基于转换点调控的怀山药多相态微波干燥及品质特性

为解决冻干和冻干-微波真空联合干燥技术存在的耗时长、能耗高、设备成本高等问题，同时获得品质较好的干制品，以怀山药为对象开展多相态微波干燥(multiphase microwave drying，MMD)研究，通过不同微波功率加载方案实现转换点调控，探究转换点干基含水率（0.36、0.59、0.79 g/g）对怀山药干制品品质的影响。并以真空冷冻干燥、微波冷冻干燥和微波真空干燥为对照,研究不同干燥方式对怀山药干燥特性、能耗和品质特性（复水性、收缩率、色泽、硬度、脆度、微观结构）的影响。结果表明：随着微波功率水平的增加，怀山药MMD转换点干基含水率增大，产品复水性降低，收缩程度增大，硬度变大，细胞结构破损程度增加。MMD方案Ⅰ（转换点干基含水率0.36 g/g）干燥时间与微波冷冻干燥相比缩短31.3%，能耗相比真空冷冻干燥、微波冷冻干燥分别降低68%、34%，同时，所得怀山药干制品具有良好的品质和均匀的微观孔隙结构，其复水比（2.44±0.04）、收缩率（0.88±0.02）、色泽、硬度（4.95±0.45）、脆度（2.48±0.51）与微波冷冻干燥无明显差异（P>0.05）。微波真空干燥虽所需能耗低，但其产品复水性最差，收缩最为严重。综合考虑高效低能耗干燥与产品品质提升的需求，可通过转换点调控的多相态微波干燥实现高品质怀山药加工。     

露地大白菜低温冻害气象指数保险费率厘定方法研究

【目的】为科学厘定露地大白菜低温冻害保险费率提供方法,为其他气象因子指数保险的保险费率厘定提供参考,为政策性农业保险的可持续发展提供助力。【方法】将1957—2018年每年初、终霜冻日期转化为儒历日,计算平均初、终霜冻日期,将平均初、终霜冻日期设定为低温冻害指数保险中的时间起赔阈值,并利用标准差分级法,对起赔阈值设置的合理性进行检验。精确统计大白菜各生长期投入成本,根据灾损率进行加权计算得出赔付比例。通过计算发生概率、灾损率与赔付比例3个因子综合得出露地大白菜低温冻害保险费率,并对种植区域进行加权计算,得出区域内的露地大白菜低温冻害保险费率。【结果】设计了露地大白菜低温冻害气象指数保险中时间和气温起赔阈值的计算方法,并制定了时间起赔阈值的检验方法。设计了低温冻害保险费率3个决定因子发生概率、灾损率和赔付比例的计算方法。【结论】经过检验,将平均初、终霜冻日期设定为丰宁满族自治县地区露地大白菜低温冻害气象指数保险的时间起赔阈值是合理的。露地大白菜在遭受轻、中、重三级低温冻害时的灾损率分别为0.3、0.7和1.0;发芽期赔付比例最高为45%,秧苗期赔付比例最高为75%,莲座期以后赔付比例最高为100%。各乡镇露地大白菜低温冻害气象指数保险费率为2%～3%,经过加权计算得出丰宁满族自治县地区低温冻害保险费率为2.14%。     

中国古代思想政治教育方法的现实启示

中国古代思想政治教育经历了几千年的发展沿革，形成了较为系统和完善的思想政治教育方法，其中一些教育方法对当今大学生思想政治教育仍具有借鉴意义。     

农用地估价方法综述

农用地估价的常用方法有：收益还原法、收益倍数法、成本法、假设开发法、市场比较法、影子价格法、享乐定价法、土壤潜力估价法、标准田法等。这些估价方法对我国农用地的可操作性、适用范围．学术界有不同的看法，文章对这些观点进行了综述与分析。     

张家界居民消费的生态足迹分析

提出了可转移生态足迹、不可转移生态足迹概念。以张家界为例,计算分析张家界市居民消费的生态占用情况。结果表明：2004~2005年张家界居民可转移生态足迹分别为741 3918、61 8518、96 815 hm2;不可转移生态足迹分别为1 592 8091、769 1381、900 515 hm2。     

改进工艺提升民营橡胶产品质量

通过对西双版纳天然橡胶产品质量较低的原因分析,通过试验研究,提出改进工艺,规范生产,采用先进生产技术以提升橡胶产品质量的意见。     

Upscaling as ecological information transfer: a simple framework with application to Arctic ecosystem carbon exchange

Transferring ecological information across scale often involves spatial aggregation, which alters information content and may bias estimates if the scaling process is nonlinear. Here, a potential solution, the preservation of the information content of fine-scale measurements, is highlighted using modeled net ecosystem exchange (NEE) of an Arctic tundra landscape as an example. The variance of aggregated normalized difference vegetation index (NDVI), measured from an airborne platform, decreased linearly with log(scale), resulting in a linear relationship between log(scale) and the scale-wise modeled NEE estimate. Preserving three units of information, the mean, variance and skewness of fine-scale NDVI observations, resulted in upscaled NEE estimates that deviated less than 4% from the fine-scale estimate. Preserving only the mean and variance resulted in nearly 23% NEE bias, and preserving only the mean resulted in larger error and a change in sign from CO₂ sink to source. Compressing NDVI maps by 70–75% using wavelet thresholding with the Haar and Coiflet basis functions resulted in 13% NEE bias across the study domain. Applying unique scale-dependent transfer functions between NDVI and leaf area index (LAI) decreased, but did not remove, bias in modeled flux in a smaller expanse using handheld NDVI observations. Quantifying the parameters of statistical distributions to preserve ecological information reduces bias when upscaling and makes possible spatial data assimilation to further reduce errors in estimates of ecological processes across scale.     

Antioxidant properties of blackberry and blueberry fruits grown in the Black Sea Region of Turkey

Seven wild and ten cultivated blackberries (Arapaho, Bartin, Black Satin, Bursa 1, Bursa 2, Cherokee, Chester, Jumbo, Navaho, and Ness), and six lowbush (Vaccinium arctostaphylos) and four highbush (Vaccinium corymbosum) blueberries fruits (Ivanhoe, Jersey, Northland, and Rekord) were analyzed for total anthocyanins, total phenolics, and antioxidant activity as ferric reducing antioxidant power (FRAP) in this study. The respective ranges of total anthocyanin and total phenolic contents of the tested samples were: blackberries, 0.95–1.97 and 1.73–3.79 mg g⁻¹ and blueberries, 0.18–2.94 and 0.77–5.42 mg g⁻¹. FRAP values varied from 35.05 to 70.41 μmol g⁻¹ for blackberries, 7.41 to 57.92 μmol g⁻¹ for blueberries. Wild blackberries had the highest FRAP values while wild blueberries had the highest total phenolic and total anthocyanin contents. A linear relationship was observed between FRAP values and total phenolics for blueberries (r = 0.981). The anthocyanin pigments in samples were isolated and characterized by high-performance liquid chromatography (HPLC) with UV–visible detection. Cyn-3-glu was the predominant anthocyanin in all blackberry fruits.     

羽叶决明代木栽培鸡腿菇的物质转化

研究羽叶决明(Chamaecrasta nictitans)代木栽培鸡腿菇(Coprinus ovatus)对其绝对生物学效率、基物失重、呼吸消耗及木质纤维素转化的影响.结果表明,羽叶决明牧草替代60%木屑(A60)栽培鸡腿菇的绝对生物学效率最高,均为10.77%.覆土前和采收后的基物失重和呼吸消耗都以A0(CK)为最高,分别为11.47%、11.47%和31.75%、25.55%,其木质素转化率也最高,为79.21%;纤维素转化率以A100(羽叶决明牧草替代100%木屑)为最高,达50.93%;半纤维素转化率以A40(羽叶决明牧草替代40%木屑)为最高,为49.74%.回归分析结果表明,绝对生物学效率和半纤维素转化率与替代比例呈抛物线相关,而基物失重、呼吸消耗及木质素、纤维素转化率与替代比例呈线性相关.     

乌龙茶饮料的反渗透浓缩试验

研究茶饮料的温度、浓度和压力对反渗透浓缩速度的影响，检验反渗透膜的再生性能，测量浓缩过程的能耗，鉴定浓缩茶饮料的品质、结果表明，该工艺与传统工艺相比，具有高品质、低成本、易操作的特点，有推广潜力。