桃树的嫁接

桃树嫁接春季最佳时间为3月中旬,秋季于9月上中旬为好,过早易产生流胶,过迟温度太低不易成活。一般果农习惯采用春夏两季嫁接。其实秋冬季也可以嫁接,这样能增加收益。1)春季嫁接:2月中旬至4月底,此时砧木水分已经上升,可在其距地面8～     

基于“三生空间”转型的盐城市生态系统服务综合分析

以盐城市为研究区域,基于1990—2020年4期地表覆盖数据,在“三生空间”框架内分析了其时空分布变化趋势及关系,采用ESV估算模型和InVEST模型,探究了空间转型对该区域生态系统服务中的生境质量、碳储存量以及生态系统服务价值的影响,以期为盐城市及同类地区国土空间资源的可持续发展提供借鉴。研究表明：（1）盐城市“三生空间”中的生产、生活及生态空间用地占比分别为80.1%、7.9%和12.0%,1990—2020年30 a间,生产空间面积持续减少,生活、生态空间面积持续增加。（2）盐城市1990—2020年各项生态系统服务指标中以生态服务为目标的碳储存总量逐渐下降,以安全服务为目标的生境质量总分值逐渐下降,以经济服务为目标的生态系统服务价值较为稳定。（3）盐城市1990—2020年“三生空间”生态系统服务综合评价空间平均分逐年下降,其中生态空间为0.439分,生产空间为0.406分,生活空间为0.212分,生产空间生态系统服务综合总得分的减少量大于生活空间生态系统服务综合总得分的增加量,再加上生态空间综合得分的减少,共同导致了该区域30 a来生态系统服务综合评价得分的减少。     

应用响应面法优化鲜核桃低温贮藏保鲜工艺北大核心CSCD

【Objective】In order to prevent the loss of nutrients and prolong the shelf life of fresh walnut during storage, the best preservation conditions of low temperature storage for fresh walnut were optimized. 【Methods】In this experiment, the fresh fruits of Qingxiang were selected as the test materias. Under the conditions of cold storage [temperature: (-1±0.5)℃, relative humidity: 70%-80%], the walnut kernel moisture content, seed coat color difference, peel color conversion index, peel browning index, fruit cracking rate and decay rate were evaluated, and the comprehensive indexes were calculated according to Hassan method. Then, single factor experiments were conducted on the number of 1-methylcyclopropene (1-MCP) preservative bags, the thickness of polyethylene (PE) bags, and the number of holes on the bags. 1-MCP was directly put into the PE bag. The response surface design was used to optimize the best preservation process parameters with the comprehensive scores as the response value. Finally, according to the best preservation process parameters, the fresh walnut fruits of Qingxiang were kept fresh for 90 days, and the comprehensive quality evaluation and sensory quality level were determined according to the consulting survey results of consumers (18-45 years old). The changes of fresh walnut flavor during the preservation period were analyzed by principal component analysis.【Results】 The best technology of low-temperature storage for 5 kg fresh walnut fruits was 1 bag (0.625 g) of 1-MCP, 40 μm PE and 1 holes on the bag (hole diameter 5 mm;fresh keeping bag 400 mm × 600 mm. The theoretical comprehensive score was 94.48. From the perspectives of sensory and flavor evaluation, the sensory quality level and comprehensive quality evaluation of fresh walnut stored at low temperature for 90 days under the best technology were less than grade 2, the color difference of seed coat could not be distinguished by naked eyes, and the flavor basically did not change, which indicated that the best technology of this experiment had a good preservation effect on fresh walnut.【Conclusion】 The results showed that the best low-temperature storage technology for 5 kg the Qingxiang fresh walnut is 1 bag of 1-MCP, 40 μm PE and 1 hole on the bag. The results of this study would provide a basis for low temperature storage of fresh walnut. © 2021, Office of Journal of the Fruit Science. All right reserved.     

待鸦阵掠过天空

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G150-1500型矿用电力机车空气压缩机故障的技术研究

ZG150-1500型电力机车原配置Z1.8型空气压缩机,使用中经常发生曲轴断裂、拉缸、曲轴箱透油和大小齿啮合等故障。本文通过对此进行设备裂化跟踪,分析故障原因,并按照分析结果对空气压缩机进行重新选型。     

火山雄姿

长白山是一个火山形成拔地而起的圆锥体,锥体顶部是是锥峰高擎的火山湖——长白山天池。火山锥巍峨雄浑,火山湖恬静灵秀,阳刚与柔美融合,成为世界著名的火山湖景观。     

日本进口花卉检疫要求

我国每年有大量的花卉出口,其中亚洲地区以日本、韩国、泰国、缅甸、新加坡为主.据最新统计数据显示,日本是2010年我国花卉的主要出口对象国,其出口额居于首位,产品主要以切花、切叶、切枝及一些观叶植物为主.日本对进口花卉的检疫要求非常严格,尤其是携带基质的产品.植物（不包括非种植用植物和法律法规公布的不容易携带有害生物的植物）及其包装材料或容器不允许进口,除非其有输出国政府有关部门签发的植物检疫证书或检疫证书副本,证明其已经过检疫,被认为没有携带有害动物和植物.     

津优36号黄瓜的温室越冬茬栽培技术

津优36号黄瓜是天津科润黄瓜研究所最新育成的杂交一代黄瓜新品种,该品种最大的特点是突出了早熟性,瓜条外观商品性和丰产性,兼具优质、抗病、耐低温、弱光的性能,达到节能、省工、有效减少农药使用的目的,具有良好的社会效益和生态效益,受到广大种植者的好评,现将该品种的特性和栽培管理要点做以下介绍.