Classification of common oysters from North China

Oysters are commonly found on rocky shores along China's northern coast, although there is considerable confusion as to what species they are. To determine the taxonomic status of these oysters, we collected specimens from nine locations north of the Yangtze River and conducted genetic identification using DNA sequences. Fragments from three genes, mitochondrial 165 rRNA, mitochondria! cytochrome oxidase I (COI), and nuclear 285 rRNA, were sequenced in six oysters from each of the nine sites. Phylogenetic analysis of all three gene fragments clearly demonstrated that the small oysters commonly found on intertidal rocks in north China are Crassostrea gigas (Thunberg, 1793), not C. plicatula (the zhe oyster) as widely assumed. Their small size and irregular shell characteristics are reflections of the stressful intertidal environment they live in and not reliable characters for classification. Our study confirms that the oysters from Weifang, referred to as Jinjiang oysters or C. rivularis (Gould, 1861), are C. ariakensis (Wakiya, 1929). We found no evidence for the existence of C. talienwhanensis (Crosse, 1862) and other Crassostrea species in north China. Our study highlights the need for reclassifying oysters of China with molecular data.

青海省不同地区人工栽培大黄氨基酸含量的比较

青海地道中药材“西宁大黄”野生资源濒临枯竭，人工种植规模不断扩大。采集青海不同地区3年生种植大黄及野生大黄，分析测定其中18种氨基酸的含量，为“西宁大黄”资源的可持续开发和利用提供依据。

Determination of free fatty acids in soil and bryophyte plants by precolumn derivatization via HPLC with fluorescence detection and tandem mass spectrometry (HPLC-MS/MS)

A sensitive method for the determination of 30 kinds of free fatty acids (FFAs, C-1-C-30) with 1-[2-(p-toluenesulfonate)-ethyl]-2-phenylimidazole-[4,5-f] 9,10-phenan- threne (TSPP) as labeling reagent and using high performance liquid chromatography with fluorescence detection and identification by online postcolumn mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive-ion mode (HPLC/MS/APCI) has been developed. TSPP could easily and quickly label FFAs in the presence of K2CO3 catalyst at 90 degrees C for 30 min in N,N-dimethylformamide (DMF) solvent, and maximal labeling yields close to 100% were observed with a 5-fold excess of molar reagent. Derivatives were stable enough to be efficiently analyzed by high performance liquid chromatography. TSPP was introduced into fatty acid molecules and effectively augmented MS ionization of fatty acid derivatives and led to regular MS and MS/MS information. The collision induced cleavage of protonated molecular ions formed specific fragment ions at m/z [MH](+)(molecular ion), m/z [M'+CH2CH2](+)(M' was molecular mass of the corresponding FFA) and m/z 295.0 (the, mass of protonated molecular core structure of TSPP). Fatty acid derivatives were separated on a reversed-phase Eclipse XDB-C-8 column (4.6 x 150 mm, 5 mu m, Agilent) with a good baseline resolution in combination with a gradient elution. Linear ranges of 30 FFAs are 2.441 x 10(-3) to 20 mu mol/L, detection limits are 3.24 similar to 36.97 fmol (injection volume 10 mu L, at a signal-to-noise ratio of 3, S/N 3:1). The mean interday precision ranged from 93.4 to 106.2% with the largest mean coefficients of variation (R.S.D.) < 7,5%. The mean intraday precision for all standards was < 6.4% of the expected concentration. Excellent linear responses were observed with correlation coefficients of > 0.9991. Good compositional data could be obtained from the analysis of extracted fatty acids from as little as 200 mg of bryophyte plant samples.Therefore, the facile TSPP derivatization coupled with HPLC/MS/APCI analysis allowed the development of a highly sensitive method for the quantitation of trace levels of short and long chain fatty acids from biological and natural environmental samples.

Distribution and species diversity of plant communities along transect on the Northeastern Tibetan plateau

The distribution and species diversity of plant communities along a 600 km transect through the northeastern Tibetan Plateau (32 degrees 42'-35 degrees 07' N, 101 degrees 02'-97 degrees 38' E) with altitudes from 3255 to 4460 m are described. The transect started from the Youyi Bridge of Banma through Dari, Maqin and Maduo to Zaling Lake. The data from 47 plots along the transect are summarized and analyzed. The mean annual temperature, the mean annual rainfall and the length of growing season decreases from 2.6 to -4.5 degrees C, from 767.2 to 240.1 mm, from 210 to 140 days, respectively, along the transect from the southeastern Banma to northwestern Zaling Lake. The number of vascular plant species recorded in 47 plots is 242 including 2 tree, 34 shrub, 206 herb species. Main vegetation types on the transect from southeast to northwest are: Sabina convallium forest, Picea likiangensis forest, Pyracantha fortuneana + Spiraea alpina shrub, Hippophae neurocarpu shrub, Sibiraea angustata + Polygonum viviparum shrub, Stellera chamaejasme herb meadow, Potentilla fruticosa + Salix obscura + Carex sp. Shrub, Kobresia capillifolia meadow, P. froticosa + Kobresia humilis shrub, Caragana jubata + S. obscura shrub, Kobresia tibetica meadow, Kobresia pygmaea meadow, K. pygmaea + Stipa purpurea steppe meadow, Stipa purpurea steppe. Plant richness and diversity index all showed a decreasing trend with increasing of elevation along transect from southeast to northwest. Detailed information on altitudinal ranges and distribution of the alpine vegetation, vascular flora and environments over the alpine zone at northeastern Tibetan Plateau provides baseline records relevant to future assessment of probable effects of global climate changes.

单元重构问题探讨

在 CIMS 环境下,采用虚拟单元技术可以解决使用成组单元的结构中出现的过量跨单元加工和加工负荷不平衡问题.本文对实现虚拟单元的关键技术——单元重构的可行性进行了分析,对单元重构的两个主要过程,即任务的时间分解过程和任务的空间分解过程进行了详细的讨论,并对所涉及到的时间划分、计划调度、工件、机器成组等问题给出了相应的策略和算法.从而证明了在 CIMS 环境下实现虚拟单元的可行性.

机器人形状记忆合金(SMA)驱动器及其控制探讨

本文在一般地介绍了形状记忆合金(SMA)的工作原理、SMA驱动器类型、SMA驱动器控制的基础上.描述了我们自行研制的单自由度的SMA驱动机构和SMA比例控制器.该控制器不论对于指定路线的程序控制还是任意给定主从遥控都能很好地完成给定的作业任务.

贵州红枫湖水体溶解有机质的剖面特征和季节变化

溶解有机氮(dissolved organic nitrogen , DON) 与溶解有机碳(dissolved organic carbon , DOC) 相结合在湖泊水体溶解有机质(dissolved organic matter , DOM) 的研究中少有报道. 本研究对贵州喀斯特地区高原性湖泊-红枫湖水体DOC 和DON 的含量进行了近2a 的测定,研究了DOM 的剖面特征和季节变化,并探讨了DOM 垂向分布和季节变化的影响因素. 结果表明,红枫湖DOC 的浓度范围为1160～3108 mg·L - 1 ,DON 的浓度范围为0110～0137 mg·L - 1 . 在湖水混合期表层和底层的DOC和DON 的浓度基本一致,在湖水分层期DOC 和DON 浓度表现出从表层往底层减小的趋势. 表层水体(0～2m 或3m) DOC 的浓度在春末夏初或夏季达到最大,DON 的浓度在春末夏初稍高于其它月份. 结合叶绿素和降雨的数据分析认为,藻类活动和陆源输入直接导致了表层水体DOM 的季节变化模式. DOM 的C/ N 在一般情况下向下增大,但在夏季南湖的垂向水柱上,DOC 和DON 的浓度在12m 以下增大,C/ N 从12m 的1811 下降为14m 的1419 ,并向下持续减小,这很有可能是颗粒态有机质发生降解释放出C/ N 较低的DOM ,成为水体内DOM 的一个内源.

现代分析技术在土壤腐殖质研究中的应用

土壤腐殖质的研究已成为土壤学、环境化学和地球化学等的热点方向之一。应用核磁共振兴谱（NMR）、红外光谱（IR）、荧光光谱（FS）、电子自旋共振谱（ESR）等现代分析技术，对在土壤腐殖质组成和结构研究中取得的主要成果进行了综述。

洞穴次生化学沉积物环境替代指标形成的地球化学动力学研究

洞穴化学沉积物气候-环境记录机理研究中,亟需了解各种环境替代指标形成的地球化学过程及其影响因子.我们以洞穴滴水为主线长期系统监测研究了气候-环境信号的传递过程和受控因素,判别了洞穴顶板土壤基本情况(自然和人为作用),分析了洞穴滴水的水动力特征,归纳了水文、水文地球化学过程及简单模型,考察了滴水的DOC、荧光强度及相关性,综合探讨了氢、氧、碳同位素信号传递过程及其受控因素,以及对不同生态系统的碳、氧同位素的对比.当前我们所获得的主要成果和认识是:发现滴水的溶解有机碳和荧光强度以每年4～6月最强,并与洞穴上覆植被条件成正相关;降雨对洞穴滴水氧同位素组成有明显的控制作用和一致的季节变化特征,蒸发作用对氧同位素信号的传递有不大于2‰的影响作用;植被条件对滴水碳同位素信号起主导控制作用,δ13C值在湿热条件下低于干冷条件,明显受降雨稀释效应、水动力过程、方解石溶解/沉积作用和CO2逃逸等因素的影响.