Simulation of beta radiator handling procedures in nuclear medicine by means of a movable hand phantom

In nuclear medicine therapies, people working with beta radiators such as (90)Y may be exposed to non-negligible partial body doses. For radiation protection, it is important to know the characteristics of the radiation field and possible dose exposures at relevant positions in the working area. Besides extensive measurements, simulations can provide these data. For this purpose, a movable hand phantom for Monte Carlo simulations was developed. Specific beta radiator handling scenarios can be modelled interactively with forward kinematics or automatically with an inverse kinematics procedure. As a first investigation, the dose distribution on a medical doctor's hand injecting a (90)Y solution was measured and simulated with the phantom. Modelling was done with the interactive method based on five consecutive frames from a video recorded during the injection. Owing to the use of only one camera, not each detail of the radiation scenario is visible in the video. In spite of systematic uncertainties, the measured and simulated dose values are in good agreement.     

Characterisation of solar cells and modules under actual operating conditions

A PC-based measuring system is presented for outdoor testing of solar cells and modules under real operating conditions. It consists of a sun-tracked sample holder, different electronic loads (including control), digital multimeters, a PC and a laser printer. Insolation is measured and recorded with pyranometers, pyrheliometers and a reference cell. Current-voltage curves are acquired in the range of irradiance from 10 W/m² to over 1000 W/m². Small single cells of size down to 3 mm by 3 mm as well as large modules and laminates up to 1 m by 1.5 m can be tested. The measurement time for one test can be varied between 5 to 15 seconds. The maximum power point (mpp) is normally detected on-line. However, it can also be determined in a subsequent mathematical analysis, if more precise mpp data are required. The maximum relative uncertainty in the efficiency (determined from mpp data) has been estimated to be less than ± 1 %, depending on type and size of cell or module and on the constancy of the insolation during the testing time. Using a new dynamic method, the temperature coefficient of the efficiency can be determined within a relative uncertainty of about ± 3 %. The coefficient is used to derive standard test condition data. Results are given for two commercial modules.     

The Control of Shrinkage and Thermal Instability in SU‐8 Photoresists for Holographic Lithography

The negative‐tone epoxy photoresist, SU‐8, expands ≈1% by volume after postexposure baking. However, if the maximum optical fluence is comparable to that at the insolubility threshold, as in a holographic exposure, the developed resist shrinks (≈35% by volume) due to the removal of light oligomers not incorporated into the polymeric network. IR spectroscopy shows that, at this level of exposure, only 15% of the epoxy groups in the insoluble polymer have reacted; consequently microstructural elements soften and collapse at >100 °C. When the light oligomers are removed, the sensitivity of the resist is unchanged, provided that 5% (w/w) of a high‐molecular‐weight reactive plasticizer (glycidoxy‐terminated polyethylene glycol) is added, but it shrinks less on development and, when used as a photonic crystal template, shows improved uniformity with less cracking and buckling. Reinforcing the polymer network by reaction with the polyfunctional amine (bis‐N,N′‐(3‐aminopropyl)ethylenediamine) increases the extent of cross‐linking and the thermal stability, allowing inverse replicas of photonic crystal templates to be fabricated from both Al:ZnO and Zr₃N₄ using atomic layer deposition at temperatures up to 200 °C.     

A Comparative Study of Urban Planning System Between Wuhan and Macao

This paper makes a comparative study of urban planning system between Wuhan and Macao,including the legislation system,administration system,and operation system of planning.Meanwhile,it also explores how to improve the current planning systems.     

每个人心中（或严肃，或轻浮）都有一座花园

欧洲中世纪的修道院是远古之流和信仰之流交织的源泉。这些修道院的中央都有一个花园,这里用于放置最重要的东西,如最美丽的植物和药草等。在规定的时间,僧侣和修道院院长会在这里聚集。花园并不是日常活动的场所     

Laminar smoke points of coflowing flames in microgravity

Laminar smoke points were measured in nonbuoyant laminar jet diffusion flames in coflowing air. Microgravity was obtained on board the International Space Station. A total of 55 smoke points were found for ethylene, propane, propylene, and propylene/nitrogen mixtures. Burner diameters were 0.41, 0.76, and 1.6 mm, and coflow velocities varied from 5.4 to 65 cm/s. These flames allow extensive control over residence time via variations in dilution, burner diameter, and coflow velocity. The measured smoke-point lengths scaled with d^−0.91u_air^0.41, where d is burner diameter and u_air is coflow velocity. The measurements yielded estimates of sooting propensities of the present fuels in microgravity diffusion flames. Analytical models of residence times in gas jet flames are presented, and although residence time helps explain many of the observed trends it does not correlate the measured smoke points.     

LNG接收终端

文章描述了液化天然气(LNG)接收终端的主要功能,介绍LNG接收终端的工艺流程,为求能使同行们更好的了解这类新兴燃气场站,同时探讨了LNG接收终端在我国的发展新方向,并对LNG接收终端在我国的发展提出了几点建议。     

万桥园

园林是有内涵的。它结合了诗歌与故事。万桥园代表了人生;一条充满不确定性与负担,同时也伴随高潮和喜悦的人生轨迹。万桥园的设计将带您领略迷宫般曲折无尽的生活旅途。它让你在自然中找到自我,并带你踏过万桥。万桥园的设计利用透视手法、极限以及惊喜的感官体验。展园周边环境的总体景观充分利用了场地完美的地理条件：