木质纤维/塑料复合材料的发展现状及应用

木质纤维/塑料复合材料是以木质纤维材料为基本体,与塑料通过不同的复合途径制成的一种新型复合材料,综合了木质纤维与塑料的性能特点,因而用途广泛.作者介绍了木质纤维/塑料复合材料的复合工艺、界面特性和改性处理以及产品的应用前景.     

基于Pro/E与ADAMS蜗轮蜗杆传动仿真研究

论述了基于Pro/E与ADAMS的蜗轮蜗杆设计及动态仿真的方法和过程,介绍了Parasolid文件接口的使用以及ADAMS齿轮副中啮合点的创建方法,对仿真结果和理论计算结果进行了对比.     

木材渗透性可控制原理研究

本文研究了木材渗透性可控制机制,探寻了渗透性可控制原理。结果表明,影响渗透性高低的最主要因素为纹孔膜微孔半径和数量,微孔大而多者,渗透性高;微孔愈小,微孔里气-液界面上毛细管张力愈高,对液体流动的影响愈大,浸注愈难,欲使浸注液深注入木材,必须施一与此微孔半径相应足以克服此张力的压力。若欲改善低渗透树种木材的难浸注性,似应从纹孔入手,用化学的、物理的和生物的等方法增大和增多有效纹孔膜微孔半径和数量,以减小毛细管张力,降低使用压力,增大流量率,提高渗透性。     

环境因子对密云水库消落带沉积物-水界面氮交换通量的影响研究

为探究不同环境因子对水库消落带沉积物中氮迁移释放的影响,以密云水库消落带为研究对象,采用原状泥柱静态培养实验,并通过单一影响因素法,开展了温度、上覆水pH、溶解氧对沉积物-水界面氮交换通量的影响研究。结果表明：消落带上覆水和沉积物中无机氮含量在夏季（落干期）和秋季（淹水期）存在明显的差异,其中沉积物中NH₄⁺-N含量变化最大,秋季较夏季下降80.4%,NO₃^--N含量下降59.7%,淹水期间三态氮（NH₄⁺-N、NO₂^--N、NO₃^--N）由沉积物释放到水中。温度、pH和溶解氧对消落带沉积物-水界面氮的迁移转化作用存在差异,升温促进NH₄⁺释放并抑制NO₃^--N释放,偏酸和偏碱条件会促进NH₄⁺-N的释放,有氧条件会加剧沉积物-水界面三态氮的交换,促进三态氮的释放。密云水库消落带沉积物C/N为7.51~9.35,其表层水体中的有机质主要来源于水体内部生物残体。因此,未来应关注密云水库消落带沉积物内源释放风险,同时完善消落带湿地建设,减少消落带氮流失对水体的污染。     

A spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands

Bighorn sheep currently occupy just 30% of their historic distribution, and persist in populations less than 5% as abundant overall as their early 19th century counterparts. Present-day recovery of bighorn sheep populations is in large part limited by periodic outbreaks of respiratory disease, which can be transmitted to bighorn sheep via contact with domestic sheep grazing in their vicinity. In order to assess the viability of bighorn sheep populations on the Payette National Forest (PNF) under several alternative proposals for domestic sheep grazing, we developed a series of interlinked models. Using telemetry and habitat data, we characterized herd home ranges and foray movements of bighorn sheep from their home ranges. Combining foray model movement estimates with known domestic sheep grazing areas (allotments), a Risk of Contact Model estimated bighorn sheep contact rates with domestic sheep allotments. Finally, we used demographic and epidemiologic data to construct population and disease transmission models (Disease Model), which we used to estimate bighorn sheep persistence under each alternative grazing scenario. Depending on the probability of disease transmission following interspecies contact, extirpation probabilities for the seven bighorn sheep herds examined here ranged from 20% to 100%. The Disease Model allowed us to assess the probabilities that varied domestic sheep management scenarios would support persistent populations of free-ranging bighorn sheep.     

What attracts elk onto cattle pasture? Implications for inter-species disease transmission

In Southwest Alberta, beef cattle and wild elk (Cervus elaphus) have similar habitat preferences. Understanding their inter-species contact structure is important for assessing the risk of pathogen transmission between them. These spatio-temporal patterns of interactions are shaped, in part, by range management and environmental factors affecting elk distribution. In this study, resource selection modeling was used to identify factors influencing elk presence on cattle pasture and elk selection of foraging patches; furthermore, consequences for inter-species disease transmission were discussed.     

色氨酸对哺乳动物母-胎界面的免疫调节作用及其机制

近年来,一些研究发现氨基酸对提高母猪繁殖能力具有重要的作用.少量的体内和体外试验研究表明,色氨酸及其代谢物能够提高母猪繁殖能力,降低流产率.本文综述了色氨酸及其犬尿氨酸代谢对哺乳动物(主要是猪和鼠)母-胎界面免疫调节(或免疫耐受)的影响,以及色氨酸及其代谢物(如犬尿氨酸和3-羟基犬尿氨酸)对哺乳动物母-胎界面蜕膜自然杀伤(dNK)细胞、调节性T细胞(Treg)和17型辅助性T细胞(Th17)的调控作用以及可能的作用机制.     

虾塘沉积物—水界面的营养盐扩散通量及其在养殖季节的变化

以自行设计的方法测定了对虾养殖环境中沉积物-水界面的营养盐扩散通量。结果表明，营养盐自底质向养殖水体的扩散贯穿于整个对虾养殖季节；该扩散通量的最大值出现在养殖后期的有机质污染区，即投铒区；在污染区，养殖后期的扩散通量大大高于养殖前期，但在非污染区却未见其随养殖季节的明显差异；污染区的扩散通量始终高于非污染区，且随养殖时间的推移，该差异逐渐增大。此外，还比较了新、旧虾塘之间的营养盐扩散通量的差异。初步探讨了底质溶出营养盐对对虾养殖环境的影响。     

漆筷广漆界面工艺改进

生漆中加入聚合桐油,名曰广漆,广泛用于漆筷和家具涂装,是我国生漆利用的一种古老方法.本研究以传统制作工艺为基础,在生漆与聚合桐油的混合阶段,引入了高速分散搅拌和研磨两种方法,从而使生漆与聚合桐油的偶连更加紧密,分散更加均匀,从而达到干燥时间短,界面涂层均匀.通过实验得出:在春秋季节,生漆与桐油的最佳配比是4:6,在夏冬季节,生漆与桐油的最佳配比应选择6:4.     

Identification and characterization of virulence-related effectors in the cucumber anthracnose fungus Colletotrichum orbiculare

The anthracnose fungus Colletotrichum orbiculare invades hosts and establishes biotrophy, later switching to necrotrophy, together with the secretion of an arsenal of effectors. In this review, we describe current progress in the study of pathogen effectors. We identified three virulence-related effectors in C. orbiculare, and revealed part of the strategy for effector-mediated infection, including suppression of immunity triggered by particular effectors. The virulence-related effectors accumulate in a unique interfacial region between C. orbiculare and cucumbers around the neck of primary biotrophic invasive hyphae. We found that the secretion of effectors toward the interface involves exocytosis and SEC22-dependent ER-Golgi traffic.