nuclear physics models. The evaluated results were benchmarked using a thick, mirror polished glassy carbon target at different beam energies and detector angles.     

布设断面测算河道水库容积及冲淤量的数学解析与概化

以河道水库容积及冲淤量测算为目标，提出了断面布设要求、容积等效概化断面间距的推算方法，探讨了容积及冲淤量计算公式的适用性，导出了比较实用的断面间宽、平均深呈线性变化情况的容积计算公式。本研究成果的实质是，构建了逻辑自洽的断面法测算河道水库容积及冲淤量的数学体系。     

一种新的冲裁间隙实验模具的设计

冲裁间隙是影响冲裁件质量、模具寿命、冲裁力的重要因素,而冲裁间隙实验又是材料加工专业中的基础实验,在专业课程的学习中具有非常重要的作用。在以往的教学中开设冲裁间隙实验时为了改变冲裁间隙的大小,需要多次更换模具,非常不方便。现开发的是一种新的冲裁间隙实验模具,能实现不拆卸模具的情况下快速更换冲裁凸模,从而为实验提供不同的冲裁间隙值,克服了传统实验中多次装卸模具、调试模具的缺点,节约了实验时间,提高了实验的可靠性和安全性。该模具已经申请了实用新型专利,并获授权。     

弧形底梯形渠道的实用经济断面计算

文中推导了有关弧形底梯形渠道水力最佳断面的一套计算公式。在此基础上进一步导出了其实用经济断面的计算公式，给出了相应的计算数据表格，并对《渠道防渗工程技术规范》SLl8—91中有关该内容论述的不足和不妥提出了意见。     

Designing parametric blends: surface model and geometric correspondence

A model based on the curve-modulation technique is proposed for designing a parametric blend between two parametrically defined surfaces. The modulants are the cross section and the spine curves. The end position and tangency conditions of the cross section are discussed. Its intermediate shape can be left to the designer's choice, and generally depends on the application at hand. Various alternative choices, that fulfill the end conditions are suggested; this provides the flexibility demanded by various applications. The spine is designed as the intersection of two derived surfaces. Two alternative surface derivations are proposed, and both are discussed in some detail with their merits and demerits. The first derivation generates the contact curves automatically and relieves the designer from specifying them; the second one accepts contact curves specified by the designer, and generates the spine accordingly. Both of them are equally important in CAD/CAM and solid modelling applications.     

Cross-sectional structural analysis of C60 nanowhiskers by transmission electron microscopy

Cross-sectional observations of C₆₀ nanowhiskers (C₆₀NWs) were successfully conducted using the focused ion beam (FIB) method. The C₆₀NWs were observed to possess the core-shell structures with porous cores and dense surface thin layers. The size and number of pores decreased from the center to the surface, showing that the densification of C₆₀NWs proceeds from the surface to the center upon drying. A cross-sectional high-resolution transmission electron microscopy (HRTEM) image of a C₆₀NW showed a disordered structure comprising the domains with sizes on the order of 10 nm. The most frequently observed cross-sections were hexagons, reflecting the solvated hexagonal crystal structures of as-grown C₆₀NWs. From the observation of various cross-sectional shapes of C₆₀NWs with different diameters and crystallographic surface analysis, it is suggested that C₆₀NWs grow longer above a critical diameter D_c with the development of low-energy crystal surfaces.     

The preparation of cross-section specimens for transmission electron microscopy

The structure and chemistry of thin solid films are best studied by transmission electron microscopy (TEM) when they are viewed in cross-section—that is, when the surface normal of the film is made perpendicular to the electron beam. In this orientation, the substrate, the thin film layers, and the interfaces between them can be imaged either simultaneously or individually. Further, information from each of these regions remains distinct from that obtained from the others, eliminating the problems of superimposition that are a consequence of viewing a layered structure in the conventional manner (i.e., parallel to the surface normal). A technique for fabricating TEM specimens that can be viewed in cross-section is described here. Although the majority of our work is with silicon-based materials, the technique can be readily adapted to the study of other systems.     

Measurement of (p,p) elastic differential cross-sections for carbon, nitrogen, oxygen, aluminium and silicon in the 500–2500 keV range at 140° and 178° laboratory scattering angles

We measured the (p,p) elastic scattering cross-sections of natural samples of carbon, nitrogen, oxygen, aluminium and silicon at energies ranging between 500 and 2500 keV and at laboratory scattering angles of 178° and 140°. Results are compared with previous literature data and simulations and are presented in graphical form. The measured cross-sections have been used to simulate spectra taken from know samples and have been found appropriate for quantitative calculations.     

服用可调人台初探

通过对现有的两类可调人台体型变化数据的分析,对可调人台的调节方式、号型分档、主要截面造型、整体造型等方面进行了研究,为研制适合我国国民体型的可调人台提供依据.