电热融化法在沥青路面冬季除雪融冰中的应用

针对冬季道路容易积雪结冰,严重影响交通安全的现状,对电热融化法在沥青路面冬季除雪融冰中的应用进行了探讨,介绍了该方法的优缺点,并对其实际使用中应注意的问题进行了分析,指出其具有广阔的应用前景。

融化-再凝结法对冰芯气泡中甲烷的提取分析

用融化 -再凝结方法对达索普冰芯气泡中的CH4 进行了提取分析 .大约 80g的冰芯样品在真空容器中融化 ,通过特殊方式 ,使融水自容器底部向上结冰 ,并经气相色谱仪对释放出气体中的CH4含量进行测试 .空白测试结果表明 ,该方法仅产生 15± 4nmol·mol-1的污染 ;对每个样品 3次重复测试结果的标准偏差上限为± 2 5nmol·mol-1.

葡萄酒冷稳定测试方法及研究进展

酒石酸氢钾饱和而析出形成沉淀,是导致葡萄酒不稳定的主要原因。生产需要进行冷稳定处理以保证酒石稳定性,即冷稳定性。而冷稳定必须通过稳定性测试才能判断,所以使用合理准确的测试方法非常重要。本文阐述了葡萄酒的冷冻-融化法、冷藏法、电导率/微接触法、饱和温度法、离子浓度积法等几种冷稳定测试方法,并比较了各方法的原理、操作方法以及特点,以期为葡萄酿酒生产提供有益借鉴。

冷冻温度对聚乙烯醇水凝胶性能的影响

目的:冷冻温度对制备性能优良的聚乙烯醇水凝胶有较大的影响,拟通过采用反复冷冻-融化方法制备聚乙烯醇水凝胶,探讨在不同冷冻温度下制备的聚乙烯醇水凝胶的物理性能和力学性能,寻求制备聚乙烯醇水凝胶的最佳冷冻温度。方法:实验于2007-04/06在中国矿业大学材料学院摩擦学与可靠性工程实验室完成。实验选用白色絮状的聚乙烯醇20-99作为原料,按一定比例将聚乙烯醇溶于去离子水中,在恒温水浴箱中于90℃下加热4h,配制成一定浓度的聚乙烯醇水溶液;然后将聚乙烯醇水溶液在超低温冷冻储存箱中冷冻成型,冷冻温度分别设为-10℃,-15℃,-20℃,-25℃,-30℃,冷冻时间为6～10h,取出试样后室温下融化2～4h,上述冷冻-融化过程重复3次制得聚乙烯醇水凝胶。实验选用聚乙烯醇的质量分数为15%,制备不同厚度的聚乙烯醇水凝胶试样若干备用。测试各种冷冻温度下制备的聚乙烯醇水凝胶的密度、含水率、再溶胀性和结晶度等物理性能以及弹性模量和应力松弛等力学性能。结果:聚乙烯醇水凝胶的物理性能和力学性能随冷冻温度的不同而明显变化;-20℃反复冷冻融化制备的聚乙烯醇水凝胶具有较好的物理性能和力学性能,其密度为1.06543g/cm3,含水率为82.61%,再溶胀率达238.8%,结晶度为74.03%,弹性模量为0.0974MPa。结论:-20℃是反复冷冻-融化法制备聚乙烯醇水凝胶的常选冷冻温度。

热处理时间对LiFePO_4的晶体影响

将氧化铁、磷酸二氢铵、碳酸锂混合,在高温条件下热处理形成熔融液,淬冷、干燥、研磨制得锂铁磷酸盐玻璃粉末,将锂铁磷酸玻璃粉末与柠檬按一定质量比混合,在氮气气氛条件下热处理制取磷酸铁锂,考察热处理时间对晶体的影响。利用X-射线衍射仪、扫描电子显微镜分析样品物相成分、晶体微观结构、晶体粒径分布。根据分析结果显示LiFePO4的结晶度、粒径与热处理时间成正比。

Driving fatigue fusion detection based on T-S fuzzy neural network evolved by subtractive clustering and particle swarm optimization

In order to improve the accuracy and reliability of the driving fatigue detection based on a single feature, a new detection algorithm based on multiple features is proposed. Two direct driver＇s facial features reflecting fatigue and one indirect vehicle behavior feature indicating fatigue are considered. Meanwhile, T-S fuzzy neural network（TSFNN）is adopted to recognize the driving fatigue of drivers. For the structure identification of the TSFNN, subtractive clustering（SC） is used to confirm the fuzzy rules and their correlative parameters. Moreover, the particle swarm optimization （PSO）algorithm is improved to train the TSFNN. Simulation results and experiments on vehicles show that the proposed algorithm can effectively improve the convergence speed and the recognition accuracy of the TSFNN, as well as enhance the correct rate of driving fatigue detection.

Synthesis and properties of physically crosslinked poly (vinyl alcohol) hydrogels

The present study is an investigation of the properties of poly(vinyl alcohol),which would be a better contact lens mate- rial than conventional HEMA in some ways.A transparent PVA hydrogel was prepared from a PVA solution in a mixed solvent consisting of water and a water-miscible organic solvent,DMSO,by the freezing-thawing method.The water content,visible light transmittance,mechanical and swelling properties of the hydrogels were evaluated as a function of PVA concentration and number of freeze-thaw cycles.The results show that the properties of PVA hydrogels depend on the polymer concentration,the number of freeze-thaw cycles and the addition of the organic solvent.

Electrochemical hydriding and thermal dehydriding properties of nanostructured hydrogen storage MgNi26 alloy

The MgNi26 alloy was prepared by three different methods of gravity casting (GC), mechanical alloying (MA) and rapid solidification (RS). All samples were electrochemically hydrided in a 6 mol/L KOH solution at 80 °C for 240 min. The structures and phase compositions of the alloys were studied using optical microscopy and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. A temperature-programmed desorption technique was used to measure the absorbed hydrogen and study the dehydriding process. The content of hydrogen absorbed by the MgNi26-MA (approximately 1.3%, mass fraction) was 30 times higher than that of the MgNi26-GC. The MgNi26-RS sample absorbed only 0.1% of hydrogen. The lowest temperature for hydrogen evolution was exhibited by the MgNi26-MA. Compared with pure commercial MgH2, the decomposition temperature was reduced by more than 200 °C. The favourable phase and structural composition of the MgNi26-MA sample were the reasons for the best hydriding and dehydriding properties.

Application of the fault diagnosis strategy based on hierarchical information fusion in motors fault diagnosis

This paper has analyzed merits and demerits of both neural network technique and of the information fusion methods based on the D-S (dempster-shafer evidence) Theory as well as their complementarity, proposed the hierarchical information fusion fault diagnosis strategy by combining the neural network technique and the fused decision diagnosis based on D-S Theory, and established a corresponding functional model. Thus, we can not only solve a series of problems caused by rapid growth in size and complexity of neural network structure with diagnosis parameters increasing, but also can provide effective method for basic probability assignment in D-S Theory. The application of the strategy to diagnosing faults of motor bearings has proved that this method is of fairly high accuracy and reliability in fault diagnosis.

冷沉淀制备辅助装置的研制

目的研制一台冷沉淀制备辅助装置,缩短冷沉淀制备的时间,保证冷沉淀中有效成分的活性。方法采用ALIENTEK Mini STM32单片机作为控制模块,采用步进电机作为执行模块,通过Keil编写开发板程序,五位按键控制四挡制备速度及正反转。结果将机械力作用于血袋管路,加速融化血浆排出,大大缩短冷沉淀制备时间。结论该装置改变只依靠虹吸原理制备的现状,解决了冷沉淀制备时间长的问题,保证制品的质量,操作简单,推广前景广阔。

Study on the Preparation of Decellularized Scaffold of Bovine Pericardium

Objective： To search for the best procedure on preparation ofacellular bovine pericardium,so to provide scaffolds for constructing tissue-engineering Methods： The bovine pericardiums were treated with 5 methods, which were divided into 6 groupsGroup A： Fresh bovinepericardium; Group B： Trypsin-detergent group;Group C： Freeze-thaw-detergent 24 h group; Group I）： Freeze-thaw-detergent 48 h group; Group Fz Freeze-thaw-nuclease group; Group F： Detergent-nuclease group. Then, by HE staining and scanning electron microscope to observe the effects ofdecellularization and fibrous changes among the 6 groups; by water content testingonechanical testing to observe the changes in physical properties of the matrix; by detecting the DNA content of each group to determine the effect of deeellularization qualitatively; by eytotoxieity test to detect the biocompatibility of bovine pericardium in each group. Results： The 5 methods can all remove the cellular components effectively, compared with the fresh bovine pericardium,the water content of each deeellularized group were increased （P〈0.05）, while the DNA content decreased （P〈0.05）, with statistically significant differences. Of group E, the fibers were a little disorder, with the largest tension and the elastic modulus increased, while the rupture tensile rate decreased. Compared with fresh bovine pericardium,the largest tension of the other decellularization groups were all decreased （P〈0.05）. The fibers of group B, group D were irregularly arranged and also with ruptures, both the elastic modulus and the rupture tensile rate decreased（P〈0.05）. In group C and F, the fibers were dense and their direction was normal, the elastic modulus and the rupture tensile rate were similar to the fresh bovine pericardium （P〉0.05）. Cytotoxicity results showed that the cell toxicity of group B, group C, group D, group E and group F were respectively 0.9, 0.6, 1.0, 1.0 and 0.5, each group were qualified toxicity test, in which group C and group F were with the lowest eytotoxieity. Conclusion： Group C and group F can remove the cell components of bovine pericardium successfully,while maintaining the major structural components and the histological and biological properties of bovine pericardium,and with low cytotoxicity.However, group C is more economical than group F,and easier to operate. So the method on freeze-thaw-detergent 24 h can be the best choice to produce a decellularized bovine pericardium.

Purification and separation of durene by static melt crystallization

The purification and separation of durene from the mixture containing durene isomers were studied.Since the boiling points of tetramethyl benzene isomers are very close but their melting points are of great differences,static melt crystallization was applied to separate and purify durene from its isomers.Crystallization experiments were carried out under various operating conditions.The effects of cooling rate,crystallization temperature,sweating temperature and sweating time on the yield and purity of crystal were investigated.Orthogonal experimental design method was adopted to analyze the factors that may affect the yield of durene.Under the optimal crystallization conditions,the purity of durene could reach as high as 99.06%with the yield of 75.3%through one crystallization process.By fitting purification data based on sweating time in isothermal operations,the purification rate coefficient was obtained.

The Variability of the Snow and Ice Melt in Alpine Rivers in Northwestern China

The study of snow and ice melt （SIM） is important in water-scarce arid regions for the assessment of water supply and quality. These studies involve unique difficulties, especially in the calibration of hydro-models because there is no direct way to continuously measure the SIM at hydrostations. The recursive digital filter （RDF） and the isotopic hydro-geochemical method （IHM） were coupled to separate the SIM from eight observed series of alpine streamflows in northwestern China. Validation of the calibrated methods suggested a good capture of the SIM characteristics with fair accuracy in both space and time. Applications of the coupled methods in the upper reaches of the Hei River Basin （HRB） suggested a double peak curve of the SIM fraction to streamflow for the multi-component recharged （MCR） rivers, while a single peak curve was suggested for the rainfall-dominant recharged （RDR） rivers. Given inter-annual statistics of the separation, both types of the alpine rivers have experienced an obvious decrease of SIM since 196os. In the past 10 years, the SIM in the two types of rivers has risen to the levels of the 1970s, but has remained lower than the level of the 1960s. The study provided a considerable evidence to quantify the alpine SIMbased on the separation of observed data series at gauge stations. Application of the coupled method could be helpful in the calibration and validation of SIM-related hydro-models in alpine regions.

500微米沸石分子筛单晶的制备方法

介绍了 2 0世纪 90年代以来 5 0 0 μm以上的沸石分子筛单晶的六种制备方法 ,包括类区域融化法、植入晶种法、有机热合成法、块状原料溶解法、氟离子效应合成法和双硅源法。这些方法通过控制反应体系中晶核的形成数量 。

A precise and accurate acupoint location obtained on the face using consistency matrix pointwise fusion method

OBJECTIVE: To develop a more precise and accurate method, and identified a procedure to measure whether an acupoint had been correctly located.METHODS: On the face, we used an acupoint location from different acupuncture experts and obtained the most precise and accurate values of acupoint location based on the consistency information fusion algorithm, through a virtual simulation of the facial orientation coordinate system.RESULTS: Because of inconsistencies in each acupuncture expert's original data, the system error could not be modified using the characteristics ofthe general weight calculation. First, we corrected each expert of acupoint location system error itself,to obtain a rational quantification for each expert of acupuncture and moxibustion acupoint location consistent support degree, to obtain pointwise variable precision fusion results, to put every expert's acupuncture acupoint location fusion error enhanced to pointwise variable precision. Then, we more effectively used the measured characteristics of different acupuncture expert's acupoint location, to improve the measurement information utilization efficiency and acupuncture acupoint location precision and accuracy.CONCLUSION: Based on using the consistency matrix pointwise fusion method on the acupuncture experts' acupoint location values, each expert's acupoint location information could be calculated, and the most precise and accurate values of each expert's acupoint location could be obtained.