哈尔滨松花江公路大桥动力特性试验

通过对哈尔滨松花江公路大桥进行动力特性实测和利用有限元程序ANSYS进行了建模和计算分析,得到的实测值和理论计算值差别不大。并通过研究获得了大桥的固有频率、模态、阻尼比和在动力荷我作用下的冲击系数,了解了该桥在动载荷作用下的实际工作状态,从而判断该桥整体结构的安全承我能力和使用条件。     

高速公路建设造成的水土流失影响及减缓措施

指出了公路工程项目属于建设性项目,穿越地形地貌复杂多样,扰动地表程度及形式复杂多变,对沿线水土流失影响较大。以高速公路环境影响评价为例,对公路建设造成的水土流失影响进行了分析和阐述,提出了可采取的减缓措施。     

论秦汉前中原古代地理发展成就

从狭义中原的地理范畴,解读各类历史典籍中所记录的秦汉前中原及与中原相关的地理内容,从中把握秦汉以前中原古代地理发展的历史脉络、地理成就、发展特点及蕴含的历史地理价值。研究认为,在中国区域性地理发展历史中,尤其是秦汉前中原古代地理发展史不仅可以独立成章,而且形成极具理性的中原古代地理体系,并深刻地影响了中国古代地理科学的历史发展过程。     

基于LID理念的西农成教学院周围景观改造研究

以西北农林科技大学南校区成教学院周边区域为研究对象,在场地调研勘测和相关资料研究的基础上,分析研究区域场地的水文、植物、土壤及土地利用情况。运用低影响开发水文分析法,计算场地现状、开发前、预期3部分径流曲线数值,确定设计降雨量及维持开发前CN所需雨水储存量,计算3个不同区域综合管理措施达到预期效果所需面积,并提出相应的景观提升与雨水排水改造措施。     

2020年通辽市开鲁县气候影响评价

本文采用统计分析方法，对2020年开鲁县国家基准气候站采集的气温、降水、日照等基本气象要素数据和相应历年值进行对比分析，并对局地大风、暴雪等重大灾害性天气进行综合分析，并根据分析结果，作出气候对生产生活影响的综合评价。结果表明，2020年气候条件对全县农业生产及人们的生活有利有弊。     

Impact of fish feed on airlift pumps in aquaculture systems

Airlift pumps are commonly used in aquaculture systems to circulate water and maintain critical gas levels. In production marine reuse systems, a significant decrease in airlift pump flowrate was visually observed immediately after feeding. In experimental systems without fish, it was found that feed additions of less than 10 mg/L decreased water flow by as much as 78% for diffuser injectors but only 10% for pumps with direct air injection. For both injector types, feed impact diminished over several hours but persisted longer in seawater than in freshwater. Video footage revealed increasing bubble coalescence with the addition of feed. The decrease in pump flow is likely attributed to water property changes due to compounds leaching out of the feed. This decrease in pumping rate has the potential to negatively impact water quality, system performance, and fish health.     

抚育间伐对森林环境的影响

根据实测资料分析了抚育间伐对森林环境的影响,结果表明：随着间伐强度的提高,林内光照强度增加,空气湿度降低;在寒冷多湿地区,土壤肥力增加;而在温暖的气候条件下,土壤肥力则降低。     

The impact of taxonomic change on conservation: Does it kill, can it save, or is it just irrelevant?

The important question of taxonomy and its impact on conservation efforts was brought to general attention by Robert May in 1990 with a News and Views article in Nature entitled “Taxonomy as destiny.” Taxonomy, however, has built-in instabilities that result in name changes, raising the question of whether name changes have a consistent impact on conservation efforts. Our review investigates three possible outcomes of taxonomic change, namely a positive impact on protection efforts, a hampering impact, or no measurable impact. We address these cases with a review of the relevant literature: specifically, government and conservation agency reports, scientific papers, and the general press, as well as correspondence with biologists active in plant and animal conservation. We found no evidence of a consistent effect of taxonomic change on conservation, although splitting taxa may tend to increase protection, and name changes may have the least effect where they concern charismatic organisms.     

抗生素对胃肠道微生态系的影响与对应举措

文章阐述抗生素对家畜胃肠道微生态系的影响与对应举措.凡进入家畜胃肠道的抗生素不仅可抑杀有害菌群、中性菌群,同时亦可抑杀有益菌群,破坏微生态系的生理组合等问题.提出了研发抗生素替代物的依据,指出中草药是理想的抗生素替代产品.     

Alternative silvicultural practices with variable retention improve bird conservation in managed South Patagonian forests

Alternative silvicultural approaches to timber management, such as regeneration treatments with different degrees of stand retention, may mitigate negative effects of clear-cutting or shelterwood cuts in forested ecosystems, including changes in old-growth forest bird communities. The aims of this work were: (a) to compare bird species richness and densities among different silvicultural designs with variable retention (dispersed and/or aggregated) and unmanaged primary forests, and (b) to assess temporal changes at community and species levels before and after treatments. A baseline avian survey was conducted prior to harvesting to evaluate canopy gap presence and forest stand site quality influences. Subsequent to harvesting, data on bird species richness and density were collected by point-count sampling during the summer season for 5 consecutive years (4 treatments × 5 years × 6 sampling points × 5 counts). Bird species richness and density (15 species and 9.2 individuals ha⁻¹) did not change significantly with forest site quality of the stands and canopy gap presence in unmanaged forests. However, both variables were significantly modified in managed forests, increasing over time to 18 species and reaching to 39 individuals ha⁻¹. Inside the aggregated retention, bird communities were more similar to unmanaged primary forests than those observed within the dispersed retention or in clear-cuts. Opting for a regeneration method with dispersed and aggregated retention has great potential for managing birds in Nothofagus pumilio forests. This method retained enough vegetation structure in a stand to permit the establishment of early successional birds (at least in dispersed retention), and to maintain the bird species of old-growth forests which could persisted in the retention aggregates.