食品塑料包装材料中化学物质的残留和分析

综述了近几年食品塑料材料中残留的化学物质和分析进展，内容包括聚乙烯、聚苯乙烯，聚氯乙烯、聚碳酸酯、三聚氰胺树脂及成型品。     

Introducing the concept of uncertainty of measurement in testing in association with the application of the standard ISO/IEC 17025

ISO/IEC 17025 requests laboratories to estimate the overall uncertainty associated with a test result. In many cases this means a new requirement to laboratories. It is essential to understand the importance of the knowledge of the uncertainty of measurements as well as the principle that not always the smallest possible uncertainty is needed, but fitness for purpose has to be achieved. The paper suggests a policy on the implementation of the concept of uncertainty and guidance on how to proceed, taking into account the present state of the art of understanding the problem.     

Up-to-date status of food irradiation

The last decade has witnessed significant advancement of the acceptance of food irradiation processing. At present 37 countries have approved one or more food items for human consumption and 25 countries have commercialized this process. More developing countries are showing keen interest to introduce irradiation processing in order to reduce post-harvest food losses, to increase export potentials and to ensure safety of food to their people. Although progress towards acceptance of food irradiation by the industry is slow, actual market trials have shown that once consumers have understood this technology, they are willing to buy irradiated foods.This paper deals with the latest developments in the field of food irradiation with particular reference to legislation, consumer acceptance, commercialization and potential application in developing countries. This paper also deals with the role played by the International Organizations, aimed at facilitating the acceptance of food irradiation.     

Conformity assessment and metrology: update on the state of affairs

A couple of years ago, ISO CASCO launched a major project of transforming all the existing ISO Guides on conformity assessment to a comprehensive series of ISO standards 17000 being now in various stages of development. As the concept of traceability underpinning all measurements has been a basic mission of metrology, a number of these standards have a direct bearing on metrology. The series is logically based on a definition standard, ISO 17000, giving, among others, a guidance which activities fall under conformity assessment. The fact that calibration does not, might have important consequences which must yet be assessed. A controversial discussion on some issues has been in progress concerning ISO 17011 on accreditation bodies which touches both on national metrology institutes (NMIs) with an accreditation function and on calibration labs at large. ISO 17040 on peer review could be used with an advantage to support mutual recognition arrangements among a limited number of bodies of a specialized expertise (e.g., CIPM MRA among NMIs under the Metre Convention). ISO 17025 has been the most important standard for the metrology community and has undergone a major overhaul taking on board the uncovered requirements from ISO 9001:2000. In general, the paper will give an update on the developments outlined above and discuss the consequences and further steps from the viewpoint of metrology.     

Testing nonlinear operators

We study testing of nonlinear operators; we want to test whether an implementation operator conforms to a specification operator. The problem is difficult, since there can be infinitely many possible inputs but we can only test finitely many of them. An implementation operator may perform well on the tested inputs but may be faulty on the untested inputs. In general, finite testing is inherently inconclusive. Consequently, we modify the problem in three different directions and obtain positive results: (1) We consider an infinite sequence of tests and prove that testing is decidable in the limit; (2) We relax the error criterion and show that finite testing is conclusive, however, the cost could be formidable; and (3) We tolerate faults on a negligible subset of inputs and develop a probabilistic testing algorithm with a significantly reduced cost. Our results indicate that test sets are universal; they only depend on the structure of the input set. In fact, they are provided by an net of the input set.This work was done while consulting at AT&T Bell Laboratories, and is partially supported by the National Science Foundation grant IRI-89-07215 and the Air Force Office of Scientific Research 91-0347.     

Strain rate sensitive compressive response of gelatine: Experimental and constitutive analysis

Gelatine is widely used as a soft tissue simulant in physical surrogates for the human body. Historically, gelatine has been used to evaluate penetrating impacts and, more recently, to evaluate blunt impact and blast loading effects on soft tissue. There is a need for material characterisation data across a wide range of strain rates, and appropriate constitutive relationships that can be used in models, particularly finite element models, to accurately predict the response of gelatine under various loading conditions. In this study, dynamic experiments were conducted using a split Hopkinson pressure bar and quasi-static tests performed on gelatine to investigate its compressive stress-strain response at both quasi-static and dynamic rates of deformation. The experimental results show that gelatine exhibits rate-sensitive and nonlinear behaviour. The Zhu-Wang-Tang constitutive model can adequately describe the rate-sensitive compressive behaviour of gelatine as good agreement was found between experimental results and model prediction.     

离轴非球面在细磨与粗抛阶段的波面再现技术

基于付科法的离轴非球面波面再现检测技术,通过对付科检测过程的数学分析,建立了离轴非球面波面再现的数学模型,提出了波面整合算法,通过对两幅阴影图灰度值积分、去倾斜及波面整合等数据处理再现出被检离轴非球面的波面误差.在被检离轴非球面两个方向的弥散斑分别为0.152mm和0.284mm时,干涉检测得到其面形误差峰谷值为1.110μm、均方根值为0.194μm,且两种检测方法的波面轮廓相一致.实验结果验证了基于付科法的离轴非球面再现技术的正确性,可以应用于指导离轴非球面在细磨粗抛阶段的加工并且实现与精抛光阶段干涉检测的有效衔接.     

方差分析在化学助剂评价中的应用

介绍用方差分析的方法处理化学助剂评价试验的数据,有效去除试验误差对评价的影响,使评价的结论科学,合理,而又正确。     

实验室能力验证的发展

实验室能力验证对于判定实验室的检测能力非常重要。回顾了国际实验室能力验证的起源和发展,重点分析了我国能力验证的发展历程和成就,探讨了我国实验室能力验证中存在的问题和有争议的技术要点。     

药灸条在施治过程中的可见和红外光谱分析

利用自制的检测仓和可见,红外单色仪,对中医药灸条在临床治病燃烧时产生的“热力”进行了光谱分析。