Growth and surface engineering of vertically-aligned low-wall-number carbon nanotubes

A novel catalyst of cobalt supported by single crystal MgO was prepared by atomic layer deposition and used for carbon nanotube growth. With CO as carbon source, vertically-aligned carbon nanotubes with predominant double-walled (82%) were produced at 700 °C. Similar carbon nanotube array with a majority of single-walled tubes (62%) was produced at 900 °C using methane as the carbon source. Due to their high flexibility compared with multi-walled carbon nanotubes, the low-wall-number carbon nanotube array could form a 3-dimensional honeycomb-like network when being spread with acetone.     

Developmental Dynamics of Math Performance From Preschool to Grade 2.

This study investigated the developmental dynamics of mathematical performance during children's transition from preschool to Grade 2 and the cognitive antecedents of this development. 194 Finnish children were examined 6 times according to their math performance, twice during each year across a 3-year period. Cognitive antecedents, that is, counting ability, visual attention, metacognitive knowledge, and listening comprehension, were tested at the first measurement point. The results indicated that math performance showed high stability and increasing variance over time. Moreover, the growth of math competence was faster among those who entered preschool with an already high level of mathematical skills. The initial level of math performance, as well as its growth, was best predicted by counting ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Survival of Escherichia coli O157:H7 in dry sausage fermented by probiotic lactic acid bacteria

Probiotic Lactobacillus rhamnosus GG, L rhamnosus E‐97800, L rhamnosus LC‐705 and commercial Pediococcus pentosaceus were studied for their ability to inhibit the growth of Escherichia coli O157:H7 in dry sausage. The strains were able to produce technologically high‐quality dry sausage. The number of E coli O157:H7 decreased from approximately 5 to approximately 2 log cfu g⁻¹ It was concluded that the above‐mentioned strains and the commercial culture were equally effective in inhibiting E coli O157:H7. © 2000 Society of Chemical Industry     

Possibilities to raise vitamin D content of rainbow trout (Oncorhynchus mykiss) by elevated feed cholecalciferol contents

Farmed rainbow trout (Oncorhynchus mykiss) is a widely consumed fish species. The cholecalciferol content in the muscle of rainbow trout is, however, quite low compared with that in several wild fish species. The present study was designed to determine whether it is possible to increase the cholecalciferol content of rainbow trout (initial weight about 500 g) with the use of cholecalciferol‐dosed feeds. Three different cholecalciferol concentrations (8.9, 17.4 and 53.9 μg 100 g ⁻¹ feed) were tested. After 4 months of feeding, the cholecalciferol determinations from samples of muscle and liver were performed using an HPLC method. Here, we suggest that the cholecalciferol content of rainbow trout muscle cannot be increased by feeding them with elevated doses of the vitamin. © 1999 Society of Chemical Industry     

Automated visual inspection of rolled metal surfaces

A prototype for an automated visual on-line metal strip inspection system is described. The system is capable of both detecting and classifying surface defects in copper alloy strips, and it has been installed for evaluation in a production line in a rolling mill. The image acquisition part of the system is based on a CCD line scan camera and condensing bright field illuminators. The inspection algorithms are based on morphological preprocessing and combined statistical and structural defect recognition. The image processing hardware consists of commercial modules. An analysis of this implementation is presented. A similar inspection principle has also been successfully applied to steel strip inspection.     

Receiver-Controlled Multi-Node Cooperation

Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping, multi-node cooperation plays an important role in ensuring the quality of service （QoS）. Based on the authors＇ previous work, this paper proposes a receiver-controlled multi-node cooperation routing protocol, known as AODV-RCC. In this protocol, nodes form a cooperation group based on signal power. In a cooperation group, signal power between a partner and a transmitter, as well as signal power between the partner and the receiver, must be larger than the signal power between the transmitter and the receiver. Otherwise, the transmission will not benefit from cooperation. To avoid collision or congestion, each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter＇ s MAC layer, because it is better for the partner to retransmit firstly, as it offers a more reliable cooperative link. In AODV-RCC, it is the receiver that chooses the partner, because the link between the partner and the receiver is the most important. According to our simulation results, AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.     

High Temperature‐Stable Perovskite Solar Cell Based on Low‐Cost Carbon Nanotube Hole Contact

Mixed ion perovskite solar cells (PSC) are manufactured with a metal‐free hole contact based on press‐transferred single‐walled carbon nanotube (SWCNT) film infiltrated with 2,2,7,‐7‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,90‐spirobifluorene (Spiro‐OMeTAD). By means of maximum power point tracking, their stabilities are compared with those of standard PSCs employing spin‐coated Spiro‐OMeTAD and a thermally evaporated Au back contact, under full 1 sun illumination, at 60 °C, and in a N₂ atmosphere. During the 140 h experiment, the solar cells with the Au electrode experience a dramatic, irreversible efficiency loss, rendering them effectively nonoperational, whereas the SWCNT‐contacted devices show only a small linear efficiency loss with an extrapolated lifetime of 580 h.     

Selective chemical functionalization of carbon nanobuds

Carbon nanobuds (CNBs) are a novel nanoscale carbon hybrid material consisting of fullerene-like structures covalently bonded to the outer surface of single-walled carbon nanotubes (CNTs). The successful covalent modification of CNBs by double carboxylic group in Bingel reaction was demonstrated. It was found that CNBs have higher chemical reactivity compared to CNTs in the reactions of cyclopropanation. Chemical structures of the modified CNBs and CNTs were confirmed by FTIR spectroscopy, TEM and EDX-spectroscopy. Using light sensitive molecule – 5,10,15,20-tetra(4-pyridyl)porphyrin, it was shown that the resistance of modified CNB network can be reversibly switched by low power UV illumination with the detection speed less than 0.3 s.