浅析沙漠化与沙尘暴对中国生态环境的影响

深入分析了沙漠化、沙尘暴形成的原因和沙漠化、沙尘暴对国民经济发展所造成的危害,并系统地提出了相应对策。

通过立法加强我国农业中农家肥资源的管理与利用

保持农业中农家肥养分资源的循环再利用是我国农业施肥的传统，在我国农业现代化进程中仍需努力保持这一传统，因为这不仅有利于农业中原有养分资源的充分利用，而且有利于提高化肥养分的利用效率，减少资源浪费和防止农业废料中养分进入环境导致农村和周边水体环境遭受污...

Studies on the Interaction between Single-strand Oligonucleotide and Ginsenosides by Electrospray Ionization Mass Spectrometry

Oligonucleotide from SARS virus was selected as a target molecule in the paper. The noncovalent complexes of ginsenosides with the target molecule were investigated by electrospray ionization mass spectrometry. The effects of experimental conditions were examined firstly on the formation of noncovalent complexes. Based on the optimized experimental conditions, the interaction of different ginsenosides with the target molecule was researched, finding that the interaction orders are relative with the structure of aglycons, the length and terminal sugar types of saccharide chains in the ginsenosides. There are certain rules for the interaction between the ginsenosides and DNA target molecule. For different type ginsenosides, the interaction intensity takes the orders 20-S-protopanaxatriol > 20-S-protopanaxadiol, and panaxatriol ginsenosides > panaxadiol ginsenosides. For the ginsenosides with the same type aglycone, tri-saccharide chain > di-saccharide chain > tetra-saccharide chain and single-saccharide chain > panaxatriol. For the ginsenosides with the same tetra-saccharide chain, the ginsenosides with smaller molecule masses > the ginsenosides with larger molecule masses.

Superhydrophobic PTFE surfaces by extension

A rather simple but yet effective way to achieve a superhydrophobic film by extending a Teflon film is proposed. The water contact angle can be increased from 118 to 165degrees by extending to ca. 190%. The fibrous crystals and the increasing distance between the fibrous crystals are believed responsible for the high water-contact angle. It indicates that the density of the aligned microstructures is very important for the superhydrophobicity.

Ho~(3+)对吸附CO电化学氧化的促进作用

研究了吸附在Pt/C催化剂上的Ho3+对吸附CO的电氧化的影响.结果表明,无论在中性和酸性溶液中,在较大的温度范围内,Ho3+对CO在Pt/C催化剂上的电氧化都有促进作用,其原因是吸附Ho3+的存在减弱了CO在Pt/C催化剂上的吸附强度.其次,在中性溶液中,Ho3+对吸附CO的电氧化的促进作用比在酸性溶液中大.第三,无论在酸性还是中性溶液中,温度的升高有利于发挥Ho3+对吸附CO的电氧化的促进作用.

Determination of surface pK(a) of SAM using an electrochemical titration method

A self-assembled monolayer (SAM) of 3-mercaptopropionic acid (HSCH2CH2COOH) was formed on a gold electrode. The effect of the charge of the end group on the electrochemical response of Fe(CN)(6)(3-) at the SAM modified electrode was studied by using cyclic voltammetry. At high pH, when the -COOH groups are dissociated, Fe(CN)(6)(3-) current is suppressed; as the solution pH is lowered, Fe(CN)(6)(3-) current increases. The electrochemical titration curve was obtained by correlating the currents to the different electrolyte pH values, from which the surface pK(a) was obtained to be 5.2+/-0.1. Furthermore, a calculation equation was presented to simulate the electrochemical titration. As comparison, the surface pK(a) was also measured by contact angle titration as 5.6+/-0.1. The surface pK(a) values determined by the two methods in our work are consistent and accurate.

Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column

A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 column was developed for the simultaneous determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus pluvialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The results showed that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry biomass in these green algae. The lower total astaxanthin levels (< 2 mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (> 16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9 mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingiensis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a remarkably lower percentage of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).

A nonlinear model for assessing multiple probabilistic risks: A case study in South five-island of Changdao National Nature Reserve in China

Several methods for estimating the potential impacts caused by multiple probabilistic risks have been suggested. These existing methods mostly rely on the weight sum algorithm to address the need for integrated risk assessment. This paper develops a nonlinear model to perform such an assessment. The joint probability algorithm has been applied to the model development. An application of the developed model in South five-island of Changdao National Nature Reserve, China, combining remote sensing data and a GIS technique, provides a reasonable risk assessment. Based on the case study, we discuss the feasibility of the model. We propose that the model has the potential for use in identifying the regional primary stressor, investigating the most vulnerable habitat, and assessing the integrated impact of multiple stressors. (C) 2006 Elsevier Ltd. All rights reserved.

底栖硅藻固定化研究

固定化是一个将酶或细胞固定到特定载体中或表面上的生物工程技术。在国际上，海藻固定化研究刚刚兴起，它作为藻类光生物反应器的一项基础技术，具有重要的理论意义，在藻类生物工程中有广泛的应用前景。用褐藻酸钙和聚氨酯泡沫塑料作载体，研究了被动包埋和主动侵入式固定化对底栖硅藻舟形藻（Navicula sp.）和新月菱形藻 (Nitzschia closterium) 的生长和生理物特性的影响，同时研究了载体本身的透光性和通透性。结果表明，褐藻酸钙固定化对底栖硅藻的光合作用有暂时的影响，但在培养过程中恢复正常。泡沫塑料固定化对硅藻无不良影响。在二种载体中，硅藻均能正常生长，光合色素组成和色素间能量传递以及光合作用和呼吸作用等生理过程都保持正常。由于载体对光的衰减和藻体相互遮光，使载体内部的藻处于弱光照，载体越大，影响越明显。硅藻的光合作用在这种固定化光照条件下表现为小环藻（Cyclotella）型的光强适应。载体为底栖硅藻提供了立体的生长空间，加大了单位水体的容量，而单位体积的褐藻酸钙的最大容量又是泡沫塑料的1.3-1.6倍。硅藻在褐藻酸钙胶球中生长曲线有明显的静止期，在泡沫塑料中无明显的静止期。胶球和泡沫塑料块的大小对硅藻的生长和最大光合速率有明显的影响。从载体的结构和特性对上述结果作了解释。上述结果为构建光生物反应器，底栖硅藻保种和大量扩种，用于鲍鱼和海参育苗生产提供必要依据。

青海湖流域沼泽化草甸形成发育的主要气候因子

青海湖是一个较特殊的巨大微咸水湖。青海湖流域沼泽化草甸具有明显的湿地生境特征,其形成发育和时空分布的主要气候因子是大于等于10 ℃的积温和5月至9月的降水及年湿润系数。根据主要气候因子作出了湿地率与该环境形成发育的主要气候因子的数学模型。

太阳活动驱动气候变化空间天气机制研究进展

大量研究表明,从数小时到十年、百年时间尺度上的天气、气候变化受太阳活动影响显著。近年来,全球云量、北大西洋冬季气旋等气候、气象要素与银河宇宙射线通量变化、太阳能量粒子事件等空间天气事件显著的统计相关被陆续发现。在此基础上,提出太阳活动驱动气候变化空间天气机制,其基本观点是:空间天气事件通过改变云物理特性影响气象、气候,其核心是:太阳活动造成的空间天气事件与云微物理过程的联系,目前空间天气理论分化为离子诱导成核机制和全球大气电路—静电云微物理机制(简称Tinsley机制) 。主要回顾和总结了近年来空间天气机制研究的发展,包括观测与理论,取得的成果,并对其未来的发展提出展望。