Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory

The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.

The heterogeneous impact of China-Europe railway express on the efficiency of logistics industry in node cities

Purpose-The spatiotemporal compression effect of China-Europe Railway Express(CR-Express)can reduce the filow costs of resources between China's node cities.Additionally,it can break through the limitations of low-added-value marine products,significantly impacting the logistics industry efficiency.However,there are few literature verifying and analyzing its heterogeneity.This study explores the impact of CR-Express on the efficiency of logistics industry in node cities and analyzes the heterogeneity.Design/methodology/approach-First,this study uses panel data to measure the efficiency of node city logistics industry.Secondiy,this study discusses the impact of the opening of CR-Express on the efficiency of logistics industry in node cities based on the multi-period differential model.Finally,according to the node city difference,the sample city experimental group is grouped for heterogeneity analysis.Findings-The results show that CR-Express can promote the urban logistics industry efficiency,with an average effect of 4.55%.According to the urban characteristics classification,the heterogeneity analysis shows that the efficiency improvement effect of logistics industry in inland cities is more obvious.The improvement effect of node cities and central cities in central and western China is stronger,especially in the sample of megacities and type I big cities.Compared with non-value chain industrial products,the CR-Express has significant promotion effects on the logistics efficiency of the cities where main goods are value chain products.Originality/value-Under the background of double cycle development,this paper can provide a scientific basis for the investment benefit evaluation of CR-Express construction and the follow-up route planning.

Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.

Combining unscented Kalman filter and wavelet neural network for anti-slug

The stability of the subsea oil and gas production system is heavily influenced by slug flow. One successful method of managing slug flow is to use top valve control based on subsea pipeline pressure. However, the complexity of production makes it difficult to measure the pressure of subsea pipelines, and measured values are not always accessible in real-time. The research introduces a technique for integrating Unscented Kalman Filter (UKF) and Wavelet Neural Network (WNN) to estimate the state of subsea pipeline pressure using historical data and a state model. The proposed method treats multiphase flow transport as a nonlinear model, with a dynamic WNN serving as the state observer. To achieve real-time state estimation, the WNN is included into the UKF algorithm to create a WNN-based UKF state equation. Integrate WNN and UKF in a novel way to predict system state accurately. The simulated results show that the approach can efficiently predict the inlet pressure and manage the slug flow in real-time using the riser's top pressure, outlet flow and valve opening. This method of estimate can significantly increase the control effect.

A Scheme Library-Based Ant Colony Optimization with 2-Opt Local Search for Dynamic Traveling Salesman Problem

The dynamic traveling salesman problem(DTSP)is significant in logistics distribution in real-world applications in smart cities,but it is uncertain and difficult to solve.This paper proposes a scheme library-based ant colony optimization(ACO)with a two-optimization(2-opt)strategy to solve the DTSP efficiently.The work is novel and contributes to three aspects:problemmodel,optimization framework,and algorithmdesign.Firstly,in the problem model,traditional DTSP models often consider the change of travel distance between two nodes over time,while this paper focuses on a special DTSP model in that the node locations change dynamically over time.Secondly,in the optimization framework,the ACO algorithm is carried out in an offline optimization and online application framework to efficiently reuse the historical information to help fast respond to the dynamic environment.The framework of offline optimization and online application is proposed due to the fact that the environmental change inDTSPis caused by the change of node location,and therefore the newenvironment is somehowsimilar to certain previous environments.This way,in the offline optimization,the solutions for possible environmental changes are optimized in advance,and are stored in a mode scheme library.In the online application,when an environmental change is detected,the candidate solutions stored in the mode scheme library are reused via ACO to improve search efficiency and reduce computational complexity.Thirdly,in the algorithm design,the ACO cooperates with the 2-opt strategy to enhance search efficiency.To evaluate the performance of ACO with 2-opt,we design two challenging DTSP cases with up to 200 and 1379 nodes and compare them with other ACO and genetic algorithms.The experimental results show that ACO with 2-opt can solve the DTSPs effectively.

Advances in Research of Mechanism of Herb-Drug Interactions

With the concurrent consumption of herbal medicines and conventional drugs,herb-drug interactions(HDIs)have become the most important clinical consequence of this practice.A general overview and the significance of pharmacokinetic and pharmacodynamic HDIs are provided,detailing basic mechanism,especially the metabolic enzymes and drug transporters,such as CYP450 and P-gp.

160 kV,10 ns上升沿脉冲触发器的研制

为了研究医学系统中乳腺癌早期诊断的关键技术,本文研制了一台用于准点X光相位差照相系统的触发器,对触发器的输出脉冲要求:峰值电压160 kV,上升时间 ≤ 10 ns,脉宽 ≤ 100 ns。该触发器由Marx发生器、火花隙开关、电容分压器及输出段构成,其中Marx发生器采用8级同轴正负极充电的双边结构,每级由6个40 kV 3800 pF的陶瓷电容器并联组成,采用紧凑回路低电感的设计;4个火花隙开关采用跨级触发放电;在输出段末端设计了环形电容分压器作为触发器的高电压测量探头。Simplorer模拟结果表明:在实际负载阻值时,输出电压169 kV,上升时间 ≤ 10 ns,脉宽 ≤ 100 ns,满足设计指标要求。

Preoperative predictors of portal vein thrombosis after splenectomy with periesophagogastric devascularization

AIM:To evaluate the predictive value of preoperative predictors for portal vein thrombosis(PVT)after splenectomy with periesophagogastric devascularization.METHODS:In this prospective study,69 continuous patients with portal hypertension caused by hepatitis B cirrhosis underwent splenectomy with periesophagogastric devascularization in West China Hospital of Sichuan University from January 2007 to August 2010.The portal vein flow velocity and the diameter of portal vein were measured by Doppler sonography.The hepatic congestion index and the ratio of velocity and diameter were calculated before operation.The prothrombin time(PT)and platelet(PLT)levels were measured before and after operation.The patients'spleens were weighed postoperatively.RESULTS:The diameter of portal vein was negatively correlated with the portal vein flow velocity(P<0.05).Thirty-three cases(47.83%)suffered from postoperative PVT.There was no statistically significant difference in the Child-Pugh score,the spleen weights,the PT,or PLT levels between patients with PVT and without PVT.Receiver operating characteristic curves showed four variables(portal vein flow velocity,the ratio of velocity and diameter,hepatic congestion index and diameter of portal vein)could be used as preoperative predictors of postoperative portal vein thrombosis.The respective values of the area under the curve were 0.865,0.893,0.884 and 0.742,and the respective cut-off values(24.45 cm/s,19.4333/s,0.1138 cm/s-1 and 13.5 mm) were of diagnostically efficient,generating sensitivity values of 87.9%,93.9%,87.9%and 81.8%,respectively,specificities of 75%,77.8%,86.1%and 63.9%,respectively.CONCLUSION:The ratio of velocity and diameter was the most accurate preoperative predictor of portal vein thrombosis after splenectomy with periesophagogastric devascularization in hepatitis B cirrhosis-related portal hypertension.

Analysis of infections in the first 3-month after living donor liver transplantation

AIM:To identify factors related to serious postoperative bacterial and fungal infections in the first 3 mo after living donor liver transplantation(LDLT).METHODS:In the present study,the data of 207 patients from 2004 to 2011 were reviewed.The pre-,intra-and post-operative factors were statistically analyzed.All transplantations were approved by the ethics committee of West China Hospital,Sichuan University.Patients with definitely preoperative infections and infections within 48 h after transplantation were excluded from current study.All potential risk factors were analyzed using univariate analyses.Factors significant at a P < 0.10 in the univariate analyses were involved in the multivariate analyses.The diagnostic accuracy of the identified risk factors was evaluated using receiver operating curve.RESULTS:The serious bacterial and fungal infection rates were 14.01% and 4.35% respectively.Enterococcus faecium was the predominant bacterial pathogen,whereas Candida albicans was the most common fungal pathogen.Lung was the most common infection site for both bacterial and fungal infections.Recipient age older than 45 years,preoperative hyponatremia,intensive care unit stay longer than 9 d,postoperative bile leak and severe hyperglycemia were independent risk factors for postoperative bacterial infection.Massive red blood cells transfusion and postoperative bacterial infection may be related to postoperative fungal infection.CONCLUSION:Predictive risk factors for bacterial and fungal infections were indentified in current study.Pre-,intra-and post-operative factors can cause postoperative bacterial and fungal infections after LDLT.

Relationship between somatostatin receptor subtype expression and clinicopathology,Ki-67,Bcl-2 and p53 in colorectal cancer

AIM： To study the SSTR1, 2, 3, 4, 5 expression and their relationships with clinico-pathological factors, cell proliferation, Bcl-2 and p53 expression in colorectal cancer cells. METHODS： Immunohistochemical staining of five SSTR subtypes, Ki-67, Bcl-2 and p53 was performed by the standard streptavidin-peroxidase （SP） technique for the paraffin sections of 127 colorectal cancers, and expression of five SSTR subtypes in 40 specimens of normal colorectal mucosae was detected with the same method. RESULTS： Positive staining for five SSTR subtypes was observed in colorectal cancer cells and normal colorectal mucosae. SSTR1 was the most predominant subtype in both colorectal cancer and normal colorectal mucosa, and the second was SSTR5 or SSTR2. As compared with normal colorectal mucosa, SSTR4 was more frequently expressed in colorectal cancer cells （2.5% vs 18.9%, P〈 0.05）; the expression of SSTR2, 4, 5 in moderately to well differentiated colorectal adenocarcinoma was significantly higher than that in poorly differentiated ones （P〈 0.05）, the SSTR1 expression in colorectal cancer with positive lymph node metastasis was significantly higher than that with negative lymph node metastasis （72.2% and 54.5%, P〈 0.05）. In addition, in the ulcerative type of colorectal cancer, SSTR2 expression was obviously decreased （P 〈 0.05）; the correlation did not reach a statistical significance between the five SSTR subtypes expression and Dukes＇stages （P〉 0.05）, but the frequency of SSTR1 expression increased with Dukes＇ stage, while SSTR3 and SSTR5 expression decreased with Dukes＇ stage. Moreover, there was no correlation between expression of the five SSTR subtypes and other clinicopathological factors such as age, sex, tumor site, tumor depth, distant metastasis. The proliferative indexes in colorectal cancer cells with negative expression of SSTR2 and SSTR3 were significantly higher than that with positive expression （P〈0.05）. The Bcl-2 expression in colorectal cancer cells with positive expression of SSTR1, 2, 3, 5 was significantly lower than that with negative expression （P〈 0.05）. There was no correlation between five SSTR subtypes and p53 expression. CONCLUSION： The most predominant SSTR subtype is SSTR1, and the second is SSTR2 or SSTR5, Five SSTR subtypes play different roles in the development of colorectal cancer, SSTR2 and SSTR3 can inhibit the proliferation and promote apoptosis of tumor cells.

Id2 regulates the proliferation of squamous cell carcinoma in vitro via the NF-κB/Cyclin D1 pathway

Squamous cell carcinoma (SCC) is a significant cause of cancer morbidity and mortality worldwide, with an incidence of up to 166 cases per 100 000 population. It arises in the skin, upper aerodigestive tract, lung, and cervix and affects more than 200 000 Americans each year. We report here that a microarray experiment comparing 41 SCC and 13 normal tissue specimens showed that Id2, a gene that controls the cell cycle, was significantly up-regulated in SCC. Enforced expression of Id2 in vitro stimulated the proliferation of SCC cells and up-regulated the transcription of nuclear factor kappa B (NF-κB) and cyclin D1. Enhancement of the NF-κB activity with p65 significantly increased the cell proliferation and the transcription of cyclin D1, whereas inhibition of the NF-κB activity with I kappa B alpha mutant (IκBα M) and pyrroline dithiocarbamate (PDTC) abrogated cell proliferation and transcription of cyclin D1. Furthermore, a mutated NF-κB binding site in the cyclin D1 promoter fully abrogated the Id2-induced transcription of cyclin D1. Taken together, these data indicate that Id2 induces SCC tumor growth and proliferation through the NF-κB/cyclin D1 pathway.

Development of calcium coke for CaC2 production using calcium carbide slag and coking coal

A type of calcium coke was developed for use in the oxy-thermal process of calcium carbide production.The calcium coke was prepared by the co-pyrolysis of coking coal and calcium carbide slag, which is a solid waste generated from the chlor-alkali industry.The characteristics of the calcium cokes under different conditions were analyzed experimentally and theoretically.The results show that the thermal strength of calcium coke increased with the increase in the coking coal proportion, and the waterproof property of calcium coke also increased with increased carbonation time.The calcium coke can increase the contact area of calcium and carbon in the calcium carbide production process.Furthermore, the pore structure of the calcium coke can enhance the diffusion of gas inside the furnace, thus improving the efficiency of the oxy-thermal technology.

The fabrication of homogeneous perovskite films on non-wetting interfaces enabled by physical modification

Conjugated polymers are commonly used as effective hole transport materials(HTMs) for preparation of high-performance perovskite solar cells. However, the hydrophobic nature of these materials renders it difficult to deposit photovoltaic perovskite layers on top via solution processing. In this article, we report a generic surface modification strategy that enables the deposition of uniform and dense perovskite films on top of non-wetting interfaces. In contrast to the previous proposed chemical modifications which might alter the optoelectronic properties of the interfacial layers, we realized a nondestructive surface modification enabled by introducing a layer of insulating mesoporous aluminum oxide(Al2O3). The surface energies of the typical non-wetting hole-transport layers(PTAA, P3 HT, and Poly-TPD) were significantly reduced by the Al2O3 modification. Benefiting from the intact optoelectronic properties of the HTMs, perovskite solar cells deposited on these interface materials show full open-circuit voltages( V OC) with high fill factors(FF) up to 80%. Our method provides an effective avenue for exploiting the full potential of the existing as well as newly developed non-wetting interface materials for the fabrication of high-performance inverted perovskite solar cells.

Corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands tropical marine atmosphere

The corrosion and pitting behavior of pure aluminum 1060 exposed to Nansha Islands marine atmosphere for 34 months was investigated based on mass loss measurement,scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and electrochemical impedance spectroscopy(EIS).The results indicated that serious pitting corrosion occurred on the surfaces of pure aluminum.The corrosion rate after exposure for 13 months was approximately 1.28 g/(m^(2)·a).The XPS results showed that the corrosion products were Al_(2)O_(3),Al(OH)_(3),and AlCl_(3).Moreover,the corrosion product layer was more protective than the native oxide film,and the protectiveness first increased and then decreased.Finally,the shape of the pits was evaluated using statistical analysis.

Anisotropic coal permeability and its stress sensitivity

This paper focuses on anisotropy of coal permeability and its stress sensitivity.Coal blocks were taken from Xinjing Coal Mine in Yangquan Coal District.Coal cores were then drilled along the strike,dip,and vertical directions.Coal permeabilities were measured with respect to stress by using a self-developed coal permeability measurement system.The used samples exhibited significant permeability anisotropy.The permeability along the strike direction was greatest among the three directions,the permeability along the vertical direction was the smallest,and the permeability along the dip direction was between the other two directions.The sensitivity of coal permeability to stress was transversely isotropic.The stress sensitivity coefficient was greater along the horizontal directions than along the vertical directions.Coal permeability exhibited anisotropic stress sensitivity due to anisotropy in Young’s modulus and porosity.The results obtained in this study are useful for optimizing the arrangement of pre-drainage boreholes.

CD24 genetic variants contribute to overall survival inpatients with gastric cancer

AIM: To investigate the role of single nucleotide polymorphisms(SNPs) in CD24 gene in susceptibility and overall survival of gastric cancer(GC).METHODS: We genotyped 3 tagging SNPs of CD24-P-534 in the promoter region, P170 in the coding region of exon 2 and P1527 in the 3′ untranslated region- using polymerase chain reaction-restriction fragment length polymorphism in specimens from 679 histologically-confirmed GC cases, 111 gastric atrophy(GA) cases and 976 tumor-free controls. Serumimmunoglobulin G antibodies to Helicobacter pylori(H. pylori) of all subjects were detected by enzyme-linked immunosorbent assay. CD24 expression was evaluated by immunohistochemistry in 131 GC specimens. Correlations between SNPs and risk of GC or GA were shown by P values and odd ratios(ORs) with 95% confidence intervals(95%CI) compared with the most common genotype of each SNP using the unconditional logistic regression model after adjusting for age, sex and H. pylori infection. Survival within each SNP group was plotted by Kaplan-Meier method and compared by log-rank test(recessive model). Hazard ratios with 95%CIs were computed by Cox regression model after adjusting for age, sex, histological type, tumor differentiation, clinical stage and post-operational chemotherapy.RESULTS: All of the three loci were in Hardy-Weinberg equilibrium in the control group. Median followup time for the 600 GC patients included in the survival analysis was 36.2 mo(range, 2.1-66.7 mo; 95%CI: 34.3-36.5 mo). Patients with the P-534 A/A genotype had significantly shorter survival(HR = 1.38, 95%CI: 1.01-1.88, P = 0.042) than did the C/C or C/A genotype carriers after adjusting for age, sex, histological type, tumor differentiation, clinical stage and post-operational chemotherapy. This trend was more evident in patients who lived longer than 2.5 years(HR = 7.55, 95%CI: 2.16-26.32, P = 0.001). The P170 T/T genotype was associated with a shorter lifespan than the non-T/T genotypes, but not significantly so. None of the three genetic variants was found to be associated with risk of GC(including tumor stage, grade and distant metastasis) or with risk of gastric atrophy. Furthermore, no difference of CD24 expression was found among the genotypes.CONCLUSION: The P-534 site in CD24 gene affects the overall survival of gastric cancer and may serve as a prognostic marker for gastric cancer.

Incomplete Kawasaki disease complicated with acute abdomen: A case report

Kawasaki disease(KD)is an acute systemic vasculitis characterized by unknown etiology.CASE SUMMARY A 4.5-year-old boy developed an acute abdomen during the onset of incomplete KD.He still had persistent abdominal pain after undergoing exploratory laparotomy and appendectomy.Ultrasound examination at early onset revealed a giant coronary artery aneurysm.The patient developed a myocardial infarction and heart failure accompanied by respiratory and cardiac arrest.He underwent coronary artery revascularization and coronary artery bypass graft using an autologous internal mammary artery.After the operation,the cardiac output increased,and the symptoms of heart failure resolved.Follow-up evaluation at 1 mo after operation showed that the patient's cardiac function had restored to New York Heart Association standard Grade I heart failure,and normal growth was obtained.CONCLUSION Coronary artery revascularization and coronary artery bypass graft is an effective method for treating myocardial ischemia in children with KD complicated with giant coronary artery aneurysm.Nevertheless,some issues still need specific attention.

Kinetic analysis and modeling of maize straw hydrochar combustion using a multi-Gaussian-distributed activation energy model

Combustion kinetics of the hydrochar was investigated using a multi-Gaussian-distributed activation energy model(DAEM)to ex-pand the knowledge on the combustion mechanisms.The results demonstrated that the kinetic parameters calculated by the multi-Gaussian-DAEM accurately represented the experimental conversion rate curves.Overall,the feedstock combustion could be divided into four stages:the decomposition of hemicellulose,cellulose,lignin,and char combustion.The hydrochar combustion could in turn be divided into three stages:the combustion of cellulose,lignin,and char.The mean activation energy ranges obtained for the cellulose,lignin,and char were 273.7-292.8,315.1-334.5,and 354.4-370 kJ/mol,respectively,with the standard deviations of 2.1-23.1,9.5-27.4,and 12.1-22.9 kJ/mol,re-spectively.The cellulose and lignin contents first increased and then decreased with increasing hydrothermal carbonization(HTC)temperature,while the mass fraction of char gradually increased.

唐诗中“酒家胡”与“胡姬”文化

唐人诗歌多胡气,以“酒家胡”及“胡姬”特色鲜明。“酒家胡”主要设置于唐都长安,伴随而来的是以歌舞侍酒的西域女郎。唐代不论有名的大诗人还是无名文士,都曾描写过她们。“酒家胡”与“胡姬”作为异域饮食文化的代表、先进的商业文化理念的承载者,给唐代社会吹进一股新风,推动了中华文化进一步发展。

Screen-printed soft triboelectric nanogenerator with porous PDMS and stretchable PEDOT:PSS electrode

The recent development on wearable and stretchable electronics calls for skin conformable power sources that are beyond current battery technologies.Among the many novel energy devices being explored,triboelectric nanogenerator(TENG)made from intrinsically stretchable materials has a great potential to meet the above requirement as being both soft and efficient.In this paper,we present a lithography-free and low-cost TENG device comprising a porous-structured PDMS layer and a stretchable PEDOT:PSS electrode.The porous PDMS structure is formed by using self-assembled polystyrene beads as the sacrificial template and it is highly ordered with great uniformity and high structural stability under compression force.Moreover,the porous PDMS TENG exhibits improved output voltage and current of 1.65 V and 0.54 nA compared to its counterpart with non-porous PDMS with 0.66 V and 0.34 nA.The effect of different loading force and frequency on the output response of the TENG device has also been studied.This work could shed light on diverse structural modification methods for improving the performance of PDMS-based TENG and the development of intrinsically stretchable TENG for wearable device applications.