木材科学与工程专业中的课程“工程图学”教学实践体会

“工程图学”是东北林业大学木材科学与工程专业的一门重要的基础课,课程教学目的是使学生掌握平行正投影的基本理论、制图工具仪器的用法,了解掌握家具制图、机械制图标准及绘图的基本方法与步骤.培养学生初步图解空间几何问题能力,空间分析能力、构思能力和表达能力、绘制和阅读工程图样能力.为工程制图和计算机绘图打下坚实的理论基础.这里从制图基本知识与实际应用相结合、教学中采用的直观教学手段和改变学生在教学过程中学习位置等方面进行探讨和研究,归纳总结一些适合于制图教学的方法和手段,可为从事制图教学教师提供一定的参考.     

秸秆“富集深还”新模式及工程技术

针对长期浅耕造成的土壤亚表层缺乏有机质和过于紧实以及目前秸秆还田成本高或效果差的实际问题,提出了一种简单而有效的快速松土培肥的秸秆还田新模式及相应机具创新和田间工程技术。该技术模式是基于优先快速培肥土壤亚表层的新理念,在条带轮耕深松土壤的同时,将秸秆富集深埋于指定条带的土壤亚表层。将这种秸秆还田新模式称为秸秆富集深埋还田(简称"富集深还"),其主要工程技术是发明研制了秸秆深还筒式犁新机具,通过机械化手段将秸秆富集、粉碎、埋入土壤。具体步骤包括:(1)用指盘式搂草机将玉米秸秆按4∶1~8∶1富集归行;(2)用秸秆还田筒式犁一体机将秸秆粉碎、风力注入指定条带土壤20~40 cm;(3)用免耕播种机在非埋秸秆条带正常免耕播种,实现种还分离,即种植条带(窄行)与埋秸秆条带(宽行)分离。该模式具有秸秆翻压还田与覆盖还田的优点,而克服二者各自的缺点,是秸秆还田与条带少免耕的完美结合,能够实现玉米秸秆连年、机械化全量还田,且不打乱土层顺序、不影响第二年种植。秸秆富集深埋还田,理念新颖,技术可行,对土壤尤其是亚表层有很好的培肥效果。有助于彻底解决秸秆还田成本高或效果差的瓶颈问题,为旱田秸秆田间处理与深厚肥沃耕层构建提供切实可行的机械化工程手段。     

食品科学与工程类大学生就业能力提升策略研究

当今,就业形势严峻,大学生就业能力成为直接影响大学生就业的重要因素。以食品科学与工程类大学生实际就业情况,剖析食品科学与工程类大学生就业现状及产生原因,提出食品科学与工程类大学生就业能力提升策略,以便帮助食品科学与工程类大学生顺利就业,学以致用,实现人生价值。     

Linking monitoring and intervention for improved management of tigers in the Sundarbans of Bangladesh

Baseline data on distribution and abundance of tigers in the Sundarbans is required to identify problem areas and evaluate management strategies. This paper outlines a khal (creek) bank survey of track set frequency throughout the Bangladesh Sundarbans to aid formulation of a management-driven monitoring program. Three teams of two observers surveyed a total of 1 201 km of waterways throughout the Sundarbans, recording 1 338 tiger track sets. These sets became unrecognizable as tiger sign after a mean 10 days (range 6-14). Proportion of detectable sign recorded was 0.91. Mean (±standard error) sample unit track frequency was 1.12 ± 0.86 track sets/km of khal. The mean coefficient of variance in sample unit track rate, estimated by multiple counts of six sample units, was 0.21 (range 0.06-0.34). Track frequency generally increased from northeast to southwest. Four sample units (6%) had signs of reproduction, with a mean litter size of 1.75 ± 0.5. Monte Carlo simulation suggests a monitoring program of one complete survey every two years will have power of 0.8 (α = 0.2), to detect track frequency declines of ?19% and increases of ?17%. We recommend this monitoring scheme be implemented on the Indian side of the Sundarbans to provide a standard assessment of the tiger population and to form the basis for setting management objectives and evaluating transboundary conservation initiatives.     

Sampling design and its effect on population monitoring: How much monitoring do turtles really need?

Marine turtles are a taxon of world-wide conservation concern. Effective long-term monitoring is hampered by the fact that populations are widely dispersed except during the breeding season. Thus most monitoring programmes focus on nesting beaches, necessitating resource intensive studies, often over months, that could conceivably, be less comprehensive and focus on more parsimonious sampling. We analyse 11 years of exhaustive monitoring data for two species of Mediterranean marine turtles (Chelonia mydas and Caretta caretta). We resample using a variety of plausible sub-sampling regimens to estimate the total annual nesting population. We project our dataset into the future applying a range of population change rates to explore how adopting a monitoring programme based on sub-sampling would, for example, affect our ability to detect population decline. We show that accurate annual population estimates can be achieved with as few as 14 days of survey effort providing monitoring spans the peak of nesting. Furthermore, the modelled impact of sampling-based monitoring suggests that the duration to detect population change is not increased greatly. Our findings have implications for all marine turtle monitoring and have applicability to other animal groups. It is often considered desirable to perform exhaustive monitoring, with aversion of basing policy recommendations on partial data. However, comprehensive long-term monitoring programmes, particularly in developing nations, although presenting a number of advantages, are often impossible. Accurate total annual censuses can be achieved through a variety of sub-sampling regimens without sacrificing the ability to detect changes in the population trends over time. In this example, a solid block of at least 3 weeks sampling that encompasses the peak of the nesting season is advised.     

悦来航电枢纽库坝区渗漏问题的分析与评价

根据松花江悦来航电枢纽工程的勘察实例,对悦来航电枢纽库坝区渗漏问题进行了分析与评价,并且较详细地介绍了工程防治处理措施。     

蜂毒肽获取方法的研究概述

蜂毒肽是蜂毒中的主要活性成分,作为典型的抗菌肽,具有镇痛、抗炎、抗病毒、抗肿瘤等药理活性,有较大的科学研究价值和广泛的医疗应用价值。但蜂毒肽纯品获取的高成本阻碍了其开发和应用。主要从蜂毒中分离纯化和生物工程技术应用两个方面概括和比较了目前获取蜂毒肽的方法,以期为相关研究提供参考。     

Simultaneous application of the vascular endothelial growth factor (VEGF) receptor inhibitor PTK787/ZK 222584 and ionizing radiation does not further reduce the growth of canine oral melanoma xenografts in nude mice

PTK787/ZK 222584 is an inhibitor of the vascular endothelial growth factor (VEGF) receptor tyrosine kinases. In this study, the effectiveness of PTK787/ZK 222584 and radiation on canine oral melanoma xenografts was assessed. Xenografts were treated with radiotherapy (4x6Gy), or with PTK787/ZK 222584, or with a combination of both. Treatment efficacy was assessed using a tumour growth delay assay, serial power Doppler and pO(2) measurements during and after therapy. There was a significant growth delay for the group treated with radiation alone and for the combined treatment group. However, tumour growth delay was similar in both groups. Tumours were hypoxic before irradiation and no significant re-oxygenation occurred during therapy. In all tumours, vascularity and perfusion were significantly lower at the end of the study but no significant differences in perfusion, vascularity and oxygenation status were observed between and within treatment groups. The combination of PTK787/ZK 222584 and radiotherapy did not perform better than radiotherapy alone in this model.     

降低除湿式木材干燥能耗初探

介绍了除浊式木材干燥机分类,除湿机的合理选配和除湿干燥室的正确配置问题。分析了除湿机运行工况对能耗的影响。并提出了相应的降低能耗的一些措施。     

一种新型链式开沟机设计参数和功率的确定

研究了一种适用于果园狭小作业空间的新型链式开沟机的结构和工作原理。通过功率消耗和作业效率等理论分析,提出了基本参数和功率消耗的确定方法,并根据果园园艺要求给出了１ＫＬＱ－８０型链式开沟机的具体设计结果,其配套动力为１１ｋＷ,最大开沟深度和宽度分别为８００ｍｍ、６５０ｍｍ,生产效率为１２５ｍ／ｈ。