不同储藏条件对稻米蒸煮品质和α-淀粉酶的影响

以稻谷粤农丝苗为原材料,置于4种不同储藏模式下,具体如下:(1)15℃储藏240d。(2)30℃储藏240d。(3)以15℃为开端,与30℃交替储藏(60d交替1次)至240d。(4)以30℃为开端,与15℃交替储藏(60d交替1次)至240d。每隔60d检测1次,比较上述4种储藏模式下,稻米蒸煮品质和α-淀粉酶活力的变化趋势。研究结果表明:随着时间的延长和储藏温度的升高,稻米品质下降;在实验时间内,以低温为开端的变温模式的稻米品质要优于以高温为开端的变温模式,但差距逐渐减小。     

严寒地区高速铁路混凝土基床聚氨酯保温特性试验研究

基于严寒区京沈客专朝阳试验段路基基床的温度监测资料分析,研究不同厚度聚氨酯保温板对高速铁路路基混凝土基床温度变化特性影响.测试结果表明:①铺设聚氨酯保温板能够有效阻断严寒区环境与路基基床间的热量传递,保温效果与板厚相关;②地温大多数时间呈阳高阴低现象,同时阴、阳坡路基温差波动幅度随埋深逐渐减小;③基床表层阴、阳面各测点的温度变化起始时间一致,而阴面的冻结时间比阳面晚一个月.由此表明,保温板能够有效降低环境与混凝土道床之间的热交换,但是对路基阴、阳坡的影响存在差异.建议在严寒地区高速铁路路基阳、阴坡可以采取不同厚度的聚氨酯保温板,减小阴阳坡地温差异,保持季冻土路基温度变化稳定.     

China feels the heat: negative impacts of high temperatures on China's rice sector

We analysed a county‐level data set of single‐season rice yield and daily weather outcomes in China to examine the effects of temperature on China's rice sector. We found that rice yield exhibited highly nonlinear responses to temperature changes: rice yield increased with temperature up to 28°C and decreased sharply with higher temperatures. Holding current growing seasons and regions constant, average rice yield in China is projected to decrease by 10–19 per cent by 2050 and 11–33 per cent by 2070 due to future warming under the global climate models HadGEM2‐ES and NorESM1‐M. These results imply that future warming poses a major challenge for Chinese rice farmers and that the effectiveness of adaptations will depend on how well they reduce the negative temperature impacts on rice yield because of very hot days.     

Model Comparison for Temperature-Based Weather Derivatives in Mainland China

Abstract:

In this paper, we provide a comparison of two models of temperature-based weather derivatives. The Alaton et al. model (2002) and the continuous-time autoregressive (CAR) model of Benth et al. (2007) are applied to temperature data from twelve cities in China. The objective is to determine which is the better model for temperature derivative modeling in Chinese cities. We found the CAR model to be more accurate in terms of normality of residuals and smaller relative errors. However, the shortcomings of both the Alaton et al. model and the CAR model are revealed in this study as well.     

田字型不同方位仓房传热情况对比分析

为提高科技储粮使用率以及使用效果,针对特殊仓型田字型仓经外界通过围护结构传进仓内热量情况进行对比分析.通过该项目的研究,了解外界传入仓内热量及内环流控温运用情况,制定合理的通风蓄冷、内环流控温方案,从而有针对性的改善储藏条件,改变储藏环境,为实现科技储粮、绿色储粮提供基础.     

基于温差发电的混合动力自行车的研究

本文主要研究了一种基于温差发电的混合动力自行车,并就其改装和发动机尾气余热利用的系统优化设计进行了集中分析,最终得出了相关结论。     

40CrNi_2Si_2MoVA钢棒材晶粒度控制

随着科技的进步与发展,以改变合金成分提高超高强度钢的强度和韧性已经很困难。本文以40Cr Ni2Si2Mo VA钢为例,探讨了通过控制晶粒度尺寸提高钢强度和韧性的方法。     

Natural and anthropogenic influences on the year-round temperature dynamics of air and water in Postojna show cave,Slovenia

Air and groundwater temperatures were measured in a rimstone pool in Postojna Cave, to advise evaluation of the impact of natural and anthropogenic influences related to heat being initially transmitted into cave air by visitors. Such heat can accumulate both in the rock mass and in water. Results show that attention must be paid to temperature changes of rimstone pool water rather than those of cave air, especially during the winter. Thanks to good ventilation deep inside the cave, short-term air temperature increases related to higher visitor numbers have not influenced flowstone precipitation or the cave fauna. However, this situation might change if winter visitor numbers increased greatly. This study does not support a suggested increase in winter visits (currently the tourism low-season) and reduction of summer visits (currently the tourism high-season).     

栀子花期低温冷害风险区划研究——以湖北蕲春为例

[目的]确定栀子花期低温冷害指标,研究栀子花期低温冷害风险区划方法,以蕲春县为例开展栀子花期低温冷害风险区划,为蕲春栀子种植提供参考。[方法]利用湖北省蕲春县1990~2010年栀子产量资料及同期气象观测资料,通过统计分析冷害持续日数、冷害期间日平均气温20℃累积危害积温、极端最低气温、降温幅度等指标与栀子产量的关系,建立了栀子花期低温冷害损失模型。以20℃累积危害积温为指标,以损失率5%、10%、30%为阈值,确定了栀子花期轻度、中度、重度、严重冷害分级标准,然后利用蕲春县1:25万数字高程模型及蕲春县逐日平均气温、最低气温观测资料,推算网格点1959~2010年5月1~20日逐日最低气温、平均气温,构建冷害风险指数,计算各网格点的冷害风险指数,进行了蕲春县栀子冷害气候风险区划。[结果]蕲春县西部低山区栀子花期冷害风险较小,适宜栀子种植;400m以上的山区冻害风险大,种植栀子只开花不结果。[结论]栀子花期低温冷害风险区划结果在蕲春栀子种植基地规划中有一定参考意义。     

The effects of ambient temperature changes on foodborne illness outbreaks associated with the restaurant industry

Foodborne illness outbreaks generate serious socioeconomic costs in the United States. Among many causes, the effects of weather change and the habit of frequently dining out at restaurants are very important topics for researchers, because ambient temperature change may influence the entire process of food consumption from farms to tables, and restaurants are considered to be the most predominant single location responsible for foodborne illness outbreaks. However, few studies have examined both factors simultaneously, although empirical findings support a significant relationship between each factor and foodborne illness outbreaks. Therefore, the objective of this study is to link the effects of ambient temperature change with foodborne illness outbreaks in restaurant business settings. Furthermore, this study aims to identify how restaurant firms have performed compared with others in regard to foodborne illness outbreaks. Finally, this study intends to suggest how restaurant firms can reduce or prevent the prevalence of foodborne illness outbreaks.