JSON在Ajax数据交换中的应用研究

基于Ajax(Asynchronous JavaScript And XML)技术的W eb程序开发和应用主要采用传统的XML数据传输格式,这种数据格式不但会产生大量数据冗余,而且还存在着解析复杂等问题.将XML和JSON进行对比分析,最终选择JSON作为Ajax中的数据传输格式,并用jQuery来解析JSON数据.JSON传输格式可以屏蔽DOM解析XML文件的复杂性,缩短数据传输时间,解决Ajax Web应用系统中数据传输效率优化问题.提出一种Ajax+JSON+jQuery传输方案,通过实例证明这种传输方案能够有效提高W eb应用系统的数据传输效率,减少客户端的请求响应时间.     

成都市商品住宅价格空间分异特征与规律

以成都市商品住宅为研究对象,通过 ＡｒｃＧＩＳ 等方法,研究成都市商品住宅价格空间分异特征和规律。 结果表明:成都 市商品住宅价格总体上呈现出由中心向外围降低的趋势,中心城区主要呈团块状分布,近郊区主要呈放射状分布,远郊区主 要呈星岛状分布;低房价区段在西部—北部—东部地区呈现 ２ 条“半环状”分布;中低房价区段呈“环状＋放射状”分布。 在中 心城区形成了环状分布,在近郊区及远郊区形成了自中心城区向外延伸的放射状分布特征;中房价区段在中心城区分布相对 集中并呈团块状分布,在近郊区呈放射状分布,远郊区呈零星分布特征;中高房价区段在中心城区、高新区、天府新区呈组团 状分布,在近郊区呈放射状分布,远郊区呈零星分布的特征;高房价区段自中心城区沿天府大道向南延伸至天府新区,形成了 南—北走向的峰值带。     

Laser cooling of a nanomechanical oscillator into its quantum ground state

The simple mechanical oscillator, canonically consisting of a coupled mass-spring system, is used in a wide variety of sensitive measurements, including the detection of weak forces and small masses. On the one hand, a classical oscillator has a well-defined amplitude of motion; a quantum oscillator, on the other hand, has a lowest-energy state, or ground state, with a finite-amplitude uncertainty corresponding to zero-point motion. On the macroscopic scale of our everyday experience, owing to interactions with its highly fluctuating thermal environment a mechanical oscillator is filled with many energy quanta and its quantum nature is all but hidden. Recently, in experiments performed at temperatures of a few hundredths of a kelvin, engineered nanomechanical resonators coupled to electrical circuits have been measured to be oscillating in their quantum ground state. These experiments, in addition to providing a glimpse into the underlying quantum behaviour of mesoscopic systems consisting of billions of atoms, represent the initial steps towards the use of mechanical devices as tools for quantum metrology or as a means of coupling hybrid quantum systems. Here we report the development of a coupled, nanoscale optical and mechanical resonator formed in a silicon microchip, in which radiation pressure from a laser is used to cool the mechanical motion down to its quantum ground state (reaching an average phonon occupancy number of 0.85 ± 0.08). This cooling is realized at an environmental temperature of 20?K, roughly one thousand times larger than in previous experiments and paves the way for optical control of mesoscale mechanical oscillators in the quantum regime.     

氢化非晶硅薄膜光吸收谱的恒定光电流测量法

本文报道了光吸收谱的恒定光电流（ＣｏｎｓｔａｎｔＰｈｏｔｏｃｕｒｒｅｎｔＭｅｔｈｏｄ）测量法，并用其测量了高速沉积的氢化非晶硅薄膜（ａ－Ｓｉ：Ｈ）的光吸收谱，同时观测了ＳｔａｅｂｌｅｒＷｒｏｎｓｋｉ（ＳＷ）效应中样品吸收系数的变化。     

关于用拉格朗日乘子法解静力学问题的一点商榷

本文指出在广义坐标下运用拉格朗日待定乘子法求解受完整约束的力学系统的静力学问题时,只能求出平衡位置而不能求出约束力,从而澄清文献[2]中的一个问题。     

Long‐memory dynamic Tobit models

We introduce a long‐memory dynamic Tobit model, defining it as a censored version of a fractionally integrated Gaussian ARMA model, which may include seasonal components and/or additional regression variables. Parameter estimation for such a model using standard techniques is typically infeasible, since the model is not Markovian, cannot be expressed in a finite‐dimensional state‐space form, and includes censored observations. Furthermore, the long‐memory property renders a standard Gibbs sampling scheme impractical. Therefore we introduce a new Markov chain Monte Carlo sampling scheme, which is orders of magnitude more efficient than the standard Gibbs sampler. The method is inherently capable of handling missing observations. In case studies, the model is fit to two time series: one consisting of volumes of requests to a hard disk over time, and the other consisting of hourly rainfall measurements in Edinburgh over a 2‐year period. The resulting posterior distributions for the fractional differencing parameter demonstrate, for these two time series, the importance of the long‐memory structure in the models. Copyright © 2006 John Wiley & Sons, Ltd.     

文化景观和土地利用自然保护O社会层面

文化景观是指居住在地球上的人类集团为满足社会经济需要所创造的景观，如：农田、城市、荒漠中的绿洲等。文化景观由人们创造，被人们利用，但是如何保持良好的生物多样性，并且与自然和谐共处呢？文化景观面临的挑战是社会经济的复杂性凌驾于自然保护的生物多样性之上。本书尝试接近这个复杂的事物，并提供理论背景、实践方针和实例。本书吸纳了来自欧洲和美国的科学家、管理者、独立顾问和政治家的观点。怀着对农业特殊的重视，     

糖皮质激素在肾小球疾病治疗中的进展

目的 :综述糖皮质激素治疗肾小球疾病的最新进展 ,以指导临床实践 ;方法 :对近年来国内外有关糖皮质激素在肾小球疾病治疗中的研究资料和文献进行综合分析 ;结果 :目前糖皮质激素对不同病因和病理类型的肾小球疾病的治疗方法和疗程都有很大的进展 ;结论 :糖皮质激素仍是治疗原发性和某些继发性肾小球疾病的主要药物 ,而用法却在不断地改进 ,临床医师应对其进行及时了解 ,以指导临床实践     

羔山羊的超数排卵及体外受精

以ＦＳＨ或ＦＳＨ－ＬＨ四种不同处理方法对２９只６８～１１０日龄羔山羊进行超排处理，结果共采集卵泡卵母细胞７０８枚，平均每只羔羊采卵２４．４枚．卵母细胞经体外培养２４ｈ后有８１．２％的卵发育为成熟卵．分别用经钙离子载体Ａ＿（２３１７８）或肝素进行获能处理的精子对体外培养成熟的卵子进行体外受精，结果精子穿入卵率分别为５４．８％和３４．４％，发育至２～４细胞胚的卵裂率分别为２８．６％和４１．９％．采用ＦＳＨ－ＬＨ（肌注）进行超排处理得到的卵子经体外受精处理后，其卵裂率明显高于采用其它超排方法得到卵子的卵裂率．