一种新型多调制模式探地雷达系统的设计

文章设计了一种基于调频连续波的多调制模式探地雷达系统,该雷达系统相较于市场上同类产品,制造成本较低,能够以四种不同的调制模式进行探测工作,很好地满足了不同场景的探测需求.该系统通过C语言程序对系统中的微处理器进行编程,从而控制不同调制模式的转换.另外,针对该系统还进行了发射和接收天线的设计,以匹配该系统的探测需求.     

乙烯利和三十烷醇对黄瓜性别及其产量的影响

以黄瓜(Cucumis Sativus L.)为材料,在四叶期至性别定型前,于叶面两次喷施乙烯利.由初花期起在叶面三次喷施三十烷醇.试验证明,100,150和200mg/l乙烯利处理能提高雌雄比值,而对照则很低.     

Optimization of recovery and maturation methods for cumulus-oocyte complexes in jennies

Embryo production in donkeys is inefficient compared with that in other livestock. Obtaining a sufficient number of MII oocytes is the first step to solving this problem. In this study, the number, morphology and maturation rates of cumulus-oocyte complexes (COCs) obtained from abattoir-derived ovaries or live jennies were compared. The diameter of follicles from abattoir-derived ovaries was measured and divided into group 1 (2–6 mm), group 2 (6–10 mm), group 3 (10–20 mm), group 4 (20–28 mm) and group 5 (>28 mm). The results showed that the number of follicles per ovary in group 2 (3.6 ± 0.28) and 3 (4.2 ± 0.90) was higher than that in the other groups (p < .05). The recovery rate in group 3 was higher than group 1 (48.8% vs. 26.8%, p = .00), but lower than group 5 (48.8% vs. 76.5%, p = .025). The percentage of grade A COCs in group 3 was higher than group 2 (59.3% vs. 39.5%, p = .00) and group 1 (59.3% vs. 26.7%, p = .00). Moreover, the percentage of grade A COCs in group 4 (55.0%, p = .710) and group 5 (46.2%, p = .351) was reduced compared with that in group 3. From the above results, the developing follicles (group ovum pick-up [OPU], 10–20 mm) and preovulation follicles (group OPU-Preov, >35 mm) were aspirated from live jennies using OPU. Although there was no difference in the recovery rates of COCs between group 3 and OPU (48.8% vs. 43.0%, p = .184), the percentage of grades A COCs in group OPU was higher than group 3 (72.5% vs. 59.3%, p = .036). There was no difference in the maturation rate between group 3 and OPU (60.3% vs. 69.3%, p = .171) after the COCs matured in vitro. The rates of recovery (72.2%) and maturation (92.3%) in group OPU-Preov were higher than those in other groups (p < .05). Moreover, the effects of maturation time and serum type on maturation rates were evaluated in groups B44 (44 h, FBS), B36 (36 h, FBS) and D44 (44 h, foetal donkey serum, FDS). These results indicated that the maturation rate in group B36 was lower than group B44 (13.1% vs. 47.0%, p = .00) and group D44 (13.1% vs. 53.3%, p = .00). In conclusion, the quality of donkey COCs from OPU was higher than that from abattoir-derived ovaries, the suitable time of donkey in vitro maturation (IVM) was 44 h, and FBS could be replaced with FDS in donkey IVM medium.     

Effects of human enclosure and farming activities on heavy metals in sediments/soils of the coastal reclamation areas in the Yangtze Estuary

Journal of Soils and Sediments - The enclosure and reclamation of wetland sediments altered soil properties and heavy metal levels in coastal areas. This study focuses on the effects of...     

预测湿润锋进程的新方法

本文根据Darcy定律和水量平衡原理建立了一种能计算土层初始含水量不均匀的入渗过程的Green—Ampt模型。传统的Green—Ampt模型成为该模型在土层初始含水量均匀情况下的一个特例。本模型除了可直接用于土层水分入渗过程外,稍加修改便可用于多孔介质中液体的扩散过程计算和模拟。     

金银花ISSR-PCR反应体系的建立与优化

以金银花叶片基因组DNA为模板,通过单因素试验,研究了退火温度、Taq DNA 聚合酶的用量及模板DNA、引物、dNTPs、Mg2+浓度等6种因素对ISSR－PCR扩增的影响,建立了适合于金银花ISSR-PCR反应体系和扩增程序,即在20 μL反应体系中,内含1×PCR反应缓冲液（Mg2＋free）、1.5 U Taq DNA 聚合酶、0.15 mmol·L-1 dNTPs、0.4 μmol·L-1引物、1.5 mmol·L-1 MgCl2、60 ng模板DNA。确定了适宜的退火温度为49.9 ℃。扩增程序为94 ℃预变性5 min ;35个循环为94 ℃变性30 s,49.9 ℃退火30 s,72 ℃延伸1.5 min;最后72 ℃延伸7 min,4 ℃保存。利用优化反应体系,从100条ISSR引物中筛选出10条稳定性和重复性高的引物;以这10条引物对22个金银花品种基因组DNA扩增,共扩增出108条带,其中多态性条带96条,多态性条带比率为88.9%。金银花ISSR反应体系的建立为利用ISSR标记技术进行金银花品种鉴别、分类、种质资源遗传多样性分析奠定了良好基础。     

不同植被恢复模式凋落物水分涵养能力比较研究————以桂西北喀斯特石漠化地区为例

植被凋落物是森林生态系统的重要组成部分,对维持森林生态系统正常的物质循环和养分平衡,保持水土等方面具有重要的作用。为了深入了解不同植被凋落物的水分涵养能力,作者对桂西北典型石漠化地区宜州、环江、平果等地进行了实地调查和采样,通过对不同植被恢复模式调查样地凋落物现存量、持水特性和土壤含水量等相关项目的分析测试及数据整理,得到不同植被凋落物的现存量及最大持水量、最大持水率、土壤含水量的大小排序。凋落物现存量的排序为：青冈栎>杂木林>湿地松>单性木兰>枫香>湿地松+桉树混交林>桉树>青檀>吊丝竹> 檵木>杉木林>任豆>黄荆;最大持水量的排序为：青冈栎>杂木林>单性木兰>枫香>青檀>湿地松+桉树混交林>吊丝竹>湿地松>桉树> 檵木>杉木林>任豆> 黄荆;最大持水率的排序为：黄荆>杉木、任豆>青檀>枫香、单性木兰、吊丝竹>檵木>青冈栎>杂木林>湿地松+桉树混交林>桉树> 湿地松;土壤含水量的排序：任豆>吊丝竹>黄荆>青冈栎>青檀>杂木林>湿地松>湿地松+桉树混交林>檵木>单性木兰>枫香>桉树>杉木。通过对实验数据的处理分析,综合考虑经济成本及气候地理等因素,作者提出了一些提高土壤水分涵养的优化植被恢复模式, 为桂西北石漠化地区生态恢复提供理论参考。     

福建烟区土壤中、微量元素丰缺状况及施肥对策

2005年采集了福建省三明、龙岩、南平3个主产烟区有代表性的植烟土壤样品557个,并进行了土壤中、微量元素分析。结果表明,该区植烟土壤平均交换性钙含量1059.3±395.3mg/kg、交换性镁171.2±125.3 mg/kg、有效硫34.1±21.7 mg/kg、水溶性硼0.18±0.14mg/kg、水溶性氯23.5±11.8 mg/kg、有效锌1.99±1.30mg/kg、有效铜2.84±1.56mg/kg、有效铁216.6±98.2mg/kg。有26.2%的土壤缺钙,有12.4%的土壤严重缺镁,有42.2%的土壤缺硫或潜在缺硫,土壤普遍缺B,土壤水溶性Cl含量在比较适宜范围,土壤Cu、Fe、Zn营养供应比较充足。为此,在烟叶生产上要因地制宜,注意增施钙镁磷肥或氧化镁,喷施硼肥。     

甘蔗渣的综合利用技术的最新进展

摘 要：甘蔗渣是重要的生物质原料。综述最近20年来中外甘蔗渣的综合利用技术的最新进展。涉及反刍动物饲料开发、食用菌栽培、功能食品开发、生物学气化、生物学液化、热化学液化,气化和通过费托反应合成烃类的间接液化、高性能吸附材料开发、绿色制浆及其木质素高值化利用、高密度纤维板的生产等广泛领域,最后对甘蔗渣热化学炼制的技术开发前景进行了展望。