175 research outputs found
Research and Application of Vehicle CAN Bus printer based on uC/OS-II
由于车载网络总线的通信数据量的急剧增加,以及仪表显示参数信息的复杂化,仪表对仪表系统的性能提出更高的要求,越来越多的汽车仪表基于RTOS(实时嵌入式系统)进行应用功能的设计。基于嵌入式技术的CAN总线汽车仪表系统是借助计算机技术,提高仪表网络通信的抗干扰性能,最大限度地利用现有的软件、硬件成熟技术,提高了仪表的柔性,增强仪表数据交换通信的实时性能,迎合当代电子设备不断更新升级的步伐。 笔者在研究生期间负责某堆高机打印仪表方案的制定和整体设计,该仪表是比较典型、应用综合的嵌入式总线仪表,本文将围绕仪表涉及的知识和技术,分析总线特点、嵌入式应用、通信系统等内容,就开发基于uC/OS-II系统的C...Due to a sharp increase in the amount of communication data in vehicle networks, as well as the increasing complexity of the parameter information displayed by the in-strument,instrument put forward higher requirements on the performance of the in-strument system,more and more automobile instrument using RTOS (real-time em-bedded systems) to design application function. Auto instrument CAN system...学位:工学硕士院系专业:物理与机电工程学院_机械电子工程学号:1992012115271
预测沙波运移的谱分析模型
沙波运移预测是海洋开发必不可少的一环。通常采用非线性谱分析方法分析沙波实测资料从而预测沙波运移。然而这种方法仅是从统计的角度进行预测,它不包含水动力、加载风速、沙质底床性质等关键因素对沙波运移的影响。对此本文提出了一种谱分析模型解决此类问题。该模型基于沙波形状不变假设,引入波谱能量平均运移速度,考虑了台风产生的风浪和涌浪,利用波浪输沙理论计算台风期间的沙波运移,厘清了一般波流作用和台风作用引起的沙波位移。模型计算结果与实测数据吻合,可以用来预测10~20年内的沙波活动和底床演化
Preparation of Crack-free Inverse-opal Films by Template/Matrix Co-assembly
近年来,由于在光学、电学和生化等领域具有广泛的潜在应用,有序多孔反蛋白石结构薄膜的研究引起了人们的广泛关注.但是其在制备过程中常常会形成一些无法; 控制的缺陷,限制了这类材料的普及和实际应用.通过使用两种基质前驱体(正硅酸乙酯或丝素蛋白)与胶体小球混合共组装,探究了二元体系共组装法制备无裂痕; 反蛋白石结构薄膜的可行性.并用扫描电镜和可见光谱对薄膜结构进行了表征.结果表明,对于正硅酸乙酯体系,在不影响胶体小球有序排列的条件下,正硅酸乙酯; 在小球间的空隙中发生溶胶凝胶转变,与微球共同组装成有序致密的整体,去除微球模板后,可以得到大规模(>200; mum)无缺陷有序的反蛋白石结构薄膜.而对于大分子丝素蛋白体系,由于它和胶体小球有较强的相互作用力,会抑制胶体小球的有序组装,导致无法形成有序结; 构薄膜.对两种二元共组装体系进行了实验探索,实验结果不仅有助于人们了解共组装方式的适用范围,而且为设计和制备无缺陷反蛋白石薄膜提供了新的途径.Recently, there has been a significant interest in utilizing well-ordered, porous inverse-opal films for applications in optical, electronic and (bio) chemical fields. However, uncontrolled defects are always formed during their preparation process, which limit their practical applications. In this work, we examine the feasibility of using template/matrix co-assembly strategies to fabricate crack-free inverse opal thin films. Polystyrene spheres (PS) are chosen as a colloidal template, and two matrix precursors [tetraethoxysilane (TEOS) precursor and regenerated silk fibroin solution] are used for the current study. Our scanning electron microscope (SEM) and optical spectrum results show that, for the TEOS-based system, the resulting silica gel due to the sol-gel transition of TEOS can effectively fill the gap between particles, but cannot affect the self-assembly of PS colloidal particles. After selective removal of the PS template, centimeter-scale crack-free and well-ordered inverse opal films can be obtained. In addition, for a constant concentration of TEOS, the film thickness and order degree of structure can be simply tuned by adjusting the concentrations of colloidal spheres. In comparison with indirect approach through template self-assembly and liquid infiltration, such a co-assembly approach can effectively minimize the associated cracking and avoid the need for matrix infiltration into the preassembled colloidal spheres. On the other hand, macro-molecule silk fibroin has a relatively strong interaction with PS colloidal particles, which is demonstrated by SEM and confocal images. Due to their interaction, silk fibroin molecules are preferably adsorbed on the surface of PS spheres, which can restrain the self-assembly of colloidal particles. As a result, it cannot form well-ordered silk film based on such co-assembly strategy. That is to say, the co-assembly approach is not suitable for systems that matrices have strong interactions with templates. These findings pave the way to use the template/matrix co-assembly strategy for rationally designing and developing crack-free inverse opal films and to apply such well-ordered and porous materials in a variety of fields.National Natural Science Foundation of China [21401154, U1405226]; 111; Project [B16029]; Natural Science Foundation of Guangdong Province; [2014A030310005]; Fundamental Research Funds for the Central; Universities of China [20720170011
Preliminary study on feeding habits and trophic niche of nine economic fish species in Beibu Gulf in summer
应用Shannon-Wiener指数、Levins指数和均匀度指数,分析了北部湾2012年7月9种个体数量占优势的经济鱼类的食物组成和食性类型,并对其营养生态位进行了初步研究。研究表明,这9种经济鱼类可划分为3种食性类型:日本发光鲷Acropoma japonicum、日本竹筴鱼Trachurus japonicus、蓝圆鲹Decapterus maruadsi和六指多指马鲅Polydactylus sextarius为浮游生物食性,主要以桡足类为食;二长棘犁齿鲷Evynnis cardinalis、日本鲱鲤Upeneus japonicus和刺鲳Psenopsis anomala为底栖生物食性,主要以长尾类为食;多齿蛇鲻Saurida tumbil和白姑鱼Pennahia argentata为游泳动物食性,以鱼类饵料占较大优势。9种鱼中,白姑鱼的营养生态位宽度值最高,多齿蛇鲻的营养生态位宽度值最低。夏季北部湾这9种经济鱼类的营养生态位宽度与其摄食习性和饵料基础密切相关。In this study, based on fish samples collected in Beibu Gulf in July 2012, diet composition, feeding habits and trophic niche breadth of nine economic fish species were analyzed using the Shannon-Wiener index, Levins index and evenness index. Results showed that nine economic fish species could be classified into three types according to feeding habits, referred to as plankton predators(including Acropoma japonicum, Trachurus japonicus, Decapterus maruadsi, and Polydactylus sextarius), benthic predators(including Evynnis cardinalis, Upeneus japonicus and Psenopsis anomala) and nekton predators(Saurida tumbil and Pennahia argentata). Trophic niche breadth of Pennahia argentata was the highest(Shannon-Wiener index=0.938 and Levins index=2.238), while trophic niche breadth of Saurida tumbil was the lowest(Shannon-Wiener index=0 and Levins index=1). The trophic niche breadth of the nine economic fish species in summer in Beibu Gulf was strongly influenced by feeding habits and feeding foundation of surrounding environments.国家海洋公益项目(201005012)~
Building Chinese- English bilingual Corpus of News Field and Resear ch on Sentence Alignment
摘要: 双语对齐的平行语料库在机器翻译和自然语言处理领域中扮演着非常重要的角色, 它的研究和制作具有重要的理论意义和实用价值, 双语语料的建设十分必要, 其中双语对齐是最基本的环节。文章首先简要介绍了语料库的建设情况, 然后结合主流的句子对齐方法提出并实现了基于词典和语言学信息的英汉双语句子对齐。英文摘要:Abstr act: Bilingual corpus plays a very important part in machine translation and natural language process field, Building and research on it both have theoretic significance and practical value. Therefore, it' s necessary to build a large- scale
bilingual corpus. Bilingual Alignment is the basic connection. This paper firstly gives a brief discussion on the construction
of the corpus, secondly discuss the main ways of sentence alignment, and finally pose another aligning method base on
lexical and language information.基本项目:福建省自然科学基金项目( 2006J0043
Salt balance mechanism in mangroves
热带、亚热带海岸潮间带的红树林生态系统处于海洋、陆地和大气的动态交界面,作为独特的海陆边缘生态系统在维持海湾河口生态系统的稳定中起着特殊的作用。生长在潮间带高盐环境中的红树植物,经长期的自然选择和进化适应,在生理生化及形态方国家自然科学基金资助项目(30200031);; 福建省自然科学基金资助项目(B0410001
春、秋季台湾海峡海-气CO2通量及其影响因素
于2014年的5月(春季)和9月(秋季)在台湾海峡及其邻近南海和东海海域,采用水气平衡法进行了2个航次的海表和大气pCO2连续走航观测,同时获取了海表温度、海表盐度、风速及气压等数据,并采用海-气CO2分压差减法估算了海-气CO2通量.结果显示,春、秋2个航次平均海表pCO2分别为387±16μatm和408±18μatm.温度是影响台湾海峡及其邻近海域海表pCO2的主控因子,水团混合和其他因素等也对海表pCO2有一定影响.2014年春、秋季节,对研究区域的海-气CO2释放通量的估算结果分别为0.11±1.60 mmol/(m2·d)和2.51±1.10 mmol/(m2·d).台湾海峡海表pCO2既存在显著的季节变化,又存在较大的空间差异.国家海洋局第三海洋研究所基本科研业务费资助项目(海三科2011015);;厦门南方海洋研究中心资助项目(14GHS016NF16,14PST63NF27
A Parallel Algorithm for Fresnel Tomography
摘要:与射线层析成像相比, Fresnel 层析成像考虑波频率的影响, 具有较高的分辨率,但所需的存储
空间和计算量更大,因此提出了Fresnel 层析成像的并行算法1 把大型层析反演方程组的求解,转化成
对其中的各个方程进行相互独立的计算,避免了大型系数矩阵的存储问题;把一个Fresnel 带的正演和
反演计算放在一个进程,不同Fresnel 带的计算相互独立进行,不需要信息传递,达到了极高的并行度;
从进程之间没有通信, 仅当从进程计算结束后,在主进程与各从进程之间有少量的数据传递,使通信开
销达到了极小的程度1 应用MPI 在Linux PC 集群环境下实现了该算法,实际测试表明,该算法具有较
高的并行度和加速比.Abstract In cont rast with ray2based t raveltime tomography , Fresnel tomography account s for the band2
limited nature of seismic waves and gives the higher resolution tomograms1 Because Fresnel tomography
demands much computer memory and much running time , a parallel algorithm for it is proposed1 The
tomographic inversion is t ransformed to resolving respectively a series of single equation in light of
backprojection principle , each equation corresponding to a Fresnel zone1 The forward and inverse
computation concerning a Fresnel zone is allocated to one process and is independent of other processes1
Then the storage and calculation of the large2scale mat rix in the tomography are avoided1 No message
delivers between the slave processes , and only a little of data delivers between a master process and the slave
ones1 By using the portable message passing interface standard (MPI ) for the communication , the
computing code of the algorithm is implemented on Linux system , which allows to dist ribute the work on
several PCs connected via standard Ethernet in an in2house network , and greatly expands the applicability
of Fresnel tomography1 The test s on the synthetic and observed seismic t ravel time data show that this
parallel algorithm has a good performance on Linux PCs1基金项目:国家自然科学基金项目(40774065) ;福建省自然科学基金项目(2006J0044
临床药师参与一例误诊为亚甲炎的急性甲状腺炎病人治疗的实践与体会
急性甲状腺炎又称急性化脓性甲状腺炎(acute suppurative thyroiditis,AST)或甲状腺脓肿,是一种十分罕见的疾病,仅占甲状腺疾病的0.1%0.7%[1]。AST是细菌或真菌经由血液、淋巴管或邻近化脓灶侵犯甲状腺组织引起的急性化脓性炎症,病人多表现为单侧甲状腺肿痛,吞咽时疼痛加剧,向齿部、两颊、耳后或枕部放射,局部肿胀导致颈部被动后伸,可有邻近组织感染征象。AST早期脓肿未形成
甘精胰岛素治疗糖尿病与恶性肿瘤发生风险的荟萃分析
目的:系统评价糖尿病患者用甘精胰岛素治疗与恶性肿瘤发生风险的相关性。方法:检索PubMed数据库、中国期刊全文数据库(CNKI)、万方数据库(Wanfang Data)、中文科技期刊全文数据库(VIP)建库至2018年2月的相关文献资料。按Cochrane系统评价方法进行文献筛选,将纳入的文献进行数据提取和质量分析后,采用RevMan 5.3软件进行荟萃(meta)分析。结果:共纳入16篇文献。分析结果显示,甘精胰岛素组发生恶性肿瘤的风险与安慰剂/其他降糖药组相似,差异无统计学意义[RR=0.98,95%CI(0.83,1.16),P=0.80]。进一步研究发现,甘精胰岛素组发生乳腺癌、结直肠癌和前列腺癌的风险均与安慰剂/其他降糖药组相似,差异无统计学意义(P>0.05)。结论:甘精胰岛素未增加糖尿病患者乳腺癌、结直肠癌和前列腺癌等恶性肿瘤的发生风险
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