Numerical simulation on stress field of subsection welding of 2219 aluminum alloy flat

Numerical simulation of 2219 aluminum alloy flat under the condition of subsection welding or no subsection welding was analyzed by the double ellipsoidal heat source model. The result shows that the residual tensile stress of subsection welding appears in the weld and nearby areas while the peak value appears in the weld. The subsection welding can greatly increase the low stress area in the weld. Moreover, the contrast of stress between the subsection welding and no subsection welding shows that if the welding sequence, namely that the double ends of the weld are welded first and then the middle part is welded, is adopted in the subsection welding, the peak value of residual tensile stress can be greatly decreased.

Diagenetic evolution of clastic reservoirs and its records in fine subsection:significance and application

It was showed that understanding of the diagenetic modifications and its associated products in the deeply to ultra-deeply buried tight sandstone reservoirs(DUDTSR)is great important for reservoir characterization and hydrocarbon prediction.However,the fine characterization of diagenetic evolution via geologic modelling in tight sandstones remains a great challenge as for complexity of lithology,temperature,pressure and formation fluid throughout the entire life cycle of tight sandstone reservoirs.To help get a comprehensive idea of the distribution of diagenetic processes on the formation of DUDTSR in the long geological period,type-I and type-II fine sections of diagenetic stage for clastic reservoirs were creatively proposed and its essence was illustrated using the Paleogene Huagang(EH)Formation in the southern Xihu Sag.Through combination of both quantitative and qualitative methods which began with current formation temperature,vitrinite analysis,illite and I/S mixed layers based on analytical testing of the EH Formation,(1)Paleotemperature(T),vitrinite reflectivity and smectite in mixed layer during burial processes were restored based on numerical analysis,(2)The accurate division of diagenetic evolution was identified from coarse to fine process using new model,(3)And finally the geological significance of fine division of the conventional diagenetic stage was illustrated for low-porosity and tight sandstone reservoirs.

Nonlinear Resistance Circuit Subsection Linearity Decomposition Fitting Analysis

The analysis of circuits is frequently required in the electricity of physics. When analyzing circuits, the general idea is to study the issues related to nonlinear resistance circuits based on commonly used physical and electrical theory. Generally, circuits can be divided into linear resistance circuits and nonlinear resistance circuits. However, for some nonlinear resistance circuit, a small part of them are decomposed through subsection linearity while most of them are adopted the form of hieroglyph combination for subsection decomposition fitting analysis. For the following contents, the author will adopt curve layout method to analyze nonlinear resistance element and relation characteristics of voltage and current;to state the characteristics and nature of common electronic elements in our life, and concepts of concave resistance and convex resistance;to analyze the characteristics of nonlinear resistance circuits through electrical circuit analysis method based on the electrical theorem of physics;finally, to analyze referring to actual cases, study the veracity, verify the feasibility and scientificity of the adopted analytical approach, apply image graphics of the resistance circuits in the convenient way to solve complicated design problems among actual electrical problems.

Differences on Condition and Mechanism of Potash Deposited in O2 m5-6 Subsection of Northern Shaanxi Salt Basin

The Northern Shaanxi salt basin locates in the east of the Ordos basin.In this area,the thick layer salt sediment exists in the Majiagou Formation of Ordovician.Especial in the sixth subsection of the Majiagou fifth member,it

Roll Subsectional Cooling Adaptive Fuzzy Control Based on Fuzzy Model Inversion

Flatness is an important equality indicator of strip rolling and roll subsectional cooling is an important method for flatness control, especially for high order flatness component control. It is very hard to build the mathematic model of roll subsectional cooling because of its characteristics of nonlinearity, hysteresis quality and strong coupling, etc. In order to improve the control effect of roll subsectional cooling control model, the roll subsectional cooling adaptive fuzzy control model based on fuzzy model inversion is built according to the separation principle of fuzzy form on the basis of the conventional fuzzy control model, where the parameters of the fuzzy controller can be dynamically regulated according to the change of rolling conditions. Simulation experiment results of the model indicate that the proposed roll subsectional cooling adaptive fuzzy control model based on fuzzy model inversion has high control precision and rapid response speed with strong self-learning and anti-interference capacity and a new method is provided for high precision flatness control.

Flow resistance and its prediction methods in compound channels

A series of experiments was carried out in a large symmetric compound channel composed of a rough main channel and rough floodplains to investigate the resistance characteristics of inbank and overbank flows. The effective Manning, Darcy-Weisbach, Chezy coefficients and the relative Nikuradse roughness height were analyzed. Many different representative methods for predicting the composite roughness were systematically summarized. Besides the measured data, a vast number of laboratory data and field data for compound channels were collected and used to check the validity of these methods for different subsection divisions including the vertical, horizontal, diagonal and bisectional divisions. The computation showed that these methods resulted in big errors in assessing the composite roughness in compound channels, and the reasons were analyzed in detail. The error magnitude is related to the subsection divisions.

NEW NONSTANDARD JOB SHOP SCHEDULING ALGORITHM

Considering the complex constraint between operations in nonstandard job shop scheduling problem （NJSSP）, critical path of job manufacturing tree is determined according to priority scheduling function constructed. Operations are divided into dependent operations and independent operations with the idea of subsection, and corresponding scheduling strategy is put forward according to operation characteristic in the segment and the complementarities of identical function machines. Forward greedy rule is adopted mainly for dependent operations to make operations arranged in the right position of machine selected, then each operation can be processed as early as possible, and the total processing time of job can be shortened as much as possible. For independent operations optimum scheduling rule is adopted mainly, the inserting position of operations will be determined according to the gap that the processing time of operations is subtracted from idle time of machine, and the operation will be inserted in the position with minimal gap. Experiments show, under the same conditions, the result that operations are scheduled according to the object function constructed, and the scheduling strategy adopted is better than the result that operations are scheduled according to efficiency scheduling algorithm.

NEW HYDRAULIC ACTUATOR'S POSITION SERVOCONTROL STRATEGY

A new hydraulic actuator-hydraulic muscle （HM） is described, and the actuator＇s features and applications are analyzed, then a position servocontrol system in which HM is main actuator is set up. The mathematical model of the system is built up and several control strategies are discussed. Based on the mathematical model, simulation research and experimental investigation with subsection PID control, neural network self-adaptive PID control and single neuron self-adaptive PID control adopted respectively are carried out, and the results indicate that compared with PID control, neural network self-adaptive PID control and single neuron self-adaptive PID control don＇t need controlled system＇s accurate model and have fast response, high control accuracy and strong robustness, they are very suitable for HM position servo control system.

To our readers: Important questions from the editors/editorial board

This letter proposes updating the World Journal of Gastroenterology(WJG) with several new items and subsections and seeks the readers' input for these suggested changes. In order to further enhance the scope of the WJG, to make it more interactive, and to accommodate our readers' interest, the editors ask the readers for their input regarding potential new proposed changes and new subsections listed below:(1) new subsection-selected highlights from other related Baishideng Publishing Group world series journals;(2) new subsection-challenging images of the week-a quiz with an answer and references on another page;(3) to re-introduce or restore for some issues the cover page on which selected illustration;(4) new subsection-new hypotheses, new concepts and revisiting old concepts in a short, commentary format;(5) preview of the forthcoming issue articles(title and authors);(6) suggestions submitted by the readers-new topics and initiatives; and(7) additional topic area-molecular basis of gastric/liver diseases as an additional area for articles submitted to the journal.

肉质花盘亚组野生牡丹资源利用价值及保护策略分析

对肉质花盘亚组(Subsect.Delavayanae)野生牡丹资源的种类及生物学特性进行了阐述,同时对肉质花盘亚组野生牡丹的药用、油用、育种潜在利用价值进行了分析,并提出了保护对策及合理利用建议,以期为肉质花盘亚组野生牡丹的有效保护和可持续利用提供参考依据。

INFLUENCE OF THE MIDDLE WEAK LAYER ON THE IMPACT BEHAVIOR OF LAMINATED STRUCTURES

In this paper, a calculation model based on the subsection displacement theory and the large deflection analysis is developed to describe the dynamic response of isotropic laminated circular plates impacted by a soft body. The model takes into account the interlaminar shear effect induced by the middle weak layer. It is proved by numerical examples that the difference between the model developed in this paper and that based on the classical laminated theory mainly depends on three factors, the elastic modulus of the glue, the radius of the circular plate and the impact force.