Review: Wearable Sweat Sensors for Diseases Prevention and Monitoring

Advanced in wireless technologies and flexible materials with great biocompatibility, wearable devices have been utilized in the field of healthcare, sports management, and diseases prevention, which have been widely applied in current electronic equipment. Sweat, as a common metabolite on the skin surface, contains a wealth of biomarkers for disease detection and diagnosis. Therefore, developing wearable sweat sensors can provide a non-invasive method for health data collecting, sports monitori...     

ANALYSIS OF TWO-PHASE FLOW PRESSURE BUILDUP DATA FROM A WELL IN AN INFINITE MULTIWELL RESERVOIR

NOMENCLATURE A1———drainage area of the tested well ( Well 1) At———total reservoir drainage area B———two-phase formation volume factor C———wellbore storage coefficient Cf———rock compressibility fator Co———oil compressibility fator Cw———water compressibility fator Ct———compressibility fator K———reservoir permeability m———slope of a semilog straight line m1———slope defined by Eq.(12) p-———average reservoir pressure-pD———di mensionless average drainag…     

A salt-induced viscosifying smart polymer for fracturing inter-salt shale oil reservoirs

Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids su er from poor tolerance to high temperature and high salinity. Thermoviscosifying polymers(TVP) whose aqueous solution shows viscosity increase upon increasing temperature and salt concentration have received considerable attention recently, which is promising for utilization in fracturing fluids to overcome these problems. In this work, both the salt-induced viscosifying property and mechanism of a TVP solution were investigated and the performance of TVP used as fracturing fluid based on the conditions of the Jianghan inter-salt shale oil reservoir in China was evaluated. It is found that the salt-induced viscosifying property of the TVP solution decreases with temperature and shear rate, but increases with polymer concentration. The number of intermolecular hydrophobic domains increases with the salt concentration contributing to the strengthening of a 3D network structure, which results in an increase in viscosity. In addition, the TVP fracturing fluid formulated with saturated brine exhibits excellent temperature and shear resistance, sand-suspending performance, and gel-breaking performance. Its viscosity remains above50 m Pa s after being sheared for 1 h even at a high temperature of 140 °C and the sand-suspending stability can be maintained for more than 1 week at 100 °C. Furthermore, the fracturing fluid can be easily broken down within 12h using 0.2 wt%–0.3 wt% potassium persulfate without residue.     

白兰地原酒的老熟

该法旨在降低酒精损耗、橡木费用和生产成本，加速白兰地原酒的老熟。在对白兰地原酒进行     

固定床煤加氢热解中载体气流量与加热速率的影响

在温度为580—650℃、压力300巴以下条件下,对英国烟煤(含碳82％,无水无矿物质基)进行的固定床加氢热解实验表明:焦油收率主要取决于相对于静态煤颗粒的载体氢气的速率。只要气体表观速率不减少,焦油收率就随压力的增加而增加。反之,由于所发生的加氢裂解反应不足以抵销因焦油分子在颗粒内部的扩散速率及脱挥发分速率较低而导致的生成炭增加,焦油收率实际上会减少。将加热速率从1℃/s升高到20℃/s时,对总转化率几乎没有影响。在消耗焦油的情况下,烃类气体产率大大地增加。此外,较高的加热速率可获得更多的芳族焦油;同时,所获得的证据有力地说明:一次挥发产物在从煤颗粒逸出之前以及在蒸气相中就被加氢裂解了。     

尖晶石CoAl_2O_4中阳离子分布的温度依赖性

本文通过X射线粉末衍射数据的Rietveld结构精化法,确定了经过750～1200℃淬火的合成尖晶石CoAl_2O_4样品的阳离子分布。其反生参数X随温度750—1200℃相应地从0.11平滑增加到0.25(±0.005),并可用带有α_(Co-Al)=45.3±0.5,β=-18.3±1.2kJ/mol的一般热力学模型描述。其β项与 O’Neill和Navrotsky(1984)提出的2—3价型尖晶石的数据(-20kJ/mol)相吻合,而CoAl_2O_4尖晶石性能相似于大多数氧化物尖晶石,显示出阳离子分布的温度依赖性。既然,Co~(2+)和 Fe~(2+)通常显示相似的高温晶体化学行为,本次研究结果强调了与近来关于FeAl_2O_4中阳离子分布的温度依赖性的研究结果不一致的性质,它们不能很好地用一般的热力学模型所描述。CoAl_2O_4中阳离子的再有序化速率在低温(700℃)下定性地相似于另一些铝酸盐尖晶石;但FeAl_2O_4是例外;由于内部的“Fe~(3+)/空穴”存在,FeAl_2O_4的阳离子再有序化速率更快。FeAl_2O_4的明显异常特性可能是由于高速动力学的人工合成所致。     

The Principle and Architecture of a Hybrid System of a Neural Network and an Expert System in Intelligent CAD of Electrical Machines

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Effect of oxygen impurity on long-term thermal stability of Zr-based metallic glasses below glass transition temperature

1Introduction Metallic glasses as disordered solids are thermo-dynamically metastable at the temperature below theirglass transition temperatures,Tg.Phase transformation ofdevitrification being activated by time and temperaturecan occur not only above Tg …     

Draining Tangjiashan Barrier Lake after Wenchuan Earthquake and the flood propagation after the dam break

Tangjiashan Barrier Lake is one of the largest barrier lakes caused by the Wenchuan Earthquake. Its risk analysis, emergency plan and effect of the emergency plan are introduced in this paper. The dam height of Tangjiashan Barrier Dam is about 105 m, and the reservoir storage capacity is 3.2×108 m3. When the dam broke the flood peak were estimated to be larger than 48000 m3/s, which might cause a enormous disaster to the downstream cities and residents. A discharge channel with 13 m deep and 8 m wide was dr...     

Relaxor behavior and electrical properties of high dielectric constant materials

Several typical high dielectric constant materials are reviewed to study the electrical properties and relaxation mechanism. It is found that a Lorenz-type law can be used to describe the dielectric permittivity of either the normal ferroelectrics with or without diffuse phase transitions (DPT) or the typical ferroelectric relaxors. The ferroelectric DPT can be well described by just one fitting process using the Lorenz-type law, while the relaxor ferroelectric transition needs two independent fitting processes. The Lorenz-type law fails at the low temperature side of the dielectric maximum of a first-order ferroelectric phase transition. Above the transition temperature, the dielectric curves of all the studied materials can be well described by a Lorenz-type law. Supported by the National Natural Science Foundation of China (Grant No. 50672075), New Century Excellent Talents (Grant No. 05-087), Natural Science Foundation of Northwestern Polytechnical University (Grant No. 200703), Xi’an Science & Technology Foundation (Grant No. CXY08006) and 111 Project (Grant No. B08040)