Imparting Designer Biorecognition Functionality to Metal–Organic Frameworks by a DNA‐Mediated Surface Engineering Strategy

Surface functionality is an essential component for processing and application of metal–organic frameworks (MOFs). A simple and cost‐effective strategy for DNA‐mediated surface engineering of zirconium‐based nanoscale MOFs (NMOFs) is presented, capable of endowing them with specific molecular recognition properties and thus expanding their potential for applications in nanotechnology and biotechnology. It is shown that efficient immobilization of functional DNA on NMOFs can be achieved via surface coordination chemistry. With this strategy, it is demonstrated that such porphyrin‐based NMOFs can be modified with a DNA aptamer for targeting specific cancer cells. Furthermore, the DNA–NMOFs can facilitate the delivery of therapeutic DNA (e.g., CpG) into cells for efficient recognition of endosomal Toll‐like receptor 9 and subsequent enhanced immunostimulatory activity in vitro and in vivo. No apparent toxicity is observed with systemic delivery of the DNA–NMOFs in vivo. Overall, these results suggest that the strategy allows for surface functionalization of MOFs with different functional DNAs, extending the use of these materials to diverse applications in biosensor, bioimaging, and nanomedicine.     

基于PCI总线的激光粒度测量系统

本文设计了基于PCI总线的激光粒度测量系统,采用专用接口芯片S5933与CPLD相结合的方式实现PCI总线接口的设计,用CPLD开发了PCI数据采集的ADD-ON逻辑,通过DMA方式实现粒度测量系统数据由ADD-ON总线向PCI总线的传输,充分利用了PCI总线的高性能、高可靠性等特点,为激光粒度测量数据的实时采集、显示、处理提供了可靠的保证。     

AJAX风格的Web开发

在过去几个月期间，结合了Asynchronous JavaScript和XML（AJAX）来开发高交互性Web应用程序的设计模式变得越来越流行。高配置的Web应用程序，如Google Maps和A9以及微软的Virtual Earth和Start．com，通常能够利用这些技术的组合来形成丰富的客户端用户体验。组成AJAX的单项技术并不是最新的开发工具——它们已经运用了一段时间，并且不断得到更新和改进。但是，它汇聚了最新的技术，从而导致各种引人注目的可能性。     

Thermodynamic Analysis of Ag_3Ge Phase Formation

In the present work a thermodynamic model is presented for the nucleation of metastable Ag3Ge phase from the undercooled melt in Ag-Ge alloy system. It is shown that under kinetically induced favourable condition, nucleation of a single phase compound with an approximate stoichiometry Ag3Ge has greater affinity for nucleation over Ag and Ge based phases requiring diffusion in the liquid.     

A model for two-step ageing

In commercial practice, two-step ageing is commonly used in Al-Zn-Mg alloys to produce a fine dispersion of η′ precipitates to accentuate the mechanical properties and resistance to stress corrosion cracking. While this is true in Al-Zn-Mg alloys, two-step ageing leads to inferior properties in Al-Mg-Si alloys. This controversial behaviour in different alloys can be explained by Pashley’s Kinetic model. Pashley’s model addresses the stability of clusters after two-step ageing. In the development of the model, the surface energy term between cluster and matrix is taken into account while the coherency strains between the cluster and matrix are not considered. In the present work, a model is developed which takes into account the coherency strains between cluster and matrix and defines a new stability criterion, inclusive of strain energy term. Experiments were done on AA 7010 aluminium alloy by carrying out a two-step ageing treatment and the results fit the new stability criterion. Thus it is found that the new model for two-step ageing is verified in the case of Al-Zn-Mg alloy.     

风速对过饱和总溶解气体释放速率的影响

通过不同风速下的过饱和总溶解气体(TDG)室内释放试验,研究风速对过饱和TDG释放过程的影响,并根据已有释放模型对释放系数进行估算,建立了过饱和TDG释放系数与风速的定量关系式。结果表明在8.5~9.5℃条件下,风速较小时,水体中过饱和TDG释放相当缓慢,随着风速的增大,过饱和TDG的释放速率显著增大;在无风工况下,TDG释放系数为0.005 42 h-1;当风速为1.08~11.33 m/s时,TDG释放系数为0.007 09~0.066 68 h-1;相对释放系数为1~12.303,拟合的相对释放系数与风速的定量关系式计算偏差在-11.76%~10.21%之间。     

Influence of incident beam divergence on the intensity of diffuse streaks

The influence of incident beam divergence on the length of the streak intercepted by the Ewald sphere is considered, as a relpHK·L of a faulted hexagonal crystal, mounted about itsc-axis on the goniometer head attached to the ø-circle, is brought into diffracting condition for the bisecting setting of a 4-circle diffractometer. For the special crystal mounting correction factors required to convert the measured intensities corresponding to a fixed length of the streak are derived. A procedure for experimentally verifying the mathematical approach employed in these derivations is also presented.     

铁矿石烧结箅条糊堵现象成因机制

箅条糊堵现象是铁矿石烧结生产面临的重要共性问题,给烧结经济技术指标及设备都带来不利影响.为弄清并解决这一问题,首先对箅条糊堵物进行了分类和物相特征分析,随后从原燃料条件、工艺条件和箅条自身性能3个方面综合分析了烧结台车箅条糊堵的形成机制及影响因素,最后基于箅条糊堵物的物相特征及形成机制总结了预防及解决箅条糊堵问题的技术...     

西藏某低品位类质同象铍矿石的回收试验研究

采用焙烧－加温酸浸方法对西藏某低品位类质同象铍矿石进行回收,考察了焙烧温度、磨矿细度、焙烧时间、浸出时间和酸矿质量比对铍浸出率的影响。对于原矿铍品位为0.1268%,确定磨矿细度-0.074mm含量为80.00%,焙烧温度为800℃,焙烧时间为4h,酸矿质量比为0.8：1,加温温度为85℃,液固比为4：1,搅拌浸出时间为24h浸出工艺条件;最终获得铍浸出率为84.16%的良好指标。表明该低品位类质同象铍矿石采用焙烧－加温酸浸工艺是可以回收利用的。