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根据起重机械设计管理的现状,分析了中小制造单位因设计力量不足、管理欠缺的因素而导致我国起重机械设计能力低下的原因.同时,分析了现有法规对设计评审方式的欠缺以及监检机构人员技术能力不足,导致设计缺陷不能有效发现.提出对设计人员实行资格认定、成立专业起重机械设计单位的建议,使设计人员得到集中管理,提高了行业的整体设计能力;完善事后追查措施,以达到提高起重机械产品设计的可靠性,减少因设计缺陷造成的事故隐患的目的. 相似文献
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针对虚拟像素显示均匀性表现的一些问题,本文通过分析典型虚拟像素和真红绿蓝像素亮度中心的形成,对比了虚拟像素显示器与真红绿蓝像素显示器像素亮度中心分布的特点。在典型虚拟像素显示器中,红、蓝子像素数量少于绿子像素。低空间频率分布的红、蓝子像素对均匀分布的绿子像素亮度分布的调制造成虚拟像素亮度中心分布均匀性下降,并影响显示均匀性表现效果。本文提出采用不均匀分布的绿子像素排布,通过红、蓝子像素的亮度调制实现虚拟像素亮度中心均匀分布。初步的傅里叶分析和视觉对比表明,新虚拟像素显示均匀性表现效果符合预期。 相似文献
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亮背景下形态学星点目标提取算法 总被引:5,自引:0,他引:5
为了有效提取星图中星点小目标,实现提高星图识别效率及姿态计算的精度,本文在分析星点目标和小目标像共性的基础上,采用了一种形态学星点提取方法.该方法根据数学形态学运算的特点,得到估计的星图背景,通过灰度形态学Top-Hat变换对消背景,得到含有目标和高频噪声的图像,本文采用自适应阈值法确定实际图像的阈值.实验结果表明此方... 相似文献
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目的: 观察静脉注射免疫球蛋白对神经病理性疼痛大鼠的治疗作用,初步探讨其作用机制。方法: 雄性Wistar大鼠104只,随机分成4组:假手术组(S组,n=8),假手术+静脉注射免疫球蛋白组(SI组,n=32),坐骨神经慢性压迫性损伤(chronic constriction injury of the sciatic nerve, CCI)模型组(NP组,n=32),CCI模型+静脉注射免疫球蛋白组(NI组,n=32)。S组只分离暴露坐骨神经不结扎,NP组分离并结扎坐骨神经,SI组和NI组分别在手术后静脉注射免疫球蛋白。分别于术前、术后3、7、14、21 d测定各组大鼠热/机械痛阈。RT-PCR检测术后3、7、14、21 d 时脊髓腰膨大部位和背根神经节(dorsal root ganglia,DRG)中 Fc gamma RI(Fc RⅠ)mRNA的表达。结果: 与S组相比,NP组术后3、7、14、21 d 大鼠热/机械痛阈显著降低(P<0.05),SI组术后3、7、14、21 d大鼠热/机械痛阈显著升高(P<0.05);与NP组相比,NI组给药后3、7、14、21 d大鼠的热/机械痛阈值显著升高(P<0.05)。与S组比较,NP组和SI组大鼠脊髓和DRG中FcγRⅠmRNA表达明显上调(P<0.05);与NP组相比,NI组大鼠脊髓和DRG中FcγRⅠmRNA明显上调(P<0.05)。结论: 静脉注射免疫球蛋白可以缓解神经病理性疼痛大鼠的疼痛程度,脊髓中的FcγRⅠ在免疫球蛋白的镇痛作用中发挥作用。 相似文献
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采用真空感应熔炼的方法制备LZ92(Mg-9Li-2Zn)双相镁锂合金,同时进行热挤压试验,其挤压比分别为10、20、30。采用OM、SEM、XRD等分析手段及硬度测试、拉伸测试,研究不同挤压比下LZ92双相镁锂合金的组织和性能。试验结果表明:挤压态的LZ92镁锂合金具有优异的力学性能;随着挤压比的增加,合金再结晶越充分,晶粒细化越明显,抗拉强度逐渐增大至203.1MPa,较铸态提高了76%,强度的提高主要是由于加工硬化和晶粒细化的综合作用;当挤压比从20增至30时,合金的延伸率却大幅下降,主要由于加工硬化对塑性变形能力降低的程度大于晶粒细化对塑性变形能力提高的程度。 相似文献
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The Shihu gold deposit is characterized by gold-bearing quartz-polymetallic sulfides and quartz veins.Both Mapeng granitoids batholith and intermediate-basic dikes intruded the metamorphic basement rocks,and are spatially associated with gold mineralization.Trace element abundances in zircons from the Shihu gold deposit,determined by laser-ablation microprobe ICPMS analysis,are sensitive to source rock type and crystallization environment.Concentrations of 21 trace elements were determined for zircons from granitoid rocks,diorites,quartz diorite porphyrites and gold-bearing quartz veins revealed some elemental characteristics and chondrite-normalized trace element patterns from different samples.There were no distinctive differences in REE concentrations of zircons from plutonic rocks and quartz veins,indicating that they probably had the same origin.Relatively flat chondrite-normalized REE patterns with(Yb/Sm)N ratios less than 60 characterized zircons from quartz diorite porphyrites and quartz veins.The highest Nb/Ta ratios were found in zircons from quartz diorite porphyrites,whereas the lowest ratios were found in quartz vein zircons.The Nb/Ta ratios were broadly correlated with HREE+Y contents,and had weak positive correlations with the depth of the Eu negative anomalies.High values U up to 0.4% and Th up to 0.1%,as well as positive correlations with REE+Y characterized zircons from quartz vein.The lowest Th/U ratios of zircons present in quartz veins reflected the relatively high concentration of U in hydrothermal fluid,and high Pb concentrations only typified quartz vein grains relatively enriched in U and Th.Zircons from quartz diorite porphyrites showed the most pronounced Ce anomalies,whereas weak Ce anomalies were typical of zircons from quartz veins,in which Eu/Eu* of zircons had a broadly negative correlation with Ce/Ce*.Trace element geochemistry of zircons from mineralized quartz veins and plutonic rocks confirmed that the sources of ore-forming materials were from Precambrian host rocks.Our results significantly enhanced the usefulness of zircon in crustal studies of the North China craton and as an indicator mineral in mineral exploration of the Taihang region. 相似文献
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