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  • Author: Peng Wang x
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Several Differentiation Formulas of Special Functions. Part IV

In this article, we give several differentiation formulas of special and composite functions including trigonometric function, polynomial function and logarithmic function.

Several Differentiation Formulas of Special Functions. Part V

In this article, we give several differentiation formulas of special and composite functions including trigonometric, polynomial and logarithmic functions.

Abstract

An empirical network model has been developed to predict the in-plane thermal conductivities along arbitrary directions for unidirectional fiber-reinforced composites lamina. Measurements of thermal conductivities along different orientations were carried out. Good agreement was observed between values predicted by the network model and the experimental data; compared with the established analytical models, the newly proposed network model could give values with higher precision. Therefore, this network model is helpful to get a wider and more comprehensive understanding of heat transmission characteristics of fiber-reinforced composites and can be utilized as guidance to design and fabricate laminated composites with specific directional or specific locational thermal conductivities for structures that simultaneously perform mechanical and thermal functions, i.e. multifunctional structures (MFS).

Abstract

This paper introduces a novel polyphase filter working at high centre frequency using multi-output current differencing transconductance amplifiers (MOCDTAs). The MOCDTA possesses characteristics of low input impedance, high output impedance, wide work frequency and linearly adjustable transconductance. The proposed filter consists of two MOCDTAs, two grounded capacitors, and no resistors. The features of low input impedance and high output impedance make it suitable for cascade. The bandwidth and centre frequency could be adjusted independently by external bias voltage VC and VCa. The image rejection ratio (IRR) could reach 31.6 dB at the centre frequency of 114 MHz, and its bandwidth could be 11.1 MHz. Besides, the centre frequency could be tuned from 38 MHz to 150 MHz with bandwidth of 20.1 MHz. Simulation results which verify the theory are included.

Abstract

To solve the problem of offshore oilfield development, based on the newly introduced pulsed neutron oxygen activation logging instrument, the application research of test design and interpretation method was carried out and applied to actual production. The structure, technical indicators and logging principles of pulsed neutron oxygen activation logging tools were introduced. The test design under different well conditions was studied, including general positive and negative injection, oil sleeve injection, single oil pipe configuration and multitubing configuration. A large amount of field test data was collected and analysed technically. A set of effective interpretation models was proposed. The corresponding interpretation software was developed. A set of test design methods and operating specifications for different well conditions were developed. Based on the conventional interpretation method, the peak selection, the double-tuber peak identification and the carbon dioxide flooding interpretation method were added. The results show that the test design and interpretation methods were applied well through a large number of field tests and production applications. Therefore, pulsed neutron oxygen activated injection profile logging technology is successfully applied in offshore oil fields.

Abstract

Textile composite reinforcement forming has been employed in many aeronautic industries as a traditional composite manufacturing process. The double-curved shape manufacturing may be difficult and can lead to defects when the composite parts have high curvatures and large deformations. Compared with the textile composites forming, surface 3D weaving can demonstrate directly the geometry of final composite part without the stages involved in 2D product. The weaving in three directions is completely designed and warp and weft yarns are always perpendicular to the surfaces of the final 3D ply. These two manufacturing techniques are applied to produce an important piece of aircraft: the corner fitting. The 3D weaving results are compared with the experimental forming by a punch as same geometry as the corner fitting part. The conveniences and limits of each technique are investigated. The comparisons show particularly a perfect final 3D fabric with homogeneous fibre volume fraction performed by the surface 3D weaving technique.

Imaging primary prostate cancer with 11C-Choline PET/CT: relation to tumour stage, Gleason score and biomarkers of biologic aggressiveness

Background. As a significant overlap of 11C-Choline standardized uptake value (SUV) between prostate cancer and benign prostate hyperplasia (BPH) tissue, controversy exists regarding the clinical value of 11C-Choline PET/CT scan in primary prostate cancer. In this study, the SUVmax of the prostate lesions and the pelvic muscles were measured and their ratios (SUVmax-P/M ratio) were calculated. Then we evaluated whether the tracer 11C-Choline uptake, quantified as SUVmax-P/M ratio, correlated with tumour stage, Gleason score, and expression levels of several biomarkers of aggressiveness.

Methods. Twenty-six patients with primary prostate cancer underwent 11C-Choline PET/CT. Tumour specimens from these patients were graded histopathologically, and immunnohistochemistry for Ki-67, CD31, androgen receptor (AR), Her-2/neu, Bcl-2, and PTEN were performed.

Results. Both SUVmax and SUVmax-P/M ratio showed no significant difference between patients with tumour stage II and III, but significantly elevated in patients with tumour stage IV. SUVmax-P/M ratio was also significantly higher in lesions with Gleason score of 4+3 or higher versus less than or equal to 3+4. SUVmax-P/M ratio was found significantly correlated with expression levels of Ki-67 and CD31. In addition, a higher SUVmax-P/M ratio was demonstrated in Her-2/neu positive subgroup than negative subgroup. At the same time, Gleason score and expression levels of these biomarkers showed no significant association with SUVmax.

Conclusions. Using the parameter SUVmax-P/M ratio, 11C-Choline PET/CT may be a valuable non-invasive imaging technology in the diagnosis of primary prostate cancer.

Abstract

The habitat selection by animals depends on different environmental and anthropogenic factors such as the season, climate, and the life cycle stage. Here, we have presented the summer habitat selection strategy of reindeer (Rangifer tarandus) in the unprotected forest area from the northern arctic region of China. In summer 2012, we investigated a total of 72 used and 162 non-used plots in the reindeer habitat to record habitat variables. We found that the reindeer used significantly higher altitude, arbour availability, and vegetation cover area as compared to the non-used habitat variables. Principal component analysis (PCA) showed that six principal components (68.5%) were mainly responsible for the summer habitat selection of reindeer such as the slope position, concealment, anthropogenic dispersion, arbour species, distance from the anthropogenic disturbance area (> 1000 m) and water quality (Wilks’ Lambda = 0.12; P = 0.0001). The local people are largely dependent on forest product resource in these regions, such as bees herding, collecting wild vegetables, hunting, poaching, and grazing. These activities highly influenced the reindeer habitat and its behaviours. This study thus confirmed that reindeers are forced to choose poor habitat in unprotected forest area with high human disturbance or interference. These factors should be considered by the concerned authority or agency to manage reindeer population in the wild.

Abstract

In the B10 isotope enrichment industry, the purification of anisole mixture makes great sense. A dynamic-accumulative operation policy of continuous distillation (DACD) with repeated filling and dumping of the still is proposed for the separation of trace heavy impurities in the recycled anisole. To simulate and optimize the purification process of anisole, a mathematical model of DACD is derived, and the computer codes are developed in the MATLAB environment. Moreover, the experiment is performed in a pilot-scale distillation column. The results show that the experimental date agrees well with simulation results. DACD could solve the difficulty of flow rate control when the bottom flow rate is very small in continuous distillation. The size of the still in this operation mode is also smaller than that in batch distillation. And the yield of anisole is raised to 99.91%. In a word, DACD is especially suitable for separating trace heavy impurities from the recycled anisole.

Abstract

We report on the development and characterization of ten microsatellite markers from repetitive DNA enriched libraries for Castanopsis fissa from lower subtropical China. The number of alleles ranged from three to thirteen. Observed and expected heterozygosities ranged from 0.265 to 0.818, and 0.270 to 0.873, respectively. These microsatellite markers will be used to study fine-scale spatial genetic structure of C. fissa in 20 ha Dinghushan plot in lower subtropical China.