汾河上游流域人类活动影响下的森林覆被变化

植被尤其是森林在人类的生存和发展过程中，具有不可替代的地位和作用．汾河上游流域，作为黄土高原生态脆弱区一个独立的流域单元，是太原市唯一的水源涵养地和供水区，其森林植被状况的好坏，直接影响到其本身的生态安全和对汾河流域的大城市的生态屏障作用能否正常发挥．所以应用历史地理学的研究方法对汾河上游流域的森林变迁的历史，追根溯源，进行研究，目的是找出人类活动对植被影响的规律，从而能够采取行之有效的方法恢复植被，为汾河上游流域的生态安全提供可靠的保障．     

Study on structure-activity relationship of mutation-dependent herbicide resistance acetohydroxyacid synthase through 3D-QSAR and mutation

Seventy-four sulfonylureas were synthesized and tested for their inhibitory activity against the whole enzyme of E. coli acetohydroxyacid synthase (AHAS, EC 2.2.1.6) isoenzyme II, and 3D-QSAR analyses were performed based on these inhibitory activities. The binding conformation of chlorimuron-ethyl, a commercial herbicide of AHAS, in the crystal structure of AHAS complex was extracted and used as template to build the initial three-dimensional structure of other sulfonylureas, and then all structures were fully geometry optimized. After systematic optimization of the alignment rule, molecular orienta- tion, grid space and attenuation factor, two satisfactory models with excellent performances (CoMFA: q2 = 0.735, r2 = 0.954, n = 7, r 2 pred = 0.832; CoMSIA: q2 = 0.721, r2 = 0.913, n = 8, r 2pred = 0.844) were estab- lished. By mapping the 3D contour maps of CoMFA and CoMSIA models into the possible inhibitory active site in the crystal structure of catalytic subunit of yeast AHAS, a plausible binding model for AHAS, with best fit QSAR in the literature so far, was proposed. Moreover, the results of 3D-QSAR were further utilized to interpret resistance of site-directed mutants. A relative activity index (RAI) for AHAS enzyme mutant was defined for the first time to relate the 3D-QSAR and resistance of mutants. This study, for the first time, demonstrated that combination of 3D-QSAR and enzyme mutation can be used to decipher the molecular basis of ligand-receptor interaction mechanism. This study refined our understanding of the ligand-receptor interaction and resistance mechanism in AHAS-sulfonylurea system, and provided basis for designing new potent herbicides to combat the herbicide resistance.     

Electroluminescence and photoluminescence of dioctylfluorene and 4,7-dithien-2-yl-2,1,3-benzothiadiazole copolymers

Dioctylfluorene (DOF) and 4,7-dithien-2-yl- 2,1,3-benzothiadiazole (DB T) copolymers synthesized in our lab with different compositions of DBT (1%, 5%, 15% and 25%) were utilized to fabricate bilayered light emitting diodes. Extern al quantum efficiency (QE) of the diode fabricated from the copolymer with 15% D BT content reaches 1.4% (ph/el), over 1.0 cd/A in luminance efficiency at the driving voltage of 4.2 V. The highest luminance can reach 3780 cd/m2 at 8.2 V. Devices emit a saturated red light centered at 675 nm with chromaticity coordinate changed from x = 0.66, y = 0.32 for PDOF-DBT1 (1% DBT) to x = 0.70, y = 0.28 for PDOF-DBT25 (25% DBT).     

Analysis Algerian’s gallstones with infrared spectrum and methods of prevention and treatment for cholelithiasis in algeria

To analyze the type of Algerian’s gallstones and put forward relative measures of prevention and treatment, The NICOLET 170SX FT-IR spectrometer was used to measure the infra-red spectrum and analyze the feature of spectrum of Algerian’s gallstones. The results shown that Algerian have cholesterol gallstones. Reasons to form Algerian’s multiple cholesterol gallstones were investigated. We have put forward five suggestions to prevent and treat cholelithiasis. Biography: Li Zong-shan (1944-), male, Professor, research direction: Biophysics.     

利用广义不确定关系计算Vaidya-de Sitter黑洞的熵

利用广义不确定关系计算量子态数目 ,进而计算Vaidya deSitter黑洞的熵 .此方法的优点是不必引入截断因子 ,就可避免发散问题     

一类具有稀疏效应的捕食者-食饵系统的周期解

利用Mawhin重合度理论研究了具有稀疏效应和Beddington-DeAngelis功能性反应的捕食者-食饵系统的正周期解的存在性问题,得到了该生物系统正周期解存在的一个充分条件,推广了相关文献的某些已知结果.     

A Multiple Negotiations Model Considering Interdependence between Discrete Issues Across Negotiations

The research of multiple negotiations considering issue interdependence across negotiations is considered as a complex research topic in agent negotiation.In th...     

含铬废水的处理方法综述

总结了含铬废水的９ 种处理方法, 并对它们的原理、工艺流程、优缺点等进行了详细评述, 以供厂家在治理此类废水时参考．     

关于不定方程x~2+y~2+z~2=2w~2的解的研究

对不定式x~2+y~2+z~2=2w~2的非零整数解进行变换,找到了变换矩阵,并通过变换矩阵和若干个易求出的解,得到了该方程的若干组解。进而求出了一个古典刁番都方程组的若干组正整数解。     

SPR生物传感系统研究

对自行研制的SPR生物传感系统各部分给出了详细描述.系统采用独特的角向会聚光路代替传统的角度机械扫描方式,采用CCD作为光电检测器件,避免了机械扫描可能带来的误差,可一次完成样品响应曲线的采集分析,提高了检测精度和速度.此外,利用M ATLAB软件对信号进行了F IR滤波分析处理,提高了信噪比.测试表明,系统的分辨率为3.59×1-0 5R IU,灵敏度为98.61度/R IU,检测范围为1.00~1.47 R IU.