红松和长白松针叶暗呼吸对连续4个生长季高浓度CO_2处理的响应

以开顶箱法研究了高浓度CO2对长白山两种针叶树—红松和长白松针叶暗呼吸作用的长期影响.对两个树种连续4个生长季进行700和500μmol·mol-1CO2处理,同时设接受大气CO2浓度(约350μmol·mol-1CO2)的开顶箱为对照,在CO2处理的第2,3和4个生长季分别测定了针叶的暗呼吸速率.结果表明:CO2处理的第2个生长季,高浓度CO2下红松和长白松针叶暗呼吸速率增加,可能与碳氮含量变化有关;CO2处理的第3个生长季,高浓度CO2条件下生长的红松针叶暗呼吸速率增加,长白松针叶的暗呼吸速率下降,两树种呈不同响应主要与植株的生长速率不同有关;CO2处理的第4个生长季,红松和长白松针叶的暗呼吸速率均受高浓度CO2抑制.第3个生长季通过改变测量CO2浓度,发现高浓度CO2对长白松针叶暗呼吸作用的短期效应与长期效应呈现一致性,红松不完全相同.红松和长白松针叶的暗呼吸作用对高浓度CO2的响应与CO2处理时间及植株个体的生长发育阶段有关,暗呼吸速率的变化是CO2直接作用与长期驯化共同作用的结果,不能用短期的测定结果预测针叶暗呼吸对高浓度CO2响应的长期效应.

不同植被对土壤侵蚀及铜元素流失的影响

通过野外天然降雨产流及人工模拟降雨试验,研究不同植被对坡面土壤侵蚀及土壤铜元素流失的影响及降雨过程中铜元素的流失规律。结果表明:(1)紫花苜蓿、绿豆、荒草3种植被覆盖小区的年径流量为5183.8,5 366.2,3 867.3 m~3/km~2,比裸地减少33%,30.8%和50.1%;侵蚀模数为379.18.482.3,15.78 t/km~2,比裸地减少34.7%,16.4%和97.2%;全年全铜流失量为12.9,25.5,0.46 kg/km~2,有效铜流失量为6.22,11.01,0.15 kg/ km~2,分别比裸地减少67.3%,35.3%,98.8%和54.6%,19.6%,98.9%;(2)在模拟降雨过程中,农地小区的产流产沙强度过程呈现波动上升趋势,产沙过程波动较产流过程剧烈。铜元素流失强度过程与产流产沙强度过程相似,但其峰值多于产流产沙过程,且最高峰出现时间不同。有效铜流失强度变化率略高于全铜。

黄土高原水土流失区粮食现状与增产潜力研究

以黄土高原10个试区的攻关资料为基础 ,从区域旱作产量潜势、试区攻关水平和试区所在县的产量现状三个层次 ,详细剖析了黄土高原水土流失区粮食现状和增产潜力。结果指出 ,该区粮食增产潜力很大 ,目前整体产量水平仅达到试区攻关水平的74.7 % ,达到旱作粮食产量潜势水平的54.2 %。在黄土台塬区和丘陵区中 ,丘陵区的粮食增产潜力较台塬区大 ,前者尚有117.6 %增产能力 ,后者仅56.6%。但考虑到人口增长和坡耕地的退垦等因素 ,未来30年内黄土高原水土流失区的粮食供需仍处于负平衡。

Crystal structures of EtEDTB center dot 1.4C(2)H(5)OH center dot 5H(2)O and H4EtEDTB(ClO4)(4)center dot C2H5OH (EtEDTB=N, N, N ', N '-tetrakis[2-(1-ethylbenzimidazolyl)methyl]-1,2-ethanediamine)

The crystal structures of EtEDTB.1.4C(2)H(5)OH.5H(2)O 1 and H4EtEDTB(ClO4)(4).C2H5OH 2 (EtEDTB = N, N,N',N'-tetrakis[2-(1-ethylbenzimidazolyl)methyl]-1,2-ethanediamine) have been determined by single-crystal X-ray diffraction method. Compound 1 crystallizes in the space group P(1) over bar with a = 11.489(2), b = 11.866(3), c = 12.002(3) Angstrom, alpha = 97.47(2), beta = 114.564(13), gamma = 114.11(2)degrees, V = 1266.6(5) Angstrom(3), Z = 1, M-r = 847.48, D-c = 1.111 g/cm(3), F(000) = 456 and mu(MoKalpha) = 0.076 mm(-1). A total of 5207 reflections were measured for 1, of which 4323 were independent. The structure of 1 was solved by direct methods and refined by full-matrix least-squares technique to the final R = 0.0706 and wR = 0.1802 for 1318 observed reflections with I > 2sigma(I). In the structure of 1, centrosymmetric EtEDTB molecules are linked by hydrogen bonds through water and ethanol to form 2-dimensional network. Compound 2 crystallizes in the space group C2/c with a = 24.260(5), b = 13.040(3), c = 17.680(4) Angstrom, beta = 97.50(3)degrees, V = 5545.2(2) Angstrom(3), Z = 4, M-r = 1140.80, D-c = 1.366 g/cm(3), F(000) = 2384 and mu(MoKalpha) = 0.289 mm(-1).

Complex aggregates of silica microspheres by the use of a polymer template

Evaporation of a droplet of silica microsphere suspension on a polystyrene and poly(methyl methacrylate) blend film with isolated holes in its surface has been exploited as a means of particles self-assembly. During the retraction of the contact line of the droplet, spontaneous dewetting combined with the strong capillary force pack the silica microspheres into the holes in the polymer surface. Complex aggregates of colloids are formed after being exposed to acetone vapor. The morphology evolution of the underlying polymer film by exposure to acetone solvent vapor is responsible for the complex aggregates of colloids formation.

Mass-transfer kinetics of ytterbium extraction with sec-nonylphenoxy acetic acid

The extraction kinetics of ytterbium with sec-nonylphenoxy acetic acid (CA-100) in heptane have been investigated using a constant interfacial area cell with laminar flow. The influence of stirring speed and temperature on the rate indicated that the extraction rate was controlled by the experiment conditions. The plot of interfacial area on the rate showed a linear relationship. This fact together with the low solubility in water and strong surface activity of CA-100 at heptane-water interfaces made the interface the most probable locale for the chemical reactions. The influences of extractant concentration and hydrogen ion concentration on the extraction rate were investigated, and the forward and reverse rate equations for the ytterbium extraction with CA-100 were also obtained. Based on the experimental data, the apparent forward extraction rate constant was calculated. Interfacial reaction models were proposed that agree well with the rate equations obtained from experimental data.

Crystal transformation of Nylon 11 using in situ WAXD

alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.

毛细管气相色谱柱轴向非均匀性对保留值的影响

用理论和实验方法研究了柱轴向非均匀性对保留时间的影响。理论计算和对典型非均匀柱的实验表明，柱管的非均匀性是影响绝对保留值的一个不可忽视的因素，在基于均匀假定的保留值模拟中会引入系统误差。提出了柱均匀性的简单判据：相同柱压和温度条件下调换柱的进出口后保留时间不变是柱均匀的充分必要条件，是柱几何对称必要条件。对梯形柱，进样口较小时保留时间较短。

Influences of acid treatments of active carbons on no reduction over carbon-supported copper oxides

Active carbon supported copper oxides were used in NO reduction. The conversions of NO reduction depends strongly on surface oxygen-containing groups on the active carbons, among them the carboxyls and lactones favored remarkably the NO reduction. However, hydrochloric acid treatment led to the decomposition of the carboxyls and lactones on C2 and C3, decreasing their reactivities for NO reduction. Concentrated HNO3 treatment of active carbon produced higher conversions of NO reduction at relatively low temperatures due to the marked increase in the amounts of the carboxyls and lactones.

Lanthanide ion induced formation of stripes domain structure in phospholipid Langmuir-Blodgett monolayer film observed by atomic force microscopy

Long-range ordered stripes domain structures were observed in Dipalmitoylphosphatidylcholine (DPPC) Langmuir-Blodgett monolayer film which was spread on the subphase of lanthanide ion (Eu3+) solution and transferred to a freshly cleaved mica substrate by vertical deposition. This novel phenomenon was discussed in terms of the competitive interaction of dipole-dipole and electrostatic interactions of the DPPC molecules combined with lanthanide ions with those DPPC molecules free of lanthanide ions.

渗透汽化法分离二氧六环－水混合物

研究了二氧六环一水混合物在ＰＶＡ（聚乙烯酸）－ＰＡＮ（聚丙烯腈）复合膜中的渗透汽化分离性能。结果表明透过速率Ｑ和分离系数α均随料液温度的提高而增大。α随料液中二氧六环浓度的提高而增大，Ｑ的变化趋势相反．有代表性的数据是在９０℃对９５％的二氧六环水溶液，α可达１９８１，Ｑ＝７３．８ｇ／ｍ２·ｈ．在低浓度二氧六环溶液时扩散过程对选择性起主要作用。而高浓度时溶解选择性是主要的，随着分离温度的提高，扩散或溶解均提高了选择性。