Risks from ionizing radiation

For the public in the United Kingdom--and the United States--natural radon is a far greater radiation hazard than are emissions from nuclear installations.     

Infrared radiation from an extrasolar planet

A class of extrasolar giant planets--the so-called 'hot Jupiters' (ref. 1)--orbit within 0.05 au of their primary stars (1 au is the Sun-Earth distance). These planets should be hot and so emit detectable infrared radiation. The planet HD 209458b (refs 3, 4) is an ideal candidate for the detection and characterization of this infrared light because it is eclipsed by the star. This planet has an anomalously large radius (1.35 times that of Jupiter), which may be the result of ongoing tidal dissipation, but this explanation requires a non-zero orbital eccentricity (approximately 0.03; refs 6, 7), maintained by interaction with a hypothetical second planet. Here we report detection of infrared (24 microm) radiation from HD 209458b, by observing the decrement in flux during secondary eclipse, when the planet passes behind the star. The planet's 24-microm flux is 55 +/- 10 microJy (1sigma), with a brightness temperature of 1,130 +/- 150 K, confirming the predicted heating by stellar irradiation. The secondary eclipse occurs at the midpoint between transits of the planet in front of the star (to within +/- 7 min, 1sigma), which means that a dynamically significant orbital eccentricity is unlikely.     

High-power terahertz radiation from relativistic electrons

Terahertz (THz) radiation, which lies in the far-infrared region, is at the interface of electronics and photonics. Narrow-band THz radiation can be produced by free-electron lasers and fast diodes. Broadband THz radiation can be produced by thermal sources and, more recently, by table-top laser-driven sources and by short electron bunches in accelerators, but so far only with low power. Here we report calculations and measurements that confirm the production of high-power broadband THz radiation from subpicosecond electron bunches in an accelerator. The average power is nearly 20 watts, several orders of magnitude higher than any existing source, which could enable various new applications. In particular, many materials have distinct absorptive and dispersive properties in this spectral range, so that THz imaging could reveal interesting features. For example, it would be possible to image the distribution of specific proteins or water in tissue, or buried metal layers in semiconductors; the present source would allow full-field, real-time capture of such images. High peak and average power THz sources are also critical in driving new nonlinear phenomena and for pump-probe studies of dynamical properties of materials.     

注册会计师职业道德视角下诠释诚信

恪守独立、客观、公正原则和职业道德是注册会计师诚信品质的基本要求。注册会计师作为一种职业是有道德要求的,既要遵循社会公德,也要遵守职业道德。本文从注册会计师职业道德的视角,诠释了诚信的涵义、诚信的会计文化演进以及诚信在注册会计师职业道德中的地位。     

注册会计师职业道德视角下诠释诚信

恪守独立、客观、公正原则和职业道德是注册会计师诚信品质的基本要求.注册会计师作为一种职业是有道德要求的,既要遵循社会公德,也要遵守职业道德.本文从注册会计师职业道德的视角,诠释了诚信的涵义、诚信的会计文化演进以及诚信在注册会计师职业道德中的地位.     

圆环形活塞声源的辐射阻抗

以圆环形活塞声源为研究对象,在频率小于8.5kHz的范围内,利用微元法计算出了一定尺寸圆环形活塞声源的辐射阻抗的理论值。结果表明:圆环形活塞声源的辐射阻抗与声源的振动频率、活塞声源的环宽密切相关。声源振动频率越大,辐射阻抗越大;声源的环宽(辐射面积)越大,辐射阻抗越大,反之亦然。最后得出了一定尺寸同心圆环形活塞声源的同振质量和平均辐射声功率。     

论道德他律到自律的形成发展规律

道德的他律与自律是道德发展的两个不同阶段，他律是道德发展的低级阶段，自律是道德发展的高级阶段。道德他律与自律具有相互转化性。这种转化的规律表现在道德他律上升为道德自律的规律、以认知发展为基础的规律、量变发展到质变的规律和以新易旧、曲折前进的规律。     

丰顺县工业企业职业危害情况调查

目的为摸清辖区主要工业企业的职业危害因素、职业危害接触人群分布,职业损害及职业病发病状况,从而为制定本地区的职业病防治决策提供科学依据。方法依据国家《职业健康监护技术规范》进行调查。结果调查企业120个,发现存在职业危害的企业有85个,占70.8%。企业的环境抽查合格率为83.6%,主要的危险因素为苯、粉尘、噪声和其它化学毒物,接触危害因素总人数有2961人,占一线工人的36.3%,职业损害发生率为0.8%,暂未发现职业病患者。结论该县工业企业不发达,以中小企业为主。主导工业为电声、木具业,职业危害情况暂不严重,职业损害发生率仅占0.8%,暂没有发现职业病患者。存在职业病危害因素的企业以小型为主,其职业卫生管理较差。建议有关监管部门在强化对企业职业卫生监督管理的同时,应持续强化企业责任人的职业卫生管理意识,引导企业树立职业健康管理理念,从而实现企业自觉防制,员工自觉防护,达到减少职业危害发生的目的。     

胃复安过量引起锥体外系反应的报告

胃复安的不慎服用会引起不同的临床症状 ,服用过量 ,容易引起锥体外系反应的中毒症状 ,易被误诊为颅脑疾病     

外部性问题的系统经济学分析

外部性产生的必要条件是相关各方属于同一个系统。因此,有多少种系统化的方式就有多少种外部性。从宏观上讲,可以把外部性划分为以下三种：生态外部性、经济外部性和社会外部性。处理外部性的根本方法就是系统解耦。