基于CFD的Venlo温室夏季组合降温措施模拟研究

针对我国南方地区夏季高温高湿的气候条件,对采用天窗、外遮阳、内喷雾降温措施的试验Venlo温室内温度状况进行了模拟研究。以室外气候参数为边界条件,考虑作物和环境的相互作用,内喷雾系统和室内环境的质热交换以源项的形式加入到控制方程中,采用CFD(computational fluid dynamics)中的稳态方法求解控制方程,模拟Venlo型温室不同调控措施及组合下的温室内温度分布特点,分析各种调控措施的调控效果。模拟结果表明:采用加入源项的方法模拟内喷雾系统和室内空气的质热交换,其模拟值和实测值均方根误差RMSB为0.514 4℃,最大绝对误差为0.75℃,平均相对误差为1.3%,说明所建立的CFD模型有效。3种降温措施下,以外遮阳+自然通风的降温贡献率最大(80.6%),能耗最高的喷雾系统降温贡献率仅为34.8%,较高的环境湿度影响了喷雾系统的降温效率。CFD夏季降温模型的建立为温室作物系统的环境控制策略的制定提供了科学依据。     

Genetic and non-genetic factors influencing KLH binding natural antibodies and specific antibody response to Newcastle disease in Kenyan chicken populations

This study aimed at investigating the influence of genetic and non-genetic factors on immune traits to inform on possibilities of genetic improvement of disease resistance traits in local chicken of Kenya. Immune traits such as natural and specific antibodies are considered suitable indicators of an individual's health status and consequently, used as indicator traits of disease resistance. In this study, natural antibodies binding to Keyhole Limpet Hemocyanin (KLH-NAbs) was used to measure general disease resistance. Specific antibodies binding to Newcastle disease virus (NDV-IgG) post vaccination was used to measure specific disease resistance. Titers of KLH-NAbs isotypes (KLH-IgM, KLH-IgG and KLH-IgA) and NDV-IgG were measured in 1,540 chickens of different ages ranging from 12 to 56 weeks. A general linear model was fitted to determine the effect of sex, generation, population type, phylogenetic cluster, line, genotype and age on the antibody traits. A multivariate animal mixed model was fitted to estimate heritability and genetic correlations among the antibody traits. The model constituted of non-genetic factors found to have a significant influence on the antibody traits as fixed effects, and animal and residual effects as random variables. Overall mean (±SE) concentration levels for KLH-IgM, KLH-IgG, KLH-IgA and NDV-IgG were 10.33 ± 0.04, 9.08 ± 0.02, 6.00 ± 0.02 and 10.12 ± 0.03, respectively. Sex, generation and age (linear covariate) significantly (p < 0.05) influenced variation across all the antibody traits. Genotype effects (p < 0.05) were present in all antibody traits, apart from KLH-IgA. Interaction between generation and line was significant (p < 0.05) in KLH-IgM and NDV-IgG while nesting phylogenetic cluster within population significantly (p < 0.05) influenced all antibody traits, apart from KLH-IgA. Heritability estimates for KLH-IgM, KLH-IgG, KLH-IgA and NDV-IgG were 0.28 ± 0.08, 0.14 ± 0.06, 0.07 ± 0.04 and 0.31 ± 0.06, respectively. There were positive genetic correlations (0.40–0.61) among the KLH-NAbs while negative genetic correlations (−0.26 to −0.98) were observed between the KLH-NAbs and NDV-IgG. Results from this study indicate that non-genetic effects due to biological and environmental factors influence natural and specific antibodies and should be accounted for to reduce bias and improve accuracy when evaluating the traits. Subsequently, the moderate heritability estimates in KLH-IgM and NDV-IgG suggest selection possibilities for genetic improvement of general and specific immunity, respectively, and consequently disease resistance. However, the negative correlations between KLH-NAbs and NDV-IgG indicate the need to consider a suitable approach that can optimally combine both traits in a multiple trait selection strategies.     

A STUDY ON HEAT AND MOISTURE STATE OF HULL LAYER FOR THERMAL INSTULATION OF A COLD STORAGE

This paper analyses the thermal moist characteristics of the hull layer beside an air layer at lower temperature in an envelope for a cold storage and presents a new method of waterproof by air layer. With test data from engineering practice, the theory on the barrier of self moisture proof at the surface sublayer of the hull layer in an attic on a cold storage is proven. The dried zone about three phase point is confirmed. It is a new knowledge for thermophysics on thermal design of a cold storage with an optimum thermal performance.     

景观生态学原理在河道生态岸堤构

分析了传统水工设计中岸堤(岸坡)构建的弊端、简要介绍了国内外学者在河流的生态整治方面的思想与观点。从景观生态学的角度着重介绍了岸堤(岸坡)生态系统的组成和主要特征、生态岸堤的多种功能和景观生态学内涵；提出了在生态岸堤设计中的坚持生态优先，同时重视景观性和稳定性；根据使用材料的不同对岸堤进行分类,对生态岸堤的植物群落的构建进行分析。本文可为从而为生态岸堤的构建、河流、洪泛区的治理提供一定的思路和参考。     

自来水行业面临的挑战及对策

自来水行业是一种关系公众切身利益的、自然垄断的经营性产业。通过分析，认为由于受旧的体制影响和多种原因，我国自来水行业目前面临着巨大的困难和挑战；指出要实现我国自来水行业的振兴，必须调整水价，改革体制，扩大市场，发展多种相关水的产业，增强全社会保护和合理利用水资源的意识。     

天然膨润土吸附Cu2+的动力学、等温线及热力学研究

文章讨论了不同影响因素如接触时间、振荡速度、膨润土用量、初始离子浓度、初始pH、温度等对膨润土吸附性能的影响,研究了Cu2+在天然膨润土上吸附的动力学、等温线和热力学理论。动力学研究数据表明,吸附满足准二级动力学模型,吸附初始阶段受界面扩散控制,45 min后受粒子内扩散控制;吸附满足Freundlich等温线模型;吸附是一个自发的、吸热的过程,而且反应不可逆。     

甘蔗新品种及主栽品种对褐条病的抗性评价

褐条病是为害甘蔗叶部的重要真菌病害,严重发病田块,一眼望去似“火烧状”,一般减产18％ ～35％,蔗糖分降低15％ ～30％[1].该病于1924年在古巴首次发现[2],至今已有20多个国家报道发生此病,常造成不同程度经济损失[3].在中国,尤其近年,感病品种加上多雨高湿导致褐条病在云南及广西等主产蔗区大面积暴发流行,...     

Total Phenolic Levels,In Vitro Antioxidant Properties,and Fatty Acid Profile of Two Microalgae,Tetraselmis marina Strain IMA043 and Naviculoid Diatom Strain IMA053, Isolated from the North Adriatic Sea

This work studied the potential biotechnological applications of a naviculoid diatom (IMA053) and a green microalga (Tetraselmis marina IMA043) isolated from the North Adriatic Sea. Water, methanol, and dichloromethane (DCM) extracts were prepared from microalgae biomass and evaluated for total phenolic content (TPC) and in vitro antioxidant properties. Biomass was profiled for fatty acid methyl esters (FAME) composition. The DCM extracts had the highest levels of total phenolics, with values of 40.58 and 86.14 mg GAE/g dry weight (DW in IMA053 and IMA043, respectively). The DCM extracts had a higher radical scavenging activity (RSA) than the water and methanol ones, especially those from IMA043, with RSAs of 99.65% toward 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS) at 10 mg/mL, and of 103.43% against 2,2-diphenyl-1-picrylhydrazyl (DPPH) at 5 mg/mL. The DCM extract of IMA053 displayed relevant copper chelating properties (67.48% at 10 mg/mL), while the highest iron chelating activity was observed in the water extract of the same species (92.05% at 10 mg/mL). Both strains presented a high proportion of saturated (SFA) and monounsaturated (MUFA) fatty acids. The results suggested that these microalgae could be further explored as sources of natural antioxidants for the pharmaceutical and food industry and as feedstock for biofuel production.     

长江经济带农业碳补偿修正测算及分析

为研究农业技术水平和自然禀赋对农业碳排放和碳汇的影响,通过修正后的农业碳补偿测算方法,计算得到2007—2016年长江经济带各省（市）的农业碳补偿额并进行对比分析。结果表明：江西和湖南的农业碳排放冗余量均为零值,农业技术水平较高,浙江和云南的农业碳排放冗余量较高,均值分别达到237.18万t和175.13万t,农业技术水平落后;浙江、江西、四川和云南的年均调整系数小于1,农业自然资源禀赋高于长江经济带的整体水平;修正后浙江和云南的碳补偿额由正数变为负数,表明这两个省从碳受偿地区变为碳支付地区,上海、江苏、安徽、湖北、湖南、重庆、贵州农业碳补偿额比修正前有所增加,江西和四川农业碳补偿额则比修正前减少。长江经济带各省域应加强农业自然禀赋的建设,提高生态背景值,增强其农业生态系统的碳汇功能,加快实现长江经济带生态补偿公平价值,并提升生态资源利用的地区公平性。     

1969-2018年黄河实测径流与天然径流的变化

[目的] 分析黄河实测径流与天然径流的变化规律,为探究人类活动对径流的影响提供依据。[方法] 基于1969—2018年黄河干流8个水文站的天然径流和实测径流数据,使用Mann-Kendall趋势检验与突变检验法,对比分析近50 a黄河干流实测径流和天然径流的变化规律。并结合近15 a各分区耗水数据探讨人类活动对于径流的影响。[结果] ①1969—2018年黄河上中下游实测径流整体呈降低趋势,兰州、花园口、利津3个代表站多年平均降低速率分别为5.10×10⁷,3.55×10⁸,4.13×10⁸ m³/a。②近50 a天然径流和实测径流趋势突变主要集中在1986和1990两个年份,结合前人研究和重要水事分析,1986年突变可能与1984年以来一系列水土保持措施实施以及1986年龙羊峡水库修建有关;而造成1990年径流突变的原因可能是80—90年代黄河流域用水量激增和流域下垫面改变。③天然径流与实测径流的差值从上游至下游水文站断面逐渐增大,这主要与近15 a平均耗水量也沿程增大相一致;另外多年平均实测径流在利津站仅占天然径流的42%。耗水量最大的两个分区为花园口以下和兰州—头道拐段,分别达到了1.06×10¹⁰和1.04×10¹⁰ m³。[结论] 人类活动中的各项耗水（尤其是农田灌溉）是造成兰州站以下地区天然径流与实测径流差值大的主要原因,因此,应进一步推进黄河流域节水农业的发展,合理分配各项耗水量。