脉冲激光轰击法连续制备纳米金掺杂YBCO

利用超声法获得钇钡铜氧（YBCO）和乙醇混合溶液,采用聚焦脉冲激光轰击浸于流动无水乙醇中的金靶,连续制备得到纳米金和乙醇混合溶胶.将纳米金和乙醇混合溶胶直接滴入接收器中的YBCO和乙醇混合溶液中,经干燥获得纳米金掺杂的YBCO材料.结果发现,纳米金未明显改变YBCO的吸放热现象,对样品的组成影响不大;掺杂0.01%、0.05%重量比例的纳米金后YBCO的结晶度和超导转变温度Tc均有所提高.     

高含沙水流水轮机转轮的改型与抗磨蚀研究

进行高含沙水流水轮机转轮的改型研究，关键是要从正确确定转轮设计参数和轴面流道型式入手，根据三维水力设计理论，考虑导叶与转轮匹配关系进行叶型设计，针对不同破坏机理选择强磨蚀区采用金属喷涂或非金属保护等综合措施，使水轮机在高舍沙水流中运行时出力增加、抗磨蚀能力提高。     

Haemolymph metabolic variables in relation to eyestalk ablation and gonad development of Pacific white shrimp Litopenaeus vannamei Boone

The present study analyses some biochemical variables in haemolymph proposed as predictive indicators of the maturation capability following eyestalk ablation. Haemolymph of captive females was obtained before and 8 days after eyestalk ablation, and levels of haemocyanin, total proteins, glucose, lactate, cholesterol, triacylglycerides and vitellogenin were determined. Biochemical variables were also analysed in the hepatopancreas at the end of the experiment. Females were grouped as immature (previtellogenic stage) and mature (vitellogenic and cortical stages) based on histological analysis done 8 days after eyestalk ablation. To analyse haemolymph variables before eyestalk ablation in relation to maturation capability, immature females were classified as those with a low maturation capability and mature females as those with a high maturation capability. Females of high maturation capability had significantly higher vitellogenin levels before eyestalk ablation than females of low maturation capability. No significant differences were found for the other biochemical variables. Vitellogenin was also higher in mature than in immature females at the end of the experiment. These results indicate that vitellogenin levels in haemolymph could be used as possible predictive criteria of maturation capability, possibly because they reflect the degree of ovarian development at the time of eyestalk ablation.     

Crack formation due to weathering of radial and tangential sections of pine and spruce

Abstract

The development of cracks and changes in appearance have been investigated on radial and tangential sections of pine (Pinus sylvestris L.) and spruce (Picea abies Karst.) after exposure outdoors for 61 months. The degradation of the sections has also been studied at the micro-level. The annual ring orientation was the most important factor affecting crack development on weathering. After 61 months of outdoor exposure, the tangential sections of spruce had 1.7–2.2 times greater mean total crack length per area unit than the corresponding radial sections. In pine, the total crack length per area unit on the tangential sections was 2.2–2.6 times greater than that on the radial sections. Tangential and radial sections show the same colour change as a result of weathering. Tangential sections have more and deeper cracks than radial surfaces. The cracks on the tangential sections occur frequently in both earlywood and latewood. On radial sections, cracks occur primarily at the annual ring borders, but to a certain extent also in the earlywood. Decomposition of the cell wall takes place in both radial and tangential cell walls, and cracks tend to follow the fibril orientation in the S2-layer of the cell wall. The radial cell wall of the earlywood has a large number of pits which are degraded at an early stage.     

Evidence of diadromy in the French Polynesian Kuhlia malo (Teleostei: Percoidei) inferred from otolith microchemistry analysis

Abstract – Strontium/Calcium (Sr/Ca) and Barium/Calcium (Ba/Ca) ratios were measured in 60 otoliths of the French Polynesian flagtail Kuhlia malo. Both elemental ratios were needed to correctly distinguish residence in marine, brackish and fresh water. High Sr/Ca and low Ba/Ca around the nucleus of all otoliths provided evidence of marine residency during the early life of all individuals. At about 0.5 mm from the core, Ba/Ca increased rapidly and remained high in all otoliths. High and unstable Sr/Ca ratios were attributed to estuarine residency, whereas low and stable Sr/Ca ratios were attributed to freshwater residency. These chemical signatures inferred that following recruitment to rivers, some fish remained in the estuary, while others moved upstream. Some individuals shared their time between fresh and brackish waters later in life. The findings of this study have important implications for the protection of nearshore, brackish and freshwater environments for the conservation of this French Polynesian diadromous species.     

When, why, and how to perform cardiac radiofrequency catheter ablation

Radiofrequency catheter ablative techniques provide a unique opportunity to cure dogs of certain supraventricular tachyarrhythmias, rather than simply controlling the rhythm with drug therapy. Accessory pathways, which can participate as one limb of a rapid, narrow complex tachyarrhythmia circuit, have a particularly high cure rate with radiofrequency catheter ablation. Focal atrial tachycardias also provide a substrate that can be amenable to ablation. Tachycardia-induced myocardial dysfunction resulting from frequent tachyarrhythmic episodes will resolve after a successful ablation. This report outlines the indications, equipment, and techniques used in dogs for performing catheter ablation with temperature-controlled radiofrequency energy delivery.     

Crack formation due to weathering of radial and tangential sections of pine and spruce

The development of cracks and changes in appearance have been investigated on radial and tangential sections of pine (Pinus sylvestris L.) and spruce (Picea abies Karst.) after exposure outdoors for 61 months. The degradation of the sections has also been studied at the micro-level. The annual ring orientation was the most important factor affecting crack development on weathering. After 61 months of outdoor exposure, the tangential sections of spruce had 1.7-2.2 times greater mean total crack length per area unit than the corresponding radial sections. In pine, the total crack length per area unit on the tangential sections was 2.2-2.6 times greater than that on the radial sections. Tangential and radial sections show the same colour change as a result of weathering. Tangential sections have more and deeper cracks than radial surfaces. The cracks on the tangential sections occur frequently in both earlywood and latewood. On radial sections, cracks occur primarily at the annual ring borders, but to a certain extent also in the earlywood. Decomposition of the cell wall takes place in both radial and tangential cell walls, and cracks tend to follow the fibril orientation in the S2-layer of the cell wall. The radial cell wall of the earlywood has a large number of pits which are degraded at an early stage.     

木材激光烧蚀设备总体结构设计

飞秒-纳秒量级脉冲激光烧蚀材料表面技术广泛应用于机械微加工、外科手术、生物分子质谱以及艺术品修复和清洁等领域。基于该技术,从激光烧蚀设备的结构、传动类型、部件选型、技术措施等方面对设备样机进行设计。     

Effects of Various Degrees of Antennal Ablation on Mating and Oviposition Preferences of the Diamondback Moth,Plutella xylostella L.

Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth （DBM;Plutella xylostella）. The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host signiifcantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed signiifcantly when less than 1/4 of both antennae were removed. However, there was a signiifcant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.