生物质/聚吡咯复合材料的电化学性能研究

在造纸行业中作为废液的木质素磺酸盐是一种含有甲氧基和酚羟基的生物质衍生物,由于具有可逆的氧化还原反应而提供赝电容.但木质素磺酸盐的导电性低,从而不能直接作为超级电容器电极.本文在含木质素磺酸钠(Lig)的体系中原位聚合吡咯(Py)制备了具有导电性能的木质素磺酸钠/聚吡咯复合材料(LP).通过扫描电镜(SEM)和傅里叶红外光谱(FTIR)测试对其形貌和结构进行表征.结果表明:当Lig与Py质量比为1∶1和电流密度为1 A/g时,复合材料具有高的比电容(346.8 F/g),相比于单纯聚吡咯(PPy)的比电容提高了约50 F/g.而且当电流密度从1 A/g升高到10 A/g时,LP1的倍率性能高达60.8%,比PPy提高了9.3%.在高电流密度10 A/g时,复合物LP1经过1 000次恒电流充放电后仍保留了47%的电容值,表明复合物LP1表现出好的循环稳定性.     

必要的敬畏

正在敬畏中,我们坚守自然的奇异性,向未知敞开心扉。无怪乎它是科学想象力的核心所在。当科学范式被打破时,科学家不得不进入未知领域。这就是科学革命来临之际,托马斯·库恩(Thomas Kuhn)所认定的。科学家的世界图景变得站不住脚,学科中公认的真理遭到彻底的怀疑。     

红皮云杉不同器官对土壤重金属的富集特征

为了解不同污染等级下红皮云杉不同器官的富集特征,运用室外采样和室内测定相结合的方法,测定了红皮云杉树叶、树枝、树皮、树根和根际土壤中3种重金属元素(Pb、Cd、Cr)的含量。在污染等级1中,各器官重金属含量大小顺序为树皮树枝树根树叶,在污染等级2中,各器官重金属含量大小顺序为树皮树根树枝树叶。各器官对Cd、Cr和Pb的富集能力为树皮树枝树根树叶。各重金属元素含量在红皮云杉中的总趋势为CrPbCd,富集能力总趋势为CdCrPb,反映出红皮云杉对Cd的低吸收高富集能力。随着土壤重金属污染等级的增加,红皮云杉对Cd和Cr的富集能力增加。单株红皮云杉不同重金属元素积累量为CrPbCd,富集效能为树根树枝树叶树皮,树根对各重金属元素的积累量明显高于其他器官。因而,红皮云杉可以作为对土壤中Cr、Pb污染场地进行修复和治理的备选树种。     

治疗良性前列腺增生药物的研究进展

良性前列腺增生是一种以前列腺增生并伴随下尿路症状为特点的常见疾病。目前治疗良性前列腺增生的药物有α-肾上腺素受体阻断剂、5α-还原酶抑制剂、植物花粉制剂以及民族医药等。现综述良性前列腺增生治疗药物的研究进展。     

方阵乘幂的一种计算方法

计算方阵的乘幂有许多不同方法,如数学归纳法、二项式法、Jordan标准型法、和拆分法等。这些方法无论在理论上,还是在计算上都没有成熟。为此,本文仅借助常系数齐次线性差分方程组和哈密顿．凯莱定理出发,推出了计算方阵乘幂的一种新方法。     

高等数学教学与工科专业结合模式探讨

结合学生学习高等数学的实际情况与笔者多年从事高等数学的教学经验,本文提出"学生的学与教师的教"中存在的一些问题。并以伊犁师范学院电子信息与科学学院为例,将传统教学模式与多媒体教学模式进行结合,并且改变原有的教材,使其与本专业的教学内容相符合。     

Long-chain branched/cyclic alkanes in recent sediment of Lake Fuxian and their environmental implications

Lake Fuxian is a large, deep, and oligotrophic freshwater lake. In recent sediment of this lake, a series of branched and cyclic alkanes, including branched alkanes with one or two quaternary carbon atoms （C2n compounds）, alkylcycloheptane, and alkylcyclohexane, were detected in high abundance. For each homolog of long-chain branched/ cyclic alkanes, molecules with only an odd or even carbon number were present in the sediment. The abundance vari- ation of each compound homolog corresponded to those of other compound homolog in the section, indicating the same origin of these compounds. The concentrations of long-chain branched/cyclic alkanes in the sediment profile exhibited variations similar to those of phytoplankton biomarkers, such as 3-methylJalkanes, short-chain odd carbon n-alkanes, hopene, polyunsaturated fatty acids, phytol, sterols, and long-chain alkyl diols, but slightly different from those of long-chain odd carbon n-alkanes, which are ubiquitous biomarkers for higher plants. Therefore, the Can compounds and long-chain cyclic alkanes in the lake sediment were most likely produced by algae and bacteria in the water, primarily, by the heterotrophic bacteria in the moderately oxygenated waters, which flourishing might be the results of specific water environments in Lake Fuxian.     

Review of galactic and extragalactic searches for class I methanol masers

Class I methanol masers are important tools for investigations of star formation throughout the Universe. Recently, a series of surveys for class I methanol masers at the 95 GHz transition toward samples of young stellar objects have been undertaken. These surveys have resulted in the detection of about 200 new class I methanol masers and combined with previous increased the number of known observations they have class I methanol masers in our Galaxy to ~400. From analysis of the relationship between class I methanol maser emission and associated astrophysical objects, it has been shown that the intensity of the class I methanol maser emission is closely correlated with the properties of the 1.1 mm Bolocam Galactic Plane Survey （BGPS） dust continuum sources and outflow properties. This further supports the hypothesis that class I methanol masers are collisionally pumped and excited in shocked regions. Based on these observations, it can be inferred that the BGPS catalog is likely to provide more reliable samples for targeting further class I methanol maser searches. A new survey for class I methanol masers toward a larger size sample of BGPS sources to test this is currently underway. The prospects for detecting class I methanol megamasers in extragalactic sources is discussed, and observations constituting the first sensitive search have been proposed.     

西藏拉萨地区198株结核分枝杆菌耐药性分析

目的：了解拉萨地区结核分枝杆菌对抗结核药物的耐药情况,为临床合理用药提供参考依据。方法：采用WHO推荐的比例法对分离自西藏拉萨地区肺结核患者的198株结核分枝杆菌进行4种抗结核药物（RFP、INH、SM、LVX）的药物敏感性试验。结果：198株结核分枝杆菌中耐药菌株有125株,总耐药率为63.1%（125/198）,总耐多药率为29.8%（59/198）,初治耐药率为55.1%（64/116）,复治耐药率为75.4%（40/53）,初治耐多药率为20.7%（24/116）,复治耐多药率为56.7%（30/53）。对RFP、INH、SM、LVX的耐药率分别为36.3%（72/198）、41.9%（83/198）、41.4%（82/198）和7.0%（14/198）。结论：西藏拉萨地区临床结核分枝杆菌耐药情况较为严重,应加强临床结核分枝杆菌耐药性监测,指导临床用药以防控耐药菌的产生。     

铜、铁与锌试剂的络合吸附波研究铝合金中微量铜、铁的同时测定

在4×10-5mol/L ZCO-0.4mol/L NH4Cl-0.6%Na2SO3溶液中,钢(Ⅱ)-ZCO与铁(Ⅱ)-ZCO络合物在单扫描示波极谱仪上可观察到两个灵敏的极谱吸附波,峰电位分别为—0.63V和—0.76V(vs.SCE),峰电流与钢(Ⅱ)铁(Ⅱ)浓度分别在1.3×10-7—2.5×10-5mol/L和3.0×10-7—3.0×10-5mol/L范围内呈线性关系,检测限分别为7.8×10-8mol/L、1.5×10-7mol/L.本文研究了产生钢、铁波的条件,探讨了波的性质、测定出铜(Ⅱ)、