开发生产长效碳酸氢铵增强小氮肥企业活力

<正>市场经济的发展使碳铵企业陷入了困境首先,从产品本身来讲,碳铵的化学性质不稳定,含氮量只有17%,氮素利用率低(25%左右),肥效期短(35～45天),

Structure identification of five unknown dilipo-alkaloids extracted from processed tuber of Aconitum carmiechaeli by electrospray ionization tandem mass spectrometry

The alkaloids in processed aconite tuber of Aconitum Carmiechaeli were studied, and five novel alkaloids in extract from processed aconite tuber were found. The first step involved the use of electrospray ionization mass spectrometry (ESI-MS), and then multi-stage tandem mass spectrometry (MSn) was used to provide structural information. Based on their MSn spectra, the structures of the five novel compounds were elucidated to be C3,C8-difatty acid esters of mesaconitine, aconitine and 10-hydroxyaconitine.

MF_2:Eu,Ce(M=Ca,Sr,Ba)中稀土离子的价态变化

我们已经实验证明并报道了Eu-Tb之间、Ce-Yb之间的电荷转移.本文首次实验证实了Ce~(3+)离子和Eu~(3+)离子之间电荷转移现象的存在,进一步阐述了稀土价态与其电子组态共轭特征的相关性.1 实验部分1.1 试剂CaF_2,SrF_2,BaF_2,NH_4HF_2、氢氟酸、盐酸均为分析纯,EuF_3和CeF_3分别由高纯Eu_2O_3(99.95%)及CeO_2(99.99%)自制.1.2 MF_2:Eu,Ce体系的合成按化学计量比(MF_2:X%CeF_2,y%EuF_3;X=1,y=0,0.1,0.3,0.5,1;X=0,0.05,0.1,0.3,0.5,y=1)准确称取原料,放人玛瑙研钵中充分研混后装入刚玉柑涡中,置于管状炉内(用氢气

钐原子激发态自然辐射寿命的测量

稀土元素钐(Sm)的基组态是4f~66s~2,其4f壳层未添满,s电子及f电子都有可能被激发,产生复杂的光谱性质。早在1969年,Handrich等人就采用能级交叉的方法测量了钐原子的4个低激发态的寿命。之后,由于寿命测量技术的发展,人们采用各种不同的方法与技

Ocean urea fertilization for carbon credits poses high ecological risks

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. (C) 2008 Elsevier Ltd. All rights reserved.

Effect of nano-TiO(2)on MP-25 resin

MP-25 resin is a chlorine-containing polymer widely used in coatings. The effects of two types of nano-TiO2 (P-25 and RM301 LP) on MP-25 were studied with saline immersion, UV irradiation, and electrochemical impedance spectroscopy. UV irradiation was evaluated in terms of gloss change and X-ray photoelectron spectroscopy (XPS). The results indicate that, compared to pigment R-930 TiO2, P-25 reduced the immersion resistance and accelerated UV aging of the MP-25 coating, whereas RM301 LP showed the opposite effects. XPS analysis showed that MP-25 resin degraded under UV irradiation via dechlorination and C-C bond breakage, similarly to poly(vinyl chloride), but RM301 LP could inhibit the aging of MP-25 to a certain extent. A skin effect of oxygen and chlorine was identified in MP-25 resin by XPS. RM301 LP could improve the impedance of the MP-25 coating because of its excellent fill capacity. Hence, rutile nano-TiO2 RM301 LP represents an excellent additive for MP-25 resin. (c) 2007 Wiley Periodicals, Inc.

人工栽培抱茎獐牙菜矿物质元素含量的研究

采集种子采收前和采收后的抱茎獐牙莱全植株，分别分析测试其钾、钠、钙、镁等矿物质元素的含量。结果表明：青海西宁廿里铺种植抱茎獐牙菜矿物质元素主要分布于植株的茎杆部位，矿物质元素含量在成熟种子采收前后具有动态性变化的特征。

糖茶藨种子脂肪酸含量分析

用超临界萃取技术对产于青藏高原上的糖茶藨种子中脂肪酸进行萃取，其萃取率为12％。用毛细管气相色谱对萃取的脂肪酸进行了分离和分析。结果表明不饱和脂肪酸的质量分数在90％以上。其中α-亚麻酸（α-linolenic acid）为27.4％，У-亚麻酸（У-linolenic acia）为2．70％。亚油酸（1inoleic acid）40．0%，油酸（oleic acid）21．0％。[著者文摘]

国外建筑业的机器人化──国外建筑机器人发展概述

目前机器人的应用正从传统的制造领域向非制造领域扩展，特种机器人已成为９０年代机器人技术的研究重点，建筑业的机器人化已是大势所趋。本文论述了建筑机器人的关键技术、种类、应用及研究现状，并预测其未来发展。

喀斯特石漠化灾害预警及其风险评估模型研究

喀斯特石漠化灾害是存在于喀斯特区的一种重要的地质一生态灾害。在喀斯特石澳化时空变化分析与驱动机制诊断的基础上, 进行喀斯特石漠化灾害预警风险分析, 设计喀斯特石澳化灾害预誉风险决策支持系统, 构建石澳化灾害预誉风险模型, 为喀斯特石澳化区的土地合理利用和防灾减灾提供科学依据。

贵州区域农业生态环境综合评价

科学地评价贵州的农业生态环境, 可以为西部大开发中的区域发展战略提供理论依据。本文应用模糊综合评价方法, 通过对贵州各个区域的自然、社会、经济环境的系统研究, 对贵州各区域农业生态环境进行了客观评价, 从定量角度对各区农业生态环境加以探讨; 并对西部大开发中贵州农业生态环境保护提出了合理建议。

铊成矿地质地球化学特征

迄今为止，铊成矿仅见我国，故研究铊成矿我国应是首开先河。从铊矿床成矿作用研究铊矿床地质地球化学特点，其目的在于强调从生物成矿角度研究微古生物在新陈代谢过程中吸收富集铊成矿和生物残骸积累铊成矿。进而从本质上认识铊在成矿演化过程中地质地球化学和生物化学等多种因素相互作用的特殊成矿机制.