基于FPGA的镜像阈值层叠滤波器实现方法

镜像阈值层叠滤波器克服了传统阈值层叠滤波器在频率响应上的局限性,增强了滤波器的频率选择能力。本文采用位串行结构(bit-serial)和半位元组串行结构(nibble-serial)在FPGA上实现镜像阈值层叠滤波器。对于数据宽度为k的图像数据,位串行结构通过一个二进制处理单元的k次循环就可实现滤波,并且k是可变的。半位元组串行结构是串行处理和并行处理的折衷形式,通过将数据字长分组来缩短滤波时间。最后给出两种实现结构的系统设计方案及仿真结果,并比较二者在滤波速度与占用面积上的差别。

电气系统的可编程序控制器设计

此项目主要是研究电气系统以及简单有效的控制气流发动机的程序和气流系统的状态。它的实践基础包括基于气流的专有控制器、自动化设计、气流系统的控制程序和基于微控制器的电子设计。

港台消息

据1986年2月香港出版的《语文建设通讯》第19期报道,台湾删除“语文法”的立法计划。1972年台湾“第一届国民大会第五次会议”上,495名“国大代表”提议制订“国语推行法”。1984年台湾“立法院第一届第七十三会期第六次会议”上,有人建议制订“文字法”。台湾“教育部国语推行委员会”恢复后。

数字时代应该了解的色彩基础

数位时代对映的当然是底片时代,基本上两者之间大部分的理论没有改变,比方说:黑白给你中性、红黄给予温暖、蓝紫给予冷或干净的联想……等等。那么不同的地方是什么呢?底片的影像形成,是透过胶卷上一层或多层金属化学成分,受到光的照射而产生变化所产生。因此在国际上,称这种模式为PhotoChemical。最早底片上所使用的溴化银,对于光线非常敏感,受到微量的光线照射就会结晶变黑,经过化学显影、定影、冲洗,原本平整的曝光面,因光学作用产生结晶,经过冲印的程序将结晶剥离,于是我们有了黑白影像。简单的来说。

Characterization of gastric cancer models from different cell lines orthotopically constructed using improved implantation techniques

AIM:To develop orthotopic gastric cancer mouse models from different cell lines and characterize the tumor features to assist further in preclinical trials and clinical treatment strategies.METHODS:Human gastric cancer SGC-7901 and BGC823 cell suspensions were injected subcutaneously into nude mice to develop solid tumors,and tumor tissue pieces were then implanted under the serous coat of the stomach.An autopsy was performed on all animals of the SGC-7901 and BGC-823 models to observe the primary tumor growth and metastases using pathological and immunohistochemical methods.RESULTS:Both models showed large tumors in situ resulting in pressure and infiltration of the adjacent organs.The gastric cavity became smaller,along with stenosis of the cardia or pylorus.There were biological and statistical differences between the two models.The metastasis rate in involved organs (lymph nodes,kidney,spleen,testis) was significantly higher in the BGC-823 model compared to the SGC-7901 model (P < 0.05 or P < 0.01).The median survival of the BGC-823 model was shorter than that of SGC-7901 (23 d vs 84 d,P < 0.05).Histopathologically,the primary tumor and metastatic lesions of the two models showed obvious atypia and mucus in the cytoplasm.Compared with the SGC-7901 model,BGC-823 appeared more poorly differentiated (absence of adenoid structure),had a smaller volume,and richer capillary structure.Immunohistochemical staining revealed cytokeratin 20 and epithelial membrane antigen expression was positive in the SGC-7901 tumors,while negative in BGC-823 ones.CONCLUSION:Models using the SGC-7901 and BGC-823 cell lines were established which could function in gastric cancer research on carcinogenesis mechanism and drug discovery.The two models showed different tumor behavior and the latter was more malignant than the former.

Meta-model Based Model Organization and Transformation of Design Pattern Units in MDA

To achieve the purpose of applying design patterns which are various in ldnd and constant in changing in MDA from idea and application, one way is used to solve the problem of pattern disappearance which occurs at the process of pattern instantiation, to guarantee the independence of patterns, and at the same time, to apply this process to multiple design pattems. To solve these two problons, the modeling method of design pattern traits based on meta-models is adopted, i.e., to divide the basic operations into atoms in the metamodel tier and then combine the atoms to complete design pattem units meta-models withtout business logic. After one process of conversion, the purpose of making up various pattem traits meta-model and dividing business logic and pattern logic is achieved.

The Moon

Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.

Leaf stable carbon isotope composition in Picea schrenkiana var. tianschanica in relation to leaf physiological and morphological characteristics along an altitudinal gradient

To understand the effects of leaf physiological and morphological characteristics on δ13C of alpine trees, we examined leaf δ13C value, LA, SD, LNC, LPC, LKC, Chla+b, LDMC, LMA and Narea in one-year-old needles of Picea schrenkiana var. tianschanica at ten points along an altitudinal gradient from 1420 m to 2300 m a.s.l. on the northern slopes of the Tianshan Mountains in northwest China. Our results indicated that all the leaf traits differed significantly among sampling sites along the altitudinal gradient(P<0.001). LA, SD, LPC, LKC increased linearly with increasing elevation, whereas leaf δ13C, LNC, Chla+b, LDMC, LMA and Narea varied non-linearly with changes in altitude. Stepwise multiple regression analyses showed that four controlled physiological and morphological characteristics influenced the variation of δ13C. Among these four controlled factors, LKC was the most profound physiological factor that affected δ13C values, LA was the secondary morphological factor, SD was the third morphological factor, LNC was the last physiological factor. This suggested that leaf δ13C was directly controlled by physiological and morphological adjustments with changing environmental conditions due to the elevation.

Zircon U-Pb geochronology, Hf isotopic composition, and geological implications of the Neoproterozoic meta-sedimentary rocks in Suizhou-Zaoyang area, the northern Yangtze Block

Suizhou-Zaoyang area is located in the southern Qinling-Tongbai-Dabie Orogen, China. A combined research on U-Pb ages and Lu-Hf isotopes for detrital zircons from three meta-sedimentary rocks in the Wudang Group is reported. The upper Wudang Group has a major age population of ca. 750 Ma and a sub-major of ca. 860 Ma. But the lower part only yields one age peak at ca. 2.03 Ga. In situ Lu-Hf analyses of the young age group of ca. 750 Ma for zircons from the upper Wudang Group yield an average εHt（t） value of -8.6 and two-stage Hf model ages （TDM2） from 1837 to 2230 Ma, respectively. However, zircons from the lower Wudang Group give an average εHf（t） value of 4.5 and TDM1 of 2220±22 Ma, close to the timing of zircon crystallization. Thus, it is suggested that, in the study area, the continental crust grew during the middle Paleoproterozoic and reworked during the middle Neoproterozoic, which shows the affinity to the Dabie Orogen. In addition, in the lower Wudang Group, two metamorphic zircon ages of 1992±91 and 1999±61 Ma are consistent with that of the middle Paleoproterozoic metamorphism event in the northern Yangtze Block, which may represent the assemblage of the Columbia Supercontinent. On the basis of the U-Pb ages and Hf isotopes, it is proposed that Suizhou-Zaoyang area was involved in the subduction-collision event in the middle Paleoproterozoic and the Yangtze Block was one of the components of the Paleo-Mesoproterozoic supercontinent.