Industrialization Progress of Nanocellulose in China

Nanocellulose, a kind of cellulose with nanometer sizes, has drawn great interest in the pulp and paper industry due to its unique structure and excellent performance. It can be divided into five categories: nanocrystalline cellulose (NCC), nanofibrillated cellulose (NFC), bacterial cellulose (BC), electrospun cellulose nanofibers (ESC), and precipitation regenerated cellulose nanofibers (PRC). In this paper, we reviewed the industrialization progress of nanocellulose in China. Furthermore, we proposed that efficient and environmentally friendly preparation methods and high value utilization would be the focus of nanocellulose development.     

Electro-conductive Nanocrystalline Cellulose Film Filled with TiO2-Reduced-Graphene Oxide Nanocomposite

Imparting electro-conductive properties to nanocellulose-based products may render them suitable for applications in electronics, optoelectronics, and energy storage devices. In the present work, an electro-conductive nanocrystalline cellulose (NCC) film filled with TiO₂-reduced-graphene oxide (TiO₂-RGO) was developed. Initially, graphene oxide (GO) was prepared using the modified Hummers method and thereafter photocatalytically reduced using TiO₂ as a catalyst. Subsequently, an electro-conductive NCC film was prepared via vacuum filtration with the as-prepared TiO₂-RGO nanocomposite as a functional filler. The TiO₂-RGO nanocomposite and the NCC/TiO₂-RGO film were systematically characterized. The results showed that the obtained TiO₂-RGO nanocomposite exhibited reduced oxygen-containing group content and enhanced electro-conductivity as compared with those of GO. Moreover, the NCC film filled with TiO₂-RGO nanocomposite displayed an electro-conductivity of up to 9.3 S/m and improved mechanical properties compared with that of the control. This work could provide a route for producing electro-conductive NCC films, which may hold significant potential as transparent flexible substrates for future electronic device applications.     

纳米晶涂层对DD98M合金热腐蚀行为的影响

为了研究纳米化对DD98M合金热腐蚀行为的影响,采用磁控溅射的方法制备了与其成分相同的纳米晶涂层。运用XRD、SEM/EDS、TEM分别分析了涂层的结构和热腐蚀性能。结果表明:沉积态的纳米晶涂层呈柱状晶结构,有大量沿沉积方向的柱状晶界,晶粒宽度为30~100 nm。涂层为单一的γ相且具有明显的(111)择优取向。在900℃Na_2SO_4+25%K_2SO_4以及Na_2SO_4+25%Na Cl盐中,DD98M合金在5 h内就发生了严重腐蚀。纳米晶涂层在熔融Na_2SO_4+25%K2SO4中表现出了良好的热腐蚀性能,但在Na_2SO_4+25%Na Cl盐中,纳米晶及其预氧化涂层对DD98M合金的抗热腐蚀性能的提高并不明显。纳米晶促进了涂层表面Al_2O_3膜在空气中和熔融Na_2SO_4+25%K2SO4盐中的快速形成,显著提高了DD98M合金在硫酸盐中的抗热腐蚀性能,预氧化处理则使涂层的抗热腐蚀能力进一步提高。     

Palladium‐Catalyzed Heck Coupling‐Hydrogenation: Highly Efficient One‐Pot Synthesis of Dibenzyls and Alkyl Phenyl Esters

An efficient method for the synthesis of industrially important dibenzyls and alkyl phenyl esters via sequential Heck coupling and hydrogenation of the alkenyl double bond in one pot with a single recyclable catalyst under mild conditions has been realised. The catalyst was recovered by simple filteration and reused for several cycles with consistent activity.     

铁基非晶及纳米晶合金在NaCl溶液中的电化学腐蚀行为

采用单辊甩带法和非晶晶化法分别制备了Fe78Si13B9非晶薄带和Fe73.5Si13.5B9Nb3Cu1纳米晶薄带,并对两种铁基合金薄带在不同温度进行了退火处理,利用电化学极化曲线分别研究了两种合金在0.1 mol/L NaCl溶液中的电化学腐蚀行为及退火温度对两种合金在NaCl溶液中耐腐蚀性能的影响。结果表明:铁基纳米晶合金比非晶合金的耐腐蚀性要好;随着退火温度的升高,非晶及纳米晶合金的耐腐蚀性能都得到提高。     

Nanocrystalline Magnesium Oxide‐Stabilized Molybdenum: An Efficient Heterogeneous Catalyst for the Aerobic Oxidation of Alcohols to Carbonyl Compounds

A nanocrystalline magnesium oxide‐stabilized molybdenum(VI) complex catalyzed the oxidation of primary and secondary alcohols to carbonyl compounds in excellent yields using molecular oxygen as stoichiometric oxidant. The nanomaterials with their three‐dimensional structure and defined size and shape act as suitable supports for metal complexes. The catalyst can be reused for four runs without any significant loss of activity.     

纳米晶磁芯螺线管微电感的模拟研究

为了研制小尺寸、高性能的片上微电感,采用Fe基非晶薄带经退火得到的纳米晶带材作为磁芯材料,并对其高频磁导率进行了测试。对纳米晶磁芯螺线管微电感建立了物理模型,模拟分析了结构参数对微电感性能的影响。结果表明:在1~10MHz频率范围内,所设计的微电感的电感量L在2~12μH,品质因数Q值在1.3~2.3,非常适用于DC-DC变换器等功率电子器件。     

SPS制备纳米晶Bi_(0.75)Er_(0.25)O_(1.5)固体电解质

以分析纯Bi2O3和Er2O3为原料,采用反向滴定共沉淀法合成Bi和Er的氢氧化物前驱体,并对共沉淀的pH值条件进行了分析。将该前驱体在500℃焙烧3h后得到Bi0.75Er0.25O1.5的纳米粉体,高温XRD结果表明该粉体主要为β相,谢乐公式计算平均晶粒尺寸为10nm,并且随温度升高在650℃转变为δ相。通过热力学计算,确定了SPS下烧结Bi0.75Er0.25O1.5陶瓷适宜的温度和氧分压条件,最后在测试温度为500℃保温1min得到了相对密度达到96%的δ相纳米晶的Bi0.75Er0.25O1.5陶瓷,平均晶粒尺寸为18nm。     

热处理对纳米钙钛矿氧化物La_（0．7）Sr_（0．3）FeO（3－δ）的电子

利用ＰＥＧ法合成了粒度约为３０ｎｍ的处于正交结构的钙钛矿型氧化物Ｌａ０．７Ｓｒ０．３ＦｅＯ３－δ；通过对此氧化物进行高温后处理得到了立方和菱方结构的同化学计量比氧化物，测量了这三种不同结构样品的ＸＰＳ谱和Ｍｏｓｓｂａｕｅｒ谱，并同由固相反应法得到的同样化学计量的正交和立方混相氧化物进行了对比．结果表明Ｓｒ３ｄ由处于体相和表面两种状态组成，随粒度的增加，体相含量增加，同时Ｆｅ２ｐ３／２亦发生了明显的变化．讨论了Ｆｅ电子状态的变化．     

Fe基非晶和纳米晶合金的热膨胀

将非晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９和Ｆｅ９１Ｚｒ７Ｂ２合金经退火制成纳米晶合金，测量了淬火态和退火态样品的热膨胀曲线，研究了退火温度对热膨胀的影响，结果表明，纳米晶粒的形成导致居里温度Ｔｃ以下的热膨胀系数急剧增加，而Ｔｃ以上的热膨胀系数几乎不随退火温度变化。