Application of variable-filtrating technique on fuzzy-reasoning neural network system predicting BOF end-point carbon content

Artificial intelligence techniques have been used to predict basic oxygen furnace(BOF) end-points. However,the main challenge is to effectively reduce the input nodes as too many input nodes in neural network increase complexity,decrease accuracy and slow down the training speed of the network.Simply picking-up variables as input usually influence validity of model.It is quite necessary to develop an effective method to reduce the number of input nodes whereby to simplify the network and improve model performance.In this study,a variable-filtrating technique combining both metallurgical mechanism model and partial least-squares(PLS ) regression method has been proposed by taking the advantages of both of them,i.e.qualitive and quantative relationships between variables respectively.Accordingly,a fuzzy-reasoning neural network(FNN) prediction model for basic oxygen furnace(BOF) end-point carbon content based on this technique has been developed.The prediction results showed that this model can effectively improve the hit rate of end-point carbon content and increase network training speed.The successful hit rate of the model can reach up to 94.12%with about 0.02% error range.

DIRECT TITRATION OF VERY WEAK ACIDS(BASES)IN AQUEOUS SOLUTION WITH STRONG BASES(ACIDS)USING VISUAL END-POINT INDICATION WITHOUT INDICATOR

This paper reports a new method of titration for very weak acids and bases using the appearance of incisions on oscillopolarogram to indicate the end-point.This method has the advantages of rapidity,simplicity,no indicator needed as well as good precision.

A MAXIMUM PRINCIPLE FOR DISTRIBUTED PARAMETER SYSTEMS WITH MIXED PHASE-CONTROL CONSTRAINTS ANDENDPOINT CONSTRAINTS

This paper considered the optimal control problem for distributed parameter systems with mixed phase-control constraints and end-point constraints. Pontryagin's maximum principle for optimal control are derived via Duboviskij-Milujin theorem.

On the Spectra of General Ordinary Quasi-Differential Operators and Their L2w-Solutions

In this paper, we consider the general ordinary quasi-differential expression τ of order n with complex coefficients and its formal adjoint τ+ on the interval [a,b). We shall show in the case of one singular end-point and under suitable conditions that all solutions of a general ordinary quasi-differential equation are in the weighted Hilbert space provided that all solutions of the equations and its adjoint are in . Also, a number of results concerning the location of the point spectra and regularity fields of the operators generated by such expressions may be obtained. Some of these results are extensions or generalizations of those in the symmetric case, while the others are new.

Isomeric pair 95m,g Nb in the photonuclear reactions on natMo at the bremsstrahlung end-point energy of 38–93 MeV

The ^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-line γ-ray spectrometric technique.The experimental isomeric yield ratio(IR) was determined for the reaction products ^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax) range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax)) and the IR for the isomeric pair ^(95m,g)Nb from the ^(nat)Mo(γ,xnp) reaction were calculated using the partial cross-sections σ(E) from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times) in the experimental IR relative to all theoretical estimates.

Prediction model of end-point phosphorus content for BOF based on monotone-constrained BP neural network

Dephosphorization is essential content in the steelmaking process,and the process after the converter has no dephosphorization function.Therefore,phosphorus must be removed to the required level in the converter process.In order to better control the end-point phosphorus content of basic oxygen furnace(BOF),a prediction model of end-point phosphorus content for BOF based on monotone-constrained backpropagation(BP)neural network was established.Through the theoretical analysis of the dephosphorization process,ten factors that affect the end-point phosphorus content were determined as the input variables of the model.The correlations between influencing factors and end-point phosphorus content were determined as the constraint condition of the model.200 sets of data were used to verify the accuracy of the model,and the hit ratios in the range of±0.005%and±0.003%are 94%and 74%,respectively.The fit coefficient of determination of the predicted value and the actual value is 0.8456,and the root-mean-square error is 0.0030;the predictive accuracy is better than that of ordinary BP neural network,and this model has good interpretability.It can provide useful reference for real production and also provide a new approach for metallurgical predictive modeling.

End-point dynamic control of basic oxygen furnace steelmaking based on improved unconstrained twin support vector regression

In order to improve the end-point hit rate of basic oxygen furnace steelmaking,a novel dynamic control model was proposed based on an improved twin support vector regression algorithm.The controlled objects were the end-point carbon content and temperature.The proposed control model was established by using the low carbon steel samples collected from a steel plant,which consists of two prediction models,a preprocess model,two regulation units,a controller and a basic oxygen furnace.The test results of 100 heats show that the prediction models can achieve a double hit rate of 90%within the error bound of 0.005 wt.%C and 15℃.The preprocess model was used to predict an initial end-blow oxygen volume.However,the double hit rate of the carbon con tent and temperature only achieves 65%.Then,the oxygen volume and coolant additi ons were adjusted by the regulation units to improve the hit rate.Finally,the double hit rate after the regulation is reached up to 90%.The results indicate that the proposed dynamic control model is efficient to guide the real production for low carbon steel,and the modeling method is also suitable for the applications of other steel grades.

Tonifying Qi and activating blood circulation in terms of Traditional Chinese Medicine: their effects in patients with myocardial infarction

OBJECTIVE: To investigate the effects of tonifying Qi and activating blood circulation(SQABC), a method in Traditional Chinese Medicine(TCM), on end-point events in patients with myocardial infarction(MI) in this retrospective cohort study.METHODS: Clinical data were obtained from the medical records of patients with acute MI(AMI),both during hospitalization and follow-up, and included general demographic information(age, gender, and contact information), TCM regimens used,and end-point events.RESULTS: A total of 1596 patients with AMI were enrolled to this study, but data of only 1210 casesare accessible till follow-up. We classified the patients based on the exposure levels of SQABC.When comparing the results between all exposure and non-exposure groups, significant differences were identified, both during hospitalization and follow-ups. During hospitalization, cardiac death(4.40% vs 21.55%, P < 0.05) and cardiac shock(3.04% vs 11.62%, P < 0.05) were significantly lower in the exposure group than the non-exposure group. Similarly, during the follow-up, cardiac death(12.04% vs 20.49%, P < 0.05), acute heart failure(7.27% vs 11.81%, P < 0.05), composite endpoint of reinfarction and stroke(9.11% vs 15.28%,P < 0.05), and rehospitalization due to angina(25.49% vs 34.38%, P < 0.05) were significantly lower in the exposure group than the non-exposure group.CONCLUSION: Our findings suggest that SQABC can significantly benefits the subjects in the management of high-risk AMI in them.

基于近红外光谱技术的大黄苏打片混合工艺终点判断方法的研究

目的:探究密度效应对模型性能的影响,旨在建立一种稳健性更好的模型来实现大黄苏打片混合终点的准确判断。创新点:通过将密度差异变量引入模型校正集中的方法,建立了一种稳健性更好的原辅料多组分定量校正模型。方法:利用15批样品建立包含密度效应和未包含密度效应的偏最小二乘回归校正模型,并利用模型对3个未知批次样品进行终点监测。同时,使用主成分分析-移动块标准偏差算法对3批样品混合终点进行定性判别。分别使用基于近红外光谱技术的定性、定量分析方法,实现对大黄苏打片混合终点进行准确监测的目的。结论:粉体密度效应对模型预测性能的提高起到了重要作用。与普通模型相比,本研究所开发的压力不敏感模型展示了更加稳健的预测性能,这种稳健建模策略具有一定的推广应用前景。

Isomeric ratio of the ^(181)Ta(γ,3n)^(178m,g)Ta reaction products at energy Eγmax up to 95 MeV

The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.

Cross-sections for the 27Al(γ,x)22Na multichannel reaction with the 28.3 MeV difference of reaction thresholds

The bremsstrahlung flux-averaged cross-sections(σ(Eγmax))and the cross-sections per equivalent photon(σ(Eγmax)Q)were first measured for the photonuclear multichannel reaction ^(27)Al(γ,x)22 Na at end-point bremsstrahlung gamma energies ranging from 35 MeV to 95 MeV.The experiments were performed with the beam from the NSC KIPT electron linear accelerator LUE-40 using theγ-activation technique.The bremsstrahlung quantum flux was calculated with the GEANT4.9.2 program and was also monitored via the ^(100)Mo(γ,n)^(99)Mo reaction.The flux-averaged cross-sections were calculated using the partial cross-sectionσ(E)values computed with the TALYS1.95 code for different level density models.Consideration is given to special features of calculating the cross-sections<σ(Eγmax)>and<σ(Eγmax)Q>for the case of the final nucleus ^(22)Na via several partial channels x:nα+dt+npt+2 n^(3) He+n2d+2 npd+2 p3 n.

Cross-sections of photonuclear reactions ^(65)Cu(γ, n)^(64)Cu and ^(63)Cu(γ, xn)^(63−x)Cu in the energy range E_(γmax) = 35–94 MeV

The flux-averaged cross-sections<σ(E_(γmax))>for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,^(63)Cu(γ,2n)^(61)Cu,and^(63)Cu(γ,3n)^(60)Cu have been measured within the bremsstrahlung end-point energy E_(γmax)range of 35–94 MeV.The experiments were performed with the electron beam from the NSC KIPT linear accelerator LUE-40 with the use of the activation and off-lineγ-ray spectrometric techniques.Theoretical calculation of the flux-average cross-sections<σ(E_(γmax))>_(th)was conducted using the cross-sectionσ(E)values from the TALYS1.95 code,run with default options.It is shown that the experimental average cross-sections for the reactions^(65)Cu(γ,n)^(64)Cu,^(63)Cu(γ,n)^(62)Cu,and^(63)Cu(γ,2n)^(61)Cu are systematically higher than the theoretical estimates based on the TALYS1.95 code.The obtained<σ(E_(γmax))values supplement the data of different laboratories for the(γ,n)and(γ,2n)reactions of^(63)Cu and^(65)Cu.For the reaction^(63)Cu(γ,3n)^(60)Cu,the values of<σ(E_(γmax))>were measured for the first time.