Light-induced conversion of an insulating refractory oxide into a persistent electronic conductor

Materials that are good electrical conductors are not in general optically transparent, yet a combination of high conductivity and transparency is desirable for many emerging opto-electronic applications. To this end, various transparent oxides composed of transition or post-transition metals (such as indium tin oxide) are rendered electrically conducting by ion doping. But such an approach does not work for the abundant transparent oxides of the main-group metals. Here we demonstrate a process by which the transparent insulating oxide 12CaO x 7Al(2)O(3) (refs 7-13) can be converted into an electrical conductor. H(-) ions are incorporated into the subnanometre-sized cages of the oxide by a thermal treatment in a hydrogen atmosphere; subsequent irradiation of the material with ultraviolet light results in a conductive state that persists after irradiation ceases. The photo-activated material exhibits moderate electrical conductivity (approximately 0.3 S cm(-1)) at room temperature, with visible light absorption losses of only one per cent for 200-nm-thick films. We suggest that this concept can be applied to other main-group metal oxides, for the direct optical writing of conducting wires in insulating transparent media and the formation of a high-density optical memory.     

High Speed Twin Roll Casting of Aluminum Alloy Strips

The twin roll caster for aluminum alloys has many a dv antages. For example, rapid solidification, low equipment cost, and low running cost, etc. However, the twin roll caster has some disadvantages. They are slow c asting speed and limitation of alloys. In the conventional twin roll caster, the casting speed is slower than 10 m/min. Aluminum alloys, which freezing range is wide, can not be cast. In the present study, break through of these problems wa s tried, and a new type twin roll caster was devised...     

173W的高自旋态和γ5/2~-[512]转动带的旋称反转

利用150Nd（28Si,5n）熔合蒸发反应居了173W的高旋态.于标准在束核谱学实验测量结果,扩展了于γ7/2＋[633],γ5/2-[512]和γ1/2-[521]准组态的转动带.首次建了173W γ1/2-[521]转动带的能量非优先分支.发现γ5/2-[512]转动带在低旋区出现旋称反转.相似的旋称劈行为表明174Reπ1/2-[541]γ5/2-[512]转动带的旋称反转来位于5/2-[512]轨道的中.旋称反转制有待进一研究.     

牛磺酸强化轮虫对眼斑拟石首鱼仔鱼的投喂效果

研究用3种不同质量浓度梯度(分别为T0组:0 mg/L;T4组:400 mg/L;T8组:800 mg/L)牛磺酸强化的轮虫(Brachionus plica tilis)对3~20日龄的眼斑拟石首鱼(Sciaenops ocella tus)仔鱼的投喂效果.结果表明,T8组的仔鱼平均全长((8.5±0.8)mm)和成活率(70.5%)都明显高于T0组(平均全长:(6.3±1.0)mm;成活率:28.4%)和T4组(平均全长:(7.0±0.8)mm;成活率:27.4%),T0组和T4组之间生长和成活率并无显著差异;T8组仔鱼的耐干露及耐高盐度(65)能力明显比T0组和T4组强,即仔鱼的抗应激能力受轮虫强化剂牛磺酸的质量浓度影响显著(P<0.05).     

Modified Multi-Resolution Telescopic Search Algorithm for Block-Matching Motion Estimation

SOFTWARE,ALGORITHM AND SIMULATION1. INTRODUCTIONRecently low cost and low-power video encoders are in demand, in which motion estimation is an importanttechnology. The block-matching motion estimation is widely used in various video encoders. The direct fullsearch block-matching algorithm (FSBMA) demands massive computational effort and is not suit for VLSIimplementation.The multi-resolution telescOPic search algorithm (MRTlcSA) [1] is considered as a good trade-off betw…     

Identification of UBIAD1 as a novel human menaquinone-4 biosynthetic enzyme

Vitamin?K occurs in the natural world in several forms, including a plant form, phylloquinone (PK), and a bacterial form, menaquinones (MKs). In many species, including humans, PK is a minor constituent of hepatic vitamin?K content, with most hepatic vitamin?K content comprising long-chain MKs. Menaquinone-4 (MK-4) is ubiquitously present in extrahepatic tissues, with particularly high concentrations in the brain, kidney and pancreas of humans and rats. It has consistently been shown that PK is endogenously converted to MK-4 (refs 4-8). This occurs either directly within certain tissues or by interconversion to menadione (K(3)), followed by prenylation to MK-4 (refs 9-12). No previous study has sought to identify the human enzyme responsible for MK-4 biosynthesis. Previously we provided evidence for the conversion of PK and K(3) into MK-4 in mouse cerebra. However, the molecular mechanisms for these conversion reactions are unclear. Here we identify a human MK-4 biosynthetic enzyme. We screened the human genome database for prenylation enzymes and found UbiA prenyltransferase containing 1 (UBIAD1), a human homologue of Escherichia coli prenyltransferase menA. We found that short interfering RNA against the UBIAD1 gene inhibited the conversion of deuterium-labelled vitamin?K derivatives into deuterium-labelled-MK-4 (MK-4-d(7)) in human cells. We confirmed that the UBIAD1 gene encodes an MK-4 biosynthetic enzyme through its expression and conversion of deuterium-labelled vitamin?K derivatives into MK-4-d(7) in insect cells infected with UBIAD1 baculovirus. Converted MK-4-d(7) was chemically identified by (2)H-NMR analysis. MK-4 biosynthesis by UBIAD1 was not affected by the vitamin?K antagonist warfarin. UBIAD1 was localized in endoplasmic reticulum and ubiquitously expressed in several tissues of mice. Our results show that UBIAD1 is a human MK-4 biosynthetic enzyme; this identification will permit more effective decisions to be made about vitamin?K intake and bone health.     

A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan

Increases in (14)C concentrations in tree rings could be attributed to cosmic-ray events, as have increases in (10)Be and nitrate in ice cores. The record of the past 3,000 years in the IntCal09 data set, which is a time series at 5-year intervals describing the (14)C content of trees over a period of approximately 10,000 years, shows three periods during which (14)C increased at a rate greater than 3‰ over 10 years. Two of these periods have been measured at high time resolution, but neither showed increases on a timescale of about 1 year (refs 11 and 12). Here we report (14)C measurements in annual rings of Japanese cedar trees from ad 750 to ad 820 (the remaining period), with 1- and 2-year resolution. We find a rapid increase of about 12‰ in the (14)C content from ad 774 to 775, which is about 20 times larger than the change attributed to ordinary solar modulation. When averaged over 10 years, the data are consistent with the decadal IntCal (14)C data from North American and European trees. We argue that neither a solar flare nor a local supernova is likely to have been responsible.