自密实混凝土工作性能检测方法探究

对自密实混凝土拌合物工作性能的各种方法的优缺点进行了分析,对其应用技术等方面的最新动态进行了论述,提出了适用于我国实际工程所用的自密实混凝土工作性能测试方法。     

废水组分对光芬顿催化降解乙基黄药的影响

以机械活化膨润土基铁铋氧体(A-BiFe/Bent)为非均相催化剂,考察了乙基黄药(EX)废水中的组分对光芬顿催化降解EX的影响。结果表明,K⁺、Mg²⁺、Ca²⁺等阳离子可导致EX降解率降低;一定浓度范围的Cu²⁺、Pb²⁺能够促进光芬顿降解EX反应,但浓度过高的Cu²⁺与Pb²⁺会清除·OH从而使EX降解率略微下降。Cl^-、S^2-、SO₄^2-、CO₃^2-、HCO₃^-和NO₃^-等阴离子均使EX降解率降低,其中S^2-对EX降解的抑制作用最显著;松醇油对EX的降解反应无明显影响。     

国产Zn-5%Al-混合稀土合金镀层高钒封闭索丝耐久性研究

以国家速滑馆首次应用的国产Zn-5%Al-混合稀土合金镀层高钒封闭索丝为研究对象,对其使用性能、基本特性及耐久性等进行研究。采用了国家速滑馆内部高空索体实际服役环境处的大气暴露试验方式,综合考虑索在加工安装过程中易产生的损伤,对索丝试件进行了划痕、刮擦、焊点的预制缺陷设计,研究了含预制缺陷的国产Zn-5%Al-稀土合金镀层高钒封闭索丝在真实使用环境中的大气腐蚀行为规律,并采用力学性能测试研究了索丝在服役环境大气腐蚀作用下的力学性能变化规律及不同缺陷对力学性能的影响。结果表明,加工安装过程中在索丝表面合金镀层产生的划痕、刮擦、焊点等损伤,会破坏合金镀层的完整性。大气暴露试验和力学性能试验中,三类缺陷对索丝金属镀层防大气腐蚀性能和单丝抗拉强度均有负面影响,其中焊点缺陷影响最大,单丝抗拉强度下降约40%。     

Micro packaged MEMS pressure sensor for intracranial pressure measurement

This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm². It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm². In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm². Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10^-2 mV/kPa.