Influence of Catalyst Thickness on Diameters of Carbon Nanotubes

Owing to unique structure and characteristic of carbon nanotubes, much more are attracted attentions since they were discovered .In recent years, carbon nanotubes have been successfully synthesized by various methods. Especially, highly aligned carbon nanotubes were grown by chemical vapor deposition (CVD). In the work, it is studied that different thickness of catalyst affects the diameters of carbon nanotubes. Carbon nanotubes were grown on silicon substrate coated with different thick NiFe films by bias-enhanced hot filament chemical vapor deposition and their growth was investigated by scanning electron microscopy,Onset of analyzing of deformation of different thick catalyst films during heating the filament. The results indicate that catalyst particles encapsulate the top ends of carbon nanotubes, and that the catalyst thickness greatly affects the diameters of carbon nanotubes, which increas with increment of the thickness of NiFe films.     

Surface Charge Distribution and Tip Electric Field about Carbon Nanotubes

Carbon nanotubes(CNTs) have some special physic properties which may own important technical values. We studied the electric characteristics of metallic carbon nanotubes including potential distribution, surface charge distribution and tip electric field based on electromagnetic theory. Our results show that the relative values of tip charge densities of short CNTs are bigger and so are the absolute values for long CNTs. We also find the electric field at the tips of metallic nanotubes is much bigger than external electric field. This is helpful for exploring theoretical problems about CNTs' field emission.     

Measurement of Resistivity and Investigation of Electronic Transport for Carbon Nanotube Film

Temperature-depended resistivity of carbon nanotube film is measured and the results show negative temperature effect because the resistivity is decreased as the temperature increased. An electronic transport model for the carbon nanotube film is set up and the resistivity calculation formula is deduced, whose calculating result is compared with experimental datum. It shows that theoretical calculation is well contented with experiment results. Then, the relationship between resistivity and diameter of the carbon nanotube is discussed.     

Preparation and characterization of carbon cones by reaction plasma

Carbon cones are prepared on Si substrates film in plasma-enhanced hot filament chemical vapor deposition system using CH4, H2 and NH3 as the reaction gas, and the substrates are deposited with Ti and carbon film, respectively. Morphology and structure of the carbon cones are characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX)and micro-Raman spectroscopy. The SEM results indicate that the carbon cones are formed on the Si substrate deposited with carbon film. Furthermore, the EDX and Raman spectra indicate that the formed carbon cones are carbon nitride structure, which are composed of sp 3 C-N, sp 2 C and sp 2 C=N bonds. According to the mechanisms of sputtering and diffusion, the formation of carbon cones is analyzed. Simultaneously, the photoluminescence background in the Raman spectrum of carbon cones is analyzed, and results indicate that the carbon cone evolves from nonpolar carbon material to polarity carbon material due to the doping of nitrogen.     

Catalytic Mechanism of Ni Particles in the Formation of Single-Wall Carbon Nanotubes

Usually Ni_clusters are served as catalyst in the formed processo f the single_wall carbon nanotubes by CVD. Because the different surfaces of Ni_clusters have different activity,carbon atoms adsorbed in Ni_clusters (liquid states)will be diffused from low_activity surfaces of Ni_cluster to high_activity ones and be deposited. As a result,the caves of carbon atoms surrounding the Ni_clusters are formed and the single_wall carbon nanotubes are produced. In addition,Ni_atoms served as substitutional atoms always located in the furthest outside of the network of single_wall carbon nanotubes are produced. In addition, Ni_atoms served as substitutional atoms always located in the furthest outside of the network of single_wall carbon nanotubes,and play a role of stabilization in growth of nanotubes,and promot their growth. Therefore,the catalytic mechanism of Ni_clusters as catalyst is introduced,and different morphologies of single_wall carbon nanotubes are also exlained.     

Superconductivity of Single-Walled Carbon Nanotubes

The electric-arc technique used to generate single-walled carbon nanotubes (SWCNTs) is introduced. Especially, the superconductivity of SWCNTS is concerned. The samples of single-walled carbon nanotubes are suspended between two superconducting electrodes and their super-currents may be observed under special conditions. It is called 'proximity-induced method'. With the method, some experiments show that SWCNTs have higher critic super-currents, and the temperature and magnetic field dependence of the critic currents exhibits unusual features.     

纳米碳管在电解法处理含铜废水中的应用研究

为了解决含铜工业废水对环境、土壤及生物的危害,以镀有纳米碳管的钢板为阴极,对含铜废液进行了电解研究。测定了不同影响因素下（电解时间及电流等）重金属铜的去除率,并分析了含纳米碳管阴极电解法去除Cu2+的机理。结果表明,在其它条件相同的条件下,随着时间和电流的增加,去除率逐渐上升。而且随钢板上纳米碳管的数量升高,去除率明显升高。本试验最佳情况下,含有纳米碳管的阴极钢板比没有含有纳米碳管的阴极钢板去除率高40%左右。     

Electrochemical Oxidation of Aqueous Phenol at Carbon Nanotube Electrode

To investigate the effects of human soluble TRAIL(sTRAIL) on cell growth and apoptosis of hepatocellular carThe electrochemical oxidation of aqueous phenol at pure carbon nanotube electrode has been studied by cyclic voltammetry.The results have shown that in the potential region of water stability,fine oxidation current curve can be obtained.The electricity of oxidation peak is partly linear with phenol concentration.Comparing with traditional carbon electrode,better results have been obtained with the pure carbon nanotube electrode.Depending on it,it is possible to obtain the complete combustion of phenol to CO_2,which can avoid electrode fouling and poor repeatability.     

江西省不同林龄杉木碳储量分配格局

在省级尺度上分析不同林龄杉木碳储量数据,以掌握江西省杉木人工林碳储量动态分配格局。本研究对江西省杉木林生态系统进行了野外调查,并对现有杉木生物量数据进行了综合分析。结果表明：江西省杉木人工林碳储量变化范围为27.82~82.61 t/hm²,其乔木层碳储量占94.2%以上。杉木林和乔木层碳储量随林龄先增加后略微下降,而各龄林的灌木层、草本层和凋落物层碳储量均没有显著差异。幼龄林、近熟林、成熟林各组分碳储量大小排序均为乔木层>凋落物层>灌木层>草本层,而在中龄林和过熟林中则为乔木层>凋落物层>草本层>灌木层。幼龄林各器官碳储量大小排序为树干>叶>根>枝,而其他林龄中的排序均为树干>根>枝>叶。     

不同碳源材料对设施土壤碳氮状况及作物生长影响研究

研究旨在改善设施土壤碳氮状况,提升菜田土壤质量,以期提高蔬菜产量与品质,对促进菜田可持续发展具有重要意义。通过施用天然木本泥炭、人工木本生物炭、人工草本生物炭等不同碳源材料研究设施菜田土壤碳氮变化及作物生长影响,分析不同材料的碳氮调控影响。研究结果表明：在0~30 cm土层,土壤有机碳改善效果依次为：处理3＞处理2＞处理1＞处理4。土壤全氮含量表现为：处理2＞处理1＞处理3＞处理4,添加碳源物质的处理较处理4土壤全氮含量提高13.8%~15.9%。土壤C/N比值依次为：处理3＞处理2＞处理1＞处理4,施碳处理均提高了土壤C/N比值,且施入碳量越高对提高C/N越明显,而3种不同碳源材料对深层土壤碳、氮影响不明显。处理2产量最高,较对照增长了11.87%。处理3促进根部生长明显。各处理对菠菜综合品质的影响依次为处理2＞处理3＞处理1＞处理4。施加碳源材料可以补充土壤碳素,同时可调节土壤氮素的转化与吸收,土壤碳氮失衡问题得到改善,最终对提高蔬菜产量与改善品质有较大促进作用。     

Progress of Study on Oriented Growth of Carbon Nanotubes

Owing to unique structure and characteristics of carbon nanotubes, much more are attracted attentions since they were discovered. In recent years, carbon nanotubes have been successfully synthesized by various methods. Especially, highly aligned carbon nanotubes were grown by chemical vapor deposition (CVD) and the oriented growth of carbon nanotubes became realized, resulting in many applications of carbon nanotubes and researches on them. In the work, the methods and mechanisms of orientation growth of carbon nanotubes were reviewed, and it was analyzed and discussed that different methods influenced on the process of growing carbon nanotubes. Simultaneously, it was emphatically analyzed that catalyst particles affected on orientation growth of carbon nanotubes during their growth.     

园林绿化废弃物堆肥过程中碳氮养分变化规律

堆肥化处理是实现园林绿化废弃物资源化利用的有效方式。为探索堆肥化处理技术,笔者研究了在不同量物质（落叶、活性污泥、土壤）的园林废弃物堆肥中C、N含量的变化规律。试验结果表明：堆腐过程中全碳含量总体呈下降趋势,而全氮含量总体变化趋势为嗜热阶段急剧上升,低温腐熟保肥阶段增加减缓。碳氮比在堆肥化处理过程中呈下降趋势。经正交试验分析,1000 g园林废弃物中加入800 g的污泥的处理E和处理H最有利于堆肥的腐熟,得到的腐熟肥碳氮含量较为合理,其碳含量分别为413.59 g/kg和611.16 g/kg;氮含量分别为17.57 g/kg和21.95 g/kg;碳氮比为23.54和27.84。     

Recent Advances in Synthesizing Single-walled Carbon Nanotubes

The main synthesis of single-walled carbon nanotubes (SWCNTS) on a large scale and in higher purity is investigated. To analyse the characteristic of different synthesis and the major parameters whose variety influence the product. The kinds and ratio of carbon source and catalyst influence the preparation of SWCNTS obviously.The factors such as current and voltage,the kind of inert gases and pressure and the cooling rate of electrodes play important roles in synthesis of SWCNTS by arc discharges. The intensity of laser bean,environmental temperature,the kind and the velocity of flow of catalyst and the frequency and interval of impulse act important parts in SWCNTS produced by laser evaporation. The flow rate of carbon resource, the grain sizes of catalyst,reaction temperature,the gases pressure and flux and matrix materials etc play key parts in SWCNTS synthesized by chemical vapor deposition.     

Responses of carbon metabolism and antioxidant system of summer maize to waterlogging at different stages

A field experiment was performed to explore responses of carbon metabolism, antioxidant system and endogenous hormone content of summer maize hybrids DengHai605 (DH605) and ZhengDan958 (ZD958) to waterlogging at the third leaf stage (V3), the sixth leaf stage (V6) and the 10th day after the tasselling stage (10VT). Results showed that waterlogging significantly decreased the contents of zeatin riboside (ZR), indole‐3‐acetic acid (IAA) and gibberellic acid (GA), compared to those of CK. However, leaf abscisic acid (ABA) content was significantly increased by waterlogging at different stages, with the most significant increase was found in the treatment of waterlogging at V3 (V3‐W), with an increase of 30% and 29% for DH605 and ZD958, respectively. Waterlogging significantly decreased antioxidative enzyme activities, accelerating leaf senescence, resulted in the disorder of leaf gas exchange parameters and chlorophyll fluorescence parameters. In addition, waterlogging decreased key enzyme activities of carbon metabolism (ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase), with the most significant reduction in V3‐W, with a decrease of 46% and 49% for DH605, and 53% and 55% for ZD958, respectively. Visibly, waterlogging disturbed carbon metabolism, affected plant endogenous hormone content, accelerated leaf senescence and eventually resulted in a significant reduction in photosynthetic characteristic and grain yield. V3 was most susceptible to waterlogging, followed by V6 and 10VT.     

秦岭火地塘林区主要森林类型碳储量和碳密度估算

火地塘林区地处秦岭南坡中段,是中国暖温带向亚热带气候的过渡带。林区森林主要为天然次生林, 树木种类丰富并具有明显的垂直分异性。准确估算森林碳储量在研究全国乃至全球碳平衡中起着重要的作用。笔者基于生物量的回归方程, 估算该林区主要森林类型碳储量和碳密度的大小，并运用GIS软件Citystar(4.0)进行数据的空间分析。结果显示：不同树种随海拔高度呈垂直地带性分布。华山松和红桦的分布范围广，且碳储量大小明显高于其它三种类型的；锐齿栎、油松主要分布于中低海拔地带；华北落叶松的平均碳密度值最大；锐齿栎和红桦的平均碳密度接近但低于华北落叶松的；油松和华山松的平均碳密度接近且较低。     

柳州市短周期桉树人工林生态系统碳储量研究

通过野外调查和实验室材料分析,对广西柳州市短周期桉树(Eucalyptus sp.)人工林生态系统碳含量、碳储量进行了研究。结果表明：2年、3年、4年桉树人工林的林下植被含碳率分别为41.9%、41.1%、40.85%,彼此间差异未达到显著水平（P<0.05）。桉树人工林枯落物含碳率表现为：2年>4年>3年。0~60 cm土层含碳率变化幅度为0.32~0.65%。4年桉树人工林碳储量分别是2年、3年的2.16、1.18倍。桉树乔木层碳储量表现出随林龄的增加而加大的趋势。3年、4年桉树林乔木碳储量占总碳储量的比例分别为38.61%、57.42%,在生态系统总碳储量中贡献率较高。2年、3年、4年桉树人工林林下植被碳储量分别占其总碳储量的0.86%、2.69%、1.49%,枯落物碳储量分别占其总碳储量的8.55%、3.98%、2.62%。林下植被和枯落物碳汇贡献率较低。2年、3年、4年桉树人工林壤碳储量分别为37.54、46.92、39.2 t/hm2,彼此间无显著差异,桉树人工林0~20 cm碳储量占了整个土壤碳储量的41.2%,20~40 cm碳储量占整个土壤碳储量的31.88%,可见0~40 cm土壤碳储量成为土壤的主体。乔木和土壤碳储量成为短周期桉树人工林重要的碳储存库,本研究为本地区提供了短周期桉树人工林生态系统碳储量数据。     

Experimental Study on the Mass Flux Characteristic of Liquid Carbon Dioxide in a Capillary

When liquid carbon dioxide goes through a adjutage, dry ice will lock it with the depressing pressure of liquid carbon dioxide. For this reason, the authors put forward a new design using a capillary to settle the actual question. They study the mass flux characteristic of liquid carbon dioxide in a capillary the length, inner diameter and input pressure of which are different. On this condition, it has been regressed experiential expression of liquid carbon dioxide's mass flux characteristic in a capillary, and it has a value of engineering field to some extent.     

碳离子注入向日葵种子的生物学效应研究

研究碳离子注入及注入次数对不同品种向日葵生长发育和遗传变异的影响。分别向‘巴葵138’、‘巴葵136’、‘巴葵118’种子注入5×1013 C/cm²碳离子,种植后采收种子进行2次辐照。继续田间试验,观察记录不同巴葵的生长状况,采用RAPD进行遗传变异分析。‘巴葵138’一次辐照组种子发芽率及植株株高、茎粗、叶片数、产量等多项性状都显著提高,二次辐照组则相反;‘巴葵136’和‘巴葵118’变异不显著。分子水平上,一次和二次辐照组与对照组的遗传距离在‘巴葵138’中依次为0.1111、0.1087,‘巴葵136’中为0.0680、0.0303,‘巴葵118’为0.0625、0.0435。碳离子注入对‘巴葵138’的生长发育有显著影响,其效应因辐照次数而异,同时能引起3个品种向日葵基因组DNA产生变异。     

草原生物量及碳密度遥感估算——以内蒙古正蓝旗为例

为了寻求从宏观上用于草原生物量遥感估算的有效方法,提高生物量遥感估算精度,以内蒙古正蓝旗为研究区,利用2010年Landsat5 TM遥感数据与同期调查样地数据,分析了TM各波段、影像变换（主成分变换,缨帽变换）、植被指数、地形因子、气候因子与草原生物量之间的相关关系,并采用多元逐步回归法建立了生物量与各指标的回归模型。结果表明：生物量与EVI（增强型植被指数）、主成分、缨帽变换等具有较高的显著相关,在草原沙化地区应选择具有剔除土壤背景信息的指标估算生物量;正蓝旗草原生物量为1196412.9 t,碳贮量约为0.54 TgC,其中温性草原类的平均碳密度为517.49 kg C/hm²,低地草甸类的平均碳密度为683.30 kg C/hm²。     

青海东部地膜覆盖对土壤固碳能力和肥力水平的影响

为探究青海东部地区地膜覆盖条件下单施化肥对土壤固碳能力和土壤肥力的影响,为实现该地区地膜覆盖种植方式生产的可持续发展提供理论依据。通过对青海东部地区旱地玉米农田连续3年田间覆膜试验,研究地膜覆盖条件下单施化肥栽培模式对耕层(0~20 cm)土壤有机碳(SOC)、活性有机碳(LOC)、碳库管理指数(CMI)、可提取腐殖质碳(C_HE)、胡敏酸碳(C_HA)和富里酸碳(C_FA)的影响。结果表明：覆膜条件下单施化肥栽培模式的SOC、LOC和CMI均小于露地对照;C_HE、C_HA和C_FA均随着种植年限的增加而有所增加,但其增加程度总体上均小于露地对照。随着种植年限的增加,至2020年地膜覆盖土壤LOC/SOC值比试验开始前降低了4.97%,而露地对照则升高了1.11%;同时地膜覆盖有机碳氧化稳定系数(KOS)均高于露地对照;土壤C_HA/C_FA值和PQ值均大于露地对照。单施化肥条件下连续地膜覆盖栽培模式使土壤固碳能力有所下降,土壤有机碳趋于稳定而不利于被生物利用;使土壤肥力下降,土壤质量向不良方向发展,长期以往可能会对该地区作物产量的稳定性和持续生产产生不利的影响。