DNA修饰电极的研究——Ⅶ.共价键合和吸附DNA-SAM/Au修饰电极的制备及表征

采用先通过 2 ,2′ 二硫二乙醇自组装得到自组装单分子层 (SAM) ,再在SAM上共价键合和吸附固定dnA的方法制备了两类dnA修饰电极 ,并对得到的dnA修饰电极进行了电化学和谱学表征 .结果表明该方法是可行的 ,也是较为理想的在电极表面固定dnA的方法 .国家自然科学基金!(批准号:39370213;39770220;29773034);厦门大学固体表面物理化学国家重点实验室基金;湖北省自然科

Study on Flow Characteristics of Circulating Standpipe of Fast Fluidized Bed

在内径50mm，高4m的快速流化床循环料腿中，以空气为流化介质，氧化铝、氢氧化铝和FCC催化剂为实验物料，进行了料腿流动特性的测定。通过氢气阶跃示踪法，热导池检测，微机采样的实验方法，测定了料腿中净气流量随固体循环量和松动风量的变化规律，求取了三种物料的曳力系数修正函数。结果表明，细颗粒的聚集成团加剧，滑移速度增大，使曳力系数值比散式流态化结果要小，且在某一空隙率范围内，有可能小于单颗粒的曳力系数值。本文建立的立管一维轴向两相流数学模型，通过实验求取模型参数。计算了立管内流动状态随操作条件的变化规律。本文同时考察了孔口和V阀的流动特性

PVDF压电薄膜在应力波测量中的应用

综合介绍了PVDF压力传感器的测试原理、动态标定实验,并采用定制的PVDF压力传感器测量了不同类型分层介质在冲击载荷作用下的压力衰减,说明了PVDF压力传感器在压力测量中有着很好的前景

Protective effect of phycocyanin against oxidative damage induced by radiation

[Background] Phycocyanin (PC) is a pigment protein present in cyanobacteria, cryptophyta, etc. [Purpose] This study aims at the protective effect of phycocyanin on oxidative damage induced by irradiation by establishing injury mouse model by X-ray irradiation. [Methods] 72 C57 BL/6 male mice were randomly divided into normal control group, irradiation model group, PC pretreatment group and positive control group. The mice were continuously fed for 7 d. On the 8th day of intragastric administration, except for the normal control group, the rest of the mice were subjected to total body irradiation to a dose of 6 Gy for the preparation of radiation damage model. The plasma and tissues were collected at 1 d, 3 d and 7 d after irradiation, and the activities of antioxidant enzymes in plasma and liver were measured. The content of reactive oxygen species (ROS) in liver tissue was detected by dihydroethidium (DHE) staining. [Results] Phycocyanin increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in the plasma of mice after irradiation, and increased the activity of SOD (p<0.05), decreased malondialdehyde (MDA) content (p<0.05), and reduced liver tissue ROS content (p<0.05). [Conclusion] The results show that phycocyanin can improve the antioxidant capacity of mice, reduce oxidative damage to the body caused by irradiation, and provide a better protective effect on irradiation injury of mice

司法孢粉学在司法鉴定中的应用

司法孢粉学是法庭科学的一门分支学科,孢粉检验可为推断嫌疑人与犯罪现场的关联、案件发生时间、毒品来源等提供重要信息。在新西兰、英国、美国等国家,孢粉检验已在多起案件的侦破中发挥了重要作用,其他国家近年来也陆续开展了相关的应用研究。本文综述了近50年来司法孢粉学的典型案例,介绍了该学科的历史和现状,探讨了其未来的研究重点和发展方向,以期提高人们对该学科的全面认识,加强今后在司法鉴定中的应用

Effect of Stress Wave Propagation on Surface Stress Relaxation in 7050 Aluminum Panel Shocked by a Nanosecond Laser

Integral panel is an important structure to reduce aircraft weight. Nanosecond laser beams can be used for the forming and surface modification in panels. To explore the propagation of laser-induced stress waves and their influence on surface stress relaxation, a simulation model is used to capture the propagation process of stress waves. The results show that the stress wave first decays rapidly, and then the attenuation rate decreases gradually. In the initial propagation stage, the attenuation of the stress wave can be fitted by &sigma;x=Ee-kx; then, after propagating a certain distance, the stress wave amplitude is more suitable to &sigma;x= Ex-k. During the propagation processing, the stress wave is reflected on the shocked and back surface. A tensile stress wave is formed by the reflection of the incident compressive stress wave, and the value of the stress wave is improved. The stress wave has a great influence on the residual stress distribution in 1mm thin panels. When the stress wave is reflected on the back surface, a stress is induced into the surface. When the stress wave is reflected by the shocked surface, the stress on the surface is relaxed because the incident wave is a tensile wave. Therefore, when a nanosecond laser is used in thin panels, the shock wave has an important influence on the stress distribution, which needs to be considered in engineering applications.</p

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies