一种结合G.719编解码器的参数立体声音频编解码扩展方法

针对ITU-T G.719全频带音频编码标准尚不支持立体声压缩编码的问题,结合G.719编解码器提出并设计基于离散傅里叶变换（discrete Fourier transform,DFT）的参数立体声音频编解码扩展模块. 输入音频信号进行 DFT变换后在子带内提取相应的空间参数,并将左右声道下混为和声道;解码时,对和声道进行能量补充,分别运用等式法和基于Givens旋转的奇异值分解法（singular value decomposition,SVD）进行解码恢复. 测试结果表明,在G.719中合理设计参数立体声编解码可以获得较好的压缩效果,对于平缓的音乐,等式法比奇异值分解法可解码得到稍高的音质,且复杂度较低;对于变化较快的音乐,奇异值分解法可得到相对较好的音质,但复杂度较高.      

慢病毒载体及其介导的RNA干扰在基因治疗中的应用研究

主要就慢病毒载体及其介导的RNA干扰技术在基因治疗中的应用研究进行了综述,并对其在该领域具有的广阔前景进行了展望.慢病毒载体作为一种新型的载体,可有效地将携带的目的基因导入宿主细胞,并将其整合到宿主细胞基因组中,从而使目的基因得以持久稳定地表达.该载体因具有高感染性、高表达效率及不易诱发宿主免疫反应等优点,已成为基因治疗研究中的一个重要工具.RNA干扰技术可以特异性抑制或关闭特定基因的表达,因此该技术可广泛应用在基因功能探究和恶性肿瘤治疗等领域.由慢病毒载体介导的RNA干扰技术能持久、稳定、特异性地抑制各类细胞中特定基因的表达,在病毒感染、肿瘤等疾病的基因治疗中被广泛应用,成为生物医学领域的新热点.     

New strategies for the repair of spinal cord injury

Spinal cord injury （SCI） leads to several neu- rologic damages to patients with sensory and motor func- tion loss. Although some inspiring results were reported in animal, even in non-human primate models, the clinical translation of these research achievements barely move forward for the SCI patients. This review mainly focused on the pathogenesis of the primary and secondary injury, the clinical therapies and the new technologies in spinal cord injury. Moreover, the key scientific issues on this field were discussed in the review. Finally, some suggestions were proposed for the scientific and clinical researches.     

Functionalized graphene oxide based on p-phenylenediamine as spacers and nitrogen dopants for high performance supercapacitors

p-Phenylenediamine （PPD） functionalized graphene oxide （GO） materials （PPDG） were prepared through a one-step solvothermal process and their appli-cation as supercapacitors （SCs） were studied. The PPD is not only as the spacers to prevent aggregating and re-stacking of the graphene sheets in the preparing process but also as nitrogen sources to obtain the nitrogen-doped graphene. The structures of PPDG were characterized by Fourier transformed infrared spectroscopy （FT-IR）, X-ray diffraction spectroscopy （XRD）, Raman spectroscopy and X-ray photoelectron spectroscopy （XPS） and the results show that the nitrogen-doped graphene was achieved with nitrogen content as high as 10.85 at.%. The field emission scanning electron microscopy （FE-SEM） and high resolu-tion transmission electron microscopy （HR-TEM） have confirmed that the morphologies of PPDG were looselayered with less aggregation, indicating that PPD mole-cules, as spacers, effectively prevent the graphene sheets from restacking during the solvothermal reaction. The special loose textures make PPDG materials exhibit excellent electrochemical performance for symmetric SCs with superior specific capacitance （313 F/g at 0.1 A/g）, rate capability and cycling stability. The present synthesis method is convenient and may have potential applications as ultrahigh performance SCs.     

Computational diffusion kinetics and its applications in study and design of rare metallic materials

Computational diffusion kinetics(CDK),with a spirit of and being coupled with the computational thermodynamics(CT,or called as the CALPHAD technique),plays increasingly important role in the alloy design/optimization and microstructure control during the processing of advanced metallic materials.This paper is to highlight recent progress of CDK in research with great focus on novel Ti and Zr alloys,which was largely performed in the authors’group.It ends with one representative example of the applications of CDK,coupled with CT,quantitative phase field,and three-dimensional(3D)statistical calculation,in designing the heattreatment schedule for the dual phase(αβ)Ti–6Al–4V alloys.     

广西近岸海域水下平原表层沉积物中有机质分布及其积累

【目的】研究广西近岸水下平原表层沉积物有机质的分布和积累,了解有机质的扩散和现状。【方法】以钦州湾口水下斜坡为界,东至铁山港口外古滨海平原的20m以浅的广西近岸水下平原为研究区,依据2007~2010年广西近岸海洋环境地质调查资料,分析该区海底表层沉积物和钻孔有机质的分布、关系和积累特征。【结果】表层沉积物有机质含量频率f分布不均;研究区可划分出3大类沉积环境和5种亚环境,在其间的有机质分布含量差异较大,对沉积环境的选择性较强;有机质分布与沉积物粒度参数也有较大关系,随着粒径(φ)和分选系数增大而升高,沉积物粒度正偏有利于有机质积聚;有机质随沉积动力减弱而聚集,以平均粒径衡量的话,呈现指数增长规律;在不同的沉积环境有机质序列有指数、线性、对数递增关系,表明不同的积累阶段;随着沉积物粒级变细,在3~6φ粒级段出现有机质吸附积累拐点,而且有机质与粘土有共聚性;在研究区西北部监测站位的有机质具有明显的年际变化,观测期间总体增幅0。【结论】虽然根据沉积物质量评价标准表层有机质尚未超标,但结合本底值计算得出的积累系数显示水下平原西北部、西南部、南部位置均出现富集,对应着不同的来源和影响程度,是陆源输入在水动力分配下聚集的结果。     

风险投资机构进入时机与企业技术创新的关系研究

以创业板有风险投资背景的上市企业数据为研究样本,研究风险投资机构进入时机与企业技术创新的关系.结果表明:在早期进入的风险投资机构对企业技术创新的影响更为积极,而在后期进入的风险投资机构对企业的技术创新的影响不显著,甚至产生抑制的作用.基于此研究结论,最后给出政策性建议:大力发展政府引导基金,鼓励风险投资机构投资种子期企业,完善风险资本的准入和退出机制,解决风险投资机构投资早期创业企业的后顾之忧.     

NOESY在地胆草倍半萜内酯化合物结构鉴定中的应用

菊科植物地胆草(Elephantopus scaber Linn.)的重要倍半萜内酯化合物——地胆草种内酯(scabertopin,1)和异地胆草种内酯(isoscabertopin,2)是一对C-2立体构型异构体.通过NOESY技术对其C-2立体构型的确定和对其1H NMR中3位和9位亚甲基中两个质子α、β取向的确定,确证了其立体结构.     

渭河宝鸡段表层沉积物营养盐分布特征及污染评价

以渭河宝鸡市区段流域为研究对象,研究了沉积物中总有机质(OM)、总氮(TN)和总磷(TP)的分布特征,分析了沉积物碳-氮-磷两两间的耦合关系,并对渭河宝鸡段沉积物中营养盐的污染状况进行了评价.结果表明:沉积物中OM浓度为0.378%~1.702%,TN浓度为0.031%~0.335%,TP浓度为0.053%~0.100%,沉积物TOC与TN和TP两两间具有显著的相关性(P0.01),且主要来源于藻类和水生生物;通过对营养盐污染评价发现,该河段沉积物有机污染较轻(有机指数均值为0.129),处于较清洁状态,N、P污染相对严重,具有造成较小生态风险的可能性,应注意控制外源氮磷的输入.     

基于职业发展的高职院校人文素质教育课程体系构建——以安徽机电职业技术学院为例

以安徽机电职业技术学院为实例,对高职院校人文素质教育课程体系构建意义、原则和内容等三个方面进行了探讨。提出高职院校人文素质教育为高职院校专业教育提供价值导向,能提高学生的就业创业能力;高职院校人文素质教育课程体系要按照"系统、切近、互补、全程"等原则进行构建;高职院校人文素质教育课程体系分为显性课程体系即第一课堂教学课程体系和隐形课程体系即第二课堂课程体系、第三课堂课程体系和校园环境课程体系,四个部分功能相互补充、相互配合,形成合力,共同实现高职院校人文素质教育目标。