EM菌在水产养殖中的应用概述

为了能改善水质、渔业增殖和修复生态环境,EM菌的应用得到了广泛的关注,成为近几年研究的热点。鉴于此,本研究系统梳理了EM菌的定义及来源,综述了国内外近几十年EM菌在水产养殖中的作用效果及其作用机理,阐述了影响EM菌作用效果的因素等;发现EM菌在调控微生物生态结构、降低水环境中有害物质、提高免疫、增重增产等方面有着显著的效果,但EM菌技术的基础理论研究还比较薄弱,且生产技术及应用过程等还存在着不足。因此今后应提高生产技术,建立和提高筛选系统,并开发EM菌在水产养殖研究和应用的新领域,为水产养殖创造更大的经济价值,并为可持续养殖提供可能。     

基于“车间实境课堂”的机械类专业实践课程教学研究

结合机械类专业实践课程特点,针对传统教学过程中在教材、教师、课程设置方面存在的问题,探索结合生产实际的"车间实境课堂"教学法,主张将车间实际场景融入到课程教学全过程,实现理论知识与工程实际的紧密结合,以提高学生的学习兴趣及工程实践与创新能力,进而有效提升应用型工程技术人才的培养质量。     

Reproductive barriers to hybridizations between narrow-leaf and broad-leaf Anoectochilus roxburghii

Narrow-leaf and broad-leaf Anoectochilus roxburghii were used as reciprocal parents to explore the reason for low seed setting rate. Pollen-pistil interaction was observed by fluorescence microscopy and hybrid embryo development by paraffin section technology. The results indicated that pollen tube growth could reach the embryo sac, and double fertilization could be completed. These findings showed that a pre-fertilization barrier was not the major factor in the cross of narrow-leaf and broad-leaf A. roxburghii. The endosperm development of the hybrid was abnormal and eventually promoted abortion of the embryos. A post-fertilization barrier appears to be the major factor for low seed setting rate in the cross of narrow-leaf and broad-leaf A. roxburghii. In addition, an efficient protocol of embryo rescue, the development of which is reported elsewhere, was used to compare the time needed for rescue between the reciprocal crosses.     

新几内亚凤仙组织培养和快繁技术研究

选取新几内亚凤仙具有顶芽或腋芽的茎段为外植体,诱导芽体萌发,进行繁殖培养。通过实验对比分别筛选出诱导芽分化和诱导生根的最佳培养基。实验结果表明：不同的激素水平对几内亚凤仙组培苗的生长有着显著的影响。其中最适宜的分化培养基为MS＋6-BA0.5 mg/L＋NAA0.1 mg/L;最适宜的生根培养基为1/2 MS＋IAA0.5 mg/L;最适宜的栽培基质为蛭石＋草炭＋珍珠岩（5∶3∶2）,成活率为95%。     

大凌河流域生态综合治理项目效益分析

葫芦岛市建昌县2014年国家农业综合开发大凌河流域生态综合治理项目分布在建昌县新开岭乡新开岭村、贺杖子乡碾房村、素珠营子乡梁杖子村.通过该项目治理后,生态环境得到明显改善,经济效益十分显著,社会效益巨大,促进了区域经济社会发展.同时工程建设也起到了科技示范作用,为推动生态环境建设奠定了坚实基础保障.     

环境管制政策的实施效果评价——以九龙江流域"限猪令"为例

环境管制一直是我国环境污染治理所采取的主要政策之一,对我国的环境保护起到了一定的积极作用,同时也存在一些弊端,致使其成效不甚显著甚至背离初始目标.在此情况下,如何评价环境管制政策绩效具有重要的理论和实际意义.本文以九龙江流域"限猪令"政策为例,选取政策目标实现度、主要环保指标实现、环保投入效益、公众参与及满意度四个方面...     

Drag force and reconfiguration of cultivated Saccharina latissima in current

The design of aquaculture systems requires an understanding of the drag forces on cultivated kelp. This study measured the drag on line segments of cultivated Saccharina latissima in a towing tank. The drag on segments of farm line with full kelp bundles and with stipes alone (fronds removed) was measured at tow speeds of 0.10 to 0.50 m/s. The drag on individual fronds cut from the line was also measured. Video images were collected to evaluate the plant reconfiguration. Both kelp blades and stipes contributed to the total drag force on the line bundle. Within the velocity range of our experiments, the kelp blades were essentially horizontal. However, the pronation of kelp stipes increased as flow velocity increased. The reconfiguration of kelp stipes was observed to decrease the vertical extent of the kelp bundle. Due to this reconfiguration, the measured force, $F$, increased with velocity, $U$, at a rate slower than quadratic, and was consistent with scaling laws derived for reconfiguration. Specifically, $F\sim U^{\alpha }$ with $\alpha =1.35\pm 0.17$.     

大学英语网络教学改革状况调查

通过调查问卷和访谈，调查学生对大学英语网络教学改革模式的看法及学生在新模式下的学习情况。调查结果发现，学生对英语网络教学持肯定的态度，但学生利用网络进行英语学习的情况仍差强人意，学生的自主学习意识及能力急需加强和提高     

内蒙古岩画中的动物群落结构及其生态环境的研究——以阴山和乌兰察布两地岩画对比研究为例

动物岩画是内蒙古地区古代动物的图解,通过岩画中的动物群落结构对比,可以推测相同地域范围内,不同时期的动物分布情况,进而推断当地的自然环境变迁的过程。