The Role of Metastable Atoms in a Homogeneous Atmospheric Pressure Barrier Discharge in Helium

A one-dimensional fluid model for homogeneous atmospheric pressure barrier discharges in helium is presented by considering elementary processes of excitation and ionization including a metastable atom effect. Using this model we investigate the behaviours of the helium metastable atoms in discharges as well as their influence on the discharge characteristics. It is shown that the metastable atoms with a relatively high concentration during the discharge are mainly produced in the active phase of the discharge and dissolved in the off phase. It is also found that the metastable atom collisions can not only provide seed electrons for discharges but also influence the concentration of ions. A reduction of matestable atom density results in a drop in the charged particle densities and causes a qualitative change in the discharge patterns.     

昆仑海岸推出JQWY系列高精度大气压力、温度一体化变送器／传感器

推出时间：2008—1 产品特点：长期稳定性好智能数字电路补偿,使用温域宽防浪涌电压和极性反相保护抗干扰设计灵敏度高,温漂小可配现场LCD显示     

标准水银气压表的总不确定度评估

本文根据标准水银气压表的结构特点、工作原理，详细分析各项误差分量的构成，利用误差合成方法，评估其总不确定度。     

地面大气压变化对义马矿区矿井瓦斯涌出的影响

通过对常村煤矿综放工作面的瓦斯涌出规律的研究,分析出大气压力变化对义马矿区的影响。在地面大气压力较小的4月至8月,重点做好采煤工作面的瓦斯防治工作,这段时间要加强关注采煤工作面上隅角及回风巷的瓦斯涌出量,采用防治瓦斯的有效措施,提高瓦斯抽采效率,通过上隅角回风的合理布局,有效地防治瓦斯异常涌出。在地面大气压力较高的11月至次年1月,适当停止瓦斯抽放泵的运行,则可以节能降耗,降低成本。     

Effects of Atmospheric Pressure Air Plasma Pretreatment on the Seed Germination and Early Growth of Andrographis paniculata

The objective of this paper is to demonstrate whether air plasma can change the seed germination characteristics, seedling emergence, as well as biochemical reactivity, in Andrographis paniculata （A. paniculata） seedlings by modifying the seed coat and finding a beneficial treatment dose. Eight treatment doses and one control were used to conduct electrical conductivity determination, a germination test, a seedling emergence test and a biochemical assay. The results showed that after being treated with air plasma excited at 5950 V for 10 s, the perme- ability of the seeds was improved significantly, resulting in the acceleration of seed germination and seedling emergence. In the meantime, the catalase activity and catalase isoenzyme expression were also improved, while the malondialdehyde content in the seedlings was decreased （which means greater counteraction with environmental stress）. After being treated with 4250 V for 10 s and 5950 V for 20 s, the seed germination was enhanced, but without an obvious change in seedUng emergence. However, after treatment with 3400 V for 20 s and 5100 V for 10 s, the permeability of the seeds was decreased, resulting in a delay in seedling emergence. These results indicate that air plasma can change the physiological and biochemical characteristics of Andrographis paniculata seeds by modifying the seed coat, combined with the effects of the active plasma species, and that different treating doses have different effects.     

Modeling heat transfer for phase transition during pressure assisted thawing treatment

The thawing time of ice and freezed Salomon fish during high pressure assisted thawing process was evaluated by computer simulation using a finite element and the results were compared with those under atmospheric pressure. The apparent specific heat method was adopted to treat the release of latent heat. The effects of different factors on the high pressure assisted thawing process were analyzed. The time reductions of different sample dimensions were estimated and the temperature contour of thawing at different conditions was obtained. The results showed that the temperature gap of phase transition was the main factor, which could shorten the thawing time. Moreover, a second order relationship was obtained between pressure and phase transition time.     

二等标准水银气压表的测量不确定度分析

文章根据二等标准水银气压表的结构原理，分析其各误差分量的构成，并进行测量结果的不确定度评估。     

云贵高原地区卷烟厂的空调设计

阐述了云贵高原地区的气象特点、大气压力变化对空调设计中有关空气参数的影响，同时分析了空气参数变化对空调设计及设备选型所带来的影响。     

大气压力变化与采空区瓦斯涌出实证研究及防治措施

大气压力的波动会引起矿井内空气压力的变化,进而对矿井瓦斯涌出、均压效果、主要通风机通风安全产生影响。针对这一现象,理论分析了矿井气压的变化对采空区瓦斯涌出的影响,并通过实证研究了平煤六矿丁5.6-21110机巷瓦斯涌出异常这一现象,最后提出了通风系统调整以及探孔抽放的综合防治措施,保证了丁5.6-21110机巷的正常生产。     

市场呼唤真空瓶替代包装

目前市场上通行的真空瓶是由一个圆柱体或椭圆体容器加一个安置在底部的活塞组成。它的设计原理是用金属弹簧的收缩力不让空气进入瓶中，造成真空状态，同时利用大气压力来推动瓶底的活塞前进。