自动脱螺纹的水杯盖三板注塑模具设计

以水杯盖为实例,探讨了具有内螺纹和侧孔的杯盖注塑模具设计方法、要点及其工作过程。对模具定模一侧斜导柱抽芯机构、液压齿轮联合传动的自动旋脱螺纹机构等的设计方法作了深入阐述。该模具结构复杂、实用可靠,对此类塑件的注塑模具设计具有参考作用。     

Measurement of lifetimes of thin carbon stripper foils produced by ion-beam sputtering

Thin carbon stripper foils used in high-intensity proton accelerators and heavy-ion accelerators must have long lifetimes. Thin carbon foils were fabricated by ion-beam sputtering using reactive and inert gas ions. The lifetime of the foils was measured using a KEK 650-keV high-intensity DC H⁻ (negative hydrogen ion) beam; changes in the foil thickness and surface deformations during irradiation were investigated. The lifetime of a typical stripper foil fabricated by heavy-ion-beam (Ar and Kr) sputtering was 60-70 times longer than that of the best commercially available foils. This paper reports a fabrication method for carbon stripper foils, along with an investigation of their lifetimes and changes in foil thickness during beam irradiation.     

The stripper design and test at HIRFL-CSR

Charge stripping is employed to produce multi-charged ions for injecting the cooling storage ring.After penetrating through the carbon foil,the widened distribution of ion charge states poses a limit to the ion injection.Therefore,the carbon foil plays a key role in the charge stripping injection.In this paper,four strippers for Heavy Ion Research Facility at Lanzhou(HIRFL)and Cooling Storage Ring(CSR)are introduced.The charge state distribution of the stripped ions is measured and the stripping efficiency of the foils is investigated.The experimental results are consistent with the theoretical values.     

HI-13串列加速器十年运行、维修与改进

对ＨＩ－１３串列加速器十年来的运行、维修与改进工作进行简要总结,给出了有关统计数据,并重点概述了在重大设备国产化和加速器及其相关技术方面的研究工作。     

The effect of using a sprung stripper in sheet metal cutting

Sheet metal cutting with punch and die is one of most fundamental processes in sheet metal presswork, and in many modern tools such as progression tooling a sprung stripper is used to help the punch withdraw from the strip after separation. The vast quantity of practical information which is available about the cutting process does not document whether the use of a spring stripper affects the cutting process. In this work, a tool with a sprung stripper was modified so that the sprung stripper was held back from the strip. Burr height readings were taken before and after the modification, as were electron micrographs of the cut edge. These were compared to determine the effect, if any, that a sprung stripper would have on the proportions of shear and tensile fracture and the burr height formed. When a sprung stripper was used, maximum burr was half as high as without. Process consistency was over twice as good with a sprung stripper. When a sprung stripper was used, burr was found to protrude into the hole, which did not happen otherwise. With a sprung stripper, there were more patches of secondary shear fracture than with no stripper contact. It is suggested that the use of a sprung stripper altered the path of tensile fracture and the amount of drawing in of the strip during cutting, thus altering the burr height and width.     

关于酸性水汽提装置节能降耗的技术探讨

通过对酸性水汽提装置塔顶、侧线、塔底三股物流特性的分析以及合理的使用,探讨装置节能降耗的技术改进.     

五板式推件板推件高压聚乙烯堵头注塑模设计

设计了高压聚乙烯堵头注塑模,论述了模具结构特点和工作原理。该模具采用五板结构,3次分型,一模两腔,点浇口进浇,推件板推出塑件。模具结构紧凑,工作可靠,操作方便,成型塑件质量好。     

The dissociation of CH and CH2 molecules in He and N2 at beam energies of 80-250 keV and possible implications for radiocarbon mass spectrometry

Isotopic ratios of ¹⁴C at natural levels can be efficiently measured with accelerator mass spectrometry (AMS). In compact AMS systems, ¹³CH and ¹²CH₂ molecular interferences are destroyed in collisions with the stripper gas, a process which can be described by dissociation cross sections. These dissociation cross sections determine the gas areal density required for sufficient attenuation of the interfering molecular beams, and are therefore key parameters in the effort to further reduce the terminal voltage and thus the size of the AMS system. We measured the dissociation cross sections of ¹³CH and ¹²CH₂ in N₂ and He in the energy range of 80-250 keV. In N₂, cross sections were constant for energies above 100 keV with average values per molecule of (8.1 ± 0.4) × 10⁻¹⁶ cm² for ¹³CH and (9.5 ± 0.5) × 10⁻¹⁶ cm² for ¹²CH₂. In He, cross sections were constant over the full measured range of 80-150 keV with average values of (4.2 ± 0.3) × 10^{− 16} cm² and (4.8 ± 0.4) × 10⁻¹⁶ cm², respectively. A considerable reduction of the terminal voltage from the currently used 200 kV while using N₂ for ¹³CH and ¹²CH₂ molecule dissociation is not possible: the required N₂ areal densities of ∼1.4 μg/cm², consequential angular straggling and a decreasing 1+ charge state fraction would reduce the ion beam transmission too much. This is not the case for He: sufficient molecule dissociation can be obtained with gas densities of ∼0.4 μg/cm², for which angular straggling is relatively small. In addition, the 1+ charge state fraction still increases at lower stripping energies. Thus, the usage of He for stripping and molecule dissociation might allow the development of even smaller ¹⁴C-AMS systems than available today.     

Mounting stripper foils on forks for maximum lifetime

While research and development continue to produce forms of carbon for longer lasting stripper foils, relatively little attention has been paid to other factors that affect their survival in use. It becomes apparent that the form of carbon is only part of the issue. Specific mounting methods increase the lifetimes of carbon stripper foils. These methods are determined in part by the specific use and carbon type for a foil. With careful handling, appropriate adhesive, and slack mounting, premature breakage can be avoided. Foil lifetimes are then primarily affected by less easily controlled factors such as high-temperature expansion, shrinkage and evaporation.     

Suppression of carbon buildup and lifetime improvement by heating carbon stripper foils

We have successfully developed a new method to reduce the amount of carbon buildup on thin cluster (less than 3.5 μg/cm²) carbon stripper foils by heating them with infrared radiation during beam bombardment. We studied the carbon buildup and the foil temperature on foil lifetime using a 2.0 ± 0.5 μA beam of 3.2-MeV Ne⁺ ions. It was found that the carbon buildup begins to rapidly suppress at 460 °C; further, at a foil temperature higher than approximately 820 °C, the initial foil thickness did not change until the foil ruptured. We also found that the carbon buildup shortens the lifetime of stripper foils.The foils treated by the newly developed present method could withstand the maximum and average total beam charges of 530 mC/cm² and 340 mC/cm², respectively, which are approximately 18 and 11 times larger than the values for the best commercially available foils and approximately 3 and 2 times greater than the values for the cluster foils that are not treated by this method.