排序方式: 共有41条查询结果,搜索用时 15 毫秒
11.
12.
引入激光技术与手动、自动酸开封相结合的新开封工艺,对小型、异形及有多块芯片的塑封器件进行开封实验。首先利用激光准确对芯片上方的塑封料进行部分刻蚀,再结合自动酸开封或手动酸开封去除芯片表面的塑封料。实验结果表明,激光开封后的器件再进行手动酸开封时间仅需8 s,相对于未引入激光开封技术的传统酸开封方法,激光开封技术在塑封器件开封中能达到定位准确、缩短开封时间、提高开封效率的效果。 相似文献
13.
14.
随着硫化氢作为人体内重要内源性气体信号分子研究的不断深入,有机小分子硫化氢供体的研究也取得了较大的进展,但目前尚无一种硫化氢供体药物上市.二甲双胍是临床上治疗糖尿病的一线药物,近年来被报道还具有减肥、抗癌、抗衰老等多种生理活性.鉴于硫化氢和二甲双胍在重大疾病治疗中的良好前景,设计了一种全新的硫化氢供体二甲双胍硫化氢盐,前人对该类有机碱硫化氢盐的系统研究几乎为空白,更无将其作为硫化氢供体的报道.首先将二甲双胍盐酸盐处理得到二甲双胍游离碱,再与硫化氢反应形成二甲双胍硫化氢盐.通过氢谱、碳谱、元素分析及X单晶衍射对其进行了结构确证.采用碘量法、醋酸铅法和荧光亚甲蓝法测定了二甲双胍硫化氢盐中硫化氢的含量,均大于96.00%;采用高效液相色谱(HPLC)测定了二甲双胍硫化氢盐中二甲双胍的含量大于98.50%,且二甲双胍硫化氢盐的溶液及固体均相对稳定.上述研究结果表明,二甲双胍硫化氢盐有望作为一种新结构类型的硫化氢供体进行深入的研究和开发. 相似文献
15.
16.
17.
ICP-AES法测定金属钇中19个杂质元素 总被引:2,自引:0,他引:2
本文介绍了用ICP-AES法测定金属钇中19个杂质元素的方法,采用基体匹配法附基体干扰,一了金属钇中19个杂质元素的含量,得到了较好的精密度和准确度,方法简便,快速,结果令人满意. 相似文献
18.
Morphological and structural damage investigation of nanostructured molybdenum fuzzy surface after pulsed plasma bombardment
下载免费PDF全文
![点击此处可从《中国物理 B》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yu-Chuan Luo 《中国物理 B》2022,31(4):45203-045203
Steady high-flux helium (He) plasma with energy ranging from 50 eV to 90 eV is used to fabricate a fiber-form nanostructure called fuzz on a polycrystalline molybdenum (Mo) surface. Enhanced hydrogen (H) pulsed plasma in a wide power density range of 12 MW/m2-35 MW/m2 is subsequently used to bombard the fuzzy Mo, thereby simulating the damage of edge localized mode (ELM) to fuzz. The comparisons of surface morphologies, crystalline structures, and optical reflectivity between the original Mo and the Mo treated with various He+ energy and transient power densities are performed. With the increase of He ion energy, the Mo nano-fuzz evolved density is enlarged due to the decrease of filament diameter and optical reflectivity. The fuzz-enhanced He release should be the consequence of crystalline growth and the lattice shrinkage inside the Mo-irradiated layers (~200 nm). The fuzz induced by lower energy experiences more severe melting damage and dust release under the condition of the identical transient H plasma-bombardment. The H and He are less likely to be trapped due to aggravated melting evidenced by the enhanced crystalline size and distinct lattice shrinkage. As the transient power density rises, the thermal effect is enhanced, thereby causing the fuzz melting loss to aggravate and finally to completely disappear when the power density exceeds 21 MW/m2. Irreversible grain expansion results in huge tensile stress, leading to the observable brittle cracking. The effects of transient thermal load and He ion energy play a crucial role in etching Mo fuzz during ELM transient events. 相似文献
19.
以TMS320F2812处理器为核心,采用恒流与恒压相结合的方法针对100 Ω、1 KΩ、10 KΩ和10 MΩ共4种量程内的电阻进行测量,并详细介绍系统硬件电路、软件设计以及ADC采样校正算法研究;经过实验证明,该系统各量程内的电阻测量精度均达到0.3%,具有量程手动或自动转换档位、电阻自动筛选、语音提示、LCD显示等功能;该测量仪功能齐全、测量精度高、性能稳定,具有一定的实用价值。 相似文献
20.
经多方调研,在很多学校、企业等集体宿舍内,使用电热棒、电饭煲、热得快等恶性负载引起的火灾开始增多。为了消除集体宿舍用电安全隐患,相关方面经常要花费很大的人力、物力、精力去检查宿舍是否使用了大功率用电器,但收效甚微。 相似文献