Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample (I center dot 4.6 mm x 5.6 mm) was scanned using high-resolution X-ray computed tomography (HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 mu m. Combined with three-dimensional (3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.

A new endoscopic ultrasonography image processing method to evaluate the prognosis for pancreatic cancer treated with interstitial brachytherapy

AIM:To develop a fuzzy classification method to score the texture features of pancreatic cancer in endoscopic ultrasonography(EUS)images and evaluate its utility in making prognosis judgments for patients with unresectable pancreatic cancer treated by EUS-guided interstitial brachytherapy.METHODS:EUS images from our retrospective database were analyzed.The regions of interest were drawn,and texture features were extracted,selected,and scored with a fuzzy classification method using a C++program.Then,patients with unresectable pancreatic cancer were enrolled to receive EUS-guided iodine 125 radioactive seed implantation.Their fuzzy classification scores,tumor volumes,and carbohydrate antigen 199(CA199)levels before and after the brachytherapy were recorded.The association between the changes in these parameters and overall survival was analyzed statistically.RESULTS:EUS images of 153 patients with pancreatic cancer and 63 non-cancer patients were analyzed.A total of 25 consecutive patients were enrolled,and they tolerated the brachytherapy well without any complications.There was a correlation between the change in the fuzzy classification score and overall survival(Spearman test,r=0.616,P=0.001),whereas no correlation was found to be significant between the change in tumor volume(P=0.663),CA199 level(P=0.659),and overall survival.There were 15 patients with a decrease in their fuzzy classification score after brachytherapy,whereas the fuzzy classification score increased in another 10 patients.There was a significant difference in overall survival between the two groups(67 d vs 151 d,P=0.001),but not in the change of tumor volume and CA199 level.CONCLUSION:Using the fuzzy classification method to analyze EUS images of pancreatic cancer is feasible,and the method can be used to make prognosis judgments for patients with unresectable pancreatic cancer treated by interstitial brachytherapy.

Shape Descriptor with Morphology Method for Color-based Tracking

Tracking images using shape descriptor can be more accurate than using other existing methods and it is most useful when the environment is complex. However the existing methods with shape descriptor get more labeled parts to compare and detect the object in an image, which makes the computation more complicated. Thus, we need a trade-off between the accuracy and efficiency requirements. This paper aims to bridge this gap between the accuracy and efficiency requirements by using morphology method. To improve the original monochromatic object detecting system, we propose a new color descriptor to preprocess the image with polychromatic object. Experiments have been conducted and shown the proposed method has made a great improvement in the time complexity minimization comparing with the performances of the original detection algorithm.

A Neurodynamical Model for Selective Visual Attention

A neurodynamical model for selective visual attention considering orientation preference is proposed.Since orientation preference is one of the most important properties of neurons in the primary visual cortex,it should be fully considered besides external stimuli intensity.By tuning the parameter of orientation preference,the regimes of synchronous dynamics associated with the development of the attention focus are studied.The attention focus is represented by those peripheral neurons that generate spikes synchronously with the central neuron while the activity of other peripheral neurons is suppressed.Such dynamics correspond to the partial synchronization mode.Simulation results show that the model can sequentially select objects with different orientation preferences and has a reliable shift of attention from one object to another,which are consistent with the experimental results that neurons with different orientation preferences are laid out in pinwheel patterns.

Direct-detection OFDM-QPSK system performance improvement enabled by DFT spread and receiver-based ISFA algorithm

We experimentally demonstrate a direct-detection orthogonal-frequency-division-multiplexing quadraturephase-shift-keying（OFDM-QPSK） system that is capable of delivering a 32 Gbaud OFDM-QPSK signal over7 km single-mode fiber-28（SMF-28）. Intra-symbol frequency-domain averaging（ISFA） channel response estimation is applied to suppress in-band noise,while discrete Fourier transform-spread（DFT-spread） is used to reduce the peak-to-average power ratio（PAPR） of the transmitted OFDM signal. With the aid of ISFA-based channel estimation and PAPR reduction enabled by DFT-spread,the bit-error ratio of the system after 7 km SMF-28 transmission can be improved from 2×10^-3 to error-free when the received optical power is -8.5 d Bm.

Research on food-chain algorithm and its parameters

Based on the characteristics of colony emer-gence of artificial organisms,their dynamic interaction with the environment,and the food-chain crucial to the life system,the rules of local activities of artificial organ-isms at different levels are defined.The article proposes an artificial life-based algorithm,which is referred to as the food-chain algorithm.This algorithm optimizes computa-tion by simulating the evolution of natural ecosystems and the information processing mechanism of natural organ-isms.The definition,idea and flow of the algorithm are introduced,and relevant rules on metabolic energy and change in the surroundings where artificial-life individuals live are depicted.Furthermore,key parameters of the algorithm are systematically analyzed.Test results show that the algorithm has quasi-life traits that include being autonomous,evolutionary,and self-adaptive.These traits are highly fit for optimization problems of life-like sys-tems such as the location-allocation problem of a distri-bution network system.

A tunneling piezoresistive model for polysilicon

Based on the trap model, the band structure and the conductive mechanism ofpolysilicon were analyzed, and then an equivalent circuit used to interpret the tunneling piezoresistive effect was proposed. Synthesizing the piezoresistive effect of the grain boundary region and grain neutral zone, a new piezoresistive model--a tunneling piezoresistive model is established. The results show that when the doping concentration is above 10^20 cm^-3, the piezoresistive coefficient of the grain boundary is higher than that of the neutral zone, and it increases with an increase in doping concentration. This reveals the intrinsic mechanism of an important experimental phenomena that the gauge factor of heavily doped polysilicon nano-films increases with an increase in doping concentration.

Systems-Based Interactome Analysis for Hematopoiesis Effect of Angelicae sinensis Radix: Regulated Network of Cell Proliferation towards Hemopoiesis

Objective: To explore the molecular-level mechanism on the hematopoiesis effect of Angelicae sinensis Radix(ASR) with systems-based interactome analysis. Methods: This systems-based interactome analysis was designed to enforce the workflow of "ASR(herb)→compound→target protein→internal protein actions→ending regulated protein for hematopoiesis". This workflow was deployed with restrictions on regulated proteins expresses in bone marrow and anemia disease and futher validated with experiments. Results: The hematopoiesis mechanism of ASR might be accomplished through regulating pathways of cell proliferation towards hemopoiesis with cross-talking agents of spleen tyrosine kinase(SYK), Janus kinase 2(JAK2), and interleukin-2-inducible T-cell kinase(ITK). The hematopoietic function of ASR was also validated by colonyforming assay performed on mice bone marrow cells. As a result, SYK, JAK2 and ITK were activated. Conclusion: This study provides a new approach to systematically study and predict the therapeutic mechanism for ASR based on interactome analysis towards biological process with experimental validations.

Tunnelling piezoresistive effect of grain boundary in polysilicon nano-films

The experiment results indicate that the gauge factor of highly boron doped polysilicon nanofilm is bigger than that of monocrystalline silicon with the same doping concentration, and increases with the grain size decreasing. To apply the unique properties reasonably in the fabrication of piezoresistive devices, it was expounded based on the analysis of energy band structure that the properties were caused by the tunnel current which varies with the strain change forming a tunnelling piezoresistive effect. Finally, a calculation method ofpiezoresistance coefficients around grain boundaries was presented, and then the experiment results ofpolysilicon nanofilms were explained theoretically.

High Q reflection filter using a gradient-index membrane with a grating surface

High Q reflection filter using a gradient-index(GI) membrane with a grating surface is proposed. The thickness of GI membrane is very small comparing with the traditional multilayer reflection filter or the GI reflection filter, and the GI membrane can also break the restriction of the resonant excitation condition of the conventional guided-mode resonance(GMR) filter. High Q filtering features can be maintained even on the high-index substrate. The grating thickness of the GI membrane filter can be used to select the resonance wavelength with different quality factors(QFs), the reflection peak is blue-shifted, and the QF is decreased from 554.4 to 207.8 as the grating thickness is increased from 50 nm to 150 nm. The gradient coefficient of the GI membrane filter can be used to tailor the number of the reflection channels. The resonant excitations of high order waveguide modes confined in the GI membrane are responsible for the high Q filtering properties with multiple channels.

Topological edge states at singular points in non-Hermitian plasmonic systems

We introduce non-Hermitian plasmonic waveguide-cavity systems with topological edge states(TESs)at singular points.The compound unit cells of the structures consist of metal-dielectric-metal(MDM)stub resonators side-coupled to an MDM waveguide.We show that we can realize both a TES and an exceptional point at the same frequency when a proper amount of loss is introduced into a finite three-unit-cell structure.We also show that the finite structure can exhibit both a TES and a spectral singularity when a proper amount of gain is introduced into the structure.In addition,we show that we can simultaneously realize a unidirectional spectral singularity and a TES when proper amounts of loss and gain are introduced into the structure.We finally show that this singularity leads to extremely high sensitivity of the reflected light intensity to variations of the refractive index of the active materials in the structure.TESs at singular points could potentially contribute to the development of singularity-based plasmonic devices with enhanced performance.