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Abstract Shared values play an important role in attracting new tourists, retaining existing ones and gaining an important competitive advantage. Building upon the Commitment-Trust model, this study tested the role of shared ecological values in the creation of tourist trust and relationship commitment, and finally tourist behavioral intention. To test the hypotheses, a sample consisting of 480 mountaineering tourists of two representative travel agencies were surveyed, and a mixed-method approach based on a quantitative survey (n = 436) and qualitative interviews (n = 60) was also adopted to examine their relationships. Results revealed that shared ecological values between tourists and travel agencies were significantly negative predictors of credibility, while credibility and benevolence emerged as significantly positive predictors of relationship commitment. Moreover, credibility and relationship commitment were partially positively predictors of tourist’s behavioral intentions. The findings enrich the extant knowledge on mountaineering tourist relationship marketing and human-nature relationships and provide implications for destination management and wildlife protection.

In order to provide a more thorough explanation of the light scattering characteristics of wake in real marine environments, this study examined the variations in light scattering characteristics of wake bubbles induced by organic matter films in real marine environments. Drawing on Mie’s scattering theory, the study simulated the scattering intensity distribution, scattering coefficient, scattering phase function, and polarization degree of clean bubbles, as well as organic bubbles enveloped in protein and lipid films, under varying wavelengths of incident light. The simulation findings reveal that the scattering coefficients of clean bubbles and the two types of organic bubbles enveloped in films fluctuate around 2.025, with the organic bubbles exhibiting significantly larger oscillation amplitudes than the clean bubbles. Notably, at a scattering angle of 180°, the scattering intensity and scattering phase function of organic bubbles experience a notable increase. These organic bubbles can amplify the amplitude of scattering coefficient oscillations and the intensity of backscattering. The simulation results offer theoretical and data support for wake detection in real marine environments and provide a practical foundation for research on marine pollution monitoring and water quality assessment.

In order to study the characteristics of the wake magnetic anomaly when multiple ships are sailing at the same time, based on the basic theoretical knowledge of ship wake, the waveform, velocity, and distribution of the induced magnetic field of the ship wake were studied, and the variation characteristics and distribution patterns of the induced magnetic field of the multi-ship wake were obtained. By taking the formation of three ships as an example, the distribution of the induced magnetic field and the distribution of the magnetic field in the directions of x and y during the movement of the ships were analyzed. The magnetic field distribution characteristics of the wake formed when the three ships sail at the same time were solved, and the abnormal induced magnetic field generated during various ship combination operations was analyzed. The experimental results obtained from the simulation were consistent with the existing measurement results. APP Design tools were used for magnetic anomaly simulation system software development of multi-ship wake. The system not only could accurately, intuitively, and quickly simulate and set the magnetic induction intensity and variation patterns of the wake of three ships in any direction but also had the advantages of simple operation and cost saving, which provided a theoretical reference and a more effective simulation platform for ship wake experiment.

In the process of navigation, the ship will produce the wake region, and the scattering phenomenon occurs when the laser passes through the wake region of the bubble. Through the detection and analysis of the scattered light, the ship can be detected and identified. In this paper, the influence of the wake bubble curtain on laser transmission characteristics was investigated, and the light intensity changes of the wake bubble curtain were detected based on a fiber optic spectrometer. The experiment simulated the light intensity change of the wake bubble curtain with a thickness of 10 cm and 15 cm under different pressures at 5, 15, and 20 cm away from the water surface and explored the variation of intensity of forward and backward scattered light with pressure. The experimental results show that with the increases in pressure, the variation of light intensity slows down, and the concentration and the radius of the bubble increase. Higher bubble concentration indicates a smaller variation of light intensity. With the increase in pressure, the intensity of forward scattered light decreases linearly, and the intensity of backward scattered light increases.

To predict the flow behavior and identify the optimal hot processing window for A100 steel, a constitutive model and a hot processing map were established using true stress-strain data extracted from isothermal compression tests performed at temperatures ranging from 1073 to 1353 K and strain rates varying between 0.01 and 10 s−1. The results indicate a strong linear trend between the logarithmic stress and the reciprocal of temperature, along with a significant quadratic relationship between the logarithmic stress and logarithmic strain rate. With a correlation coefficient of 0.9913, the new constitutive model demonstrates an excellent predictive capability for the flow behavior of A100 steel. A significant dynamic recrystallization occurs when the energy dissipation rate exceeds 25 %, resulting in a uniform equiaxed grain structure after deformation. The unstable regions primarily occur in high strain rate and low-temperature zones, where the microstructures are typically coarse and elongated. This structural characteristic adversely affects the mechanical properties. Avoiding these conditions during hot forming of A100 steel is crucial. The optimal hot forming windows for A100 steel are achieved within a temperature range of 1153–1353K and a strain rate range of 0.01–10 s−1, where complete dynamic recrystallization occurs.

Backgrounds: Given the global prevalence of colorectal cancer (CRC), advancements in prompt and accurate diagnosis are crucial. Long non-coding RNAs (lncRNAs) in serum exosomes are emerging as potential diagnostic biomarkers. This study evaluated the feasibility of using serum exosomal lncRNAs for early-stage CRC diagnosis in clinical practice. Methods: Candidate serum exosomal lncRNAs were identified through an integrated analysis of two GEO datasets (GSE100206 and GSE100063) containing non-coding RNA expression profiles in serum exosomes. Exosomes isolated from participants' serum were validated using transmission electron microscopy (TEM) and immunoblotting. The expression levels of serum exosomal PCAT1 were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analysis. Results: Serum exosomal PCAT1 levels were evaluated in 150 CRC patients, 66 patients with benign colorectal lesions, and 128 healthy controls. ROC analysis demonstrated high diagnostic efficacy of serum exosomal PCAT1 for CRC. Notably, the predictive performance was sufficient to distinguish early-stage CRC patients. Additionally, the diagnostic value was significant for CRC patients with low serum carcinoembryonic antigen (CEA) levels. Measuring serum exosomal PCAT1 could complement CEA assessment, enhancing CRC diagnostic accuracy. Conclusions: Serum exosomal PCAT1 can complement CEA assessment, aiding in early CRC diagnosis and helping to differentiate the disease, especially in patients with low CEA levels.

To address the issue of accommodating large-scale wind power integration into the grid, a unit commitment model for power systems based on an improved binary particle swarm optimization algorithm is proposed, considering frequency constraints and demand response (DR). First, incentive-based DR and price-based DR are introduced to enhance the flexibility of the demand side. To ensure the system can provide frequency support, the unit commitment model incorporates constraints such as the rate of change of frequency, frequency nadir, steady-state frequency deviation, and fast frequency response. Next, for the unit commitment planning problem, the binary particle swarm optimization algorithm is employed to solve the mixed nonlinear programming model of unit commitment, thus obtaining the minimum operating cost. The results show that after considering DR, the load becomes smoother compared to the scenario without DR participation, the overall level of load power is lower, and the frequency meets the safety constraint requirements. The results indicate that a comparative analysis of unit commitment in power systems under different scenarios verifies that DR can promote rational allocation of electricity load by users, thereby improving the operational flexibility and economic efficiency of the power system. In addition, the frequency variation considering frequency safety constraints has also been significantly improved. The improved binary particle swarm optimization algorithm has promising application prospects in solving the accommodation problem brought by large-scale wind power integration.

(1) Studying the dynamic correlation between land use and the eco-environment in the Dianchi Basin is important for improving the basin's spatial layout and enhancing ecological development and conservation; (2) Through dynamic analysis and comprehensive evaluation of land use, the introduction of ecological and environmental quality index, and the use of FLUS models, the impacts on eco-environments in the Dianchi Basin for the recent 20 years were analyzed; (3) The past two decades witnessed a constant increase in the construction land in the Dianchi Basin and a decline in the farmland at an average annual rate of 0.93 %; The utilization level of land in the Dianchi Basin presented a negative correlation with the quality of the area's eco-environment, which reduces first and then increases; When natural production becomes a priority, both the construction land and farmland have witnessed growth. However, when ecological protection becomes a priority, it is projected that by 2035, the Dianchi Basin will achieve its highest eco-environmental quality index; (4) Studying how the change of land use types affects eco-environment is crucial for optimizing the current allocation of land resources and promoting sustainable development in the basin.

To investigate the deformation behavior and optimize the hot processing parameters for 2219 aluminum matrix composite, the constitutive equation and hot processing maps were established. Initially, hot compression experiments on 2219 aluminum alloy (2219A) were conducted using a Gleeble-3500 thermal simulation tester to obtain high-temperature rheological data. The deformation temperatures tested were 573, 623, 673, 723, and 773 K, with strain rates of 0.01, 0.1, 1, and 10 s−1, and a maximum deformation of 60 %. Subsequently, material parameters such as the activation energy, Zener–Hollomon parameter, power dissipation efficiency, and instability coefficient for 2219A were calculated. Analytical expressions for these material and deformation parameters were formulated, and a hot processing map for 2219A was constructed. The hot processing map, along with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and the Entropy Weight Method (EWM), were used to optimize the thermal deformation process parameters. The stability processing area and the optimal processing area identified by both methods were largely consistent. According to the hot processing map, the stability processing areas were identified in the temperature ranges of 580–660 K and 690–773 K with strain rates of 0.01 s−1 and 0.01–0.6 s−1, respectively. Using the TOPSIS and EWM methods, the stability processing areas were defined between 573 and 640 K and 0.01 s−1, 640–690 K and 0.01–0.1 s−1, and 690–773 K and 0.01–1 s−1. The consistency and accuracy of these optimization results were confirmed through microstructure analysis.

At present, the Monte Carlo simulation of the wake bubble curtain is mostly used to simulate the photon scattering direction, and few scholars have studied the distribution of photon transmission time. In this paper, based on the volume scattering function of Henyey-Greestein, a forward scattering model of pulsed laser in water was established. The propagation process of photons in bubble curtain was simulated by the Monte Carlo method based on this model, and the distribution of transmission time of photons in water containing bubble curtain was obtained. The model was used to simulate the photon transmission time under different bubble curtain thicknesses, bubble sizes, and detection distances. The simulation results show that greater thickness of the bubble curtain indicates longer photon transmission time in the bubble curtain and greater backward movement of the pulsed laser, which is manifested as a broader and wider pulsed laser. A larger bubble size represents a greater scattering degree of the laser by the bubble and greater backward movement of the pulsed laser. As the distance between the laser light source and the bubble curtain becomes larger, the photon transmission time is shifted backward, and the pulse width and peak intensity change slightly. According to the start-stop time of photons detected by the detector and the peak change of photon number, the characteristics of wake can be reflected, thus realizing the accurate positioning, identification, and measurement of wake.

When the ship is sailing, the bubble curtain is generated due to the stirring of the propeller and the influence of the air and sea water, and a wake is formed at the tail of the ship. At present, the research on wake optics mainly focuses on macroscopic sea surface imaging to determine the shape of the wake and the scattering characteristics of the underwater wake bubble curtain. Few scholars have studied the spectral characteristics of the wake bubble curtain. In view of this, the wake bubble curtain was simulated by the generator designed in the laboratory, and the change process of the bubble, including the size and force of the bubble, was analyzed. An optical fiber spectrum acquisition system was used to obtain the transmission spectra of the bubble curtain under different pressures, and the spectral characteristics of the wake bubble curtain under different pressures were analyzed. The results show that the transmission spectrum distribution is roughly the same under different experimental conditions; the bubble concentration has a great influence on the measured values of the spectrum, and higher bubble concentration indicates lower transmission; the measured value of the spectrum is also affected by the different degrees of attenuation of light in different bands in the air. Among them, the long-wave transmission is larger, so the air more absorbs light in the band of 430–550 nm. In comparison, the transmission in the band of 600–730 nm is high.

On the backdrop of dwindling conventional reserves, unconventional reservoirs have emerged as a pivotal chapter in resource extraction. Despite their challenges, such as low permeability, complex fluid storage, and flow mechanisms, hydraulic fracturing technology has underpinned the development of unconventional reservoirs. Consequently, this has brought about a shift in the sequence of flow regimes, e.g., the transient radial flow regime has been largely shortened by the lengthy transient linear flow regime due to the low permeability of unconventional reservoirs. Moreover, straight-line analysis (SLA), the simplest technique in rate transient analysis (RTA), is a fundamental and potent tool for swiftly extracting reservoir and hydraulic fracture information, estimating oil and gas reserves, and furnishing crucial initial data for subsequent historical matching processes. However, there is currently a dearth of review papers pertaining to a necessary guide of applying SLA in various transient linear flow (TLF) regimes and different unconventional reservoirs. Hence, this paper commences by elucidating the classification of TLF regimes, commonly used methods for recognizing flow regimes, and the diverse SLA methods used for different TLF regimes. Subsequently, it delves into a discussion of different modification techniques for variable rate/flowing pressure, gas phase, complex reservoir characteristics in unconventional reservoirs, and dynamic drainage area concepts etc. Furthermore, the application of SLA in specific domains, namely core analysis and the flowback period, is described. It culminates by surveying the advancements through an integration of novel technologies to enhance estimation accuracy. The paper also highlights certain drawbacks of current SLA technology and proposes new research directions. Ultimately, this paper would serve as an indispensable resource, offering foundational knowledge for the application of SLA in TLF to promote the production of global unconventional resources in a cost-effective and environmentally sustainable fashion in the face of a climate-resilient world.

Objective: Previous studies from outside China showed that the knowledge, attitudes, and practice (KAP) of chronic refractory cough (CRC) was moderate among physicians. This study examined the KAP toward CRC in Chinese healthcare providers. Methods: This single-center cross-sectional study was conducted at The Sixth Affiliated Hospital of Nantong University, Yancheng Third People's Hospital, from July 2022 to January 2023 and enrolled healthcare providers. The demographic characteristics and KAP scores were collected using a questionnaire (Cronbach's α = 0.934) developed based on CRC guidelines. Results: The study included 539 healthcare providers. The mean knowledge score was 8.27 ± 2.37 (maximum of 14, 59.07%), indicating poor knowledge. The highest rates of inaccuracies pertained to knowledge about the definition of chronic cough, empirical treatment methods, and potential risks of different treatments, suggesting a need for unified training in all aspects of CRC for medical staff. The mean attitude score was 49.74 ± 63.63 (maximum of 60, 82.90%), indicating favorable attitudes. Most healthcare providers believed that CRC affects normal work and life and that it would be necessary to provide more help to patients from the perspectives of drug treatment and psychological counseling. The mean practice score was 23.20 ± 6.28 (maximum of 35, 66.29%), indicating poor practice. Conclusion: This study suggests that healthcare providers in Yancheng have poor knowledge, favorable attitudes, and poor practice of CRC. This study provides points that should be targeted in future training and continuing education activities.

Abstract Objective Compare and analyze clinical data of total laparoscopic pancreaticoduodenectomy (TLPD) cases for surgeons with / without first assistant experience (FAE) in TLPD. Probe influence of FAE in TLPD on the learning curve for an operator. Methods The clinical data of 239 patients, that underwent TLPD performed by two surgeons between January 2017 and January 2022) in our department, were consecutively collected and divided into two groups (A and B). Group A cases were operated by Surgeon A, with FAE of 57 TLPDs in our department prior to initial TLPD as an operator. Group B cases were operated by Surgeon B with no FAE of TLPD. Cumulative sum (CUSUM) method developed learning curves. Clinical data and both surgeons’ learning curves were statistically compared between both groups. Results Between both groups, no statistically significant variations were observed for pre-operative health conditions. Reduced surgical duration, blood loss and transfusion volume during surgery, together with reductions in major post–operative complication rates and reduced hospital/ICU stays were identified within Group A, having statistically significant variations. The technical plateau phases of the learning curves were approximately 25–41 cases and 35–51 cases, for Surgeon A and Surgeon B, respectively. Conclusion FAE in TLPD can accelerate the learning curve of TLPD for an operator, with safer surgical procedures and enhanced post–operative recovery.

Abstract Nano-cutting is an important development direction of the modern manufacturing technology. However, the research on the mechanism underlying nano-cutting lags far behind the practical application, which restricts the development of this advanced manufacturing technology. The chip formation process is the basic process of nano-cutting, and it is of key importance for the mechanism research of nano-cutting. In this paper, the nano-tensile behavior of single crystal copper was studied based on the molecular dynamics simulations. The toughness and brittleness characteristics of the copper at different temperatures were analyzed. Then, the molecular dynamics simulations of nano-cutting for single crystal copper with different toughness and brittleness were studied. The crystal structure, cutting force, stress–strain distribution and atomic motion characteristics were systematically investigated. The nano-chip formation mechanism of single crystal copper was revealed. The results show that the chip is formed through two ways, namely the shear and extrusion. The material near the free surface of the workpiece undergoes continuous shear slip and periodic long-distance slippage along the primary shear direction, forming the block chip in which the FCC and HCP structures are orderly distributed. The material near the tool-chip interface is extruded by the tool, block chip and stagnation zone to form the flowing chip with amorphous structure. As the temperature increases, the occurrence frequency of long-distance slippage in the block chip increases, while the slippage degree decreases. Besides, with the increase in temperature, the thickness of block chip formed by shear slip decreases, while the thickness of flowing chip formed by extrusion increases.

Abstract Pancreatic cancer has an extremely terrible prognosis and is a common cause of cancer death. In this study, the clinic value, biological function and underlying mechanisms of Zinc finger protein 655 (ZNF655) in human pancreatic cancer were evaluated. The expression level of ZNF655 in pancreatic cancer was determined by immunohistochemistry (IHC) staining. The biological effects of ZNF655 in pancreatic cancer cells was investigated by loss/gain-of-function assays in vitro and in vivo. The downstream molecular mechanism of ZNF655 was explored using co-immunoprecipitation (Co-IP), dual-luciferase reporter and chromatin immunoprecipitation (Ch-IP). ZNF655 expression was significantly elevated in human pancreatic cancer and possessed clinical value in predicting poor prognosis. Functionally, ZNF655 knockdown inhibited the biological progression of pancreatic cancer cells, which was characterized by weaken proliferation, enhanced apoptosis, arrested cell cycle in G2, impeded migration, and suppressed tumor growth. Mechanistically, ZNF655 played an important role in promoting the binding of E2F transcription factor 1 (E2F1) to the cyclin-dependent kinase 1 (CDK1) promoter. Furthermore, knockdown of CDK1 alleviated the promoting effects of ZNF655 overexpression in pancreatic cancer cells. The promotive role of ZNF655 in pancreatic cancer via CDK1 was determined, which drew further interest regarding its clinical application as a promising therapeutic target.

This paper provides an evaluation framework to explore the linking mechanisms between customer knowledge management competence (CKMC) and Balanced Scorecard (BSC). With a case study from Chengdu-Chongqing Economic Circle of China, this paper attempts to empirically justify the framework. An index system was established for evaluating CKMC based on BSC and knowledge management process, the weight design and consistency check of the indexes were implemented by using the analytic hierarchy process (AHP), and the overall evaluation value and concrete index scores at all levels were obtained via the fuzzy evaluation method. Empirical results show that CKMC performance measurement indicators were ranked in order of importance as Business process performance dimensions (0.465), System support dimensions (0.289), Customer communication dimensions (0.152) and Market performance dimension (0.094). It also shows that the overall score of CKMC was 3.404, reflecting that the CKMC was in a state of general satisfaction. This research also identifies key factors hindering implementation of CKMC, including Attention from senior leaders (2.871), customer knowledge sharing efficiency (2.928), and information technology level (3.133). This research could contribute to CKM theory by extending customer knowledge management competence research with BSC initiatively. For practitioners, this study may provide useful suggestions to identify key factors promoting business CKMC, and finally promotes sustainable development of Agritourism.

The adoption of a vegetarian diet might have public health and environmental benefits. However, little is known about urban and rural Generation Z tourists' attitudes toward vegetarianism or vegetarian consumption within the Chinese urban and rural settings. Hence, to address this gap, the present study adopted a sequential and mixed research approach based on a survey (n = 212) and laddering interviews (n = 20) to validate post-millennial tourists' motives for adopting a vegetarian diet. The results identified the top four motives as environmental protection and resource conservation, ethical consideration, personal taste and choice, and personal healthcare issues. The top four barriers to vegetarianism were unavailability and limited choice, peer pressure, traditional prejudice/habit, and the inability to change. The results also demonstrated that both rural and urban tourists adopt vegetarianism mainly for environmental protection and ethical consideration, a subtle difference between them is that urban vegetarians emphasized ethical considerations more but rural ones emphasized food and variety. Urban consumers considered unavailability and limited choice as the topmost barriers to being vegetarian, while rural vegetarians found traditional prejudice to be restricting. Due to traditional dietary habits and peer influence, rural tourists face many more challenges when adopting a vegetarian diet. Understanding the perceived benefits and barriers to being vegetarian in different regions will not only enrich the theory of food nutrition but also expand Generation Z tourists' consumption behavior and practices.

Abstract To develop a predictive model and a nomogram for predicting postoperative hemorrhage in preoperative patients undergoing laparoscopic pancreaticoduodenectomy (LPD). A total of 409 LPD patients that underwent LPD by the same surgical team between January 2014 and December 2020 were included as the training cohort. The preoperative data of patients were statistically compared and analyzed for exploring factors correlated with postoperative hemorrhage. The predictive model was developed by multivariate logistic regression and stepwise (stepAIC) selection. A nomogram based on the predictive model was developed. The discriminatory ability of the predictive model was validated using the receiver operating characteristic (ROC) curve and leave-one-out method. The statistical analysis was performed using R 3.5.1 ( www.r-project.org ). The predictive model including the risk-associated factors of postoperative hemorrhage was as follows: 2.695843 − 0.63056 × (Jaundice = 1) − 1.08368 × (DM = 1) − 2.10445 × (Hepatitis = 1) + 1.152354 × (Pancreatic tumor = 1) + 1.071354 × (Bile duct tumor = 1) − 0.01185 × CA125 − 0.04929 × TT − 0.08826 × APTT + 26.03383 × INR − 1.9442 × PT + 1.979563 × WBC − 2.26868 × NEU − 2.0789 × LYM − 0.02038 × CREA + 0.00459 × AST. A practical nomogram based on the model was obtained. The internal validation of ROC curve was statistically significant (AUC = 0.7758). The validation by leave-one-out method showed that the accuracy of the model and the F measure was 0.887 and 0.939, respectively. The predictive model and nomogram based on the preoperative data of patients undergoing LPD can be useful for predicting the risk degree of postoperative hemorrhage.

Internet of Things (IoT) has been widely used in various fields of our daily life in the past years. Obviously, in the future, the significance of its security will be more evident and enormous. However, there are still many security issues in the IoT, which makes it vulnerable to be attacked easily by some potential factors. Targeting at these issue, in this paper, we propose a secure access management scheme in IoT based on blockchain. Firstly, in our work, by using the Decisional Learning with Error (DLWE) problem, we propose a secure Key-policy Attribute-based Encryption (KP-ABE) scheme, it can implement fine-grained access control in IoT. Secondly, we use blockchain to solve the authentication and access management challenges. In addition, the smart contract in blockchain can process transactions automatically, which greatly reduces the management cost and running time for this scheme. Last but not the least, we further analyze the security of our proposed scheme. The result shows that our scheme can resist some common attacks in IoT, and it is more secure and efficient.

Based on the measurement mechanism of mobility in pressure measurement while drilling, through analyzing a large number of mobility data, it is found that under the condition of water-based mud drilling, the product of mobility from pressure measurement while drilling and the viscosity of mud filtrate is infinitely close to the water phase permeability under the residual oil in relative permeability experiment. Based on this, a method converting the mobility from pressure measurement while drilling to core permeability is proposed, and the permeability based on Timur formula has been established. Application of this method in Penglai 19-9 oilfield of Bohai Sea shows: (1) Compared with the permeability calculated by the model of adjacent oilfields, the permeability calculated by this model is more consistent with the permeability calculated by core analysis. (2) Based on the new model, the correlation between the calculated mobility of well logging and the actual drilling specific productivity index bas been established. Compared with the relationship established by using the permeability model of an adjacent oilfield, the correlation of the new model is better. (3) Productivity of four directional wells was predicted, and the prediction results are in good agreement with the actual production after drilling. Key words: mobility from pressure measurement while drilling, permeability, irreducible water saturation, Timur formula, productivity prediction, Penglai 19-9 oilfield

To study the hot deformation behavior of and obtain the optimal hot processing parameters for 2219 aluminum alloy, a new, precise constitutive model based on the partial derivative of flow data was constructed and hot processing maps were constructed based on the new model. First, isothermal compression experiments were conducted at strain rates of 0.01–10 s−1 and temperatures of 573–773 K, and the high-order differences of the logarithmic stress with respect to the temperature and logarithmic strain rate were calculated. Second, a new, precise constitutive model based on the high-order differences was constructed, and the predictive accuracies of the new model and the Arrhenius model were compared. Finally, the hot processing maps of 2219 aluminum alloy were constructed using the new model, and its optimal hot processing parameters were validated with metallographic experiments. The results showed that a first-order approximation between logarithmic stress and temperature and a third-order approximation between logarithmic stress and the logarithmic strain rate need to be considered to construct a high-precision constitutive model without significantly increasing material parameters. The new model exhibited a significantly higher prediction accuracy than the Arrhenius model at a high strain rate and low temperature levels. With an increase in temperature, the energy dissipation increased at a constant strain rate, and with an increase in the strain rate, the energy dissipation first increased and then decreased at constant temperature. The best region for hot processing was located in the temperature range of 673–773 K and the strain rate range of 0.1–1 s−1. The results of microstructure analysis were in good agreement with the prediction results of hot processing maps. Hot processing maps can be used to guide the hot working process formulation of 2219 aluminum alloy.

Pulverizing system is an important part in the clean and efficient utilization of coal in thermal power plant, and the optimal control of the system is an important way to achieve this goal. This paper presents a stair-like multivariable generalized predictive control scheme for a pulverizing system. This control scheme focuses on the problem of predictive control algorithm in practical application, and integrates the feedforward experience in traditional control schemes of pulverizing system. Simulation results showed that the scheme are able to realize the decoupling control of the pulverizing system, avoid the problem of matrix inversion, reduce the amount of calculation, and has certain engineering application value.

A new method for converting a microdroplet on a piezoelectric substrate into continuous fluid flow in microchannels is presented. An interdigital transducer with 27.5 MHz center frequency is fabricated on a 1280 yx-LiNbO3 piezoelectric substrate for exciting surface acoustic wave. A PDMS (Polydimethylsiloxane) microchannel is mounted on the piezoelectric substrate. One end of the microchannel is connected with water absorbing paper, while the other end of the microchannel is in touch with a droplet to be converted. The surface acoustic wave is used for controlling the evaporation velocity of the fluid in the microchannel. Part of fluid in the droplet can be entered into the microchannel and transported there due to the evaporation and capillary effects. Red dye solution is used to demonstrate the conversion of the droplet and the transportation of the fluid in the microchannel. Results show that the droplet on the piezoelectric substrate can successfully be converted into continuous fluid. The flow velocity is increased with the power of the electric signal applied to the interdigital transducer. Average flow velocity is 0.0235μl/s when the power of the electric signal is 30.0dBm. The work is helpful for piezoelectric microfluidic devices for biochemical analysis.

The epidemiology of hepatitis D virus (HDV) in China is fairly unknown. The mechanisms whereby HDV leads to accelerated liver disease in hepatitis B virus (HBV)/HDV co-infected patients and the histological characteristics of chronic hepatitis D (CHD) patients need further investigation.The prevalence of HDV was retrospectively evaluated in all consecutive hospitalized patients with chronic HBV infection from May 2005 to October 2011. HBV/HDV co-infected patients and HBV mono-infected patients were compared clinically and histologically. Significant histological abnormality was defined as significant necroinflammation (grade ≥A2) and/or significant fibrosis (stage ≥ F2).6.5% of patients (426/6604) tested positive for IgM anti-HDV. HDV was more common in patients over 50 years old than those under 50 (11.7% vs. 5.1%, P5×ULN respectively.The prevalence of HDV is not low in patients with chronic HBV infection. HDV may contribute to progression to ESLD through late-phase HBV DNA reactivation.