Showing papers by "Kai Zhang published in 2016"
TL;DR: Quantitative score systems showed higher diagnostic efficacy than single quantitative CEUS parameters, while qualitative score system improves the performance of CEUS greatly in discrimination of benign and malignant breast lesions.
47 citations
TL;DR: In this article, an effective displacement process of residual adsorbed CH4 in calcite slit nanopores by CO2 was performed, and it was found that the displacement efficiency was enhanced with an increase in the bulk pressure.
Abstract: Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulation methods were used to investigate the adsorption and diffusion properties of CH4 and CO2 in calcite slit nanopores with a pore width of ∼22 A. It was found that, in contrast to CH4, CO2 molecules have a much higher capacity to be adsorbed onto calcite pore surfaces. The diffusion capacity of CO2 molecules is much less in comparison with that of CH4 molecules, which could be attributed to diverse interactions between CO2 gas molecules and calcite nanopore surfaces. An effective displacement process of residual adsorbed CH4 in calcite slit nanopores by CO2 was performed, and it was found that the displacement efficiency was enhanced with an increase in the bulk pressure. This work provides microscopic information about the adsorption and diffusion properties of CH4 and CO2 in calcite nanopores, and confirmed the feasibility of the displacement of adsorbed CH4 in calcite nanopores by CO2, with the purpose of providing useful guidance for enhancing the extraction of shale gas by injecting CO2.
41 citations
TL;DR: In this article, an innovative method is proposed to determine a reasonable sealing depth for seam gas drainage boreholes by monitoring the response of the drift while drilling the boreholes, which reveals that high stress and gas pressure are the main factors accounting for the rapid increase of idle pressure.
27 citations
TL;DR: The idea in this paper is originated from the idea presented by Onwunalu and Durlofsky (2011, “A New Well-Pattern-Optimization Procedure for Large-Scale Field Development,” SPE J., 16(3), pp. 594-607), which focuses on well pattern optimization, and the innovations are as follows.
Abstract: For a long time, well pattern optimization mainly relies on human experience, numerical simulations are used to test different development plans and then a preferred program is chosen for field implementation. However, this kind of method cannot provide suitable optimal well pattern layout for different geological reservoirs. In recent years, more attentions have been paid to propose well placement theories combining optimization algorithm with reservoir simulation. But these theories are mostly applied in a situation with a small amount of wells. For numerous wells in a large-scale reservoir, it is of great importance to pursue the optimal well pattern in order to obtain maximum economic benefits. The idea in this paper is originated from the idea presented by Onwunalu and Durlofsky (2011, “A New Well-Pattern-Optimization Procedure for Large-Scale Field Development,” SPE J., 16(3), pp. 594-607), which focuses on well pattern optimization, and the innovations are as follows: (1) Combine well pattern variation with production control to get the optimal overall development plan. (2) Rechoose and simplify the optimization variables, deduce the new generation process of well pattern, and use perturbation gradient to solve mathematical model in order to ensure efficiency and accuracy of final results. (3) Constrain optimization variables by log-transformation method. (4) Boundary wells are reserved by shifting into boundary artificially to avoid abrupt change of objective function which leads to a nonoptimal result due to gradient discontinuity at reservoir edge. The method is illustrated by examples of homogeneous and heterogeneous reservoirs. For homogeneous reservoir, perturbation gradient algorithm yields a quite satisfied result. Meanwhile, heterogeneous reservoir tests realize optimization of various well patterns and indicate that gradient algorithm converges faster than particle swarm optimization (PSO).
21 citations
TL;DR: It is concluded that left‐side varicocele could cause epididymal hypoxia and epididmal dysfunction and HIF‐1α maybe act as useful factor to predict germ cell apoptosis in varicoCele.
Abstract: To investigate the relationship between hypoxia and epididymal dysfunction and the mechanism of epididymal dysfunction in rats with left-side varicocele, a total of 45 male Wistar rats were randomly divided into three groups in average. The expression of hypoxia-inducible factor-1α (HIF-1α) was detected by Western blot and immunohistochemical analysis respectively. HIF-1α was expressed in the experimental group, and the positive rate was significantly higher than that of either the sham or the control group (P < 0.05). The apoptosis index (AI) of epididymal epithelium was higher in the experimental group (7.25 ± 2.56) than that in either the sham (0.52 ± 0.57, P < 0.01) or the control group (0.08 ± 0.13, P < 0.01). Additionally, the levels of sialic acid and carnitine were lower in the experimental group than that in either the sham or the control group (P < 0.05) and were significantly negatively correlated with HIF-1α expression (r = -0.620, P = 0.014, and r = -0.610, P = 0.016 respectively). It is concluded that left-side varicocele could cause epididymal hypoxia and epididymal dysfunction. Moreover, HIF-1α maybe act as useful factor to predict germ cell apoptosis in varicocele.
19 citations
TL;DR: Differences in the apparent expression levels of CEA, CA153 and CA125 in patients with nipple discharge and healthy persons were validated and suggest that CEA and CA153 might potentially be useful in the differential diagnoses of benign tumors and breast cancer.
Abstract: Background
The aim of this study was to assess the diagnostic values of three breast tumor markers (i.e., CEA, CA153 and CA125) in milk and nipple discharge in the prediction of different breast diseases diagnoses.
17 citations
TL;DR: A new method based on an augmented Lagrangian function and the Stochastic Gradient and the Finite Difference for nonlinear constrained production optimization is proposed, which can accelerate computation and improve accuracy of the approximate gradient.
17 citations
TL;DR: Wang et al. as discussed by the authors analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings.
Abstract: With concealment and hysteresis, water-inrush from Karst collapse column has become an important security hazard of lower group coal mining in North China. Based on the MTS815.02 seepage test system, we analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings. The results show that: (1) The permeability of collapse column fillings is of the order of 10−16–10−15 magnitude and decreases with an increase in consolidation pressure and decrease in initial moisture content. (2) The essence of filling seepage law change is the change in porosity, and a power function relationship exists between the permeability ratio and porosity ratio. (3) With increasing confining pressure, the permeability of fillings decreases. However, under low confining pressure (1.2–4 MPa), the change of confining pressure has no obvious influence on the permeability.
15 citations
15 citations
28 Oct 2016
TL;DR: A new algorithm is designed to solve Multiple Traveling Salesman Problem (MTSP) that avoiding the path intersection among the traveling salesmen by combining the K-means algorithm and genetic algorithm.
Abstract: In this paper, a new algorithm is designed to solve Multiple Traveling Salesman Problem (MTSP) that avoiding the path intersection among the traveling salesmen. There are three objectives in this problem including the shortest path of every salesman, the balance of each salesmans task and avoiding the crosses of each routes. We combine the K-means algorithm and genetic algorithm. K-means algorithm is designed to divide all points into several subsets and choose the start city for the genetic algorithm, and then using GA to process every subsets in parallel. This method not only achieve these multiple objectives, but also use much less time, since we have divided all the points into several parts and make them calculated at the same time.
15 citations
TL;DR: In this paper, a two-stage history matching procedure was proposed to increase the precision, firstly matching the facies distribution and then adjusting the continuous petrophysical parameters based on the updated facies distributions.
TL;DR: The low-frequency transducer was more sensitive than the high-frequency Transducer in breast CEUS using SonoVue as the contrast agent, and a new contrast agent with a higher resonance frequency, specially designed for high- frequency transducers, may be helpful in improving the clinical value of Breast CEUS.
Abstract: Objective:To explore the effectiveness of different transducers in breast contrast-enhanced ultrasound (CEUS) using SonoVue® (Bracco, Plan-Les-Ouates, Switzerland) as the contrast agent.Methods:Breast CEUS was performed in 51 patients with 51 breast lesions using a low-frequency transducer (probe C5-1) and a high-frequency transducer (probe L12-5) separately. All image processes were reviewed for the presence of local blood perfusion defects and surrounding vessels. McNemar's test was conducted to compare the detection effectiveness between these two transducers.Results:Pathological results revealed 38 malignant and 13 benign lesions. The two transducers showed no difference in detecting benign lesions. Among malignant lesions, CEUS conducted by probe C5-1 (frequency range from 1 to 5 MHz) presented 23 (60.5%) lesions with local blood perfusion defects and 26 (68.4%) lesions with surrounding vessels. Meanwhile, probe L12-5 (frequency range from 5 to 12 MHz) showed only 12 (31.6%) lesions with local blood ...
TL;DR: Zhang et al. as discussed by the authors determined the instantaneous rock drillability according to the operating conditions of a drifter, which is an engineering requirement in coal mines, and this idea is the motivation for the present research study.
Abstract: Groundwater inrush and gas outburst pose serious threats in the coal industry of China (Bai et al. 2013). Among the many measures taken to prevent such risks, borehole drilling is the most widely used preventive measure. Many cases have shown that the accidents frequently occur near the zones of the geological conditions undergoing great change, such as faults and lithological interfaces. In practice, there are currently two methods used to determine these geological conditions. The first method is by using a drilling core, and the other is by an estimation according to the stone dust produced during the drilling of the boreholes. Since the first method has been found to be inefficient, the second method is the most widely used. However, the results of the second can be heavily influenced by the method operators. With regard to different rock types, the operating parameters of a drifter, such as the rotation and penetration velocities, may vary. Therefore, it may be possible to assess the rock drillability and geological conditions based on the operating parameters of a drifter. This idea is the motivation for the present research study. The previous rock drillability indices (Zare and Bruland 2013) were indirect measures of the rock drillability, and determined based on the laboratory tests of rock cores. Only a few research studies have focused on the determination of the instantaneous rock drillability according to the operating conditions of a drifter, which is an engineering requirement in coal mines (see aforementioned statement), and this is the subject of the present study.
27 Jun 2016
TL;DR: This paper proposes a novel framework using probabilistic matrix factorization technique to predict retweeting behavior and proposes a set of metrics to construct the embeddings among messages based on messages' structural and textual features.
Abstract: Retweeting is an important mechanism for information diffusion, popular event prediction, and so on. Due to the increasing requirements, in recent years, the task has attracted extensive attentions. In this paper, we propose a novel framework using probabilistic matrix factorization technique to predict retweeting behavior. Our study consists of three components. First, we convert retweeting behavior problem to a matrix factorization problem. Second, following the intuition that a user's social network will affect his retweeting behavior, we extensively study how to model social information to improve the prediction accuracy. Finally, message semantic embedding information is employed in designing a semantic regularization term to constrain the matrix factorization objective function. We also propose a set of metrics to construct the embeddings among messages based on messages' structural and textual features. The empirical results and analysis demonstrate that our methods perform better than the state-of-the-art approaches.
TL;DR: In this article, three kinds of inorganic alkali are introduced into tetraethylenepentamine (TEPA) and polyethyleneimine (PEI)-modified MCM-41 as the CO2 adsorbents.
Abstract: Three kinds of inorganic alkali are introduced into tetraethylenepentamine (TEPA) and polyethyleneimine (PEI)-modified MCM-41 as the CO2 adsorbents. X-ray diffraction, N2 adsorption, fourier-transform infrared and thermo gravimetric analysis are used to characterize the surface structures and the thermal stability of adsorbents. Chemical titration method is used to measure the alkali amounts of adsorbents. Thermo-gravimetric analysis with 10% CO2/90% N2 as the simulated flue gas is used to test the CO2 adsorption performance of adsorbents. The results show that all three kinds of inorganic alkali-containing adsorbents exhibit higher CO2 adsorption capability than traditional TEPA and PEI modified samples. Ca(OH)2 and PEI modified samples exhibit the highest adsorption capacity and recyclable property. The introduction of inorganic alkali changes the chemical adsorption mechanism between CO2 and adsorbent surface due to the increased hydroxyl groups. The CO2 adsorption capacities have a linear dependence relation with the alkali amounts of adsorbents, indicating that alkali amount is a critical factor for the exploration of novel adsorbents.
TL;DR: A novel mapping algorithm with power-aware optimization for NOC that can reduce the power consumption in communication and the performance enhanced is proposed.
TL;DR: A hierarchical grid based method is proposed to define location ID, and location's property is taken full advantage of when extracting features, in which way to exploit users' spatial information more sufficiently.
TL;DR: Using physical model simulation, the paper investigates the bearing characteristics of the reinforced rock under different bolt parameters with incrementally increased load, finding that increasing the density of the bolt support and the length and diameter of the bolts improves the load-bearing performance of the reinforcing rock, including its strength, internal peak stress, and residual stress.
Abstract: Roadways supported by bolts contain support structures that are built into the rock surrounding the roadway, referred to as reinforced rocks in this paper. Using physical model simulation, the paper investigates the bearing characteristics of the reinforced rock under different bolt parameters with incrementally increased load. The experimental results show that the stress at the measurement point inside the structure varies with the kinetic pressure. The stress increases slowly as the load is initially applied, displays accelerated growth in the middle of the loading application, and decreases or remains constant in the later stage of the loading application. The change in displacement of the surrounding rock exhibits the following characteristics: a slow increase when the load is first applied, accelerated growth in the middle stage, and violent growth in the later stage. There is a good correlation between the change in the measured stress and the change in the surrounding rock displacement. Increasing the density of the bolt support and the length and diameter of the bolt improves the load-bearing performance of the reinforced rock, including its strength, internal peak stress, and residual stress. Bolting improves the internal structure of the surrounding rocks, and the deterioration of the surrounding rock decreases with the distance between the bolt supports.
17 Dec 2016
TL;DR: The hybrid algorithm is proposed in order to use the advantages of both of the two algorithm, PSO and ACO, to achieve the design target with fast and accurate search.
Abstract: Particle swarm optimization (PSO) and Ant Colony Optimization (ACO) are two important methods of stochastic global optimization. PSO has fast global search capability with fast initial speed. But when it is close to the optimal solution, its convergence speed is slow and easy to fall into the local optimal solution. ACO can converge to the optimal path through the accumulation and update of the information with the distributed parallel global search ability. But it has slow solving speed for the lack of initial pheromone at the beginning. In this paper, the hybrid algorithm is proposed in order to use the advantages of both of the two algorithm. PSO is first used to search the global solution. When it maybe fall in local one, ACO is used to complete the search for the optimal solution according to the specific conditions. The experimental results show that the hybrid algorithm has achieved the design target with fast and accurate search.
TL;DR: The construct had a phenotype similar to that of normal cornea, and integrated well with the implanted host corneal tissue, and the implant cornea maintained transparency in the 6-month follow-up, although there was a slight haze in the central cornea area.
Abstract: The aim of this study was to construct a rabbit anterior corneal replacement for transplantation using acellular porcine corneal matrix (APCM) and rabbit epithelial or stromal cells. APCM was prepared from fresh porcine cornea treated with 0.5% (wt./vol.) sodium dodecyl sulfate (SDS) solution. The expanded stromal cells were first injected into APCM parallel to its surface and were cultured in a shaking culture system for 7 days to obtain the stromal construct. Next, corneal epithelial cells were cultured on the stromal construct surface for another 7 days to obtain rabbit anterior corneal lamella. The construct had a phenotype similar to that of normal cornea, with high expression of cytokeratin 3 in the epithelial cell layer and vimentin in the stromal cells. More importantly, the construct integrated well with the implanted host corneal tissue, and the implant cornea maintained transparency in the 6-month follow-up, although there was a slight haze in the central corneal area. The endothelium in the surgery cornea had a similar cell density and mosaic pattern with normal cornea as shown by confocal laser corneal microscopy, and the regenerated corneal epithelial cells on the implant surface showed a similar morphology to that of natural epithelial cells. These results demonstrate that the constructed anterior corneal replacement exhibits an excellent biological property for lamellar keratoplasty and might be a possible alternative to human corneal tissue in the future.
29 Aug 2016
TL;DR: A novel feature selection which is based on Multiple Twin Bound Support Vector Machines Recursive Feature Elimination (MTWSVM-RFE) is proposed and results showed that the proposed method detect the region of architecture distortion with high accuracy.
Abstract: Architecture distortion is one of the most common signs of breast cancer in mammograms, and it is difficult to detect due to its subtlety. Computer-Aided Diagnosis (CAD) technology has been widely used for the detection and diagnosis of breast cancer. In this paper, Gabor filters and phase portrait analysis are used to locate suspicious regions based on the image characteristic of architectural distortion. Twin bounded Support Vector Machine (TWSVM), a kind of binary classifier, is employed reduce the large amounts of false positives. In this paper, we proposed a novel feature selection which is based on Multiple Twin Bound Support Vector Machines Recursive Feature Elimination (MTWSVM-RFE). The results showed that our proposed method detect the region of architecture distortion with high accuracy.
TL;DR: In this paper, a modified borehole jack has been designed in the present research, which overcomes the drawbacks of the Goodman jack, such as the bending of the platens induces extra values in the displacement gauges (LVDTs), which causes the calculated modulus to be smaller than the actual figure.
17 Dec 2016
TL;DR: A novel task scheduling algorithm is proposed for multi-core systems based on optimized particle swarm algorithm, which is used to find the optimal solution for the task scheduling.
Abstract: Multi-core processors have been the mainstream in computer architecture. It also provides the enhancement of the parallelism degree of multiple tasks. An emerged challenge is how to schedule the multiple tasks to the cores for high efficiency. In this paper, a novel task scheduling algorithm is proposed for multi-core systems. This algorithm is based on optimized particle swarm algorithm, which is used to find the optimal solution for the task scheduling. The experimental results have showed that the proposed algorithm can improve the efficiency of task scheduling for multi-core systems.
TL;DR: In this article, an effective parallel hybrid genetic algorithm is proposed, which consists of genetic algorithm and a local optimization strategy for solving maximum clique problem, which is implemented parallel on OpenCL.
Abstract: The maximum clique problem is to find the maximum sized clique of pairwise adjacent vertices in a given graph, which is a NP-Complete problem. In this paper, an effective parallel hybrid genetic algorithm is proposed, which consists of genetic algorithm and a local optimization strategy for solving maximum clique problem. In this algorithm, selection, crossover, mutation, fitness evaluation and replacement operators are implemented parallel on OpenCL. In addition, we have tested our algorithm by using a set of benchmark instances from the DIMACS graphs. The comparison results shows that the implementation on GPU provide better performance that CPU, even when the benchmark graphs become more large and complicate.
22 Aug 2016
TL;DR: In this article, three kinds of inorganic alkali are introduced into tetraethylenepentamine (TEPA)- and polyethyleneimine (PEI)-modified MCM-41 as the CO2 adsorbents.
Abstract: Three kinds of inorganic alkali are introduced into tetraethylenepentamine (TEPA)- and polyethyleneimine (PEI)-modified MCM-41 as the CO2 adsorbents. FT-IR and TGA are used to characterize the surface groups and the thermal stability of adsorbents. Chemical titration method is used to measure the alkali amounts of adsorbents. Thermo-gravimetric analysis with 10% CO2/90% N2 as the simulated flue gas is used to test the CO2 adsorption performance of adsorbents. The results show that all three kinds of inorganic alkali-containing adsorbents exhibit higher CO2 adsorption capability than traditional TEPA and PEI modified samples. Ca(OH)2 and PEI modified samples exhibit the highest adsorption capacity and recyclable property. The introduction of inorganic alkali changes the chemical adsorption mechanism between CO2 and adsorbent surface due to the increased hydroxyl groups. The CO2 adsorption capacities have a linear dependence relation with the alkali amounts of adsorbents, indicating that alkali amount is a critical factor for the exploration of novel adsorbents.