Wind energy resource assessment for five locations in Saudi Arabia

The analysis of recently collected wind data at five sites in Saudi Arabia namely, Dhulum, Arar, Yanbu, Gassim and Dhahran is presented. The five sites represent different geographically and climatologically conditions. The data collected over a period spanned between 1995 and 2002 with different collection periods for each site. Daily, monthly and frequency profiles of the wind speed at the sites showed that Dhulum and Arar sites have higher wind energy potential with annual wind speed average of 5.7 and 5.4 m/s and speeds higher than 5 m/s for 60 and 47% of the time, respectively. The two sites are candidates for remote area wind energy applications. The costal site's, i.e. Yanbu and Dhahran wind speed data indicated that the two sites have lower annual wind speed averages and wind blows at speed higher than 5 m/s during afternoon hours. That makes the two sites candidates for grid connected wind systems for electrical load peak shaving. The data of Gassim site showed that the site has the lowest wind energy potential compared to the others. The annual energy produced by a Nordex N43 wind machine is estimated to be 1080, 990, 730, 454 and 833 MWh for Dhulum, Arar, Yanbu, Gassim and Dhahran, respectively. The analysis showed that the estimated annual energy produced by the machine based on 10 min averaged data is 2.5% higher than the estimated energy based on 30 min averaged data.     

基于叶片形态特征的葡萄品种自动识别

葡萄在全世界种植范围较广,葡萄品种识别对葡萄资源统计、新品种鉴定及遗传资源保护都有重要意义。以成熟叶片为基本材料,不变矩、面积、周长、主叶脉长度和叶柄长度等11维特征向量为基础数据,采用叶片特征选择、图像处理、特征值提取、建立分类模型等方法,运用国际葡萄与葡萄酒组织形态分类方法和改进的欧式距离等技术开发一个基于葡萄叶片数字图像的葡萄品种自动识别软件。共测试17种酿酒和3种野生葡萄,识别率达87%。该方法具有自动化、识别速度快、花费低、省时省力等特点,可应用于葡萄病虫害的识别、杂交新品种双亲的判定等。     

中国铝型材企业如何适应未来的市场需求

介绍了目前我国铝型材的市场状况，指出中国铝型材企业未来的市场状况将与日本15年前的市场状况相似，也指出了我国型材企业目前与先进国家的差距及如何赶上的措施。     

我国化肥催化剂工业现状

全国48家化肥催化剂制造厂总能力为57Kt/a,产量近30kt/a,设备利用率不到50%。平均万吨氨耗催化剂10.36t,高于国外5.60t水平。现生产31个品种203个型号的催化剂中有103种经部级鉴定,但经常使用的约50种。目前化肥催化剂工业水平与国外相比还存在四方面差距。     

Effect of excess boron fertilization on status and availability of boron in calcareous soils

Field experiments were conducted at Al-Qatif area in the eastern region of Saudi Arabia to study the status and availability of B under B fertilization regime in three types of calcareous soils and to evaluate the response of two alfalfa varieties, Hassawi (local variety) and Hyden (american variety), to increasing levels of added B.Boron was applied at 7 rates as Na₂B₄O₇.10H₂O. Four cuttings were taken from each site at different intervals. Data showed that extractable B by hot-water and NH₄HCO₃-DTPA (8 days after borax application) was significantly (p <0.001) affected by soil type and B applications. The amount of B recovered by hot-water from the three soils, 200 days after borax application, was in the following order: sandy loam > sandy clay loam > clay loam.Total dry matter of alfalfa (4 cuttings) was significantly (p <0.05) affected by soil type, borax application rates and alfalfa variety.The critical level of B in plant as determined by Cate and Nelson analysis, ranged from 148 to 652 mg kg^–1 dry matter for Hassawi cultivar and 138 to 521 mg kg^–1 for Hyden cultivar in the first harvest. However, the upper critical levels for the 2nd, 3rd and 4th harvests were 800, 875 and 935 mg B kg^–1 dry matter for Hassawi and 603, 723 and 812 mg B kg^–1 for Hyden varieties, respectively. Nevertheless, the lower critical levels for 2nd, 3rd and 4th harvests ranged from 148 to 153 mg B kg^–1 dry matter for Hassawi and 138 to 142 mg B kg^–1 for Hyden.     

应用分子蒸馏技术分离提纯玫瑰精油

应用刮膜式分子蒸馏装置对玫瑰精油的提纯进行了研究。考察了进料速率、进料温度、蒸发温度和刮膜器转速等因素对玫瑰精油分离效果的影响。通过试验,初步得到了工艺参数的范围:进料速率为50~70 mL/h,进料温度为53~60℃,蒸发温度Ⅰ为100~108℃,蒸发温度Ⅱ为120~130℃,操作压力1.5 Pa,刮膜器转速150~160r/m in,得到的玫瑰精油产品的纯度在86%以上,分离过程总收率大于60%,并为今后工艺参数优化奠定了基础。     

玫瑰香精油化学成分分析

应用气相色谱-质谱联用(GC/MS)方法,定性定量地分析了山东平阴玫瑰精油、新疆玫瑰精油、北京妙峰山玫瑰精油和保加利亚玫瑰精油的化学成分,各鉴定了29、37、23和24个成分.它们的主要成分均为香茅醇及其脂类、香叶醇、芳樟醇、玫瑰醚和丁香酚,其中北京妙峰山玫瑰油与其他油品有较大差异.各种香精物质含量上的差异使得这几种玫瑰油的香气产生了微妙的出入.详细地讨论了这4种玫瑰油的化学成分与香气间的关系,指出国内玫瑰油的不足之处,为提升我国玫瑰精油的品质提供借鉴和依据.     

虎红定量光度法测定乳糖酸阿奇霉素

基于乳糖酸阿奇霉素与虎红形成离子缔合物,该离子缔合物的最大吸收在波长560nm处,此处其吸光度与质量浓度呈现线性关系,提出了一种测定乳糖酸阿奇霉素的定量光度法。详细研究了该显色反应的各种影响条件,在条件优化基础上建立了乳糖酸阿奇霉素的测定方法,结果表明乳糖酸阿奇霉素质量浓度的线性范围在5.0~25.0g·L-1之间。所拟方法成功地应用于乳糖酸阿奇霉素注射剂的测定。     

Natural Plant Materials as Dielectric Layer for Highly Sensitive Flexible Electronic Skin

Nature has long offered human beings with useful materials. Herein, plant materials including flowers and leaves have been directly used as the dielectric material in flexible capacitive electronic skin (e‐skin), which simply consists of a dried flower petal or leaf sandwiched by two flexible electrodes. The plant material is a 3D cell wall network which plays like a compressible metamaterial that elastically collapses upon pressing plus some specific surface structures, and thus the device can sensitively respond to pressure. The device works over a broad‐pressure range from 0.6 Pa to 115 kPa with a maximum sensitivity of 1.54 kPa^?1, and shows high stability over 5000 cyclic pressings or bends. The natural‐material‐based e‐skin has been applied in touch sensing, motion monitoring, gas flow detection, and the spatial distribution of pressure. As the foam‐like structure is ubiquitous in plants, a general strategy for a green, cost‐effective, and scalable approach to make flexible e‐skins is offered here.