Adsorption mechanism of rare earth elements and humic acids in the system of iron oxyhydroxide

实验考察稀土元素(La3+、Ce3+、Ho3+、Yb3+)在水合氧化铁表面的吸附动力学过程,对比研究腐殖酸对吸附机制的影响.当腐殖酸与稀土元素共存时,腐殖酸通过化学吸附优先占据氧化铁表面的吸附点位,颗粒物表面特性因覆盖有机膜而得到修饰.初期的动力学过程主要表现为腐殖酸的竞争吸附,随后转变为吸附态腐殖酸对稀土元素的表面结合.轻稀土因较强的结合能力而比重稀土易于被吸附去除,这与天然水体中发生的稀土元素分异现象保持一致.Kinetics of rare earth elements(La~(3+),Ce~(3+),Ho~(3+),Yb~(3+)) adsorption to the iron oxyhydroxide were investigated,and the effects of humic acid on adsorption mechanism were revealed.Coexisting humic acid with rare earth elements(REEs),the surface sites of iron oxyhydroxide might be occupied preeminently by the humic acid through the chemical adsorption,and the characteristics of the solids are decorated by covering the organic membrane.The adsorption kinetics of REEs initially shows the competitive adsorption with humic acid,and then is the surface binding with the adsorbed humic acid.The LREEs tend to be adsorbed on the solids and removed from the liquid due to their stronger binding ability with humic acid than the HREEs,which is consistent with the fractionation of the REEs taking place in the natural waters.国家教育部资助优秀青年教师项目(1999

企業發行新直接金融工具決策之研究

在全球資本市場逐漸趨於整合，直接金融工具不斷推陳出新的金融環境裡，如何從資本市場籌措資金，以滿足企業在投資、營運與理財活動上的需求，並作為企業策略上的競爭武器，已是國內企業必須面臨的一項重大課題。本研究主要之目的包括：(1)以國內企業發行新直接金融工具之個案為樣本，探討產業類型、金融工具與融資金額間的相互關係。(2)以四家個案公司為例，探討企業界在融資實務上的作法是否吻合財務管理理論，若有差異其中可能的因素為何?(3)探討企業發行新直接金融工具的決策模式，並比較不同類型公司融資政策的異同點。(4)透過對企業、銀行、主管機關之訪談，探討企業發行金額、幣別、時機、上市地點、選擇主辦銀行等實務，以提供企業發行決策之參考。本研究首先根據所蒐集的次級資料，利用二因子變異數分析的方法，探討新直接金融工具、企業特性與發行金額之間的關係。其次遴選曾多次發行新直接金融工具的上市公司，與承辦經驗較豐富的投資銀行進行實地深入訪談，探討企業界在融資實務上的作法是否吻合財務管理理論，若有差異其中可能的因素為何?研究結果顯示：(1)發行新直接金融工具企業的資本額平均數顯著大於全體上市公司資本額平均數。(2)發行新直接金融工具企業的營業成長率平均數與全國前一千大製造業營業成長率平均數並無顯著不同。(3)大型企業與中型企業發行金額之間有顯著差異。(4)成長型企業與成熟型業發行金額之間並無顯著差異。(5)融資工具特性（權益相關或純負債）與發行金額之間無顯著差異。(6)海外直接金融工具籌資每筆發行金額顯著高於國內直接金融工具每筆發行金額。(7)四家個案公司的目標資本結構，融資政策與投資政策配合、外幣融資政策、發行時機、投資銀行之選擇等實務大體上與財務管理理論相吻合

Study on Rice Yield and Quality Estimated by Remote Sensing Techniques

本四年期計畫的總目標為開發推估水稻產量與稻米品質之遙測技術，建立可實用之作業系統。本年度之工作重點在於測試應用抽穗期單時段衛星多光譜影像推估水稻產量之準確性與實用性，開發應用多時段衛星多光譜影像推估水稻產量的遙測技術，以及應用衛星多光譜影像和機載高光譜影像推估田間稻米品質之遙測模式。預期可建立利用多光譜遙測影像判釋田間水稻產量的技術，提高糧政單位對當期水稻產量估測之準確度，將有助於進行糧食供需調控的作業。也可建立利用高光譜遙測影像判釋稻米品質的技術，提供作為農民調整田間栽培管理措施的依據，將有助於提升國產稻米的品質與競爭力。The final goals of this four-year study are to develop remote sensing techniques for estimating rice yield and rice quality. The goals set for this year are to to test the accuracy and practical applicability of using satellite images at heading stages to estimate rice yield, develop techniques of using multi-temporal images to estimate rice yield, and to collect ground truth data to develop remote sensing models for detecting rice quality. It is expected that remote sensing techniques capable of estimating rice yield, using single and multi-temporal images can be developed. The accuracy and efficiency of current rice production estimation can thus be elevated. It is also expected that remote sensing models, capable of estimating rice quality, using multispectral and hyperspectral images can be developed. These techniques can help farmers to adjust their field management practices to raise the quality of rice produced

Study on Vegetable Damage Survey by Remote Sensing Techniques

國內蔬菜生產易受降雨影響，且常為災害前後民眾所關注的生活必需品，如能精確掌握災損狀況，將可做為政府採行因應決策之參考。本研究擬進行應用遙測技術辨識及估算蔬菜作物雨害災損程度與範圍可行性之探討，作為後續進行蔬菜雨害遙測技術研究的基礎。預期可獲得下述成果。1. 建置蔬菜雨害地真光譜資料庫，可供後續發展災損遙測判釋模式，提高應用光學遙測技術進行災損程度調查的準確度。2. 探討應用雷達衛星監測土壤濕度的可行性，以便應用遙測影像於災後判釋蔬菜雨害可能受災範圍，以利農友和相關單位採行必要之因應措施。3. 建立西螺蔬菜生產區GIS資訊，當災害發生後，可快速獲得較精確之統計數字。Vegetables are commodities required in daily life but the productions are easily damaged in rainy season. Accurate estimation about the extent and degree of damages is the basis for making response strategies. In this study, the feasibilities of estimating the extent and degree of vegetable damages by remote sensing techniques during rainy season are to be evaluated and served as the basis for follow up researches. It is expected to achieve following objectives.1. To establish a canopy reflectance spectrum database for vegetables for further development of remote sensing models to evaluate the damage loss of vegetables.2. To explore the techniques of retrieving soil moisture from active microwave images for estimating the areal extent damaged. 3. To establish a GIS database for Shi-Lo vegetable production area so that more accurate damage statistics can be obtained

Study on the Binding Sites of Humic Acids with Rare Earth Elements and Its Characterization

采用红外光谱(FTIR)与核磁共振波谱(1H NMR和13C NMR)技术,对来自森林土壤和湖泊沉积物的两种腐殖酸及其与三价稀土离子(RE3+)沉淀反应的产物进行对比研究.结果表明,腐殖酸结构中活性官能团特征以及它的拥有量因腐殖化程度不同而存在较大差异.腐殖酸与RE3+沉淀反应产物在性质上属于一种有机弱酸盐,羧基-COOH和酚羟基-OH为主要结合点位,结合反应过程中它们的质子被RE3+交换出来.Two types of humic acids taken from forest soil and lake sediment,and their precipitation reaction products with the trivalent rare earth elements are identified comparatively by FTIR,~1H NMR and ~(13)C NMR spectroscopy.The FTIR and NMR spectra indicate that the structural framework of two humic acids are similar principally due to their same origin,but there is great difference in the structural characteristics and functional groups amount of humic acids because of their different humification degree.Forest soil humic acid(FHA) has more Ar-COOH with strong binding strength than lake sediment humic acid(SHA),which has more Ph-OH with weak binding strength due to its high humification degree.The explicit evidences of humic acids binding with trivalent rare earth elements are found from FTIR and NMR spectroscopy,which the Ar-COOH and Ph-OH are the main binding sites of humic acids with RE~(3+).The precipitation reaction products of humic acids with RE~(3+) belong to a kind of undissolved organic weak acid salts,which are similar to the binding reaction mechanism of weak acid with metal ions.In the reaction procedure of humic acids with RE~(3+),the results of pH monitoring of the solutions demonstrate that the protons of ArCOOH and Ph-OH can be exchanged out by RE~(3+).教育部优秀青年教师基金资

官厅水库及永定河枯水期水体氮、磷和重金属含量分布规律

于枯水期 (冬季和春季 )在官厅水库库区及永定河沿线 1 3个地点采集了表层水样品 ,分别测定了原水和过滤水中 N、P和重金属的含量 ,同时进一步分析了过滤水中不同形态氮的含量 ,初步探讨了枯水期官厅水库和永定河水体 N、P及重金属含量的分布规律及污染特征。研究结果表明 ,官厅水库库区及永定河沿线重金属基本没有污染 ,大多低于地表水 类标准 ,极个别样点超过 类但仍低于 类标准。 N、 P污染比较严重 ,大部分样点的总氮、总磷指标超过湖泊水库 类标准 ,个别样点甚至超过 类标准。不同地点 ,各形态 N的含量有显著差别 ,体现了外源污染的区域分布规律