A novel method to prepare mineralized fibroin fiber

In this paper, a novel method was developed to prepare mineralized fibroin fiber. We used fibroin gel to control the biomineralization of calcium phosphate and obtained one kind of mineralized fibroin fiber with the length of 1–2 mm. It has the potential to be used to enhance the strength of tissue engineering scaffold. Scanning electron microscopy (SEM) results showed that hydroxyapatite (HA) was mainly deposited on the surface of mineralized fiber. Fourier transform infrared spectroscopy (FTIR) results displayed the red shifts of absorption bands of amide II and amide III (9 and 5 cm⁻¹, respectively), which were related to the strong chemical interaction between HA and fibroin. It was also found that HA was at low content (12.5%) and the ability of gelled fibroin to induce mineralization decreased greatly because of the formation of β-structures in gelled fibroin molecules, which showed the importance of molecular structure in the regulation of the biomineralization process.     

结晶器保护渣性能和使用工艺

对结晶器保护渣的性能作了描述；对结晶器保护渣的性能与工艺条件、钢种的优化匹配进行了探讨。     

板坯连铸结晶器非正弦振动技术的应用

介绍了武汉钢铁（集团）公司第三炼钢厂结晶器液压正弦/非正弦振动技术，对非正弦振动与正弦振动的特点进行了比较。研究VAI提供给我厂的振动参数之间的关系，对振动参数进行了优化调整，降低负滑脱时间，明显减少板坯振痕深度和改善了表面质量，同时增加了正滑脱时间，降低了粘连漏钢的风险，提高了操作安全性。     

Use of Recombinant Bioluminescent Bacteria for On-Site Monitoring of Toluene Analogs at Petroleum Contaminated Sites

This paper describes the application of a genetically engineered microorganism, Pseudomonas putida mt-2 KG1206, to monitor toluene analogs in groundwater collected from petroleum hydrocarbon contaminated sites. KG1206 contains the intact TOL plasmid and a second plasmid with the Pm-lux gene allowing it to produce bioluminescence in the presence of toluene analogs and their derivatives such as toluene, xylenes, and m-toluate. The simple bioluminescence assay consisted of mixing one volume of groundwater sample with four volumes of broth culture followed by bioluminescence measurement after 30?min. The maximum bioluminescent response with pure chemicals followed the order: m-methyl benzyl alchohol>m-toluate>toluene>m-xylene>benzoate>p-xylene>o-xylene. The bioluminescence production was well correlated to the m-toluate concentrations (R2>0.97) in field samples, with concentrations predicted from the bioassay falling within 75–158% of true concentration. However, no strong correlation was observed between the bioluminescence intensity and the total inducer concentration in the groundwater. Results from this study demonstrate the potential of using recombinant bioluminescent bacteria as a rapid and simple tool for monitoring specific pollutants at contaminated sites.     

双支腿循环流化床锅炉冷渣器问题分析

介绍了新型300 MW循环流化床锅炉通用的风水联合冷渣器的结构、特点及应用方式,并对其应用中的一些问题提出了自己的见解。     

基于组分磁性差异制备ZrO2/Ni功能梯度材料研究

根据不同组分的磁性差异，提出一种在梯度磁场中，采用粉浆浇注法制备铁磁性／非磁性功能梯度材料的方法，并用此方法制备出成分连续变化的ZrO2／Ni功能梯度材料．采用能谱分析仪、光学显微镜和X射线衍射仪对ZrO2／Ni功能梯度材料的成分分布、微观结构和相组成进行了研究．结果表明，在0．5T／m的磁场梯度作用下，浆料中Ni和ZrO2颗粒由于所受磁场作用不同而发生重新排列，形成沿样品厚度方向成分的梯度分布．此外，建立了功能梯度材料成分与颗粒粒度、饱和磁化强度以及磁场梯度之间的定量关系．     

Self-assembled ultrafine hierarchical ZnS treelike nanoarchitectures

Ultrafine hierarchical tree-shaped nanoarchitectures of ZnS were synthesized by a H₂-assisted thermal evaporation and condensation technique. Morphology and composition of the ZnS deposit were studied by means of field emission scanning electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. The deposit was found to consist of a layer of oriented submicrorods partly covered by microsheets and randomly oriented submicrowires, and three-dimensional treelike nanoarchitectures grew epitaxially on various submicrorods, microsheets, and submicrowires. The growth of the nanostructures is a spontaneous and self-assembled process. Vapor-solid (VS) growth mechanism is proposed for the formation of the treelike nanostructures because catalyst was not introduced during the synthesis process. This novel hierarchical ZnS nanoarchitecture may offer great potential for applications, including three-dimensional nanoelectronics and high efficient spatial resolved photon detector.     

Microstructure and electrical properties of ZnO-based varistors prepared by high-energy ball milling

ZnO-based varistor ceramics were prepared at sintering temperatures ranging from 900 °C to 1,300 °C, by subjecting the mixed oxide powders to high-energy ball milling (HEBM) for 0, 5, 10 and 20 h, respectively. Varistor ceramics prepared by HEBM featured denser body, better electrical properties sintered at low-temperature than at traditional high-temperature. The high density is due to the refinement of the crystalline grains, the enhanced stored energy in the powders coming from lattice distortion and defects as well as the promotion of liquid-phase sintering. Good electrical properties is attributed to proper microstructure formed at low-temperature and improved grain boundary characteristics resulting from HEBM. With increasing sintering temperatures, the electrical properties and density became worse due to the decrease in amount of Bi-rich phase. Temperature increased up to 1,200 °C or above, the Bi-rich phase vanished and the ceramics exhibited very low nonlinear coefficient.     

Effect of glycerol cross-linking and hard segment content on the shape memory property of polyurethane block copolymer

Effect of glycerol cross-linking and hard segment content on the shape memory property of polyurethane block copolymer is comprehensively investigated. Phase separation of hard and soft segment is dependent on glycerol cross-linking and hard segment content as judged from FT-IR and DSC data. Hydrogen bonding and dipole–dipole interaction between hard segments provides strong interaction between copolymer chains in addition to chemical cross-linking by glycerol. As the hard segment content increases, the copolymer shows better tensile mechanical properties and higher melting temperature of soft segment (T _m). Effect of glycerol cross-linking on mechanical properties and T _m of soft segment is low compared to hard segment effect. Although XRD peak at 2θ = 19.5° is observed, clear difference between the copolymers with various hard segment and cross-linking content is not observed. Significant increase in shape recovery rate in the case of 30 wt% hard segment copolymer is observed after glycerol cross-linking. The drastic change of the properties of polyurethane block copolymer is discussed in the point of copolymer chain interaction.     

TCP Performance in IEEE 802.11-Based Ad Hoc Networks with Multiple Wireless Lossy Links

We propose a packet-level model to investigate the impact of channel error on the transmission control protocol (TCP) performance over IEEE-802.11-based multihop wireless networks. A Markov renewal approach is used to analyze the behavior of TCP Reno and TCP Impatient NewReno. Compared to previous work, our main contributions are listed as follows: 1) modeling multiple lossy links, 2) investigating the interactions among TCP, Internet Protocol (IP), and media access control (MAC) protocol layers, specifically the impact of 802.11 MAC protocol and dynamic source routing (DSR) protocol on TCP throughput performance, 3) considering the spatial reuse property of the wireless channel, the model takes into account the different proportions between the interference range and transmission range, and 4) adopting more accurate and realistic analysis to the fast recovery process and showing the dependency of throughput and the risk of experiencing successive fast retransmits and timeouts on the packet error probability. The analytical results are validated against simulation results by using GloMoSim. The results show that the impact of the channel error is reduced significantly due to the packet retransmissions on a per-hop basis and a small bandwidth delay product of ad hoc networks. The TCP throughput always deteriorates less than ~ 10 percent, with a packet error rate ranging from 0 to 0.1. Our model also provides a theoretical basis for designing an optimum long retry limit for IEEE 802.11 in ad hoc networks.