An easy and eco-friendly method to fabricate three-dimensional Pd-M (Cu,Ni) nanonetwork structure decorated on the graphene nanosheet with boosted ethanol electrooxidation activity in alkaline medium

A new rapid and facile strategy for the preparation of Pd-Ni/G and Pd-Cu/G catalysts with a three-dimensional porous structure are presented in this paper. Both catalysts are formed using the same strategies in two steps: 1) The reduction of Ni(OH)₂ and Cu(OH)₂ to the metallic form on the surface of G/GC Electrode using the Zn/HCl reducer, 2) The galvanic displacement of Ni and Cu by Pd²⁺. Afterwards, three-dimensional Pd nanonetwork is generated on the glassy carbon electrode via the galvanic displacement. Compared to the other routes, this strategy depicts several advantages (e.g. fast way, facile, surfactant and reductant free, cheap, and eco-friendly.) Both catalysts are applied towards Ethanol Oxidation Reaction (EOR). Both porous structures show higher electrocatalytic activity and stability toward EOR compared to the commercial Pd/C. The extraordinary catalytic activity and durability of the both proposed catalysts for EOR can be related to the two vital reasons:1) The combination of Ni and Cu with Pd will efficiently promote the catalytic performance of Pd-Ni/G and Pd-Cu/G samples due to synergetic effects. 2) The porous structure of the as-prepared catalysts renders a high surface area and leads easier mass transport through the pores.     

某水库排沙孔检修闸门更换方案比选研究

结合某70 m高混凝土双曲薄拱坝排沙孔进口检修闸门更换的方案比选,详细对比了放空水库方案与水下更换方案的优缺点。对比发现,两方案均不可行。放空水库方案主要是因为非技术方面的原因无法采用,水下浮体门封堵方案则存在一系列风险和限制条件,不适宜在本工程中采用。因此,下一步应加强水下修补技术的研究。     

Intracellular Delivery of Proteins with Cell-Penetrating Peptides for Therapeutic Uses in Human Disease

Protein therapy exhibits several advantages over small molecule drugs and is increasingly being developed for the treatment of disorders ranging from single enzyme deficiencies to cancer. Cell-penetrating peptides (CPPs), a group of small peptides capable of promoting transport of molecular cargo across the plasma membrane, have become important tools in promoting the cellular uptake of exogenously delivered proteins. Although the molecular mechanisms of uptake are not firmly established, CPPs have been empirically shown to promote uptake of various molecules, including large proteins over 100 kiloDaltons (kDa). Recombinant proteins that include a CPP tag to promote intracellular delivery show promise as therapeutic agents with encouraging success rates in both animal and human trials. This review highlights recent advances in protein-CPP therapy and discusses optimization strategies and potential detrimental effects.     

Analysis based on EU Regulation No 517/2014 of new HFC/HFO mixtures as alternatives of high GWP refrigerants in refrigeration and HVAC systems

The EU Regulation No 517/2014 is going to phase-out most of the refrigerants commonly used in refrigeration and air conditioning systems (R134a, R404A and R410A) because of their extended use and their high GWP values. There are very different options to replace them; however, no refrigerant has yet imposed. In this paper we review and analyze the different mixtures proposed by the AHRI as alternative refrigerants to those employed currently. These mixtures are composed by HFC refrigerants: R32, R125, R152a and R134a; and HFO refrigerants: R1234yf and R1234ze(E). It is concluded, from the theoretical analysis, that most of the new HFO/HFC mixtures perform under the HFC analyzed (although some experimental studies show the contrary) and, in most cases, do not meet the GWP restrictions approved by the European normative. Furthermore, some of the mixtures proposed would have problems due to their flammability.     

Least fresh first cache replacement policy for NDN-based IoT networks

In-network caching in Named Data Networking (NDN) based Internet of Things (IoT) plays a central role for efficient data dissemination. Data cached throughout the network may quickly become obsolete as they are transient and frequently updated by their producers. As such, NDN-based IoT networks impose stringent requirement in terms of data freshness. While various cache replacement policies were proposed, none has considered the cache freshness requirement. In this paper, we introduce a novel cache replacement policy called Least Fresh First (LFF) integrating the cache freshness requirement. LFF evicts invalid cached contents based on time series forecasting of sensors future events. Extensive simulations are performed to evaluate the performance of LFF and to compare it to the different well-known cache replacement policies in ICN-based IoT networks. The obtained results show that LFF significantly improves data freshness compared to other policies, while enhancing the server hit reduction ratio, the hop reduction ratio and the response latency.     

Application of the phase extension method in virus crystallography

The procedure for phase extension (PX) involves gradually extending the initial phases from low resolution (e.g. ～8?Å) to the high-resolution limit of a diffraction data set. Structural redundancy present in the viral capsids that display icosahedral symmetry results in a high degree of non-crystallographic symmetry (NCS), which in turn translates into higher phasing power and is critical for improving and extending phases to higher resolution. Greater completeness of the diffraction data and determination of a molecular replacement solution, which entails accurately identifying the virus particle orientation(s) and position(s), are important for the smooth progression of the PX procedure. In addition, proper definition of a molecular mask (envelope) around the NCS-asymmetric unit has been found to be important for the success of density modification procedures, such as density averaging and solvent flattening. Regardless of the degree of NCS, the PX method appears to work well in all space groups, provided an accurate molecular mask is used along with reasonable initial phases. However, in the cases with space group P1, in addition to requiring a molecular mask, starting the PX at a higher resolution (e.g. 6?Å) overcame the previously reported problems due to Babinet phases and phase flipping errors.     

大气影响带对膨胀土边坡稳定的影响及对策

以南水北调中线南阳某段膨胀土渠坡工程为依托,针对大气影响带深度对膨胀土边坡的影响及应对措施,采用GTS-NX岩土有限元数值计算软件建立有限元模型并进行边坡抗滑稳定分析。结果表明,当大气影响急剧层深度大于1.0 m后,边坡安全系数明显下降,当深度到达2.0 m,边坡接近极限平衡状态,水泥改性土换填厚度宜取2.0 m。     

A condition-based maintenance strategy for heterogeneous populations

This paper develops a maintenance strategy, called inspection–replacement policy, to cope with heterogeneous populations. Burn-in is the procedure by which most of the defective products in a heterogeneous population can be identified and removed prior to being placed in service. However, modern manufacturing is so well developed that a defective product is able to function for a long period of time even under aggravated operational conditions. Instead of weeding defective products out via costly burn-in tests, use can be made of them in field operation where maintaining actions will be performed to prevent early in-use failures. The inspection–replacement policy consists of an inspection, conducted in an early stage with the purpose of identifying and replacing defective products, and a preventive replacement, carried out at a later stage to prevent wear-out failures. The preventive-replacement time is dynamically determined, depending on the information obtained by the inspection. The inspection–replacement policy is compared with a joint burn-in and age-based-replacement policy to show its practicability and competence.     

柱混凝土失去承载力加固置换处理技术的应用

针对某综合楼工程B区负2层11/Q轴柱混凝土失去承载力,采用加固置换处理技术进行了处理,处理效果较好,满足使用功能要求。该文对该项处理技术措施、材料选择、施工工艺及方法等进行了详细介绍。