HYDROTHERMAL SYNTHESIS AND MAGNETIC PROPERTIES OF NANOSIZED NICKEL ZINC FERRITE POWDER

用水热法分别在200℃和220℃下反应5h制备了纳米级镍锌铁氧体(Ni0.5Zn0.5Fe2O4)粉体。用X射线衍射(X-ray diffraction,XRD)分析合成的纳米Ni0.5Zn0.5Fe2O4的物相,结果表明:200℃水热反应5h得到的纳米Ni0.5Zn0.5Fe2O4粉体中含有γ-Fe2O3,220℃水热反应5h可以得到纯纳米Ni0.5Zn0.5Fe2O4粉体。用透射电镜(transmission electronmicroscope,TEM)、Mssbauer谱(Mssbauer spectroscopy,MS)、Fourier红外分析(Fourier transform infrared spectroscopy,FTIR)、振动样品磁强计(vibrating sample magnetometer,VSM)等方法表征纯纳米Ni0.5Zn0.5Fe2O4粉体。TEM结果表明:纳米Ni0.5Zn0.5Fe2O4粉体粒子为球形,粒径约为20nm。室温MS结果表明:大部分纳米Ni0.5Zn0.5Fe2O4粉体粒子表现出铁磁性,少量的表现出超顺磁性。FTIR分析表明:样品在577cm-1和420cm-1处出现NiZn铁氧体的特征峰。磁滞回线结果表明:纳米Ni0.5Zn0.5Fe2O4粉体粒子的饱和磁化强度为38.14A?m2/kg,剩磁为17.32A?m2/kg,矫顽力为29275.29A/m。Nanosized nickel zinc ferrite(Ni0.5Zn0.5Fe2O4)powder was synthesized by the hydrothermal synthesis method at 200℃ and 220 ℃for 5h,respectively.An X-ray diffraction(XRD)was adopted for the characterization of Ni0.5Zn0.5Fe2O4 powder.It is concluded that the Ni0.5Zn0.5Fe2O4 powder containedγ-Fe2O3 when it is synthesized at 200 ℃for 5h,and pure Ni0.5Zn0.5Fe2O4 powder were prepared by the hydrothermal synthesis at 220 ℃for 5h.The pure powder was characterized by a transmission electron micro-scope(TEM),Mssbauer spectrum(MS),Fourier transform spectroscopy(FTIR),and magnometry using a vibrating sample magne-tometer(VSM).The TEM results show that Ni0.5Zn0.5Fe2O4 nanoparticles are round,and are about 20 nm in diameter.The MS results reveal that most of the Ni0.5Zn0.5Fe2O4 nanoparticles show ferromagnetism and a small quantity of Ni0.5Zn0.5Fe2O4 exhibit superpara-magnetic relaxation.The FTIR results show that the bands at 577 cm-1 and 420 cm-1 are the characteristic bands of NiZn ferrite.The saturated magnetization,remanence and coercivity of Ni0.5Zn0.5Fe2O4 powder are 38.14 A·m2/kg,17.32 A·m2/kg and 29 275.29 A/m,respectively.The powder exhibits good magnetic properties.深圳大学科研(4CHQ)资助项

Observation on Morphological Structure of Pineal Organ of Mudskipper(Boleophthalmus pectinirostris)

鱼类松果体是传达外界信息到体内的主要传感器之一,其分泌的褪黑激素与鱼类生殖活动密切相关.为了阐明大弹涂鱼松果体形态结构与其功能的关系,运用组织细胞学方法研究了大弹涂鱼松果体的形态结构.结果表明,大弹涂鱼松果体位于端脑和中脑之间,由松果体柄和终囊两部分组成,具有背囊结构.松果体柄细长,细胞排列紧密,柄中有空腔,开口与第三脑室相通;松果体终囊膨大成梨形,且有空腔,腔内有皱褶,终囊顶部表面有黑色素细胞;背囊位于终囊下方,形状不规则,其囊壁向囊腔内反复折叠,形成许多复杂、盘旋曲折的内褶,背囊内部可见血细胞.研究结果为将来揭示大弹涂鱼半月周期产卵的机制提供了基础资料.Pineal gland is a transducer that transmits environmental message to the brain in fishes.It produces melatonin to regulate fish spawning behaviors.In order to elucidate the relationship between the structure and functions of the pineal gland in the mudskipper(Boleophthalmus pectinirostris),the morphological structure of pineal organ of the mudskipper was studied using histocytology.Results showed that pineal organ of the mudskipper located between telencephalon and midbrain,was composed of pineal stalk and pineal vesicle,and had a dorsal sac.The pineal stalk was long and thin in shape,the cells arrangement was tight,and there was a cavum in the middle of the stalk.The opening of pineal organ was connected with the ventriculus tertius.Pineal vesicle was expanded as a pear in shape and had a cavum with rugas inside.The top surface of the vesicle was covered by melanophore.The dorsal sac lied under the pineal vesicle and was irregular in shape with a cavum.The inner wall of the sac cavum had many complicated,spiral and tortuous emboles.The blood cells were visible inside the dorsal sac.The data from the present study will be useful to future research on the mechanisms of spawning with semilunar periodicity in the mudskipper.国家自然科学基金项目(40976095);福建省科技计划重点项目(2008N0041

基于高阶统计量的OFDM子载波调制识别算法

针对OFDM（正交频分复用）信号子载波调制方式识别的问题,提出了一种将高阶矩和高阶累积量相结合的联合识别算法。该算法首先运用基于高阶矩的特征量把MPSK（多进制相移键控）调制（M=2、4）、64QAM（六阶正交幅度调制）和16QAM（四阶正交幅度调制）区分开,然后再利用基于高阶累积量的特征量区分BPSK（二进制相移键控）调制和QPSK（四相相移键控）调制。从理论上进行了推导与分析,该算法对多径衰落与噪声干扰不敏感。计算机仿真结果表明,所提算法在多径信道条件下具有良好的识别性能

复合氧化物催化剂及其制备方法和应用

本发明提供一种丙烷部分氧化制丙烯酸的复合氧化物催化剂，该催化剂的制备方法包括如下步骤：(1)溶解或胶溶催化剂活性组分前体，以制备均匀分散体；(2)溶解或胶溶催化剂载体组分前体，以制备均匀分散体；(3)将步骤(1)得到的活性组分前体的均匀分散体与步骤(2)得到的载体组分前体混合，以得到稳定的混合溶胶；(4)干燥步骤(3)的混合溶胶得到复合氧化物催化剂前体；和(5)焙烧所述复合氧化物前体，以制备复合氧化物催化剂。采用该方法得到的催化剂具有较高的比表面积和空隙率较大，并且活性组分均匀地分散在载体组合物中。带填

一种用于丙烷氧化制丙烯醛膜反应器的制法和应用

一种用于丙烷部分氧化制丙烯醛的膜反应器，采用混合溶胶及AgBiVMoO络合粉体的方法制备，于AgBiVMoO在α-Al2O3膜管表面形成一薄层均匀连续的膜，膜管上的催化剂的负载量达到50-100mg，厚度大约为6-7um，具有白钨矿结构。该膜反应器在丙烷氧化制丙烯醛反应中应用时，一方面使反应气体丙烷在膜反应器中通过时都要与催化剂层接触，被活化发生反应，提高丙烷的转化率；另一方面，生成的丙烯醛能迅速离开催化剂层，避免深度氧化，提高丙烯醛的选择性。带填

取样光栅分布布拉格反射半导体激光器的制作方法

一种取样光栅分布布拉格反射半导体激光器的制作方法，包括:在n型InP衬底上分别外延InP缓冲层和介质膜;在介质膜上刻出条形凹槽，并依次生长InGaAsP下限制层、InGaAsP/InGaAsP多量子阱、InGaAsP上限制层和InP光栅制作保护层;去除介质膜;刻出多条取样光栅窗口;制作取样光栅;腐蚀保护层;依次生长p-InP层、p-InGaAsP刻蚀阻止层、p-InP层和p+-InGaAs层;形成脊形波导;刻蚀形成电隔离沟;在p-InGaAsP刻蚀阻止层上进行He离子注入;在上述步骤制作的器件结构的上表面和脊形波导的侧面淀积介质绝缘层;在器件的上表面溅射p电极;将衬底减薄，并蒸发n电极，解理管芯，完成器件的制作

紫茎泽兰入侵对土壤细菌的群落组成和多样性的影响

外来生物入侵可能对生物群落结构和生态系统功能产生多种影响,但入侵植物与土壤微生物群落组成和多样性的关系尚不清楚。为了揭示外来植物紫茎泽兰(Eupatorium adenophorum)入侵对土壤化学性质和细菌群落组成及多样性的影响,本研究利用第二代高通量测序技术,比较了紫茎泽兰不同入侵程度的生境(本地植物群落、紫茎泽兰与本地植物混生群落、紫茎泽兰单优群落)土壤中细菌群落的差异。土壤化学性质分析表明,土壤p H值、有机质、全N和全K随着紫茎泽兰的入侵而逐渐降低,而土壤全P则在入侵程度最高的生境土壤中最高。通过测序共获得7,755个细菌OUT(operational taxonomic unit)。结果表明,紫茎泽兰入侵对土壤的细菌多样性影响较小,ACE和Chao指数在3种不同生境间的差异不显著。细菌在紫茎泽兰与本地植物混生群落中的Shannon指数最低,即细菌的多样性在中等入侵程度的生境最低。此外,紫茎泽兰入侵改变了土壤细菌组成和结构,酸杆菌门(Acidobacteria)和疣微菌门(Verrucomicrobia)的相对丰度,从本地植物群落、混合群落到紫茎泽兰单优群落,呈现出先增加后减少的趋势。可见,紫茎泽兰入侵一定程度上改变了土壤微生物的多样性和群落结构,并改变了土壤的化学性质