可穿戴设备的数值型流数据差分隐私均值发布

可穿戴设备实时产生的用户健康数据（如心率、血糖等）对健康监测及疾病诊断具有重大意义，然而健康数据属于用户的隐私信息。针对可穿戴设备的数值型流数据均值发布，为防止用户的隐私信息泄漏，提出一种基于自适应采样的可穿戴设备差分隐私均值发布方法。首先，引入适应可穿戴设备流数据均值波动小这一特点的全局敏感度；然后，采用基于卡尔曼滤波调整误差的自适应采样的方式分配隐私预算，提高发布数据的可用性。在发布两种健康数据的实验中，所提方法在隐私预算为0.1时，即高隐私保护强度下，在心率和血糖数据集上的平均相对误差(MRE)分别为0.01和0.08，相较于差分隐私时序监测的滤波和自适应采样（FAST）算法分别降低了36%和33%。所提的均值发布方法能够提高可穿戴设备均值流数据发布的可用性。     

银吡唑甲基吡啶配合物的制备及其摩擦学性能研究

针对润滑油高温润滑性能突变失效问题,设计制备3种高温自适应的微纳米级别的银吡唑甲基吡啶配合物（配合物1[Ag(LMe)\]2(BF4)2,配合物2[Ag(Li-Pr)n](BF4)n和配合物3[Ag(LMe)(NO3)]2）;考察银吡唑甲基吡啶配合物作为润滑油添加剂的摩擦学性能,并分析其摩擦磨损机制。结果表明：配合物1、2在200~400 ℃温度区间内表现出良好的抗磨减摩性能,而配合物3由于严重的团聚现象,并没有起到预期的抗磨减摩效果;具有层状结构的配合物1的抗磨减摩效果最好,其质量分数为0.5%时的润滑油的润滑性能最好。热重分析结果表明,银吡唑甲基吡啶配合物在高温下生成的银微粒能够有效填补摩擦表面的凹坑,使摩擦副的磨损形式由二体磨损向三体磨损,降低材料表面的磨损程度。因此银吡唑甲基吡啶配合物可作为可控后备润滑添加剂。     

珠江口盆地白云凹陷13.8 Ma前后深水扇差异沉积过程及主控因素

珠江口盆地白云深水区是南海北部油气勘探重要的前景地区,但是目前对白云深水扇的体系域构成及沉积演化过程的理解仍有待加强。基于三维地震剖面、钻测井数据和平面属性综合分析,探讨了珠江口盆地白云凹陷13.8 Ma前后FSST和LST的划分识别依据,描述并对比了两体系域内深水扇的沉积展布特征和时空演化过程。分析后认为FSST为垂向上砂质单点源供给的小型舌状扇体,而LST扇体脱离三角洲主物源,为砂泥混合、多线源供给的大型不规则多期叠合扇体。多因素耦合条件下前者可向后者逐渐转化,推测陆架坡折处充足的沉积物供给和相对海平面变化等综合因素提供了背景基础,同时,强烈的自西南向东北的沿岸流是转化的有利因素。     

Recent Advances of Solid-State NMR Spectroscopy for Microporous Materials

Microporous materials have attracted a rapid growth of research interest in materials science and the multidisciplinary area because of their wide applications in catalysis, separation, ion exchange, gas storage, drug release, and sensing. A fundamental understanding of their diverse structures and properties is crucial for rational design of high-performance materials and technological applications in industry. Solid-state NMR (SSNMR), capable of providing atomic-level information on both structure and dynamics, is a powerful tool in the scientific exploration of solid materials. Here, advanced SSNMR instruments and methods for characterization of microporous materials are briefly described. The recent progress of the application of SSNMR for the investigation of microporous materials including zeolites, metal–organic frameworks, covalent organic frameworks, porous aromatic frameworks, and layered materials is discussed with representative work. The versatile SSNMR techniques provide detailed information on the local structure, dynamics, and chemical processes in the confined space of porous materials. The challenges and prospects in SSNMR study of microporous and related materials are discussed.     

大型发电机定子铁心损耗试验方法及故障分析

分析利用6 kV厂用电进行发电机定子铁心损耗试验的可行性,阐述试验参数的计算方法、试验步骤及注意事项.针对试验过程中发现的铁心一处过热故障,通过消缺后复测效果明显,从而避免发电机带缺陷运行,保证设备安全稳定运行,也为其他运行单位进行现场定子铁心损耗试验提供参考.     

A Novel Way to Prepare Hollow Sphere Ceramics

Recent developments in the fabrication of hollow spheres have allowed our group to prepare a new type of macroporous ceramics: hollow sphere ceramics (HSCs). Alumina hollow spheres were first produced by centrifugal spray‐drying of particle‐stabilized foam slurry. The obtained hollow spheres were sintered together to form HSC at high temperatures. The effect of the sintering temperature on the linear shrinkage, porosity and compressive strength of HSC samples was investigated. When the sintering temperature was increased from 1400°C to 1600°C, the samples shrunk increasingly and the porosity decreased from 59% to 42%, which lead to an increase in the strength of the alumina foams from 6.9 (at 1400°C) to 100.0 MPa (at 1550°C). The mechanical strength of the HSC highly depends on the contact area between the hollow spheres, which could be increased by increasing the sintering temperature, decreasing the size of hollow spheres or by slurry infiltration.     

An effective way to simultaneous realization of excellent optical and electrical performance in large‐scale Si nano/microstructures

Despite the optical advantage of near‐zero reflection, the silicon nanowire arrays (SiNWs)‐based solar cells cannot yet achieve satisfactory high efficiency because of the serious surface recombination arising from the greatly enlarged surface area. The trade‐off between reflection and recombination fundamentally prevents the conventional SiNWs structure from having both minimal optical and electrical losses. Here, we report the simultaneous realization of the best optical anti‐reflection (the solar averaged reflectance of 1.38%) and electrical passivation (the surface recombination velocity of 44.72 cm/s) by effectively combining the Si nano/microstructures (N/M‐Strus) with atomic‐layer‐deposition (ALD)‐Al₂O₃ passivation. The composite structures are prepared on the pyramid‐textured Si wafers with large‐scale 125 × 125 mm² by the two‐step metal‐assisted chemical etching method and the thermal ALD‐Al₂O₃ treatment. Although the excellent optical anti‐reflection is observed because of the complementary contribution of Si N/M‐Strus at short wavelength and ALD‐Al₂O₃ at long wavelength, the low recombination has also been realized because the field effect passivation is enhanced for the longer and thinner SiNWs through the more effective suppression of the minority carrier movement and the reduction of the pure‐pyramid‐textured surface recombination. We have further numerically modeled the Al₂O₃‐passivated Si N/M‐Strus‐based solar cell and obtain the high conversion efficiency of 21.04%. The present work opens a new way to realize high‐efficiency SiNWs‐based solar cells. Copyright © 2014 John Wiley & Sons, Ltd.     

旋转式布料杆在圆型水工构筑物施工中的应用

旋转式布料杆浇筑混凝土工艺是泵送混凝土工艺在圆形水工构筑物施工中的进一步发展 ,此项技术不仅可以加快混凝土浇筑速度 ,减轻劳动强度 ,而且能够提高大型水工构筑物施工质量 ,在施工中值得推广应用。     

不同地区油菜籽脂肪酸组成及含量

采用气相色谱法对不同地区多个品种油菜籽的脂肪酸组成及含量进行分析。结果表明：不同地区各油菜籽品种所含脂肪酸组成基本相同,均含有17种脂肪酸,脂肪酸种类比较丰富;油菜籽中含量较多的脂肪酸有油酸、芥酸、亚油酸、亚麻酸和花生一烯酸,各品种油菜籽间油酸、芥酸和花生一烯酸含量差异较大,亚油酸和亚麻酸含量差异较小;杂交、丰油10号和杂双5号油菜籽可作为丰富的油酸、亚油酸来源,搏优6号和皖油13油菜籽可作为丰富的花生一烯酸来源,南阳红、秦优9号、花菜子和四月红油菜籽可作为丰富的芥酸来源,杂双5号油菜籽可作为低芥酸菜籽油的原料来源;种植土壤对杂交油菜籽脂肪酸含量影响较大,而丰油10号油菜籽脂肪酸含量不受种植土壤的影响,无论是杂交油菜籽还是丰油10号油菜籽,在相同种植土壤条件下,即使来自不同地区,同品种油菜籽脂肪酸含量均无明显差异。     

自修复固井前置液自修复机理

将水灰比为0.44的油井水泥净浆灌入钢管中养护,然后切片并造缝,制作成钢管切片样品,放入清水和固井自修复前置液中浸泡养护,通过测试抗窜强度和对比分析样品微观结构与水化产物组成特征,研究固井自修复前置液的自修复机理。运用X-射线衍射仪对样品的物相组成进行分析,利用热重(TG/TGA)方法测定样品中Ca(OH)2含量,采用压汞仪对样品的孔结构变化进行分析,最后利用环境扫描显微镜对样品的微观形貌进行观测,并对测试样品的微区进行X射线能谱定性、定量分析。研究结果表明,GSN自修复前置液和NMFSJ自修复前置液能够渗透到样品的微裂缝中,与裂缝附近的氢氧化钙和未水化产物发生水化反应,形成硅酸钙结晶或水化硅酸钙凝胶和碱式碳酸钙等水化产物,自动修复样品的微裂缝;NMFSJ自修复前置液还能够渗透到样品固化体本体的孔隙中,激活水化反应;另外其有一部分组分不参与直接生成结晶体,而是催化水泥环中未水化的水泥颗粒水化。