多晶硅表面金属催化化学腐蚀法制绒研究现状

在多晶硅太阳能电池的生产过程中, 金刚线切割技术(Diamond wire sawn, DWS)具有切割速度快、精度高、原材料损耗少等优点, 受到了广泛关注。金刚线切割多晶硅表面形成的损伤层较浅, 与传统的酸腐蚀制绒技术无法匹配, 金属催化化学腐蚀法应运而生。金属催化化学腐蚀法制绒具有操作简单、结构可控且易形成高深宽比的绒面等优点, 具有广阔的应用前景。本文总结了不同类型的金属催化剂在制绒过程中的腐蚀机理及其形成的绒面结构, 深入分析和讨论了具有代表性的银、铜的单一及复合催化腐蚀过程及绒面结构和电池片性能。最后对金刚线切割多晶硅片表面的金属催化化学腐蚀法存在的问题进行了分析, 并展望了未来的研究方向。     

GPS辅助的城市物业精细化管理解决方案及应用

对城市物业管理中出现的问题进行了分析研究,提出了一种基于位置服务的物业精细化管理解决方案。该方案基于GPS定位、Http/Socket通讯等技术,实现了社区物业精细化、标准化管理,同时对工作人员实时监督,提升了物业服务企业的监管力度,保障了物业管理工作的顺利进行。     

Headspace fingerprinting approach to identify the major pathway influencing volatile patterns of vinasse-cured duck processed by high pressure,as well as its impact on physicochemical and sensory attributes

As a decisive attribute, flavour could be influenced by HP treatments through multiple physical and chemical pathways within the high pressure (HP)-assisted meat curing process. This investigation aimed to identify the major pathway influencing volatile flavour patterns of two representative vinasse-cured duck (VCD) products with HP treatments (150–300 MPa/15 min), including wet and dry types, by employing headspace fingerprinting as an untargeted approach. Results suggested that HP treatments greatly lowered moisture contents and increased Warner-Bratzler shear force and thiobarbituric acid reactive substances of the cured samples. According to multivariate models, the volatile flavour patterns of the HP-processed VCD could be clearly separated from the unprocessed samples, but the VCD pressurised at different intensities represented similar volatile fingerprinting, which was validated by e-nose analysis. The discriminant analysis (OPLS-DA) model outlined vinasse-derived ethanol, acetic acid, 3-methyl-1-butanol, 2-methyl-1-butanol, phenethyl alcohol and 2-methyl-3-octanone as the major discriminant aromas across the unpressurised and pressurised samples.     

Behavior of sulfate in preparation of single light rare earth carbonate by Mg(HCO_3)_2 precipitation method

The precipitation of the water-leaching solution of Baotou mixed rare earth(RE) concentrate roasted with sulfuric acid using ammonium bicarbonate for producing RE carbonate produces a mass of ammonia-nitrogen wastewater because of the relatively low solubility of rare earth sulfate.To solve the serious problem of ammonia-nitrogen pollution,new precipitators need to be developed urgently so as to meet the requirements of environmental protection and impurities content of the product(SO_4~(2-)1.8 wt% in RE carbonates products).In this paper,we studied the effects of feeding modes on the behavior of SO_4~(2-) during the preparation of light RE carbonate(RE=La,Ce,Pr,Nd) from their sulfate solutions using Mg(HCO_3)_2 as a precipitant.The results indicate that the contents of SO_4~(2+) in the La and Ce precipitates using positive feeding mode exceed 16 wt% because of the formation of La2(CO_3)_(2.15)(-SO_4)_(0.85)·4 H_2 O and Ce2(CO_3)_(2.15)(SO_4)_(0.85)·3 H_2 O,while those of the Pr and Nd precipitates are 4 wt%-5 wt%since they exist in the form of n-carbonate.The precipitates prepared using synchronous feeding mode are all RE carbonate with only 4 wt%-5 wt% of SO_4~(2-) enclosed in the precipitation.The content of SO_4~(2-) in the RE carbonate obtained using reverse feeding mode is the lowest.Among them,the content of SO_4~(2-) in La precipitate is only 1.40 wt%.Both synchronous and reverse feeding modes can effectively reduce the content of SO_4~(2-)in RE carbonate,which provides theoretical guidance for the preparation of qualified light RE carbonate products by Mg(HCO_3)_2 precipitation method.     

含功效成分电子烟对动物模型止咳平喘作用研究

为考察电子烟作为功效成分递送器具的效果,选取L-薄荷醇、L-茶氨酸、丁香酚、木香烃内酯、西贝碱、菖蒲酮、7,4'-二羟基黄酮7种功效化合物和1种臭灵丹提取物,通过氨水引咳小鼠咳嗽模型和卵清蛋白(OVA)引喘大鼠哮喘模型,评价上述物质在电子烟中止咳平喘疗效.结果 显示:1)止咳效果方面.上述8种物质均减少了咳嗽模型小鼠的咳嗽次数,同时不同程度延长了咳嗽模型小鼠咳嗽潜伏期;2)平喘效果方面.上述8种物质对哮喘模型大鼠肺功能各指标均有改善,其中L-薄荷醇对呼气时间(简称"Te")、50％的呼气流速(简称"EF50％")有明显改善;L-茶氨酸对Te、最大呼气流速(简称"PEF")和EF50％有明显改善;丁香酚对PEF、EF50％和呼气量(简称"EV'")有明显改善;木香烃内酯对PEF和EV有明显改善;西贝碱对Te、PEF有明显改善;菖蒲酮对Te、PEF有明显改善;7,4'-二羟基黄酮对PEF和EV有明显改善;臭灵丹提取物对PEF和EF50％有明显改善;3)Model组大鼠存在明显哮喘病理改变:肺基底膜增厚并发生玻璃样变,相比Model组,8组接受功效型电子烟烟雾暴露的哮喘模型大鼠支气管哮喘均有改善.以上说明,电子烟作为具有止咳平喘功效成分的递送器具效果明显,这为功效型电子烟的开发提供了参考.     

融合重检测机制的卷积回归网络目标跟踪算法

针对基于人工特征的背景感知相关滤波（CACF）算法在形变、运动模糊、低分辨率情形跟踪效果较差以及跟踪器遇到严重遮挡等情形容易陷入局部最优而导致跟踪失败的问题，提出一种融合重检测机制的卷积回归网络（CRN）目标跟踪算法。在训练阶段，将相关滤波作为CRN层融入进深度神经网络，使网络成为一个整体进行端到端训练；在跟踪阶段，通过残差连接融合不同网络层及其响应值，同时引入重检测机制使算法从潜在的跟踪失败中恢复，当响应值低于给定阈值时激活检测器。在数据集OTB-2013上的实验表明，所提算法在50个视频序列上精确度达到88.1%，相比原始CACF算法提高9.7个百分点，在具有形变、运动模糊等属性的视频序列上相比原始算法表现更优秀。     

An Improved Torque Sensorless Speed Control Method for Electric Assisted Bicycle With Consideration of Coordinate Conversion

In this paper, we propose an improved torque sensorless speed control method for electric assisted bicycle, this method considers the coordinate conversion. A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling. A DC motor provides assisted power driving, the assistance method is based on the real-time wheel angular velocity and coordinate system transformation. The effect of observer is proved, and the proposed method guarantees stability under disturbances. It is also compared to the existing methods and their performances are illustrated through simulations. The proposed method improves the performance both in rapidity and stability.      

淬火温度对G105钢组织和性能的影响

利用硬度计、拉伸试验机、冲击试验机和光学显微镜等手段,研究了G105钢分别在890、910和930 ℃保温150 min淬火,随后进行630 ℃保温180 min回火处理后组织和性能变化。结果表明:随着淬火温度的升高,G105钢淬火硬度越来越高;经回火处理后,淬火温度为890 ℃和910 ℃时,调质硬度无太大差异,分别为33.2 HRC和32.7 HRC,淬火温度为930 ℃的调质硬度相对提高约1.5 HRC。试验钢强度随着淬火温度的升高也呈现升高趋势,但冲击韧性呈先升高后下降的趋势,这主要是由于调质后存在粒状碳化物的析出现象,导致其冲击韧性显著下降,故认为当淬火温度选取910 ℃时,获得的G105钢综合力学性能较佳。     

Encapsulation and characterisation of grape seed proanthocyanidin extract using sodium alginate and different cellulose derivatives

Grape seed proanthocyanidin extract (GSPE) has health benefits. However, these phenolic compounds undergo degradation reactions and have undesirable sensorial characteristics. GSPE was encapsulated using sodium alginate (SA), SA-methyl cellulose (MC) and SA-hydroxypropyl methylcellulose (HPMC) for promoting controlled release, pH stability, temperature and storage period tolerance of GSPE. The microcapsules were characterised using scanning electron microscopy (SEM) and Fourier transform infra-red (FTIR) analysis. The SA-MC and SA-HPMC microcapsules appeared to have a more compact surface than SA-alone microcapsules. FTIR analysis indicated successful immobilisation of GSPE into the polymeric microcapsules. Moreover, the SA-MC and SA-HPMC microcapsules showed higher thermal stability. The microcapsules showed a relatively higher amount of released GSPE at a pH above six than at a lower pH. The SA-MC and SA-HPMC microcapsules could be used to retain more GSPE content in the gastric phase and to release it in the intestinal phase for possible absorption. Furthermore, after 28 days of storage at 25 °C, the GSPE retention rate of the microcapsules was still higher than 80%. GSPE encapsulated in SA-MC and SA-HPMC microcapsules results in lesser degradation and can be absorbed more effectively. This method has potential for the delivery of colon-specific materials while exhibiting a sustained-release characteristic.