东北北部冻土退化与寒区生态环境变化

我国东北地区位于中高纬度欧亚大陆东缘,大、小兴安岭多年冻土区是欧亚大陆高纬冻土区向南最突出的部位,属于高纬山地冻土.东北多年冻土区是我国,乃至全球范围内,受气候变暖和人为活动影响最显著的冻土区之一.过去40 a来该区冻土显著退化,主要表现在:1)冻土南界及不连续多年冻土各分区边界北移而导致总面积减小、空间分布破碎化;2)活动层加深,融区扩大,局地冻土岛消失;3)冻土温度升高、厚度减薄、热稳定性降低等.由于各种因素的共同影响,寒区生态环境也发生了一系列变化.这具体表现为以兴安落叶松占绝对优势的天然林带锐减,整个北方森林带北移,沼泽湿地面积减小等,寒区生态系统和环境已出现恶性循环.关注、研究、整治和管护寒区环境对区域社会、经济和生态可持续发展不可或缺

Electrodeposition of CIGS Thin Film with Special Structure Using Laser Etching Template

       本文利用激光刻蚀模板，在水溶液中电沉积制备金属铜薄膜，讨论了温度、电流、硫酸铜浓度对薄膜形貌的影响. 采用SEM对制备的铜薄膜进行表征，结果表明在沉积温度为30 ℃，沉积电流为4 A·dm-2(表观工作电流密度)，硫酸铜浓度在20 ~ 50 g·L-1的水溶液中电沉积可以得到中空馒头状和开口碗状结构的铜薄膜. 利用激光刻蚀模板，在离子液体1-丁基-3-甲基咪唑三氟甲磺酸盐([BMI][TfO]) - 30 Vol%丙醇混合电解质中电沉积CIGS薄膜，研究了沉积电势、沉积时间对薄膜形貌的影响. SEM观察发现，在沉积电势为-1.8 V，沉积时间为1.5 h条件下电沉积可以得到近似柱状的簇状花束样的CIGS薄膜， 电沉积铜后再进一步电沉积CIGS，得到了均匀有序的鼓包柱状结构的Cu/CIGS复合薄膜. 用恒电势方波法对制备的薄膜真实表面积进行测试，计算结果表明，与无模板电沉积制备的CIGS薄膜相比，激光刻蚀模板法制备的Cu/CIGS复合薄膜的表面积提高了约8倍.Copper indium gallium selenide (Cu1.00InxGa1-xSe2.00, CIGS) thin film solar cells have a wide application in semiconductor thin film batteries. The CIGS absorbing layer is the key of the thin film solar cell material. Therefore, it is of theoretical and practical significance to carry out researches in CIGS thin films. In this work, the CIGS thin films with special structures were prepared by using laser etching template. The copper thin film was firstly electrodeposited in aqueous solution with Laser etching template. The influences of temperature, current and concentration of copper sulfate on morphology and structure of the thin film were studied. The results showed that a hollow steamed bun shape and open bowl structure was formed at the surface of copper thin film electrodeposited at 30 oC and at the apparent current density of 4 A·dm-2 in the aqueous solution with the concentrations of CuSO4·5H2O being 20 ~ 50 g·L-1. The CIGS thin films were electrodeposited by using laser etching template in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIm][TfO]) - 30 Vol% propyl alcohol mixed electrolyte solution at different deposition potentials, substrates and deposition time. It was demonstrated that the clusters of flowers with approximate columnar CIGS thin film could be prepared at 1.8 V for 1.5 h. Furthermore, the electrodeposition of CIGS thin films was done on the previously electrodeposited copper substrate by Laser etching template. A uniform and orderly spheroidal structure of Cu/CIGS composite film was obtained. The apparent surface area of the Cu/CIGS composite film, calculated by constant voltage square wave method, was about 8 times larger than that of the CIGS thin film prepared without using template, which greatly enhanced absorption of light on the thin film and increased the output of the carrier. Therefore, it can be expected that the CIGS thin film with globular special structure electrodeposited in ionic liquid by laser etching template may highlight the electric conversion efficiency.国家自然科学基金项目（51474080）资助作者联系地址：哈尔滨工业大学化工与化学学院，黑龙江哈尔滨 150001Author's Address: School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China通讯作者E-mail：mzan@hit. edu. c

600MeV~（40）Ar＋~（197）Au反应碎片角分布

在４π立体角范围内收集反应产物，采用离束γ射线测量方法测量了６００ＭｅＶ４０Ａｒ＋１９７Ａｕ反应的给定质量数的碎片角分布．讨论了中能重离子反应碎片角分布特征和产生碎片的反应机制．The angular distributions of the fragments in the range of 4π solid angle for the 600 MeV 40 Ar+197Au reaction have been measured using the beam-off γ-ray spectroscopy technique. The features of the fragment angular distributions and the reaction mechanisms of the production of fragments have been discussed