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1.
为满足水果追溯条码清晰、耐久的要求,选取橘子为试验对象,对比纳秒激光和皮秒激光在其表面打印二维码的效果。试验结果表明:与纳秒激光相比,皮秒激光在橘子表皮上打印的线条平直度佳,轮廓清晰,对表皮的损伤更小。 相似文献
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通过诱变筛选纤溶酶活性高的枯草芽孢杆菌菌株,得到突变株HDBF-N7HN5。使用氦氖激光诱变,设置不同的诱变时间,通过不同的蛋白平板处理,筛选高产突变株并检测纤溶酶活力。实验结果表明,在氦氖激光诱变处理45 min后,最高产突变株纤溶酶活力达到429.89±5.74 IU/mL。突变株经过10次传代培养后,保持稳定的高产纤溶酶特性。纤溶酶粗酶液处理血凝块的绝对溶解率可达到57.74±0.72%,10倍稀释液处理血凝块的绝对溶解率也能达到26.89±0.68%,菌株产生的纤溶酶具有良好的体外溶栓效果。本研究结果既提高了微生物纤溶酶活性,也为该菌株产纤溶酶的产业化提供了依据。 相似文献
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The aim of the study was to assess the influence of high-intensity laser therapy (HILT) on vein diameter and on body surface temperature changes in the tarsal joint area in a group of clinically healthy racehorses. The hypothesis of the study was that HILT increases vein diameter and body surface temperature in healthy tissue. The study involved 16 Thoroughbreds being subjected to ultrasonographic examination to assess changes of diameter of the cranial branch of the medial saphenous vein and thermographic examination to indicate temperature change of the dorsal surface of the tarsal joint, just before and immediately after HILT treatment. Vein diameter and mean surface temperature of the tarsal joint significantly increased after HILT treatment. In addition, the study was the first to describe the photothermal effect of HILT in healthy horses. More studies are necessary to specify the parameters of the procedure, that is, wavelength, energy density, or time of the procedure, depending on the patient’s individual characteristics and type of tissue. 相似文献
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Lennart Noordermeer Terje Gobakken Erik Næsset Ole Martin Bollandsås 《Scandinavian Journal of Forest Research》2021,36(1):55-67
ABSTRACT Forest productivity is a crucial variable in forest planning, usually expressed as site index (SI). In Nordic commercial forest inventories, SI is commonly estimated by a combination of aerial image interpretation, field assessment and information obtained from previous inventories. Airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) data can alternatively be used for SI estimation, however the economic utilities of the inventory methods have not been compared. We compared seven methods of SI estimation in a cost-plus-loss analysis, by which we added the expected economic losses due to sub-optimal treatment decisions to the inventory costs. The methods comprised direct and indirect estimation from combinations of ALS, DAP and stand register data, and manual interpretation from aerial imagery supported by field assessment and information from previous inventories (conventional practices). The choice of method had great impact on both the accuracy and the economic value of the produced estimates. Direct methods using bitemporal ALS and DAP data gave the best accuracy and the smallest total cost. DAP was a suitable and low-cost data source for SI estimation. Estimation from single-date ALS and DAP data and age obtained from the stand register provided practical alternatives when applied to even-aged stands. 相似文献
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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. 相似文献
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Application of an airborne laser scanner to forest road design with accurate earthwork volumes 总被引:1,自引:0,他引:1
In this study we developed a forest road design program based on a high-resolution digital elevation model (DEM) from a light detection and ranging (LIDAR) system. After a designer has located the intersection points on a horizontal plane, the model first generates the horizontal alignment and the ground profile. The model precisely generates cross-sections and accurately calculates earthwork volumes using a high-resolution DEM. The model then optimizes the vertical alignment based on construction and maintenance costs using a heuristic technique known as tabu search. As the distance between cross-sections affects the accuracy of earthwork volume calculations, the results were examined by comparing them with the exact earthwork volume calculated by the probabilistic Monte Carlo simulation method. The earthwork volumes calculated by the Pappus-based method were similar to those calculated by the Monte Carlo simulation when the distance between cross-sections was within 10m. The model was applied to a high-resolution DEM from the LIDAR of Capitol Forest in Washington State, USA. The model generated a horizontal alignment, length 827m, composed of five horizontal curves. We examined the number of grade change points. The results indicated that tabu search found the best solution ($61.42/m) with five grade change points. This was composed of two vertical curves that almost followed the ground profile. As the accuracy of a high-resolution DEM from LIDAR increases, the model would become a useful tool for a forest road designer because it eliminates or at least reduces the time-consuming process of road surveys. 相似文献