Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract： The short-term corrosion behavior of X70 steel and Q235 steel buried for 1 a in soil of a select site at Singapore were investigated in terms of characterizing the corrosion products by means of scanning electron microscopy and X-ray diffraction, as well as the physical and chemical parameters of the soil, and measuring the corrosion mass lass. It was found that the soil at the select site was an acidic soil; where the average corrosion rate of Q235 steel was higher than that of X70 steel; the two steels all suffered form local corrosion, while that of Q235 steel was more serious; the corrosion products of these two steels were similar and mainly composed of Fe2O3, Fe3O4, FeOOH and FeOCl, the surface of products were rough and there were some cracks in the products scale, which seemed harmful to its protectiveness.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract： An alloy Mg94Cu4Y2 with a large quantity of long-period stacking ordered (LPSO) phases bearing Cu and Y was designed and prepared in this paper. The microstructural transformations and the hydrogen absorption/desorption properties of the alloy were characterized during hydrogenation and dehydrogenation processes. The cast Mg94Cu4Y2 alloy consists of phases such as Mg, Mg2Cu and LPSOs with 18R or 14H type. The LPSOs decomposed at the first hydrogenation, and in situ formed highly even dispersed nanocomposite (MgH2+MgCu2+YH3). The Mg/MgH2 was the main reaction during the subsequent dehydrogenation cycles. The alloy exhibits excellent hydrogen absorption and desorption kinetics because the nano-sized and even dispersed Mg2Cu and YH2 catalyzed effectively the Mg/MgH2 reactions.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： Underwater acoustic communication is a key technology in the field of underwater activities including underwater surveillance, underwater operations, and military actions. The complexity of the underwater communication channel strongly restricts underwater communication speed, distance, and reliability. Incoherent communication is more robust to channel variation and is wildly used today. Coherent communication is ten times faster than incoherent communication. But it is more vulnerable to channel variation. It is still under developing. To further improve underwater communication performance, the community is keeping improving adaptive equalization algorithms, error correction coding, etc., and developing new technologies like time reversal technology, MIMO technology, etc. Many Chinese organizations joined in the development of underwater communication and networking technology. They carried out theoretical researching, prototypes building, lake and sea trials, and achieved much progress. Especially in last fifteen years, with enhanced support from Chinese government funding, China shortened the gap in underwater communication and networking technology between the leading counties in the world but still at least five years behind them in both theory research and commercial product development. China needs to keep working hard in all fields of underwater communication including algorithm research, networking protocol design, more lake and sea trials, more application, hardware developing and commercial products developing.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： The stimuli newly associated with the self are apt to gain perceptual saliency and display advantages in attentional attraction. Another line of studies demonstrated that perceptual saliency could facilitate active suppression through a top-down control. Therefore, we hypothesize that, if the WM feature is to be suppressed voluntarily, self-associated stimuli was more easily inhibited compared with other information in the visual search task. In current study, participants first completed an associating learning task to form four pairs of color-label links (e.g., green-self, blue-stranger, red and yellow-neutral). Then, they took a Working Memory-guided visual search task in which they needed to search a target shape among several items. Before searching, participants were asked to memorize a specific color, which was one of the four colors used in the learning task. They were informed that items with this cue color were distractors in the search task. After the search task, participants were asked to recall the memorized cue color. The results showed the RTs of the search task were significantly shorter when the informed distracter color was self-associated compared with when the color was stranger-associated or neutral, no significant difference in searching time between stranger-associated color and neural color condition. Analyses of search accuracy and memory accuracy also revealed no significant difference across conditions. These results conformed the facilitation of search performance when the known distracters were in previously link to self, participants could inhibit the distracters more easily and search target more rapidly. To summarize, although valuable objects such as self-relevant information are attractive in nature, people often encounter situations where they would prefer to aviod such distraction while focusing on the task goal. The present study confirmed our hypothesis that the self-associated information was actively suppressed more easily and thus enhanced participants’ performance in visual research. These findings demonstrate a flexible role of learned self association on cognitive control.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-19 Cooperative journals: 《中国科学院院刊》
Abstract： Biodiversity is not only important strategic resource, but also the safeguard to the ecological security and success of the development of ecological civilization. Gathering “big data” of biological sciences at different levels, the in-depth data mining and novel discoveries stemmed from cross disciplines will switch life sciences to the new data-intensive science paradigm, and eventually leads to the change of the way how life system should be understood, and how biodiversity resources should be utilized sustainably. Therefore, to establish an infrastructure for the big biodiversity data in China is urgently needed. This infrastructure incorporates big biodiversity data from both macro and micro scales, and integrates data services and data mining system. It incorporates in-depth data mining tools, simulation models, standards for compiling and sharing data of biodiversity and ecosystems. In this system, the big data from palaeontology and genomics, diversity of species and ecosystems are well integrated. The datasets from geography, climatology, remote sensing, environmental and social sciences, and economics are also included as a comprehensive visualized big data platform being available to the public. It could be used to promote sound decision making for biodiversity conservation and ecological security in China. These services will also contribute greatly to the advancement of biodiversity science, the industrial innovation and development, providing fundamental information for fulfilling the national obligations in implementing the Convention on Biological Diversity, the prevention and control of invasive alien species and the monitoring of international trade of wildlife, and so on.
Subjects: Psychology >> Cognitive Psychology submitted time 2018-09-07 Cooperative journals: 《心理学报》
Abstract： 研究采用注意网络测验任务(attention network test, ANT), 分别检验自我相关信息在注意的警觉、定向和执行控制网络上的加工效率差异, 以揭示自我信息识别优势的注意机制。实验1考察了面孔类型(自我面孔或他人面孔)在3种注意网络下的加工效率差异; 实验2采用自我联结学习范式对实验1进行验证; 实验3将颜色类型(红色或绿色)作为目标刺激, 面孔类型作为背景, 以考察任务无关自我信息是否对注意网络加工效率有影响。研究结果发现, 当自我信息为目标时, 个体在注意定向网络上存在加工效率优势, 而警觉和执行控制网络上没有加工效率差异。当自我相关信息与任务无关时, 在注意的警觉、定向和执行控制网络中均未表现出加工效率优势。说明了自我信息的注意优势发生在注意定向网络上, 且受任务优先性影响。
Subjects: Biology >> Ecology submitted time 2018-05-18 Cooperative journals: 《生态学报》
Abstract：城市化过程中，城市生态用地变化与安全格局构建对于城市生态系统健康、城市居民生活质量和城市可持续发展有着重要意义，生态用地的变化直接影响生态安全格局变化，生态用地安全格局又对生态用地的规划有指导作用。基于GIS技术，对海口市1991年至2016年生态用地的时空变化过程进行研究，进而分析生态用地演变。选取高度、坡度、水资源安全作为生态安全影响单因子，并分级赋值，构建综合生态用地分布格局。以底线型生态用地为源，基于最小累计阻力模型（MCR），以阻力阈值作为分级边界，划分不同安全水平的生态用地区域，进而确定源间生态廊道、辐射道与战略点，构建生态用地安全格局。分析结果表明：1991年至2016年，海口市三类生态用地变化最大，其中林地减少13.33%，园地增加9.136%，坑塘水面增加3.71%。南渡江以西生态用地从以林地为主转为园地与建设用地为主，其余地区变化较少。生态用地安全变化区域集中在海口市西部与东部，其中西部高安全水平区减少，整体安全水平急剧恶化，东部高安全水平区略有提升。故需要制定和实施合理的生态用地保护政策，对生态用地格局进行优化调整，以期构建区域内生态环境协调发展的可行方案。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-15 Cooperative journals: 《金属学报》
Abstract：简述了外场辅助球磨技术的发展及其在材料制备中的应用。介绍了近年来发展的介质阻挡放电等离子体辅助球磨（DBDP-milling）新技术的基本原理和方法，阐述了DBDP球磨利用等离子体的热效应、高能电子轰击效应和球磨机械力效应的协同作用，增强粉体在球磨过程中的组织细化、活性激活、化学反应等效果和机理。在此基础上，简要介绍了该方法在硬质合金、锂离子电池负极材料、储氢材料等制备中的应用。研究结果表明，采用等离子体辅助球磨制备上述材料，不仅极大提高了球磨方法制备材料的效率，而且通过形成独特的结构显著提高了材料的性能；此外，还有可能建立新的材料生产制备工艺。已取得的研究成果表明，等离子体辅助球磨技术在粉末材料细化、材料表面改性、机械合金化、复合材料制备和气固反应等方面具有巨大的潜力。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：通过现场试验(1年)，并结合腐蚀形貌宏观观察、SEM、XRD及失重法对纯铜和铜包钢在大港土壤环境中的腐蚀行为进行了研究。研究表明: 现场埋样1年的纯铜、电镀铜包钢和连铸铜包钢的平均腐蚀速率分别为1.01 g/dm2?a、1.05 g/dm2?a和1.07 g/dm2?a，其平均腐蚀速率接近，纯铜的腐蚀速率略小；腐蚀特征均表现为非均匀的全面腐蚀，腐蚀程度有所差异；腐蚀产物均主要由Cu2O、Cu(OH)2组成。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：采用极化曲线和电化学阻抗技术对连铸铜包钢在含水量20%-30%（质量分数）的大港滨海盐渍土中的腐蚀电化学行为进行研究。研究结果表明：埋样初期，连铸铜包钢腐蚀速度大致相等，含水量对其腐蚀行为影响较小，电极过程主要为活化控制；埋样后期，连铸铜包钢腐蚀速度先减小后趋于平稳，这是含水量对电极过程两个相反作用（氧浓度降低的阻滞作用和环境水化的促进作用）的综合结果，电极过程表现为阴极的氧扩散控制。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-11 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：采用高压釜模拟海底集输环境，通过电化学测试技术，浸泡实验，扫描电镜（SEM）及X射线衍射（XRD）分析技术研究了H2S浓度和pH值对X65钢焊接接头腐蚀行为的影响。结果表明， X65钢焊接接头中热影响区的开路电位最负，焊缝最正，母材介于两者之间，腐蚀电流密度从大到小的顺序为热影响区、母材和焊缝；焊接接头平均腐蚀速率在0.1-0.25mm/a之间，硫化物浓度增加、pH降低均可导致腐蚀速率增加； X65钢海管焊接接头在模拟现场工况条件下以均匀腐蚀为主，焊缝腐蚀程度低于热影响区。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-11 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：通过电化学测试、浸泡实验和表面分析技术研究了交流电频率(50-400Hz)对X80钢在鹰潭酸性土壤模拟溶液中腐蚀行为的影响。研究结果表明随交流电频率增加，X80钢的腐蚀速率逐渐减小，腐蚀程度减弱。交流电作用下X80钢生成的腐蚀产物疏松，裂纹多，对基体的保护性很差。X80钢的腐蚀电位偏移量随交流电频率增加而减小。随交流电频率的增大，阴阳极极化曲线的振荡幅度逐渐减弱。交流电的施加不仅使阴阳极的电流密度增大，还使阴极反应由混合控制逐渐向活化控制转变。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-09 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：通过现场试验(1、2、2.5 年)和电化学阻抗谱(EIS)的测试，并结合腐蚀形貌宏观观察、SEM、XRD及失重法对纯铜在北京土壤环境中的腐蚀行为及机理进行了研究。研究表明：现场埋样 1、2、2.5 年的纯铜的腐蚀特征均为非均匀的全面腐蚀，腐蚀程度较轻微。随埋样时间的延长，纯铜的腐蚀速率近乎以呈线性关系减小，岛屿状腐蚀产物中的空隙等缺陷减少，其致密性有所改善。腐蚀产物均主要由 Cu2(CO3)(OH)2、CuO·3H2O、CuCl 组成
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-07 Cooperative journals: 《中国腐蚀与防护学报》
Abstract：通过现场试验(1、2、2.5年)和交流阻抗谱(EIS)的测试，并结合腐蚀形貌宏观观察、SEM、XRD及失重法对Q235钢在北京土壤环境中的腐蚀行为及机理进行了研究。研究表明：现场埋样1、2、2.5年的Q235钢的腐蚀特征均表现为全面腐蚀，且局部点蚀程度严重。随埋样时间的延长，Q235钢的腐蚀速率先增加后略有减小， 其平均点蚀深度和最大点蚀深度均增加。腐蚀产物均主要由α-FeOOH、β-FeOOH、γ-FeOOH及γ-Fe2O3组成。随埋样时间的延长，α-FeOOH相对含量有所增加，腐蚀产物层的致密性及连续性有所改善，但腐蚀产物层不具有良好的保护性。
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