Separation of Recombinant Geranylgeranyl Diphosphate Synthase of Deinococcus radiodurans from Expressed Strain Cell Homogenate by Immobilized Metal Affinity Chromatography on a Characterized Monolithic Cryogel Column

Geranylgeranyl diphosphate synthase (GGPPS) plays a key role in the biosynthesis of antioxidative carotenoid from the extremely radioresistant bacterium Deinococcus radiodurans. In this work, the recombinant GGPPS expressed in Escherichia coli by cloning and transforming the gene dr1395 of D. radiodurans was isolated rapidly by an immobilized metal affinity supermacroporous cryogel, i.e., Cu²⁺-iminodiacetic acid (IDA)-cryogel. The properties of the Cu²⁺-IDA-cryogel were characterized using capillary-based mathematical model and experimental measurements. The obtained protein samples were analyzed by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The porosity of the present Cu²⁺-IDA-cryogel is 90.4% and the water permeability is 5.04×10^-12 m². From the capillary-based model, this cryogel presents a slightly wide normal pore (capillary) size distribution with the mean diameter of 55.2 μm, the standard deviation of 28.0 μm and the half of skeleton wall thickness of 2.8 μm. The pore size distribute from about 10 to 141 μm and the effective tortuosity of these capillary pores increases from 2.60 to 9.05. The isolation of the GGPPS from cell homogenate can be achieved at the flow velocity of 3.40×10^-4 m·s^-1 by the Cu²⁺-IDA-cryogel bed. High-purity GGPPS (about 91.4%) is obtained according to the SDS-PAGE analysis of the elution samples, indicating that the present method is a promising, simple and effective approach to isolate GGPPS from cell homogenate of engineering strains.     

网间多点互联

伴随着互联网运营的市场化过程,必然会涌现出越来越多的电信公司运营互联网业务,在一定的范围内,归属不同运营商的骨干网之间互联互通的要求大量涌现.为了降低互联互通成本,许多骨干网之间采用了多点互联的方式,即在多个节点实现网络间的物理互联,保证业务的互通.在骨干网多点互联的情况下,网间流量的控制成为一个比较复杂的问题,但其根本目的仍然是为了保证数据流向的合理性和互联的可靠性.本文将对多点互联的流量控制方式和BGP路由协议在不同的控制方式中的应用进行详细的讨论.     

利用VB实现网络多点通信

利用Microsoft公司的开发软件VB提供的”Winsock”的Activex控件，实现了“套接字”编程，介绍了通信控件及其在Windows平台下的通信软件设计方法，并结合具体实例给出了基本的通信程序。     

叠合断陷盆地"源热双控"生烃特征研究:以丽水-椒江凹陷为例

为揭示东海丽水-椒江凹陷的油气富集规律,综合地震、钻测井及盆模等方法,综合研究了凹陷的成盆及油气生成演化史.结果表明:凹陷经历了断陷-拗陷-区域沉降3个演化阶段,具典型叠合断陷盆地特征.月桂峰组湖相暗色泥岩为凹陷主力烃源岩,各次凹中央洼陷带为凹陷高温中心;凹陷生烃演化受"源热双控"影响.     

Effect of post annealing on phase transformation of Ni-Mn-Ga ferromagnetic shape memory alloy particles prepared by ball milling

The effect of post annealing on the phase transformation of Ni52Mn24Ga24 ferromagnetic shape memory alloy particles prepared by ball milling was studied. Ni52Mn24Ga24 alloy particles at micron scale were prepared successfully by ball milling the crushed bulk alloy. SEM observation reveals that the shape of the as-milled particle is regular polygon and a lot of cracks can be seen at the surface of the particles. For as-milled particles, the widening of characteristic peak can be found in the XRD pattern, and no transformation characterization can be detected by DSC. Post annealing at the elevated temperature will recover the transformation behavior of milled particles to the same level as that of bulk sample. It is shown that with increasing annealing temperature above 400 ℃, Ms decreases and As increases, while the magnetic transition temperature keeps constant. XRD results indicate that the change of grain size of the particles results in such an effect of post annealing.     

浅谈如何做好特大火灾事故调查

针对特大火灾事故调查工作的特殊性，从特大火灾事故调查的具体工作出发，对特大火灾事故调查工作中存在的问题进行了简要分析，提出了一些解决方法和改进措施。     

毫米波宽带波导功率合成器设计

毫米波宽带功率放大器是毫米波电子对抗系统的关键部件之一,宽带低损耗的波导合成器是实现毫米波宽带大功率合成放大器的关键。根据设计目标,分析比较了四端口波导合路器和无耗三端口波导合路器的优缺点,提出了毫米波宽带波导合成器的设计方案,用电磁场仿真软件HFSS对宽带波导功率合成器进行了建模和设计仿真,并制作了工作频率范围在26~40 GHz的功率合成器,对测试指标和仿真曲线进行了对比分析。实际测试结果表明,设计的波导合路器具有良好的工程实用价值。     

K频段八路功率合成器设计

功率放大器是电子对抗系统的关键部件之一,宽带低损耗的波导合成器是实现大功率合成放大器的关键。根据设计目标,分析比较了带隔离端口的功率合成器和无耗功率合成器,提出了八路功率合成器的设计方案,用高频结构仿真软件（CST）对该功率合成器进行了建模和设计仿真,并给出了工作频率范围在17GHz～24GHz的设计实例,并对测试指标和仿真曲线进行了对比分析。结果表明设计的K频段八路功率合成器具有良好的工程实用价值。     

能源互联网环境下用户侧微电网的形态及优化运行

随着能源互联网的发展,各类新技术将最先接入用户侧微电网,改变传统的发电、用电以及运营模式。用户侧微电网融合多种分布式能源、储能设备以及可控负荷,为能源互联网环境下更加灵活、高效的能源转换和利用提供支撑。对能源互联网环境下用户侧微电网的形态、关键技术和运营模式进行了展望,并研究了微电网内部和微电网间的协调运行方式。基于分布式电源功率预测与用户负荷预测技术,提出了用户侧微电网优化运行方法。运用分布式模型预测控制技术在线更新预测信息和微电网运行状态,优化上下层运行策略从而收敛于最优平衡状态,为用户侧微电网的调度和运行提供了参考。