聚乙二醇修饰的Fe3O4催化水合肼还原硝基苯

以聚乙二醇(PEG)为修饰剂,采用共沉淀法制备了磁性Fe_3O_4/PEG。用X-射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR)对Fe_3O_4/PEG进行表征。粒子中的Fe_3O_4为立方晶系,加入PEG6000和PEG20000能有效分散Fe_3O_4,避免颗粒团聚。考察了Fe_3O_4/PEG对水合肼还原硝基苯制备苯胺的催化活性,加入PEG6000和PEG20000作为分散剂制备的Fe_3O_4/PEG具有较高的活性和较好的重复性。1.23 g(10 mmol)硝基苯,0.1 g Fe_3O_4/PEG6000(或Fe_3O_4/PEG20000)催化剂,2.0 g水合肼在乙醇中回流反应1 h,苯胺收率接近100%,催化剂重复使用9次活性基本不变。     

关于人类对光的本性认识的发展过程的再认识

对光本性的认识贯穿于物理学光学学科发展的整个过程。时至今日,光本性问题在光学这个古老而又常新和充满希望的学科中仍占有重要位置。本文从光学的发展史入手,阐述了不同时代的科学家在探讨光的本性问题的曲折过程。通过人们逐步对光的本性的认识,思考科学的艰辛历程,感受科学家的治学精神和探究方法。     

城镇燃气管网应急处置知识图谱构建与应用

标准是一种重要的信息传导工具和知识载体,其为社会经济的持续发展提供了必要的技术支持。当前城市燃气管网领域已具有相对充分的标准资源,但非系统化的燃气标准规范难以满足事故应急响应快速性和精准性查询和匹配要求。本文聚焦城镇燃气管网应急标准文献,借助知识图谱构建技术,针对 城镇燃气领域的标准文献进行逻辑辨析和整理,构建城镇燃气管网应急处置和救援的知识图谱,通过实例挖掘展现出知识图谱在燃气管网事故应急处置中的决策支持价值以及相关标准化系统自我完善中的纠错工具价值。     

星斗山自然保护区秃杉资源及人工林生物量、生长规律研究

对星斗山自然保护区秃杉母树资源及人工林生物量、生长规律进行了研究，结果显示：湖北省秃杉母树40株，其中保护区内28株，平均胸径82．1cm，平均树高43．05m.16年生秃杉生物量为75．40kg，各组分之间分配比例存在差异。胸径、树高、材积平均生长量和连年生长量随年龄增加呈现规律性变化。     

广西猫街鸟类自然保护区苔藓植物初步研究

通过对采自广西西林县猫街鸟类自然保护区的413份苔藓植物标本整理和鉴定,得到该区苔藓植物33科66属153种（含亚、变种）。其中藓类植物23科53属116种,苔类植物10科13属37种,有65种为广西首次记录。其区系地理成分多样,与其他区系紧密联系。该区以东亚成分为主,占总数的32.03%,温带和热带成分所占比例也较高,反映该地具有南北过渡的特点,与其所处的地理位置相一致;中国特有成分较高,占总数的12.42%,处于我国特有种属分布中心的过渡地带上。在进行的优势科、属分析中,优势科为青藓科Brachytheciaceae、灰藓科Hyp-naceae、丛藓科Pottiaceae、曲尾藓科Dicranaceae、地萼苔科Geocalycaceae、凤尾藓科Fissidentace-ae、叶苔科Jungermanniaceae,占优势的属为凤尾藓属Fissidens、曲柄藓属Campylopus、青藓属Brachythecium、灰藓属Hypnum、叶苔属Jungermannia和异萼苔属Heteroscyphus.该地苔藓植物主要成分以热带、亚热带成分和温带成分为主,处于温带向热带过渡的地段上。     

产学研过程中的科技中介系统作用机理问题研究

产学研在本质上是一个科技研究与创新活动的完整过程,科技中介系统在产学研过程中发挥着枢纽作用,科技中介系统在产学研中发挥枢纽作用的内在机理在于利润驱动,只有加强科技中介系统的市场化、企业化发展,产学研的合作才能真正建立起来,实现产学研的根本价值和目标。     

三种麻醉剂对动物组织器官生理特性影响的探讨

主要探讨了氨基甲酸乙酯、水合氯醛、戊巴比妥钠等3种麻醉剂对动物组织器官生理特性的影响,以寻找动物生理实验过程中更适合某种组织器官的麻醉剂。提出:水合氯醛更适合于对动物心肌收缩力、胃运动等实验的研究;戊巴比妥钠更适合于对动物心率、骨骼肌、坐骨神经、十二指肠、子宫等实验的研究,可供研究动物生理的科研工作者参考。     

Does flagship species tourism benefit conservation? A case study of the golden snub-nosed monkey in Shennongjia National Nature Reserve

Tourism has been widely used as a conservation strategy that directly compensates local people or management authorities, thereby contributing to development and creating incentives to preserve the landscape. Reserves or parks that are inhabited by flagship species may be able to generate more revenue through tourism than those without such species because flagship species have great potential for raising funds and creating publicity for conservation goals. In this paper, we examine flagship species tourism...     

Potential release of hydrogen fluoride from domestic coal in endemic fluorosis area in Guizhou,China

Almost half of the total rural area of Guizhou Province and many regions within the 11 adjacent provinces in southwestern China have a long history(at least 70 years) of endemic fluorosis,including dental fluorosis and osteofluorosis along with its associated deformities and disabilities.Over decades of research,this specific type of endemic fluorosis has been defined as coal-burning fluorosis,which is distinct from drinking-water fluorosis.It is generally acknowledged that indoor burning and combustion of high-fluorine coal leads to food contamination,and fluorine then enters the human body.However,the exact chemical form of fluorine during its release and transfer to the body is still unknown.In the present study,21 domestic coal samples from outcrop and semi-outcrop coal collected in five villages with fluorosis were analyzed by time-of-flight secondary ion mass spectrometry(TOF-SIMS).The total mass fraction of sulfur in the samples ranged from 0.24%-5.58% and total fluorine content ranged 90.2-149.2 mg/kg.H3O+,H2SO4+ and HSO4-were detected in the samples by TOF-SIMS,which indicated that sulfuric acid hydrate(H2SO4.H2O) was present in the samples.F-was detected in all of these,which suggested the samples contain ionic fluorine compounds.Under certain circumstances,such as heating or burning,the prevalence and coexistence of the acid(H2SO4.H2O) and base(F-) would lead to a neutralization reaction producing volatile hydrogen fluoride(HF,bp = 19.5℃).This would be the chemical form of fluorine released from the coal.Further studies using HF and SO2 test tubes on headspace gas over coal samples heated to 200℃ in the laboratory and on headspace gas over stoves or chimney tops at rural residences confirmed the release of HF.     

广西元宝山自然保护区黑熊春季觅食生境特征

在广西元宝山自然保护区野外设置了82个20 m×20 m样方,初步分析黑熊春季觅食地生境特征,对16个生态因子进行主成分分析和单因子适合度检验。结果表明：黑熊觅食地生境特征的主要影响因子为水源距离、海拔和灌木密度;次要因子为食物丰富度因子(树径、乔木密度、乔木距离、灌木距离)、地理性因子(坡向、坡位、坡度)、干扰性因子(树桩密度、树桩距离、倒木距离、人为干扰距离)和微生境因子(避风性、郁闭度)。对黑熊的生境喜好程度分析发现：水源丰富、一定海拔、避风性适中、植物茂盛(乔木密度、灌木密度、乔木距离、灌木距离)、坡向向阳、郁闭度好(30 %～80 %)、坡度较大的山嵴和山坡位为其最适生境。由于人类活动增加,干扰因子(树桩密度、树桩距离、倒木距离、人为干扰距离)成为影响黑熊生境选择的重要因素。