Investigation of the Equivalence of National Dew-Point Temperature Realizations in the ?50?°C to +?20?°C Range

In the field of humidity quantities, the first CIPM key comparison, CCT-K6 is at its end. The corresponding European regional key comparison, EUROMET.T-K6, was completed in early 2008, about 4?years after the starting initial measurements in the project. In total, 24 NMIs from different countries took part in the comparison. This number includes 22 EURAMET countries, and Russia and South Africa. The comparison covered the dew-point temperature range from ?50?°C to +20?°C. It was carried out in three parallel loops, each with two chilled mirror hygrometers as transfer standards in each loop. The comparison scheme was designed to ensure high quality results with evenly spread workload for the participants. It is shown that the standard uncertainty due to the long-term instability was smaller than 0.008?°C in all loops. The standard uncertainties due to links between the loops were found to be smaller than 0.025?°C at ?50?°C and 0.010?°C elsewhere. Conclusions on the equivalence of the dew-point temperature standards are drawn on the basis of calculated bilateral degrees of equivalence and deviations from the EURAMET comparison reference values (ERV). Taking into account 16 different primary dew-point realizations and 8 secondary realizations, the results demonstrate the equivalence of a large number of laboratories at an uncertainty level that is better than achieved in other multilateral comparisons so far in the humidity field.     

Endcoding complexity versus minimum distance

A bound on the minimum distance of a binary error-correcting code is established given constraints on the computational time-space complexity of its encoder where the encoder is modeled as a branching program. The bound obtained asserts that if the encoder uses linear time and sublinear memory in the most general sense, then the minimum distance of the code cannot grow linearly with the block length when the rate is nonvanishing, that is, the minimum relative distance of the code tends to zero in such a setting. The setting is general enough to include nonserially concatenated turbo-like codes and various generalizations. Our argument is based on branching program techniques introduced by Ajtai. The case of constant-depth AND-OR circuit encoders with unbounded fanins are also considered.     

Waveform recognition in the presence of domain and amplitude noise

In this paper, we discuss the problem of recognizing single-dimensional, real-valued, functions in the presence of domain noise (i.e., noise that affects the domain rather than the amplitude). This problem is inspired by the field of on-line character recognition where it is more natural to view the hand as deforming the domain of the character rather than adding noise to its amplitude. The results obtained illustrate the difficulties one faces when dealing with both domain and amplitude deformation of waveforms or images. Our major result is a set of sufficient conditions that a recognition metric has to satisfy. Examples of metrics that satisfy these conditions, and hence are appropriate for recognition when the deformation affects the domain rather than the amplitude, include the supnorm metric and the total variation metric. Furthermore, we extend the results to the case when a waveform is corrupted by both amplitude and domain deformation     

Synthesis of Silica Vesicles with Controlled Entrance Size for High Loading,Sustained Release,and Cellular Delivery of Therapeutical Proteins

A rationally designed two‐step synthesis of silica vesicles is developed with the formation of vesicular structure in the first step and fine control over the entrance size by tuning the temperature in the second step. The silica vesicles have a uniform size of ≈50 nm with excellent cellular uptake performance. When the entrance size is equal to the wall thickness, silica vesicles after hydrophobic modification show the highest loading amount (563 mg/g) towards Ribonuclease A with a sustained release behavior. Consequently, the silica vesicles are excellent nano‐carriers for cellular delivery applications of therapeutical biomolecules.     

Kurzzeitkriechverhalten des Warmarbeitsstahles X40 CrMoV 51

Untersuchung des Kriechverhaltens des Warmarbeitsstahles X40 CrMoV 51, vergütet auf 40 HRC, bei Temperaturen zwischen 500°C und 700°C. Zusammenhang zwischen Bruchverlängerung, Brucheinschnürung und wahrer Dehnung beim Bruch einerseits und Spannung und Temperatur andererseits. Gültigkeit der Monkman-Grant-Regel. Einfache empirische Interpolationsformel für Zeitstanddaten im untersuchten Temperaturbereich, mit der auf anschauliche Weise der Einfluß von Temperatur und Spannung auf die Standzeit bestimmt werden kann.     

Miniaturized Two-Pressure Generator for Relative Humidity

The concept and design of a miniaturized two-pressure humidity generator are presented. The generator is suitable for achieving relative humidity ranging from 10% to 95% with uncertainties of under 1% at ambient temperature and can be used for the calibration of relative humidity instruments in the laboratory and on site. By virtue of the concept, the relative humidity achieved is traced to only two pressure measurements. Further references are not necessary. A special adjustment algorithm enables standard industrial pressure sensors to be used. The two pressure sensors are synchronized by aligning their readings at ambient pressure. The resulting correlation of the uncertainties leads to very small systematic errors in the humidity display. Each humidity generator can still be individually adjusted through comparison with a chilled-mirror hygrometer, the total uncertainty of the generator being largely determined by the uncertainty of this hygrometer. Any drift of the pressure sensors that occurs can be compensated at any time by performing an alignment at ambient pressure without changing the individual adjustment of the generator. It can be demonstrated that the uncertainty of the displayed humidity remains practically unchanged over the course of a year by virtue of this alignment process.