DDFSGEN

This paper presents a functional compiler for the automatic design of Direct Digital Frequency Synthesizer (DDFS) integrated circuits (ICs) using a ROM based table look-up architecture. The compiler allows the user to specify high-level specifications such as the acceptable spurious response and it generates the IC architecture, floorplan, and layout. To construct the layout for different specifications, a library of parameterized macrocells has been developed in 1.2 m CMOS technology.A test chip with a quadrature DDFS module has been generated, using the compiler, and fabricated. The chip has two input signals: one is for frequency control while the other is for phase initialization. Input and output word lengths are 16 bits and 6 bits respectively. The chip complexity is approximately 12,000 transistors (DDFS core) and the die size is 4.8×2.9mm ². A maximum sample rate of 80 MHz has been attained implying a maximum sine (cosine) output frequency of 40 MHz and a frequency resolution of 1.22 kHz. The maximum spurious level measured is –46 dB.     

海尔兹山纪念堂

正海尔兹山纪念堂是一个独特的纪念场所。为了纪念耶路撒冷所有阵亡的士兵,设计中包含了他们名字。这是和平年代期冀希望的象征。尽管临近耶路撒冷繁华路段,纪念堂设计为一个平静的圣经式场地,整个空间孤隐而静谧。建筑主体空间通过挖掘山体而成,形成个人或集体纪念活动的私密空间。纪念堂上方的山体,以耶路撒冷石塑造出新的曲线。纪念堂形成一个波形漏斗状结构,缓缓通向天际。这种不规则的涡旋状结构为纪念堂营造出不断变化的自然光。     

Age-related decline in auditory plasticity: Experience dependent changes in gap detection as measured by prepulse inhibition in young and aged rats.

Young adult and aged F344 rats were compared on a silent gap variant of the prepulse inhibition paradigm. Animals were tested using a 50-ms single tone cue, followed by 8 days of silent gap testing. The first 3 days of gap testing were long gaps (range 2 to 100 ms) followed by 5 days of short gaps (range 2 to 10 ms). The effects of gap length, prior experience, and age, on the magnitude and direction (facilitation vs. attenuation) of the acoustic startle response, were examined. The young rats showed stronger and more reliable acoustic startle responses (uncued trials) during all acoustic startle tasks as compared to the old. The younger animals also exhibited a more consistent attenuated response across cues and days. Depending on silent gap length, both reduction (inhibition) and enhancement (facilitation) of startle were observed. Finally, only the young adult animals showed an experience-related shift from facilitation to attenuation in response to very short silent gap cues, and this initial early facilitation predicted later attenuation following additional experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

斯坦哈特自然历史博物馆

正新的博物馆将成为特拉维大学自然历史类收藏品的新家,该建筑设计包含展览和研究两种功能。通常未展出的收藏品都会放置在一个大木箱里——珍贵的植物和动物标本储存箱。设计师正是借鉴了标本箱这一形象,将建筑体打造成一个神秘的宝箱,邀请人们进入参观。盒子式建筑体象征着永恒,兼具历史与未来两种象征意义。     

创业国家中心

正创业国家中心(SNC)坐落于特拉维夫市中心,为以色列科技基金会而建。这里原有的六层独立大楼,改造为共用空间、办公室、会议室和展览区。办公区位于两处正式活动空间之间,打造休闲舒适的工作氛围。作为针对科技和计算机领域人员的建筑,设计上追求精确性和实     

The application of cryo-SEM techniques to the study of the symbiotic association in the Azolla leaf cavity

The preparation of frozen-hydrated samples for scanning electron microscopy to observe symbionts in Azolla is described and compared to the conventional method of chemical fixation followed by critical-point drying. The frozen-hydrated specimens preserve the structure of the associating symbionts and the liquid phase in the Azollaleaf cavity. The leaf cavity structure and the endosymbionts in the frozen-hydrated specimens were intact and unharmed throughout the fixation. The cyanobiont cells were distributed along the envelope of the leaf cavity, and did not aggregate around the hair cells, as reported for chemical fixation specimens. The mucilage layer removed by the chemical fixation could be observed in the cryo-fixation specimens, especially at the lower part of the cavity.     

博客追踪：最新流行的客服方式

听到"客服"这个词,你的第一反应是什么?应该是不同于家庭交流的吧.不过,得益于互联网的即时性和交互性,事情正在逐渐转变.     

雷霍沃特社区中心

正雷霍沃特社区中心勾勒出一种新的公共空间规模,摒弃了以往大规模社区中心的模式。社区中心设有两栋大楼,中间是一个广场。两栋大楼和广场的位置如此排布,使得更多行人可以从社区中心穿过,连通了社区中心东边的学校和北边的体育中心。     

贝丝哈罗契姆康复中心

正贝丝哈罗契姆康复中心坐落于贝尔谢巴市郊区,处于城市与荒漠(内格夫沙漠)的交界地带。这里是残疾退伍军人及其家属的安居所。沙漠的炽阳和景观是设计的灵感来源,建筑最终呈现出岩石般堆砌的形式,形成一个私密的保护空间。