用旋转筛及辊筛筛除木屑

木屑通常是在削片过程产生的木材碎末或在锯木厂某些操作过程中混入木片中的锯末,是需要在制浆前去除的成分.传统方法是配置不同网眼层细筛的振动筛(旋转筛)对其进行处理,旋转筛的一些局限性促使了其他技术的开发,包括现在所用的辊筛.     

响应面法优化电炉炼钢粉尘中Zn的选择性浸出

研究浸出参数对电炉炼钢粉尘灰中选择浸出性Zn的影响,以Zn和Fe的浸出率为响应变量,以硫酸浓度、浸出温度、浸出时间和液固比为独立变量,采用基于三水平Box?Behnken的响应面法对浸出参数进行优化。对试验结果进行ANOVA分析和验证。在硫酸浓度为2.35 mol/L,浸出温度为25℃,浸出时间为56.42 min,液固比为5的条件下,可得到Zn的最大浸出率为79.09%, Fe的最小浸出率为4.08%。通过ANOVA分析表明,对Zn和Fe浸出率影响最大的因素为硫酸浓度和浸出温度。基于响应面法的模型与试验数据具有很好的一致性,Zn和Fe浸出率的相关系数分别为0.98和0.97。     

Alzheimer’s Disease as Type 3 Diabetes: Common Pathophysiological Mechanisms between Alzheimer’s Disease and Type 2 Diabetes

Globally, the incidence of type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD) epidemics is increasing rapidly and has huge financial and emotional costs. The purpose of the current review article is to discuss the shared pathophysiological connections between AD and T2DM. Research findings are presented to underline the vital role that insulin plays in the brain’s neurotransmitters, homeostasis of energy, as well as memory capacity. The findings of this review indicate the existence of a mechanistic interplay between AD pathogenesis with T2DM and, especially, disrupted insulin signaling. AD and T2DM are interlinked with insulin resistance, neuroinflammation, oxidative stress, advanced glycosylation end products (AGEs), mitochondrial dysfunction and metabolic syndrome. Beta-amyloid, tau protein and amylin can accumulate in T2DM and AD brains. Given that the T2DM patients are not routinely evaluated in terms of their cognitive status, they are rarely treated for cognitive impairment. Similarly, AD patients are not routinely evaluated for high levels of insulin or for T2DM. Studies suggesting AD as a metabolic disease caused by insulin resistance in the brain also offer strong support for the hypothesis that AD is a type 3 diabetes.     

In vitro studies of bioglass material by X-ray diffraction and solid-state MAS-NMR

Bioactive glass 46S6 has been elaborated by melting method at high temperature. “In vitro” experiments of 46S6 glass were carried out by soaking in a simulated body fluid for different times. The kinetics of chemical reactivity and the bioactivity of this biomaterial was investigated by X-ray diffraction and elucidated by using an original structural analysis method based on solid-state MAS-NMR. After in vitro assays, X-ray diffraction confirmed the high bioactivity of bioglass 46S6. The ²⁹Si MAS-NMR spectra showed the emergence of two new species: Q _Si ³ (OH) Q _Si ⁴ and which are characteristic of the dissolution of vitreous network of 46S6 glass while the ³¹P MAS-NMR spectra highlighted the formation of new component attributed to hydroxycarbonate apatite. The bioglass 46S6 have presented the rapid formation of a biological active hydroxycarbonate apatite layer after soaking in simulated body fluid fluid.     

Study on Thermomechanical Treatment, Mechanical Properties and Fatigue of Nitinol Superelastic Thin Sheet

A wide range of different thermomechanical treatments was performed on commercially available superelastic Nitinol thin sheet. The ingot composition in the range of standard superelastic material with about 50.8?at.% Ni, balance Ti, was used to manufacture a series of samples with different thermomechanical conditions. Production parameters such as cold work, heat treatment temperature, and heat treatment time were varied. All finished samples were of the same final thickness of 0.3?mm and received the same industrial surface finishing process to obtain a smooth, defect, and oxide-free, shiny surface. Before carrying out the laser cutting, the material was characterized by tensile testing, DSC, and bend-and-free recovery test. Miniature dogbone specimens were cut from the as-manufactured sheets in both directions, longitudinal as well as transverse to the rolling direction. These samples were surface finished using standard deburring and electropolishing processes. For some specific parameter combinations, there were also samples taken at 45?? to the rolling direction. All qualified samples were then exposed to fatigue testing in a bending mode until fracture or run-out. The results showed there is a significant effect on the fatigue performance of the samples from both the applied thermomechanical treatment as well as the sheet anisotropy. It is also obvious that the achieved strain data is on average lower than the data obtained in comparable studies on tube or wire, which can be attributed to the different test setup (bending mode in air at 37???C) as compared to most other studies as well as the larger surface.     

芳醚树枝形聚合物体系的设计合成以及构象的研究

树枝形聚合物是一类围绕中心核外围链段随着代数的增加以指数级别增长的化合物，它具有高度的几何对称性、精确的分子结构、分子内存在空腔、分子本身具有纳米尺寸等特点．由于其具有精美的结构，树枝形聚合物在高分子、催化、光化学、材料科学等方面具有广泛的应用前景．材料的结构决定它的性能以及应用，为了拓宽树枝形聚合物的应用范围，对其结构以及构象的研究就显得颇为重要．     

A regenerative multiple zone model for HCCI combustion

A new conserved scalar approach, the so-called regenerative multiple zone (RMZ) model, is introduced to simulate combustion in homogeneous charge compression ignition (HCCI) engines with significant products of combustion. In this approach, two conserved scalars are introduced, the mixture fraction Z and the initial exhaust gas fraction J, to determine uniquely the state of the reactive system as a function of the two conserved scalars and time. For the numerical solution of the HCCI combustion, the conserved scalar plane is divided into different zones, which represent homogeneous reactors with constant initial exhaust gas level. Particularly, the zones are created based on the distribution of the initial exhaust gases and are mixed and regenerated at every time step during combustion in order to account for the history effects which are due to the finite rate chemistry. A proper methodology to create and initialize the new zones during the combustion, the so-called zone creation strategy (ZCS), is also proposed. For validation, the RMZ model is implemented in the 2DRD code, which is a computational fluid dynamics code that solves the governing equations for a two-dimensional reaction-diffusion problem. Initially, the consistency of the new model is validated in a one-dimensional reaction-diffusion (RD) case. Subsequently, the necessity for a proper zone creation strategy is demonstrated by a two-dimensional RD case. Next, a parametric study is performed to investigate the sensitivity of the new model on the maximum number of zones that is used. Finally, the limitations as well as the advantages of the RMZ model are discussed.     

炭黑/ 硅橡胶复合材料的压阻特性研究与改

我们对柔性挤压应力传感器,炭黑/硅橡胶复合材料的压阻特性进行了研究,提出了其压力-电阻的简化理论计算公式.实验研究表明,通过添加有机溶剂和SiO2纳米粉可以有效地提高炭黑分布的均匀程度和复合材料的弹性模量,从而改善复合材料的压阻性能.用这种复合材料制备的力敏元件不受被测物体表面形状的限制,可以被广泛应用于各种规则和不规则曲面的挤压应力测量.     

激光烧结纳米ZnO 气敏传感器制备及其气敏特性研究

以激光-感应复合加热法制备的纳米ZnO为原料，用激光烧结法制成的气敏传感元件，对乙醇、丙酮等五种挥发性有机化合物的敏感性进行了测定，同时又对所制成的传感元件作了SEM分析。实验表明，采用激光烧结的纳米ZnO较之电炉烧结的敏感度高，孔洞细小、孔隙率增多；且随着激光加工功率的提高，达到最大敏感度的温度却有所降低。