从索洛模型看中国电力消费对经济增长的影响

电力工业作为国民经济的基础性产业,不仅维系国民经济命脉、国家能源安全和社会稳定,同时也是衡量一个国家现代化水平高低的重要标志之一。自20世纪70年代末以来,学术界对能源消费与经济增长之间因果关系进行了大量的实证研究

Dynamics of soil organic carbon in Caragana microphylla forest and its relationship with environment factors in loess hilly region

以黄土丘陵区柠条人工林为研究对象,采用野外调查与室内分析相结合的方法,探讨柠条生长过程中土壤有机碳储量的变化规律。结果表明:1)土壤有机碳主要分布在0～20 cm土层,占0～50 cm土层总储量的49%～63%;2)相对于对照地,柠条林地土壤有机碳储量随柠条生长年限的增加先减小再升高最后趋于稳定,10、26、40、50 a柠条林地土壤总有机碳储量分别为1.555、3.236、2.775、2.444 kg/m2,26 a林地土壤有机碳储量最高,随林龄增大其变化趋于稳定;3)相关性分析结果表明,土壤有机碳质量分数与土壤密度之间呈显著负相关关系,各林地土壤密度随柠条生长年限的增加而减小,说明柠条可以通过改变土壤性质间接增加土壤总有机碳储量,土壤有机碳质量分数与根系生物量、土壤全氮质量分数之间呈极显著正相关关系,说明柠条的根系生长和固氮特性有助于有机碳的积累

PM_(2.5) in Northern Coastal Area of Shandong Peninsula: Correlation between Its Acidity and Chemical Composition in Winter

To investigate the acidity variation characteristics of fine particulate matter (PM_(2.5)) in the areas down-wind of Jing-Jin-Ji region in winter, the Qimu Island Environmental Monitoring Station, situated in Shandong peninsula, conducted a PM_(2.5) sampling project for the period from 3 January-11 February, 2014 according to the sample collection schedule: one sampling every 12 hours. The analytic results of the samples showed that the average mass concentrations of PM_(2.5) during the sampling period were (77.1&plusmn;58.7) &mu;g/m~3; the total content of water soluble ions including SO_4~(2-), NO_3~-, Cl~-, NH_4~+, Ca~(2+), K~+, Na~+ and Mg~(2+) accounted for (37.3&plusmn;16.3)% of PM_(2.5) mass, among others, the share of SO_4~(2-), NO_3~-and NH_4~+ were the most, and no obvious variation of the contents of PM_(2.5) and the ions was noted day and night, but the variation was comparatively remark- able according to the trajectory classification of clustered air mass. On the basis of the assessment by the ion balance method and modeling of ISORROPIAⅡ, total acidity and in-situ acidity were (309&plusmn;544) nmol/m~3and (193&plusmn;292) nmol/m~3, respective- ly, and no notable variation of total acidity of PM_(2.5) was observed for the day and night but the change was significant according to classified clustered air mass. The M-K test indicated that acidity decreased when the 2nd class clustered air mass oc- curred, and the linear regression analysis suggested that it was the in-situ acidity that notably influenced the total acidity and the water content in PM_(2.5) was unlikely the main factor that restricted acidity of PM_(2.5).</p

Effects of nutrient on fatty acid composition in Spirulina platensis

本文研究不同浓度的氮、磷和碳以及不同的氮源对螺旋藻脂肪酸组成和含量的影响 .结果表明 :改变营养盐的浓度对藻体TSFA和TPUFA均有较大影响 ,而对TMUFA无显著影响 ;氮源NaNO3浓度为 0 .5 g dm3、磷源K2 HPO4 浓度为 0 .3～ 0 .5g dm3、碳源NaHCO3浓度为 4.5 g dm3时 ,藻体均可合成亚麻酸C1 8∶3,藻体TPUFA有最大值分别为 44.0 7%、46 .47%和 5 1 .98% ;以尿素和硫酸铵为氮源 ,藻体含有C1 6∶2、TPUFA分别可提高 4.46 %和 7.2 8% .以谷氨酸为氮源 ,藻体含有C1 6∶2和C1 8∶3、TPUFA可提高 6 .43%Under batch culture condition,the effect of different nitrogen (NaNO 3,glutamic acid,urea and ammonium sulfate),phosphorus and carbon sources on the fatty acid composition in Spirulina platensis was carried out. Results showed that the algal could synthesize linolenic acid and TPUFA contents raise a peak value when the concentration of NaNO 3., K 2HPO 4. and NaHCO 3. was 0.5,0.3～0.5 and 4.5g/dm.3 respectively. Result also indicated that taking glutamic acid,urea and ammonium sulfate as nitrogen source, the algal contains C18∶3 and TPUFA contents increases 6.43%,4.46% and 7.28%, respectively. In addition, taking glutamic acid as nitrogen source, the algal also could synthesize linolenic acid.国家自然科学基金!资助项目 (39870 5 6 5

The study of variations of the fatty acids in Spirulina platensis with culture time, temperature and nutrient

研究了螺旋藻脂肪酸随培养时间(生长周期、昼夜)、温度和营养盐(氮、磷、碳和铁)的变化.结果表明在螺旋藻的生长周期内,其体内脂肪酸随培养时间而变化,呈现出多样性的趋势,随温度的变化亦是如此.不论用Zarrouk配方或MSS-1配方培养的螺旋藻,其体内均富含C18∶4,C18∶2和一定量的γ-亚麻酸(C18∶3).用Zarrouk配方淡水培养时,体内总不饱和脂肪酸含量在4～13d内最高为4 5%～5 2%(以干重表示),7d后产生γ-亚麻酸;用MSS-1配方海水培养,其体内总不饱和脂肪酸含量在2～7d内最高为4 4%～6 6%,仅第10～13天含C18∶3.在一个日变化中螺旋藻体内总不饱和脂肪酸和C18高度不饱和脂肪酸含量早上08:00最高,1d的变化幅度为51%～57%.螺旋藻在30℃培养,其体内脂肪酸组成最丰富,γ-亚麻酸含量最高;在20～30℃随着温度升高,总不饱和脂肪酸增加21%,C18高度不饱和脂肪酸下降8%;在35℃总不饱和脂肪酸和C18高度不饱和脂肪酸均下降,幅度为65%～70%.此外,营养盐氮、碳和氮、铁分别是总不饱和脂肪酸和C18高度不饱和脂肪酸的主要影响因子.Variations of the fatty acids (FA) in S. platensis with culture time, temperature and nutrient (such as nitrogen, phosphorus, carbon and iron) have been studied. It is shown that (1) S. platensis both grown in Zarrouk and MSS-1medium is rich in unsaturated acids 18∶4, 18∶2 and contains considerable amounts of 18∶3 (γ-linolenic acid); the total unsaturated fatty acids (TUFA) of the alga cultured in Zarrouk medium were 4.5%～5.2% of the total fatty acids (TFA) (on dry weight) at 4th to 13th day, and the alga contained 18∶3 after 7 d; TUFA of the alga grown in MSS-1 medium were 4.4%～6.6% of TFA at 2nd to 7th day, and the alga contained only 18∶3 at 10th to 13th day; (2) the contents of total unsaturated fatty acids (TUFA) and C_(18) polyunsaturated fatty acids (PUFA) during diurnal cycle were the highest at morning 08:00; The change range of TUFA and C_(18) PUFA in a day and night was 51%～57%; (3) S. platensis grown in Zarrouk medium at 30 ℃ was abundant in components of UFA, and had high concentration of 18∶3; TUFA and C_(18) PUFA were respectively, increased 21% and decreased 8% with temperature increased from 20 to 30 ℃, and also obviously decreased 65%～70% at 35 ℃; (4) the major influence factors of TUFA and C_(18) PUFA are respectively nitrogen, carbon and nitrogen, iron.国家自然科学基金资助项目(39870565)