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Stability diagrams are of great importance for investigating deoxidation equilibrium and controlling inclusions in molten steel. Combined with programming for calculation and drawing, the three-dimensional stability diagrams of MgO, MgO·Al2O3, and Al2O3 in the Fe–Al–Mg–O system were successfully drawn, which can visually explain the meaning of the iso-oxygen contours and the borderlines among different phases. They also offer straight evidence that the borderline method is imperfect. The three-dimensional stability diagrams can visually show more vital details that cannot be illustrated by the iso-oxygen contours. The most significant advantage of three-dimensional stability diagrams is not only judging the most stable phase in the specific component area but also visually showing the transformation trend among the phases from a three-dimensional perspective, especially when the equilibrium surfaces of these phases are relatively close. Besides, an interesting transformation of inclusions in the Fe–Al–Mg–O system was found. When the magnesium content is higher than 0.0065% and the aluminum content is lower than 0.21%, the equilibrium products of aluminum-magnesium composite deoxidation may be transformed from MgO to MgO·Al2O3 and Al2O3 in turn, which can be directly observed from the three-dimensional stability diagram based on the calculations.

The growth control and enrichment of Si crystals using Si-50 at.% Sn melts via upwards and downwards directional solidification at various moving rates was investigated. As expected, a large area of quasi-bulk Si (98.6% enrichment percentage) was successfully obtained at the 0.01 mm/min upwards moving rate. Moreover, after HCl leaching, the residual at.% of Sn in the enriched Si area was easily reduced to the 0.00132–0.00163 range, which was almost the same as that for the solid solubility of Sn in Si. Furthermore, a model was established to explain the crystal growth process and enrichment mechanism during directional solidification. In conclusion, we chose the upwards moving direction for the follow-up experiments, which solved the most critical first step of using Si-based alloy solvent refining to produce solar grade Si.

Cleanliness control in steel has always been a topic discussed by researchers. Many methods were used to remove residual elements from steel. Adding rare earth elements to molten steel is one of the potential ways. However, to remove arsenic from steel using lanthanum, many issues need considerations. The effects of steel-crucible reactions, vaporation, and slags on the removal of arsenic from the molten steel were investigated. The results show that using the alumina crucible is more conducive to removing arsenic from the molten steel by rare earth elements, because LaAlO3 can inhibit the further reactions between lanthanum and the crucible. Magnesia crucible, however, does not have similar effects. BN crucibles drop powders and decrease the cleanliness of steel. Besides, when the concentration of arsenic is low, arsenic can be barely removed by volatilizing under normal pressure. Furthermore, due to the existence of the interfacial tension, the molten slag is easy to separate from the molten steel and makes the fluidity of slag become worse. Although the molten slag can remove arsenic from the molten steel to some extent, it also has harmful corrosion effects on the crucibles.

Cleanliness control is an eternal theme to improve the properties of steel products. With the increasing recycling rates of scrap steel, the removal and stabilization of residual elements have become a vital issue for improving the performance of steel products. Thermodynamic and mismatch calculations plus laboratory experiments were carried out to study the heterogeneous nucleation phenomena of inclusions when lanthanum was employed to remove arsenic from molten steel and stabilize arsenic in solid steel. The effect of heterogeneous nucleation on the mechanism of arsenic removal was discussed. A series of heterogeneous nucleation phenomena of inclusions in the La-O-S-As system were discovered, and the heterogeneous nucleation among the inclusions turned out to be selective. As the vital product of arsenic removal, La-S-As is most likely to generate with LaS as heterogeneous nucleation cores, and its possible chemical formula turned out to be 3LaS⸱LaAs. Sulfur plays an essential role in removing arsenic from molten steel by adding lanthanum. It needs to control the initial sulfur content in an appropriate range, because the high initial content causes too much loss of rare earth, and the low initial content cannot produce LaS and La-S-As.

Trace element arsenic is detrimental to the quality and properties of steel products. We used lanthanum to modify the distribution of arsenic by the formation of arsenic rare earth inclusions and investigated all inclusions on the full profile of the ingots prepared in the laboratory. The results show that the addition of lanthanum has dramatically influenced the distribution of arsenic in the ingots by the formation of arsenic inclusions. The arsenic inclusions turn out to be mainly the cluster-shaped La-S-As, as well as its composite inclusions combined with LaS and La-As. La-S-As can be considered a solid solution of LaS and LaAs. They distribute mainly at the top surface of the ingots within 3 mm, at the side and bottom surfaces within 1.5 mm, leading to a dramatic decrease of arsenic concentration at the inner part of the ingots. This distribution characteristic of La-S-As can be used to manufacture steel ingots with very low arsenic concentration by peeling off these (La-S-As)-containing layers. On the contrary, the distribution of composite inclusions (La-S-As)-(La-As) and single-phase La-As, is uniform. Except for the reaction with arsenic, lanthanum can also react with phosphorous and antimony to modify the existing state of these trace elements.

It is a feasible method to improve the quality of steel products by adding rare earth to change the state of arsenic in steel to avoid its harm. In this study, the As-bearing rare earth inclusions in steel were extracted by non-aqueous electrolysis method, and their types were fully understood. Wagner activity model and non-equilibrium solidification model were used to calculate the formation process of rare earth inclusions in liquid and solidification process. The formation mechanism of single-phase and complex As-bearing rare earth inclusions was verified by laboratory experiments. The results showed that La2O3 and La2O2S were formed in the liquid phase, then the As-bearing rare earth inclusions La–S–As and La–As began to form during the solidification process of steel liquid. The composite inclusions of La–O–S–As with distinct stratification were further precipitated.

The formation of RE-O-S-As inclusions is an inevitable issue when rare earth (RE) elements are used to modify the existing state of residual element arsenic. The evolution process of La-O-S-As inclusions in high carbon steels was investigated under conditions of different La contents. An in-situ sample preparation method was used to prepare film samples. The results show that it is practical to add RE elements to stabilize arsenic by generating As-bearing RE inclusions. A new type of As-bearing RE inclusion was discovered and identified as LaAsO4. As La content increased from 0.003 to 0.089 wt pct, the dominant inclusions of the La-O-S-As system changed from La2O3 to La2O2S, then to La2O2S-LaAsO4, and finally to LaAsO4. A full model of the inclusion formation of the RE-O-S-As system was also established to describe what kind of inclusion to form in conditions of different atomic ratios of RE/O and RE/S. The first As-bearing RE inclusion is RE-O-As or RE-S-As, and RE-O-S-As inclusions can be controlled to form certain inclusions that make O and S useful to modify the existing state of arsenic.

This paper reviews the definition methods of active and reactive powers for three-phase power system, and proposes a new power definition method based on Tan-Sun coordinate transformation system, where the parameters in the power definition formulas can all be acquired in real time, so as to improve the accuracy and response speed of power calculation for three-phase unbalanced power system.

The black start process is very important for smart microgrids. In order to ensure that the output current of the grid-connected inverter is synchronized with the grid voltage, the phase-locked loop is used to lock the detected grid voltage and it is used as a reference voltage. The bandwidth of the phase-locked loop affects the instantaneous phase difference between the grid-connected inverter and the grid, which in turn affects the stability of the grid-connected system. In order to ensure the stability of the system under weak grid, the impedance model of the droop control inverter is first derived. An impedance model of the inverter waiting to be connected in parallel with the system is then established, which includes a voltage-current closed loop and a phase locked loop. Based on the impedance stability criterion, the inherent causes of the instability of the parallel process are discussed, and the dynamic parallel process and the final operating state are linked. The experimental results verify the effectiveness of the method.

The formation of RE-O-S-As inclusions and corresponding arsenic content of equilibrium solid solubility were two core issues concerned when adding rare earth to restrain the harm of residual arsenic in steel. In this paper, some databases of rare earth inclusion were supplied. The influence of different La content on the formation of inclusions during solidification of As-bearing steel was calculated. The results showed that with the increase of rare earth content, the original inclusions MnS, Al6Si2O13 and Mn2Al4Si5O18 in steel were replaced by La2Al2O6, La2O2S, La2S3, La3S4 and LaS. The formation mechanism of As-bearing rare earth inclusions was analysed under the condition of excess rare earth, and the results showed that the As-bearing rare earth inclusions were formed during the solidification process due to enrichment of solidification frontier elements.

In order to determine strategies for removing arsenic from rare earth arsenic-containing steels, the evolution of inclusions in the whole steelmaking process with alumina crucibles was investigated. It has been proven that adding lanthanum has a significant effect on both the existing state and content of arsenic in steel. The content of arsenic steeply decreased after adding 0.148% lanthanum by generating La&ndash, S&ndash, As inclusions. The addition of 0.054% lanthanum did not dramatically affect the content of arsenic. Both 0.148% and 0.054% additions of lanthanum modified the existing Si&ndash, Mn&ndash, Al&ndash, O inclusions, making them first change to La-containing inclusions, and then change back to Si&ndash, O inclusions. During this process, the compositions of inclusions changed from (SiO2&ndash, MnO)-rich to Al2O3-rich ones, owing to the reactions between lanthanum and alumina crucibles. The addition of 0.148% lanthanum resulted in a relatively severe reaction with the alumina crucible. This led to the decomposition of a part of the existing La&ndash, As inclusions and a slight increase in the arsenic content. Therefore, it is noted that choosing an appropriate holding time after adding rare earth elements to molten steel has a significant effect on the arsenic removal and saving the consumption of rare earth elements.

In order to precise control the breeding process and monitor layer healthy growth in real time online, the design scheme of the environment monitoring system based on Internet of things was put forward on the main environmental parameters that affect the growth of layer. And according to the layer environment characteristics, the appropriate sensor and sensor placement were chose. By using RS-485 bus technology the information acquisition module, display module, communication interface and control interface monitoring terminal were built up. For the wiring is not conducive to the place in the layer room, its environmental information preclude the use of wireless sensor networks. In order to obtain the perceived data more accurately and effectively, loss-based retransmission detection based on the ACK scheme is adopted in the wireless sensor network. Experimental results show that this method can effectively improve the reliability of the data.

Ligament geometry is crucial to surgical treatment success in anterior cruciate ligament (ACL) injury. This study aimed to optimize the MRI technique to elucidate the geometry of the patellar ligament (PL) and ACL in vivo. A 1.5-T superconducting MRI system with a special surface coil and fast spin echo was used to acquire high-resolution T1-weighted images (H-T1WI) of the ACL. The sagittal plane angle was 10° to 15° towards the inner side of the vertical line of the tangent line axis of the femoral intercondylar fossa. The H-T1WI images of the PL were centered at the lower margin of the patella and the center of the tibial tuberosity. The lengths of the PL and ACL were measured using a Radworks 5.1 workstation. ACL and PL lengths were compared between left and right knees and between genders, and left PL length measurements obtained separately by three doctors underwent correlation analysis. The quality of the images satisfied the clinical measurement requirements. The duration of sagittal image acquisition was 2 min and 25 s. The average PL length was 42.20 ± 4.21 and 40.15 ± 4.00 mm, and the average ACL length was 36.98 ± 4.12 and 35.80 ± 4.67 mm, in male and female subjects, respectively. The intraclass correlation coefficients of the PL lengths obtained by the three specialists were greater than 0.997. This MRI technique provides highly stable and repeatable in vivo data of PL and ACL geometry relevant to ACL reconstruction surgery with PL grafts.

The present study retrospectively examined 24 cases of pathologically confirmed synovial sarcoma and analyzed the clinical presentation and imaging findings in order to explore the imaging features of synovial sarcoma. The majority of the lesions were large (>5 cm; 88%), rounded or lobulated, relatively well-defined tumor masses in the extremities near the joints or deeply located. On computed tomography (CT) scans, the lesions demonstrated intensity signals similar to those of muscle. Six cases exhibited punctate calcification in the periphery of the tumor. On T1-weighted images, the largest lesions of >5 cm, were usually heterogeneous, with a signal intensity similar to or slightly higher than that of muscle. On T2-weighted images, heterogeneous high-intensity or slightly high-intensity signals were observed, with 12 cases exhibiting a high signal consistent with hemorrhage and 12 presenting signals that indicated internal septations. Contrast-enhanced scanning revealed heterogeneous enhancement in the majority of the lesions and no enhancement in areas of cystic necrosis or internal septations. Synovial sarcoma has specific imaging features, and comprehensive analysis of CT and magnetic resonance imaging can improve the accuracy of the pre-operative diagnosis.

Computer software size continues to grow recently. But it is difficult to collect information to support software development and maintenances. Data mining technology can be used to automatically discover knowledge from software testing data. It is helpful to increase software developing process and improve software quality. At first, correlation analysis is adopted to study the relevance among the software parameters. Subordination ingredients are eliminated; software parameters are pretreated according to parameter correlation. Software size, testing case number and testing defect number are kept down as analysis object. Association rule algorithm can't be applied to deal continuous quantity. Thus testing case density per hundred line and defect density per thousand line are introduced and dispersed to build the analyzing model. Next, Apriori algorithm is used to construct association rule algorithm model. By iterative analysis, construct associations are obtained between testing case density and defect density. Finally, this paper analyzed the construct associations and discussed their purposes.

A Maglev system with delayed acceleration feedback control is disturbed by the deflection of flexible guideway, and resonant response may take place. We have investigated sup-resonant response of the Maglev system by employing center manifold reduction and the method of multiple scales. We present the dynamic model and expand it to a third-order Taylor series. Taking time delay as its bifurcation parameter, we discuss the condition for the occurring of Hopf bifurcation. We apply center manifold reduction to get the Poincare normal form of the nonlinear system and employ the perturbation technique to study sup-resonant response of the system. This yields the sup-resonant periodic solution of the normal form. We analyze the stability condition of the free oscillation in the solution and discuss the relationship between guideway excitation and periodic solution. Finally, numerical results show how time delay, control, and excitation parameters affect the system response. With the proper system parameter, the free oscillation may vanish and only the periodic solution plays a part. Time delay can control amplitude of the forced oscillation. The appearance of the chaos phenomenon can also be governed by regulating time delay. And judiciously selecting a control parameter makes it possible to suppress the response.

The response of the guideway induced by moving maglev vehicle is investigated in this paper. The maglev vehicle is simplified as evenly distributed force acting on the guideway at constant speed. According to the experimental line, the guideway structure of rail–sleeper–bridge is simplified as Bernoulli–Euler (B–E) beam—evenly distributed spring—simply supported B–E beam structure; thus, double deck model of the maglev guideway is constructed which can more accurately reflect the dynamic characteristic of the experimental line. The natural frequency and mode are deduced based on the theoretical model. The relationship between structural parameters and natural frequency are exploited by employing the numerical calculation method. The way to suppress the vehicle–guideway interaction by regulating the structural parameter is also discussed here. Using the normal coordinate transformation method, the coupled differential equations of motion of the maglev guideway are converted into a set of uncoupled equations. The closed-form solutions for the response of the guideway subjecting the moving load are derived. It is noted that the moving load would not induce the vehicle–guideway interaction oscillation. The analysis of the guideway impact factor implies that at some position of the guideway, the deflection may decrease with the increase of the speed of the load; several extreme value of the guideway displacement will appear induced by different speeds, with different acting place, the speeds are different either. The final numerical simulation verifies these conclusions.

Using software testing data collected, this paper established a software safety defects S curve model based on Weibull model theory. χ2 testing and prediction error testing are employed to verify the matching ability of the Weibull model and applicability of the predicting result. How to select truncation error is also discussed here. Results show that better predictive effect can be achieved if computational formula of truncation error is properly adjusted. The application of predicting model was also developed in this paper. Small sample fault data prediction and predicting error problems are discussed here. If the amount of fault data accumulated is not big enough, prediction cannot carry out. Analyzing results point out that it can be solved through the combination of different types of data. Then variation tendency of small sample fault data can be predicted.

Magnetic field has a great effect on the crystallization behavior of mold flux and properties of the flux film between mold and strand, on which the surface quality of strand was deeply depended in continuous casting process. Therefore, studying the change law of the crystallization properties of mold flux in magnetic field is of great significant. In the present work, based on intensity of the applied magnetic field with the range from 0mT to 60mT, the crystallization ratio, crystal size and mineralogical phases of the flux film were discussed. The results show that crystallization ratio increases with the increasing magnetic field intensity, and the crystal size becomes bigger at the same time. The magnetic field promotes the crystallization ratio and growth speed of the crystallized grains of mold flux. However, magnetic field doesn’t change types of the mineralogical phases.

The Drum-Tower District is a historic site in the Inner place of Tianjin which represents the commercial culture, ecdemic culture, exotic culture and civilian culture of Tianjin. The buildings of this region are usually made of wood and other highly combustible materials. Once there be a fire, the influence will be very serious. The study of fire spread model Drum-Tower District is necessary. In the model of fire spread the cellular automaton rules were used. The effects of the different influence coefficients on the evacuation time were investigated, and the typical characteristics of space-time dynamics were analyzed. The numerical simulations show that the model is very good and can be used as a tool to predict fire.

Subarachnoid hemorrhage (SAH), one of the serious types of stroke incurred by bleeding into the space surrounding the brain, occurs when brains are deprived of oxygen by various factors, particularly an interruption to the blood supply or a ruptured aneurysm. Cerebral vasospasm (CVS) is one of the most common complications of SAH. It has been proposed that platelet‑derived growth factor (PDGF) is involved in CVS. The aim of the present study was to analyze expression of PDGF in rabbit models of CVS. Post-SAH CVS rabbit models were created using endovascular puncture and employed to analyze the expression patterns of PDGF by enzyme-linked immunosorbent assay and immunohistochemistry. The results indicated that the creation of the rabbit model of CVS induced using endovascular puncture was successful and demonstrated the double phase changes observed in human CVS. The acute stage started at 12 h post-SAH with narrowing of the vascular lumen diameter. This narrowing appeared again on the seventh day in delayed CVS alongside increased thickness of vessel walls. PDGF-β expression was observed in vascular smooth muscle cells of the rabbit models. PDGF-β was expressed as early as 3 h post-SAH, it was evident after 1 day and reached a peak in 7 days, suggesting that PDGF-β is involved in the early stages of CVS. In the current study, it was confirmed that PDGF-β expression was present in the rabbit models of CVS, which may aid the elucidation of the pathogenesis of CVS, and also provide useful information for diagnosis and treatment of CVS.

The aim of this study was to obtain geometric data of in vivo patellar ligament (PL) and anterior cruciate ligament (ACL) by MRI and to analyze the correlation of the two with body weight, height and gender. A total of 157 cases with normal sagittal images of bilateral PL and ACL were enrolled. The PL and ACL lengths in the images were measured using the Radworks 5.1 application. The intraclass correlation coefficient for the data measured independently by three doctors was 0.997–1.000. In individuals aged 15–24 years, the values of PL and ACL length and the PL to ACL ratio were 43.95±4.25 mm, 38.45±4.62 mm and 1.15±1.09 in males and 42.03±0.94 mm, 36.00±1.06 mm and 1.18±0.1 in females, respectively. In individuals aged 25–64 years, the values in males were 40.99±4.45 mm, 36.06±3.74 mm and 1.14±0.09 and in females were 39.84±0.64 mm, 36.50±0.81 mm and 1.11±0.02, respectively. In individuals aged ≥65 years, the values in males were 41.43±3.08 mm, 36.62±3.44 mm and 1.15±0.09 and in females were 38.94±0.79 mm, 34.36±0.85 mm and 1.13±0.07, respectively. There was a significant difference between PL and ACL length on the same side (P

The safety analysis process of a kind of signal indicating embedded software is shown in this paper. A quantitative method is presented to model and evaluate software safety. The basic theory frame of Finite State Machine (FSM), Markovian theory and definition of gray entropy are presented. FSM safety model of the embedded software is built. 1-step transition probability matrixes are constructed referencing transition probability matrix concept of Markovian theory. After that, the safety of the software and the whole embedded system are discussed in detail. The analysis indicates that improving safety of the software and system is a complicated work. Hardware, algorithms and training of the operators etc. are the aspects that need to be carefully regarded. It also shows the way to accurately measure the safety of the software. The analyzing results of the software are extended to a general situation. The safety of software is predicted by using 1-step transition probability matrixes. Finally, numerical calculation is applied to validate the above analysis.

this paper attempts to provide a new approach to discover conserved regions such as motifs in either DNA or Protein sequences. We not only use the idea of de Bruijn graphs, but also follow a parallel approach to solve this problem. The de Bruijn graph has been successfully adopted to solve problems such as local alignment and DNA fragment assembly. To accelerate the speed, our method harnesses the power of parallelism to discover the conserved regions in a DNA or protein sequence. We have found that the algorithm was successful in mining signals for larger number of sequences and at a faster rate when compared to some popular motif searching tools.

In this paper we introduced the Dynamic Particle Swarm Optimization (DPSO) algorithm to resolve graph's peaks in chromatographic analysis. To accelerate the convergence speed, clustering degree and evolution velocity, inertia weight was adopted. The algorithm was tested on both simulated and real overlapping chromatographic peaks. Results indicate that the presented algorithm has fast convergence speed, high accuracy and reliability, and in some cases better than existing techniques.

Since sequence alignment is an approximate matching process there is a need for good approximate algorithms. The process of matching in sequence alignment is generally finding longest common subsequences (LCS). However, finding a longest common subsequence may not be the best solution. This paper attempts to provide a fuzzy approach to multiple sequences alignment (MSA). It is attempted to improve the speed and flexibility of sequences identification. This algorithm is a hybrid algorithm for MSA. The algorithm involves Dynamic Programming (DP) technique to align sequences progressively. Fuzzy logic is used to increase the flexibility. We have found that the algorithm was useful and in some cases better than existing techniques.

Eukaryotic genomes are typically large and filled with both genes and multiple classes of repetitive DNA. The repetitive DNAs are a rapidly evolving genome component that can provide the raw material for novel selected functions and also indicate the mechanisms and history of genome evolution in any ancestral lineage. In order to facilitate a broader range of repeat analyses, we present a graph method for repeat family detection and characterization by using the sparse de Bruijn graphs. This program was written in JAVA and with numerous adjustable parameters. Testing of this program indicated that it can found all of the major repeats.

The linear model of the magnetic levitation system was built. The controller of the system was designed based on the optimal control theory. A state observer of the system was formed based on symmetry root locus (SRL) method. The mass of the model was uncertain; when the system was running on to the slope, the strike of the rail to the system can not be neglected. The traditional control algorithms wouldn't solve these problems effectively. The methods using state observer to optimize the control algorithms was given here. Simulation results show that it work well.