Experimental analysis of the abrasive belt follow-up grinding of Zirconium-4 alloys tubes and pipes

Abrasive belt grinding experiments of Zr-4 nuclear power tube are carried out by using three different abrasive belts with same size, and the interactive generating mechanism between abrasive and workpiece is analyzed, the main factors of material removal rate and surface roughness of Zr-4 alloys are obtained. With the help of the advanced test facilities, the abrasive grain abrasion and surface topography of the workpiece are observed. The metallographic structure and microhardness of the layer of burnt surface during Zr-4 alloys Grinding are analyzed. Some conclusions are given as follows: the material removal rate and surface roughness are mainly affected by the factors of belt speed, grinding pressure, hardness of the contact wheel and abrasive type, of which, the belt speed is the strongest factor. The adhesion wear of the Zirconium corundum and aluminium oxide abrasive grit is more serious, the most important wear form of silicon carbide is abrasion wear. With the onset of grinding burn, the mechanical properties of Zr-4 alloys are deteriorated obviously. The results provide a theoretical and experimental basis for technical optimization in the grinding of Zr-4 alloys with efficiency and high quality.     

The development of martensitic stainless steel 4Cr10Si2 for durable knives and scissors

After introducing the development of knife and scissor materials at home and abroad, the chemical composition of 4Cr10Si2 steel is designed according to the steel alloying principle and Schaeffler diagram. Then 4Cr10Si2 steel sheet with the thickness of 6 mm is prepared. After the tests of hardness, microstructure, tensile property and EBSD, etc., heat treatment test of the steel sheet is carried out and the heat treatment parameters of making kitchen knives and scissors are confirmed. Then, after the bending strength and resistance electrochemical corrosion tests by using the samples treated with optimum heat treatment process, the steel is made into kitchen knives. The testing and trial show that 4Cr10Si2 steel has better performance than 4Cr13 except slightly lower Ecorr and Icorr.     

Test Method of Indoor Noise for Micro-surfacing Mix

Micro-surfacing mix has been wildly used in the pavement maintenance for its water proofing, anti-skidding and wear resistance. However, micro-surfacing pavement has higher noise than the common asphalt pavement and its noise can not be measured effectively and accurately. Therefore, the indoor noise test method of micro-surfacing mix based on wet track abrasion test was explored. The micro-surfacing mix specimens were used to imitate the micro-surfacing pavement. The wet track abrasion tester was used to provide the vehicle loads. The sound level meter was used to measure the noise between tire and pavement. Furthermore, the indoor noise of nine kinds of micro-surfacing mixes with different gradation was examined. The results show that the equivalent sound level in the second time period has good relationship with the surface texture depth by sad patch method. Then the test method and test procedure for the indoor noise of micro-surfacing mix based on wet track abrasion test were given. Finally, two micro-surfacing mixtures with different gradations were made to validate the test method. The results show that the evaluation method can effectively distinguish the difference of micro-surfacing mixes with different gradation and can supplement the mix design method of micro-surfacing mixes.     

LASER REMELTING OF THE NiCoCrAlY PROTECTIVE COATING

NiCoCrAlY protective coating is remelted on the GH140 alloy surface by 2KWCO2 gas laser,the results of which show that,by controlling proper laser technological parameters, the constitution can be fined,the composition can be well distributed,and the coating compactness and adhesion can be obviously enhanced in the laser-remelting zone. Thus,corrosion resistance and thermal fatigue resistance is effectively improved,and the good plasticity of the original coating is remained.     

基于穿刺测试和TPA法的板栗果实质地分析

为比较不同板栗品种之间果实质地差异,采用质构仪穿刺测试和质地多面分析（TPA）法测定了16个品种板栗果实的质地特性。结果表明：板栗果实表型和质地性状变异丰富,穿刺果面硬度、果肉平均硬度、TPA硬度间呈极显著正相关,且均与果面韧性、果面脆性和紧实度呈极显著正相关（P<0.01）;单果质量和果实横径与果实硬度呈显著负相关（P<0.05）。主成分分析将17个指标（果实表型和质构仪参数指标）组合形成果实硬度、咀嚼特性、果实大小和黏附性因子4个主成分,其累计方差贡献率为89.298%。聚类分析可将这些板栗品种根据质地和表型参数分为7类,不同类别之间差异较大,表明这些特征参数可作为板栗种质资源的评价指标,为板栗鲜食品质鉴定、加工利用和品种选优提供科学依据。     

农业装备零部件表面镀层性能的研究

农业装备零部件在工作过程中极易发生磨损、腐蚀等现象,导致其过早失效。结合国内外的研究,磁场可以提高镀液的分散及覆盖能力,进而对镀层的微观结构及形貌有很大影响,为了改善农业装备零部件镀层的表面性能,试验在电镀的过程中引入垂直离子沉积方向上的外加恒定磁场,采用光学显微镜观察分析了Ni-Co镀层的表面形貌,并用显微硬度计对镀层的性能进行了测试。结果发现：磁场的引入改变了离子的沉积状态,使Ni-Co镀层表面更加平整致密,恒定磁场影响下制备的镀层与无磁场影响制得的镀层相比,硬度值提高了38 HV。为提高农业装备零部件镀层表面性能提供了一种简单、实用的方法,为今后研究提供了一定参考。     

植物乳杆菌对糯米粉发糕品质的影响

以优化糯米粉发糕的制作工艺为目的,从发酵时间、发酵温度及植物乳杆菌的添加量这3个影响因素着手,分别对这3个影响因素设立单因素试验,找出较优的水平,然后在单因素试验的基础上,进行三因素和三水平的正交试验,以确定糯米粉发糕生产过程的最佳水平。以糯米粉发糕的感官评价、持水力、硬度、黏附性、感官弹性为评价指标,通过对正交试验的结果分析,最终确定最佳的发酵工艺为发酵时间60 min,发酵温度45℃,植物乳杆菌添加量3%的水平下,在此工艺条件下制作出的糯米粉发糕品质最佳。     

Disease pattern and grade distribution of coast erosion in Liaodong bay

To identify distribution and development of coast erosion in Liaodong bay, erosion situations of typical coastal zone are studied on the basis of field investigation data. The results show that according to erosion landform features, coast erosion in Liaodong bay can be divided into five patterns: washing and abrasion type, wave collapse type, block avalanche type, karst depression type, interface slip type; according to degree of corrosion and siltation, coast erosion in Liaodong bay can be divided into five grades: serious erosion, intensive erosion, erosion, micro-erosion, stability. Sandy coast is eroded mainly in wave collapse type, rocky coast is eroded mainly in block avalanche type and karst depression type, and silty mud coast is eroded mainly in washing and abrasion type. Investigation on disease pattern and grade distribution of coast erosion is helpful to prevention of coastal zone in Liaodong bay.     

选区激光熔化TC4生物腐蚀和生物相容性分析

选区激光熔化(SLM)为降低TC4钛合金医用植入体的弹性模量、减小应力屏蔽效应提供了一种有效的解决方案,但这种材料在投入实际应用前尚需有充分的生物安全性评价。采用SLM技术制备出致密度为99.5%的TC4合金,通过电化学实验、溶血实验和细胞毒性实验测试了SLM成形TC4的生物腐蚀性能和生物相容性,并与传统铸轧工艺制备的合金进行了对比。实验结果表明：前者相比于后者有着更好的耐蚀性能,并且SLM成形TC4还具有优良的生物相容性,在生物医用植入物方面展现出很好的应用前景。     

Analysis on the method of selecting nodes on the erosion diagnosisof grounding grid

The number of underdetermined equation, which is limited by the grounding down lines, reduces the grounding grid corrosion diagnostic precision. Based on the grounding grid fault diagnosis method and sensitivity analysis, the value of slip resistance change on the impact of the port resistance in several cases, such as small span, large span and edge, center and symmetrical cross line of the grounding grid, is analyzed. A new method which is used to select the node pairs to calculate the corrosion situation of grounding grid is presented. Based on this method, the simulation analysis and field test has been done. The experimental results show that this method could improve the accuracy and efficiency of grounding grid fault diagnosis.     

自制硅酸盐对传统糯米灰浆性能的影响

采用灰浆性能表征和扫描电镜（SEM）、X射线衍射（XRD）、红外光谱（FTIR）等技术手段,探讨了自制硅酸盐对糯米灰浆的影响及作用机理。结果表明：自制硅酸盐对糯米灰浆的表面硬度、抗压强度、耐冻融性和耐水性均有一定程度的改善。6%自制硅酸盐糯米灰浆的综合性能最佳,其66 d抗压强度高达1.41 MPa,耐冻融性较之空白样品提高了133%,耐水性能提高了43.8%。改性糯米灰浆耐水性等性能的提高,可能与灰浆中水化硅酸钙的生成有关。     

氯氧镁水泥混凝土中钢筋的腐蚀与防护试验研究

结合氯氧镁水泥混凝土耐水性,研究氯氧镁水泥混凝土中钢筋的腐蚀与防护,试验变量包括钢筋种类、混凝土保护层厚度和腐蚀龄期等。钢筋种类包括裸露钢筋和美加力涂层钢筋;混凝土保护层厚度包括25、50 mm;腐蚀龄期包括60、120、180、240、300、360 d。试验采用自来水长期浸泡至试块2/3处,并采用扫描电子显微镜（SEM）和能谱仪（EDS）对腐蚀后的钢筋微观结构和化学元素组成进行分析,研究钢筋的腐蚀机理。结果表明,通过软化系数分析,氯氧镁水泥混凝土的软化系数处于0.78～0.87,说明试验设计的氯氧镁水泥混凝土可用于干燥地区、受潮较轻地区或次要建筑结构。通过极化曲线及其电化学参数分析,裸露钢筋腐蚀速率为美加力涂层钢筋腐蚀速率的40～80倍,说明涂层防腐效果明显。     

Meso-scale numerical investigation on the crack process of concrete cover induced by rebar non-uniform corrosion

Concrete cover cracking induced by corrosion of steel reinforcement is a major influencing factor for durability and serviceability of reinforced concrete structures. In order to investigate the cracking process of concrete cover induced by rebar corrosion, the heterogeneity of concrete meso-structure and non-uniformity of rebar corrosion are accounted for. The undamaged concrete is assumed to be a three-phase composite material composed of aggregate, mortar matrix and the interfacial transition zone (ITZ). And a concrete random aggregate structure is established for the study on the mechanical behavior of the non-uniform radial corrosion expansion. In the present simulations, non-uniform radial displacement is adopted to simulate the non-uniform corrosion of the rebar; the plasticity damaged model is used to describe the mechanical behavior of the mortar matrix and the ITZ, and the aggregate is assumed to be elastic. The cracking of concrete cover due to the non-uniform corrosion of the middle located rebar is numerically simulated. The comparison of the analysis and the test result on failure pattern of cover concrete shows fairly good agreement. And then the failure patterns under uniform corrosion and non-uniform corrosion obtained from the macro-scale homogeneous model and the meso-scale heterogeneous model are compared. Furthermore, the influences of concrete cover thickness and rebar diameter on the failure pattern of concrete cover, the expansive pressure and the corrosion rate of the rebar when cover concrete cracks are investigated.     

Study of Silane Film for Metallic Surface Resisting Corr

Silane agent is applied directly for metallic surface corrosion resisting, which can replace phorsphating technique.SA film is prepared under the optimal processing conditions, and reflective FTIR spectroscopy is used to analyse component and structure of SA film. Film thickness is detected by elliptical spectroscopy method, and results of electrochemical corrosion processing detecting and CuSO 4 solution point corrosion experiment are used to verify corrosion resistance of SA film.     

Study on the Effects of Air Pollution on Corrosion of Carbon Steel

This paper summarizes the results obtained from the first year atmospheric corrosion test of carbon steel specimens exposed in 12 sites in Asia. As shown by the results, the corrosion rates of carbon steel vary with the atmospheric environment and the difference can reach a factor of 16. Among the environmental pollution factors, the most detrimental factor is atmospheric sulfur deposition for atmospheric corrosion of carbon steel. Especially, in Chongqing, the high SO_2 levels plus humid and warm climate lead to the most serious atmospheric corrosion of carbon steel.     

Preliminary Study on Laser Property Improving for Boronized Layer

The effects of laser treatment on morphology of Boronized Layer of 20CrNiMo steel are studied in this paper. And laser property improving on the layer are initially discussed. The research indicates that laser treatment will change its morphology, increase thinkness and reduce brittleness of the layer, without reducing hardness and wear resistance.     

小麦主要品质性状相关性及主成分分析

为了评价小麦主要品质性状对小麦品质贡献关系，对219份小麦品系品质性状进行相关性和主成分分析。本研究主要通过多种粉质仪和近红外谷物分析仪依并依据国家粮食检验标准对小麦多个品质性状进行检验。结果表明：变幅较大的是容重和最大拉伸阻力，变幅较小的是湿面筋含量和吸水率；稳定时间变异系数最大，为41.85%。容重与硬度，蛋白质含量和湿面筋含量呈极显著负相关；硬度与吸水率和延展性相关性最高；除了容重，沉降值与其它品质呈极显著正相关；蛋白质含量和湿面筋含量与容重呈极显著负相关；吸水率与延展性和最大拉伸阻力呈现极显著正相关，与稳定时间呈极显著负相关；稳定时间与拉伸面积、延展性和最大拉伸阻力呈极显著正相关；拉伸面积与延展性和最大拉伸阻力皆呈极显著正相关。主成分分析可将小麦主要品质性状综合为沉降因子、面团因子和容重因子，累积贡献率达到93.54%，基本反映小麦品质性状的全面信息。研究结果将为小麦品质性状的有效改良及优良品质小麦品种选育提供理论基础和参考依据。研究结果将为小麦加工品质的预测及小麦优质品种选育提供理论基础和参考依据。     

白枇杷保鲜技术的研究

以宁海白枇杷为试验材料,对其在不同温度和湿度条件下的保鲜贮藏效果进行试验研究,通过测定白枇杷不同处理在贮藏过程中的腐烂率、硬度、可溶性固形物及酸含量的变化,探讨白枇杷的最佳贮藏条件。     

‘龙麦35’与寒地多年生麦草杂交后代的分子细胞遗传分析

本研究利用黑龙江省哈尔滨地区冬季寒冷的气候特点以及形态学和分子细胞遗传学研究手段,对‘龙麦35’与6份寒地多年生麦草杂交后代F1进行选育和分析。结果表明,寒地多年生麦草同中间偃麦草染色体组构成一致,具有出色的抗寒性;寒地多年生麦草1-1-4和7-31花期同‘龙麦35’同步,杂交结实率明显高于其他组合。杂种F1为两亲中间型,植株成活率低,减数分裂时期寒地多年生麦草的染色体可同‘龙麦35’染色体发生配对,但染色体组配对不完全,单价体数量多于二价体,导致植株不育。F₁植株虽不具有抗寒性,但具有割后再生性。8个F₁株系,仅株系F₁18731结实,GISH检测结果表明,F₂18731染色体组带有27条‘龙麦35’染色体,14条麦草染色体和1条小麦-麦草易位染色体,染色体数为42条。本研究可为寒地多年生麦草染色体组的研究和利用提供理论基础。     

Stress Corrosion of Concrete Exposed to the Action of Freezing-thawing Cycles

Through the method of accelerated freezing-thawing and room-temperature corrosion, the stress corrosion of three kinds of concretes subjected to 5.0%MgSO4(in mass)solution was studied. The considered concretes include High Strength Concrete(HSC), High-Volume Mineral Admixture Concrete(HVMAC) and High Durable Concrete(HDC) added with high-volume mineral admixture, air-entraining agent, superplasticizer, fibers and expansion agent. The results showed that the relative dynamic elastic modulus of concrete went through strengthen and deterioration stages subjected to stress corrosion, whether the room temperature or freezing and thawing conditions. The length of time of these two stages are closely related with the experimental temperature. Freezing and thawing action significantly accelerated the process of sulphate stress corrosion damage. Under the action of freezing and thawing, stress corrosion strengthening the period length of HSC shorter 96%, deterioration section of the length of time shorter 88%, compared with the length of time at the corresponding room temperature. Deterioration section of the length of time of HVMAC is reduced by 98%, while the HDC reduced by 71%. The effect of freezing and thawing, HDC freezing-thawing cycles when the stress corrosion damage occurred were longer 1.5 times and 13 times than the HSC and HVMAC. Thus in the cold regions, HDC showed more resistance to sulfate stress corrosion.