发酵增效剂对黄霉素发酵效价的影响

试验研究了发酵增效剂在黄霉素发酵过程中对促进黄霉素效价的影响。结果显示,在发酵摇瓶中添加不同含量的发酵增效剂,有助于黄霉素发酵效价的提高,其中以添加300ppm浓度的增效剂效果最佳。     

Brief note on equality constraints in pure dual SAO settings

Structural and Multidisciplinary Optimization - We reflect on using equality constraints in a pure dual setting, to augment the predominant use of inequality constraints only in pure dual...     

X-ray quantum limited portal imaging using amorphous silicon flat-panel arrays

We have measured the linearity, spatial resolution (MTF), noise (NPS), and signal-to-noise characteristics (DQE) of an electronic portal imaging device (EPID) based on an amorphous silicon flat-panel array. The array has a 128 x 128-pixel matrix and each pixel is 0.75 x 0.75 mm2 in dimension so the array covers an area of 96 x 96 mm2. The array acts like a large area light sensor and records the optical signals generated in a metal plate/phosphor screen x-ray detector when the detector is irradiated by a megavoltage x-ray beam. In addition, approximately 0.5% of the total signal is generated by nonoptical processes. The noise measurements show that the device is quantum noise limited with the noise power generated by the x-ray quanta being up to 100 times greater than the noise added by the external readout electronics and flat-panel light sensor itself. However, the flat-panel light sensor does reduce the spatial resolution (compared to a perfect optical sensor with infinitesimal pixel size) because of its moderate pixel size and because optical spread can occur in the transparent glues used to attach the phosphor screen to the flat-panel light sensor. The response of the sensor is very linear and does not suffer from the glare phenomenon associated with TV camera-based EPIDs--characteristics which suggest that the amorphous silicon EPID will be well suited to transit dosimetry. Nevertheless, some limitations need to be overcome before these devices can be used clinically. These include developing larger flat-panel light sensors, the elimination of "noisy" pixels with high dark signal, and improvements in the uniform sensitivity of the sensors. This last requirement is only needed for transit dosimetry applications where it would greatly simplify calibration of the device. In addition, an image acquisition scheme must be developed to eliminate artifacts created by the pulsed x-ray beam generated by linear accelerators. Despite these limitations, our studies suggest that the amorphous silicon EPIDs are very well suited to portal imaging.     

Space-time topology optimization for additive manufacturing

Structural and Multidisciplinary Optimization - A general method of lifetime distribution selection for multi-level complete and censored testing data is developed. To alleviate the scarcity of...     

Poverty and poor housing in Scotland: The relationship between income and housing condition

The paper examines the relationship between income and poor housing conditions. It considers the role of housing outcome measures in relation to the different concepts of poverty, deprivation and social exclusion and examines the relationship between equivalised incomes, socio-economic household characteristics and a wide range of possible measures of housing deprivation. It concludes that income alone does not provide an adequate proxy for the quality of housing outcomes and that multiple housing measures are more satisfactory than the use of any single indicator. It also argues that such measures could be gathered in large-scale surveys but that many commonly used indicators in the UK (such as those derived from the census) would benefit from expansion and updating.     

An Improved Algorithm for Identifying Objects in Code

The identification of abstractions within existing software systems is an important problem to be solved to facilitate program comprehension and the construction of a set of reusable artifacts. In particular, of interest is the identification of object-like features in procedural programs. Existing techniques and algorithms achieve some level of success but do not, in general, always precisely identify a coherent set of objects. The identified objects tend to contain spurious methods that are only tenuously related to the object and require a great deal of human effort and understanding to unravel. This paper presents an improved algorithm that overcomes these drawbacks and enables the precise identification of objects with less human intervention and understanding by exploiting simple statistical techniques. The algorithm is applied to several sample programs and the results are compared with existing algorithms. Finally, the application of the algorithm to a real medium-size system is described and discussed. The algorithm was developed as part of the RE² project in which the identification of object-like features in existing systems is the basis for a re-engineering process aimed at populating a repository of reusable assets.     

Strain hardening and anisotropy in tensile fracture properties of sheared model Mozzarella cheeses

We studied the tensile fracture properties of model Mozzarella cheeses with varying amounts of shear work input (3.3–73.7 kJ/kg). After manufacture, cheeses were elongated by manual rolling at 65°C followed by tensile testing at 21°C on dumbbell-shaped samples cut both parallel and perpendicular to the rolling direction. Strain hardening parameters were estimated from stress–strain curves using 3 different methods. Fracture stress and strain for longitudinal samples did not vary significantly with shear work input up to 26.3 kJ/kg and then decreased dramatically at 58.2 kJ/kg. Longitudinal samples with shear work input <30 kJ/kg demonstrated significant strain hardening by all 3 estimation methods. At shear work inputs <30 kJ/kg, strong anisotropy was observed in both fracture stress and strain. After a shear work input of 58.2 kJ/kg, anisotropy and strain hardening were absent. Perpendicular samples did not show strain hardening at any level of shear work input. Although the distortion of the fat drops in the cheese structure associated with the elongation could account for some of the anisotropy observed, the presence of anisotropy in the elongated nonfat samples reflected that shear work and rolling also aligned the protein structure.