Inflammatory bowel disease(IBD),encompassing Crohn’s disease and ulcerative colitis,manifests as a chronic,recurrent,and refractory intestinal inflammatory condition significantly impacting patients’quality of life....Inflammatory bowel disease(IBD),encompassing Crohn’s disease and ulcerative colitis,manifests as a chronic,recurrent,and refractory intestinal inflammatory condition significantly impacting patients’quality of life.Despite ongoing research,its etiology and pathogenesis remain incompletely understood.Recent advancements in medical research highlight the critical role of drug combination therapies in managing IBD.This paper employs the strengths,weaknesses,opportunities,and threats framework to evaluate the four strategic elements(strengths,weaknesses,opportunities,and threats)pertaining to combination therapies for IBD.Among the strengths,the paper underscores the efficacy of multi-targeted strategies,the advancement of personalized medicine,and the mitigation of drug resistance.Nonetheless,the analysis identifies significant weaknesses,including the prohibitive cost of treatment,issues with patient compliance,and the necessity for comprehensive long-term safety data.The paper also delineates opportunities to augment therapeutic success through the incorporation of biomarkers,the application of artificial intelligence,and extensive international collaborative efforts.In contrast,the paper does not shy away from addressing the threats,which include the potential for therapeutic resistance and the logistical challenges inherent in global therapy deployment.These initiatives aim to refine future therapeutic practices,fostering safer,more effective,and personalized treatment paradigms for IBD patients.展开更多
To determine the extrusion force of pipe fabricated by continuous casting and extrusion (CASTEX) using an expansion combination die, the metallic expansion combination die was divided into diversion zone, expansion zo...To determine the extrusion force of pipe fabricated by continuous casting and extrusion (CASTEX) using an expansion combination die, the metallic expansion combination die was divided into diversion zone, expansion zone, flow dividing zone, welding chamber, and sizing zone, and the corresponding stress formulae in various zones were established using the slab method. The deformation zones of CASTEX groove were divided into liquid and semisolid zone, solid primary gripping zone, and solid gripping zone, and the formulae of pipe extrusion forces were established. Experiments were carried out on the self-designed CASTEX machine to obtain the aluminum pipe and measure its extrusion force using the expansion combination die. The experimental results of radial extrusion force for aluminum pipe are in good agreement with the calculated ones.展开更多
To improve the accuracy and speed in cycle-accurate power estimation, this paper uses multiple dimensional coefficients to build a Bayesian inference dynamic power model. By analyzing the power distribution and intern...To improve the accuracy and speed in cycle-accurate power estimation, this paper uses multiple dimensional coefficients to build a Bayesian inference dynamic power model. By analyzing the power distribution and internal node state, we find the deficiency of only using port information. Then, we define the gate level number computing method and the concept of slice, and propose using slice analysis to distill switching density as coefficients in a special circuit stage and participate in Bayesian inference with port information. Experiments show that this method can reduce the power-per-cycle estimation error by 21.9% and the root mean square error by 25.0% compared with the original model, and maintain a 700 ＋ speedup compared with the existing gate-level power analysis technique.展开更多
Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds...Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits, and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition, seedling height, diameter above ground, diameter at breast height （DBH） of 17 cross combination progenies were investigated. The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross combinations and seedlings. Further more, the result of multiple comparison showed that P.deltoides ‘Lux＇× P.deltoides ‘D324＇, P.ussuriensis cl. ‘U4＇× P deltoides ‘T66＇, P.ussuriensis cl. ‘U4＇× P. deltoides ‘T26＇, P.deltoides ‘Lux＇× P.ussuriensis cl. ‘U3＇, （P.tomentosa×P.bolleana）×（P.alba×P.glandulosa）, （P.alba×P.tomentosa）×（P.alba×P.glandulosa）, and （P.alba×P.glandulosa‘No.2＇）× P. tomentosa ‘Lumao 50＇ were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further test.展开更多
Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechani...Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechanism and therapeutic strategies have not been clarified.This study aimed to identify potential roles of mi RNA/m RNA axis in the pathogenesis and drug combinations in the treatment of NASH.Methods:Microarray GSE59045 and GSE48452 were downloaded from the Gene Expression Omnibus and analyzed using R.Then we obtained differentially expressed genes(DE-genes).DAVID database was used for Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment pathway analysis.Protein-protein interaction(PPI)networks were used for the identification of hub genes.We found upstream regulators of hub genes using mi RTar Base.The expression and correlation of key mi RNA and its targets were detected by q PCR.Drug Pair Seeker was employed to predict drug combinations against NASH.The expression of mi RNA and hub genes in HCC was identified in the Cancer Genome Atlas database and Human Protein Atlas database.Results:Ninety-four DE-genes were accessed.GO and KEGG analysis showed that these predicted genes were linked to lipid metabolism.Eleven genes were identified as hub genes in PPI networks,and they were highly expressed in cells with vigorous lipid metabolism.hsa-mi R-335-5 p was the upstream regulator of 9 genes in the 11 hub genes,and it was identified as a key mi RNA.The hub genes were highly expressed in NASH models,while hsa-mi R-335-5 p was lowly expressed.The correlation of mi RNA-m RNA was established by q PCR.Functional verification indicated that hsa-mi R-335-5 p had inhibitory effect on the development of NASH.Finally,drug combinations were predicted and the expression of mi RNA and hub genes in HCC was identified.Conclusions:In the study,potential mi RNA-m RNA pathways related to NASH were identified.Targeting these pathways may be novel strategies against NASH.展开更多
We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve param...We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.展开更多
Objective:To explore the rules of acupoint combination in acupuncture treatment of post-stroke pseudobulbar palsy(PBP),based on acupuncture prescriptions retrieved from literature and using complex network analysis.Me...Objective:To explore the rules of acupoint combination in acupuncture treatment of post-stroke pseudobulbar palsy(PBP),based on acupuncture prescriptions retrieved from literature and using complex network analysis.Methods:The articles were searched from China National Knowledge Infrastructure(CNKI),Wanfang and VIP databases as the source of data.The eligible articles were selected in accordance with inclusion and exclusion criteria.The relevant data were extracted to set up the acupoint prescription database in acupuncture treatment of PBP.By using co-occurrence relationship in acupoint prescriptions,the core acupoints and the combination rules were analyzed in acupuncture treatment of PBP.Results:A total of 194 articles were eligible finally,with 202 acupoint prescriptions extracted.19 core acupoints were collected in total,i.e.Liánquán(廉泉CV23),Fēngchí(风池GB20),Bǎihuì(百会GV20),Jīnjīn(金津EX-HN12),Yùyè(玉液EX-HN13),Fēngfǔ(风府GV16),Yǎmén(哑门GV15),Shuǐgōu(水沟GV26),Nèiguān(内关PC6),Fēnglóng(丰隆ST40),Wángǔ(完骨GB12),Sānyīnjiāo(三阴交SP16),Yìfēng(翳风TE17),Tōnglǐ(通里HT5),Tàichōng(太冲LR3),Hégǔ(合谷LI4),Hǎiquán(海泉EX-HN11),Jùquán(聚泉EX-HN10)and Yìntáng(印堂EX-HN3).The core acupoint groups were CV23-GB20,EX-HN12-EX-HN13 and GV26-PC6-SP6.Acupoints were mostly selected from governor vessel.The methods of acupoint combination included the combination of distal and nearby points,and the combination of the acupoints located in the front and on the back.Conclusions:In treatment of PBP with acupuncture,biaoben(manifestation and root cause)theory is emphasized,the methods for dispelling wind,resolving phlegm,regaining consciousness,and opening orifices are recommended.Moreover,the attentions are paid on spirit regulation,holistic adjustment,and syndrome differentiation in treatment.展开更多
Listeria monocytogenes is the pathogen of listeriosis and it causes severe infections like septicemia, encephalitis, and meningitis, especially in immunocompromised individuals, newborns, and pregnant women. Its wide ...Listeria monocytogenes is the pathogen of listeriosis and it causes severe infections like septicemia, encephalitis, and meningitis, especially in immunocompromised individuals, newborns, and pregnant women. Its wide distribution in the environment and ability to survive or even grow under adverse conditions has made L. monocytogenes an important public health concern and in food industry.展开更多
Power analysis is a non-invaslve attack against cryptographic hardware, which effectively exploits runtime power consumption characteristics of circuits. This paper proposes a new power model which combines Hamming Di...Power analysis is a non-invaslve attack against cryptographic hardware, which effectively exploits runtime power consumption characteristics of circuits. This paper proposes a new power model which combines Hamming Distance model and the model based on the template value of power consumption in combinational logic circuit. The new model can describe the power consumption characteristics of sequential logic circuits and those of combinational logic as well. The new model can be used to improve the existing power analysis methods and detect the information leakage of power consumption. Experimental results show that, compared to CPA（Correlation Power Analysis） method, our proposed attack which adopt the combinational model is more efficient in terms of the number of required power traces.展开更多
AIMTo compare the efficacy of intravitreal ranibizumab (IVR) alone or in combination with photodynamic therapy (PDT) vs PDT in patients with symptomatic polypoidal choroidal vasculopathy (PCV).METHODSA systematic sear...AIMTo compare the efficacy of intravitreal ranibizumab (IVR) alone or in combination with photodynamic therapy (PDT) vs PDT in patients with symptomatic polypoidal choroidal vasculopathy (PCV).METHODSA systematic search of a wide range of databases (including PubMed, EMBASE, Cochrane Library and Web of Science) was searched to identify relevant studies. Both randomized controlled trials (RCTs) and non-RCT studies were included. Methodological quality of included literatures was evaluated according to the Newcastle-Ottawa Scale. RevMan 5.2.7 software was used to do the Meta-analysis.RESULTSThree RCTs and 6 retrospective studies were included. The results showed that PDT monotherapy had a significantly higher proportion in patients who achieved complete regression of polyps than IVR monotherapy at months 3, 6, and 12 (All P≤0.01), respectively. However, IVR had a tendency to be more effective in improving vision on the basis of RCTs. The proportion of patients who gained complete regression of polyps revealed that there was no significant difference between the combination treatment and PDT monotherapy. The mean change of best-corrected visual acuity (BCVA) from baseline showed that the combination treatment had significant superiority in improving vision vs PDT monotherapy at months 3, 6 and 24 (All P<0.05), respectively. In the mean time, this comparison result was also significant at month 12 (P<0.01) after removal of a heterogeneous study.CONCLUSIONIVR has non-inferiority compare with PDT either in stabilizing or in improving vision, although it can hardly promote the regression of polyps. The combination treatment of PDT and IVR can exert a synergistic effect on regressing polyps and on maintaining or improving visual acuity. Thus, it can be the first-line therapy for PCV.展开更多
AIM:To assess the effects of the fixed combination of0.005% latanoprost and 0.5% timolol(FCLT) vs their individual components for primary open angle glaucoma(POAG) and ocular hypertension(OHT).· METHODS:After sea...AIM:To assess the effects of the fixed combination of0.005% latanoprost and 0.5% timolol(FCLT) vs their individual components for primary open angle glaucoma(POAG) and ocular hypertension(OHT).· METHODS:After searched PubMed, EMBASE, the Cochrane Library and SCI, all randomized controlled clinical trials(RCTs) and cross-over studies were included. The control groups were the monotherapy or the concomitant therapy of latanoprost and timolol. The outcomes were visual field defect, optic atrophy, mean intraocular pressure(IOP) and IOP fluctuation. The analysis was carried out in RevMan version 5.1 software.RESULTS:Thepost-interventionmeanIOPofFCLTwas significantly lower compared to timolol [mean difference(MD)-2.92, 95%CI-3.28 to-2.55, P 【0.00001] and latanoprost(MD-1.11, 95%CI-1.51 to-0.72, P 【0.00001). The postintervention IOP fluctuation was also significantly lower compared to timolol(MD-0.88, 95%CI-1.23 to-0.53, P 【0. 00001) and latanoprost( MD- 0. 63, 95 % CI- 1. 04to-0.22, P =0.002). The mean IOP was higher in FCLT morning dose group than the one in unfixed combination of 0.005% latanoprost and 0.5% timolol(UFCLT)(MD1.10, 95% CI 0.81 to 1.39, P 【0.00001). Otherwise, there was no difference between FCLT evening dose group and UFCLT(MD 0.34, 95% CI-0.01 to 0.69, P =0.06).There was no statistical difference for the incidence ofvisual field defect and optic atrophy between FCLT and the monotherapy of components.CONCLUSION:A better IOP lowering effect has been demonstrated for FCLT compared to the monotherapy of components. The IOP lowering effect was worse for FCLT morning dose and almost same for FCLT evening dose compared to the UFCLT. We need more long-term high quality RCTs to demonstrate the outcomes of visual field defect and optic atrophy.visual field defect and optic atrophy between FCLT and the monotherapy of components.CONCLUSION:A better IOP lowering effect has been demonstrated for FCLT compared to the monotherapy of components. The IOP lowering effect was worse for FCLT morning dose and almost same for FCLT evening dose compared to the UFCLT. We need more long-term high quality RCTs to demonstrate the outcomes of visual field defect and optic atrophy.展开更多
To screen out the rapeseed(Brassica napus) combinations that are suitable for the production of both oilseed and vegetable, we carried out a field experiment for 11 new combinations(hybrids) of rapeseed and then perfo...To screen out the rapeseed(Brassica napus) combinations that are suitable for the production of both oilseed and vegetable, we carried out a field experiment for 11 new combinations(hybrids) of rapeseed and then performed grey relation analysis and cluster analysis on 12 traits including the yield and quality of young stem,seed yield, and several agronomic traits after harvesting of young stem. The results showed that A11, A7, and A4 had higher main stalk yield than other combinations.The young stem/leaf ratios of A11, A5, A7, A4, A3, and A1 were in line with the quality requirements for young stem commodity. The soluble sugar content of A2,A8, and A10 was higher than that of CK(Fengyou 737), and the seed yields of A4,A3, A2, A1, A5, and A6 were higher than that of CK. The 11 rapeseed combinations were classified into 3 grades by grey relation analysis and cluster analysis. Two combinations, A4(Y20A×95C4R) and A11(3194A×09-5R), showed the weighted relation degrees higher than 0.95, which were clustered into grade I by cluster analysis. They had good agronomic traits and good performance as both oilseed and vegetable. A8, A5, A3, A7, A2, A10, A6, and A1 were clustered into grade Ⅱ and A9 into grade Ⅲ. In this study, the oilseed and vegetable dual-purpose rapeseed combinations were screened out based on grey relation analysis and cluster analysis,which can provide reference for the breeding of oilseed and vegetable dual-purpose rapeseed combinations.展开更多
Objective: To test the therapeutic effect of integrated traditional Chinese and western medicine on venous ulcer of lower limbs by Meta analysis method, and then to propose the best clinical treatment scheme. Methods:...Objective: To test the therapeutic effect of integrated traditional Chinese and western medicine on venous ulcer of lower limbs by Meta analysis method, and then to propose the best clinical treatment scheme. Methods: Domestic databases in the past 20 years (January 1999-December 2019) were searched by computer, including China Journal Full-text Database (CNKI), VIP, Wanfang and CBM. Literature was screened according to inclusion and exclusion criteria. Cochrane risk assessment tool was used to evaluate the quality of the included literature. Two-classification method was used to extract data. RevMan 5.3 software was used to make statistical analysis of the data. Results: Eleven articles were finally included, totaling 1,576 patients, 804 cases in the treatment group and 772 cases in the control group. Meta-analysis results show that there is no difference in heterogeneity and bias among the included literatures. The total effective rate (risk ratio [RR]=1.12, 95% confidence interval [CI]=1.09-1.15) of integrated traditional Chinese and western medicine in treating venous ulcer of lower limbs is higher, which is obviously better than that of western medicine alone. Conclusion: Through data analysis, it is concluded that in the study population, the treatment of integrated traditional Chinese and western medicine has a significant effect on venous ulcer of lower limbs. Make up for the deficiency of simple western medicine treatment, improve the cure rate and reduce the recurrence rate. However, there is currently a lack of relevant high-quality literature, so a large sample size, rigorous and standardized experimental design and randomized double-blind clinical study are needed to further test the conclusions.展开更多
Quick, simple to perform, and cheap biomarkers were combined in a rapid assessment approach to measure the effects of metal pollutants, Cu, Cd, Pb and Zn in meadow burozem on wheat. Analysis of orthogonal design showe...Quick, simple to perform, and cheap biomarkers were combined in a rapid assessment approach to measure the effects of metal pollutants, Cu, Cd, Pb and Zn in meadow burozem on wheat. Analysis of orthogonal design showed that the significant zinc factor indicated both the inhibition rate of shoot mass and that of root elongation were affected by zinc(P<0.05 and P<0.01, respectively). The first toxicity canonical variable (TOXI), formed from the toxicity data set, explained 49% of the total variance in the toxicity data set; the first biological canonical variable(BIOL) explained 42% of the total variation in the biological data set. The correlation between the first canonical variables TOXI and BIOL (canonical correlation) was 0.94 (P<0.0001). Therefore, it is reliable and feasible to use the achievement to assess toxicity of heavy metal combined polluted soil using canonical analysis. Toxicity of soil combined polluted by heavy metals to plant community was estimated by comparing the IC 50 values describing the concentration needed to cause 50% decrease with grow rate compared to no metal addition. Environmental quality standard for soils prescribe that all these tested concentration of heavy metals in soil should not cause hazard and pollution ultimately, whereas it indicated that the soils in second grade cause more or less than 50% inhibition rates of wheat growth. So environmental quality standard for soils can be modified to include other features.展开更多
Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were per...Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure （1-25 atm）, temperature （600-1300 K）, carbon dioxide to methane ratio （0-2） and oxygen to methane ratio （0-1）. The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition.展开更多
Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produc...Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produced from capturing the pressure energy has been calculated. Based on the comprehensive thermodynamic analysis, two systems have been proposed to capture pressure energy of natural gas to generate electricity. In this study, the expression of exergy is given which can be used in evaluating purposes. A problem with this multidisciplinary study is the complicated boundary condition. In conclusion, a technical prospect on recoverable natural gas pressure energy has been presented based on total energy system theory.展开更多
Anti-jamming performance evaluation has recently received significant attention. For Link-16, the anti-jamming performance evaluation and selection of the optimal anti-jamming technologies are urgent problems to be so...Anti-jamming performance evaluation has recently received significant attention. For Link-16, the anti-jamming performance evaluation and selection of the optimal anti-jamming technologies are urgent problems to be solved. A comprehensive evaluation method is proposed, which combines grey relational analysis (GRA) and cloud model, to evaluate the anti-jamming performances of Link-16. Firstly, on the basis of establishing the anti-jamming performance evaluation indicator system of Link-16, the linear combination of analytic hierarchy process(AHP) and entropy weight method (EWM) are used to calculate the combined weight. Secondly, the qualitative and quantitative concept transformation model, i.e., the cloud model, is introduced to evaluate the anti-jamming abilities of Link-16 under each jamming scheme. In addition, GRA calculates the correlation degree between evaluation indicators and the anti-jamming performance of Link-16, and assesses the best anti-jamming technology. Finally, simulation results prove that the proposed evaluation model can achieve the objective of feasible and practical evaluation, which opens up a novel way for the research of anti-jamming performance evaluations of Link-16.展开更多
For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft moveme...For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.展开更多
Diffusions of multiple components have numerous applications such as underground water flow, pollutant movement, stratospheric warming, and food processing. Particularly, liquid hydrogen is used in the cooling process...Diffusions of multiple components have numerous applications such as underground water flow, pollutant movement, stratospheric warming, and food processing. Particularly, liquid hydrogen is used in the cooling process of the aeroplane. Further, liquid nitrogen can find applications in cooling equipment or electronic devices, i.e., high temperature superconducting(HTS) cables. So, herein, we have analysed the entropy generation(EG), nonlinear thermal radiation and unsteady(time-dependent) nature of the flow on quadratic combined convective flow over a permeable slender cylinder with diffusions of liquid hydrogen and nitrogen. The governing equations for flow and heat transfer characteristics are expressed in terms of nonlinear coupled partial differential equations. The solutions of these equations are attempted numerically by employing the quasilinearization technique with the implicit finite difference approximation. It is found that EG is minimum for double diffusion(liquid hydrogen and heat diffusion)than triple diffusion(diffusion of liquid hydrogen, nitrogen and heat). The enhancing values of the radiation parameter R_(d) and temperature ratio θ_(w) augment the fluid temperature for steady and unsteady cases as well as the local Nusselt number. Because, the fluid absorbs the heat energy released due to radiation, and in turn releases the heat energy from the cylinder to the surrounding surface.展开更多
Cycle slip detection and repair is one of the key technologies for GNSS high-precision positioning.We introduce an enhanced methodology for detecting and repairing BDS four-frequency cycle slips,utilizing fuzzy cluste...Cycle slip detection and repair is one of the key technologies for GNSS high-precision positioning.We introduce an enhanced methodology for detecting and repairing BDS four-frequency cycle slips,utilizing fuzzy clustering analysis.Firstly,based on fuzzy clustering analysis,the optimal combinations for the BDS four-frequency,including extra-wide lane(EWL),wide lane(WL),and narrow lane(NL),were selected.Secondly,the feasibility of this method was verified using actual static and dynamic observation data,and different types of cycle slips were simulated for further validation.Meanwhile,the proposed method was compared with the classical Turbo-Edit method through experiments.Finally,cycle slips were repaired using the least squares method.According to the experimental results,the optimal geometry-free phase combinations(-2,2,1,-1),(1,-1,1,-1),(3,2,-2,-3),and the pseudo-range phase combination(-1,1,1,-1),selected based on fuzzy clustering analysis,were used for cycle slip detection.The proposed method accurately detected small,large,and specific cycle slips simulated in the actual data.Compared with the Turbo-Edit method,the proposed methodwas able to detect specific cycle slips that Turbo-Edit could not.It is worth noting that during the repair process,the coefficients of the combined observation values are integers,preserving the integer cycle characteristic of the observation values,which allows cycle slips to be fixed directly,eliminating the need for complex searching procedures.Consequently,by enhancing the precision and reliability of the detection of BDS four-frequency cycle slips,our proposed method provides the support for the high-precision localization of BDS multi-frequency observations.展开更多
文摘Inflammatory bowel disease(IBD),encompassing Crohn’s disease and ulcerative colitis,manifests as a chronic,recurrent,and refractory intestinal inflammatory condition significantly impacting patients’quality of life.Despite ongoing research,its etiology and pathogenesis remain incompletely understood.Recent advancements in medical research highlight the critical role of drug combination therapies in managing IBD.This paper employs the strengths,weaknesses,opportunities,and threats framework to evaluate the four strategic elements(strengths,weaknesses,opportunities,and threats)pertaining to combination therapies for IBD.Among the strengths,the paper underscores the efficacy of multi-targeted strategies,the advancement of personalized medicine,and the mitigation of drug resistance.Nonetheless,the analysis identifies significant weaknesses,including the prohibitive cost of treatment,issues with patient compliance,and the necessity for comprehensive long-term safety data.The paper also delineates opportunities to augment therapeutic success through the incorporation of biomarkers,the application of artificial intelligence,and extensive international collaborative efforts.In contrast,the paper does not shy away from addressing the threats,which include the potential for therapeutic resistance and the logistical challenges inherent in global therapy deployment.These initiatives aim to refine future therapeutic practices,fostering safer,more effective,and personalized treatment paradigms for IBD patients.
基金Projects(51334006,50274020)supported by the National Natural Science Foundation of China
文摘To determine the extrusion force of pipe fabricated by continuous casting and extrusion (CASTEX) using an expansion combination die, the metallic expansion combination die was divided into diversion zone, expansion zone, flow dividing zone, welding chamber, and sizing zone, and the corresponding stress formulae in various zones were established using the slab method. The deformation zones of CASTEX groove were divided into liquid and semisolid zone, solid primary gripping zone, and solid gripping zone, and the formulae of pipe extrusion forces were established. Experiments were carried out on the self-designed CASTEX machine to obtain the aluminum pipe and measure its extrusion force using the expansion combination die. The experimental results of radial extrusion force for aluminum pipe are in good agreement with the calculated ones.
文摘To improve the accuracy and speed in cycle-accurate power estimation, this paper uses multiple dimensional coefficients to build a Bayesian inference dynamic power model. By analyzing the power distribution and internal node state, we find the deficiency of only using port information. Then, we define the gate level number computing method and the concept of slice, and propose using slice analysis to distill switching density as coefficients in a special circuit stage and participate in Bayesian inference with port information. Experiments show that this method can reduce the power-per-cycle estimation error by 21.9% and the root mean square error by 25.0% compared with the original model, and maintain a 700 ＋ speedup compared with the existing gate-level power analysis technique.
文摘Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits, and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition, seedling height, diameter above ground, diameter at breast height （DBH） of 17 cross combination progenies were investigated. The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross combinations and seedlings. Further more, the result of multiple comparison showed that P.deltoides ‘Lux＇× P.deltoides ‘D324＇, P.ussuriensis cl. ‘U4＇× P deltoides ‘T66＇, P.ussuriensis cl. ‘U4＇× P. deltoides ‘T26＇, P.deltoides ‘Lux＇× P.ussuriensis cl. ‘U3＇, （P.tomentosa×P.bolleana）×（P.alba×P.glandulosa）, （P.alba×P.tomentosa）×（P.alba×P.glandulosa）, and （P.alba×P.glandulosa‘No.2＇）× P. tomentosa ‘Lumao 50＇ were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further test.
基金supported by grants from Key ProgramNational Natural Science Foundation of China(81930016)+3 种基金National Natural Science Foundation of China(81702858)Key Research&Development Plan of Zhejiang Province(2019C03050)National S&T Major Project(2017ZX10203205)National Natural Science Funds for Distinguished Young Scholar of China(81625003)。
文摘Background:Nonalcoholic fatty liver disease and its advanced stage,nonalcoholic steatohepatitis(NASH),are the major cause of hepatocellular carcinoma(HCC)and other end-stage liver disease.However,the potential mechanism and therapeutic strategies have not been clarified.This study aimed to identify potential roles of mi RNA/m RNA axis in the pathogenesis and drug combinations in the treatment of NASH.Methods:Microarray GSE59045 and GSE48452 were downloaded from the Gene Expression Omnibus and analyzed using R.Then we obtained differentially expressed genes(DE-genes).DAVID database was used for Gene Ontology(GO)analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment pathway analysis.Protein-protein interaction(PPI)networks were used for the identification of hub genes.We found upstream regulators of hub genes using mi RTar Base.The expression and correlation of key mi RNA and its targets were detected by q PCR.Drug Pair Seeker was employed to predict drug combinations against NASH.The expression of mi RNA and hub genes in HCC was identified in the Cancer Genome Atlas database and Human Protein Atlas database.Results:Ninety-four DE-genes were accessed.GO and KEGG analysis showed that these predicted genes were linked to lipid metabolism.Eleven genes were identified as hub genes in PPI networks,and they were highly expressed in cells with vigorous lipid metabolism.hsa-mi R-335-5 p was the upstream regulator of 9 genes in the 11 hub genes,and it was identified as a key mi RNA.The hub genes were highly expressed in NASH models,while hsa-mi R-335-5 p was lowly expressed.The correlation of mi RNA-m RNA was established by q PCR.Functional verification indicated that hsa-mi R-335-5 p had inhibitory effect on the development of NASH.Finally,drug combinations were predicted and the expression of mi RNA and hub genes in HCC was identified.Conclusions:In the study,potential mi RNA-m RNA pathways related to NASH were identified.Targeting these pathways may be novel strategies against NASH.
基金supported by the Science and Technology Project of Guangdong Province of China(Nos.2014A020213016,2014A020212445)the University-enterprise Joint Research Project"Intelligent detection network technology joint research centre"(No.40115031).
文摘We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.
基金Supported by Qilu Chinese Medicine Academic Heritage Project:[2020]No.132。
文摘Objective:To explore the rules of acupoint combination in acupuncture treatment of post-stroke pseudobulbar palsy(PBP),based on acupuncture prescriptions retrieved from literature and using complex network analysis.Methods:The articles were searched from China National Knowledge Infrastructure(CNKI),Wanfang and VIP databases as the source of data.The eligible articles were selected in accordance with inclusion and exclusion criteria.The relevant data were extracted to set up the acupoint prescription database in acupuncture treatment of PBP.By using co-occurrence relationship in acupoint prescriptions,the core acupoints and the combination rules were analyzed in acupuncture treatment of PBP.Results:A total of 194 articles were eligible finally,with 202 acupoint prescriptions extracted.19 core acupoints were collected in total,i.e.Liánquán(廉泉CV23),Fēngchí(风池GB20),Bǎihuì(百会GV20),Jīnjīn(金津EX-HN12),Yùyè(玉液EX-HN13),Fēngfǔ(风府GV16),Yǎmén(哑门GV15),Shuǐgōu(水沟GV26),Nèiguān(内关PC6),Fēnglóng(丰隆ST40),Wángǔ(完骨GB12),Sānyīnjiāo(三阴交SP16),Yìfēng(翳风TE17),Tōnglǐ(通里HT5),Tàichōng(太冲LR3),Hégǔ(合谷LI4),Hǎiquán(海泉EX-HN11),Jùquán(聚泉EX-HN10)and Yìntáng(印堂EX-HN3).The core acupoint groups were CV23-GB20,EX-HN12-EX-HN13 and GV26-PC6-SP6.Acupoints were mostly selected from governor vessel.The methods of acupoint combination included the combination of distal and nearby points,and the combination of the acupoints located in the front and on the back.Conclusions:In treatment of PBP with acupuncture,biaoben(manifestation and root cause)theory is emphasized,the methods for dispelling wind,resolving phlegm,regaining consciousness,and opening orifices are recommended.Moreover,the attentions are paid on spirit regulation,holistic adjustment,and syndrome differentiation in treatment.
文摘Listeria monocytogenes is the pathogen of listeriosis and it causes severe infections like septicemia, encephalitis, and meningitis, especially in immunocompromised individuals, newborns, and pregnant women. Its wide distribution in the environment and ability to survive or even grow under adverse conditions has made L. monocytogenes an important public health concern and in food industry.
基金supported by Major State Basic Research Development Program(No. 2013CB338004)National Natural Science Foundation of China(No.61402286, 61202372,61202371,61309021)National Science and Technology Major Project of the Ministry of Science and Technology of China (No.2014ZX01032401-001)
文摘Power analysis is a non-invaslve attack against cryptographic hardware, which effectively exploits runtime power consumption characteristics of circuits. This paper proposes a new power model which combines Hamming Distance model and the model based on the template value of power consumption in combinational logic circuit. The new model can describe the power consumption characteristics of sequential logic circuits and those of combinational logic as well. The new model can be used to improve the existing power analysis methods and detect the information leakage of power consumption. Experimental results show that, compared to CPA（Correlation Power Analysis） method, our proposed attack which adopt the combinational model is more efficient in terms of the number of required power traces.
基金Supported by the National Natural Science Foundation of China(No.81373826,No.81100658)Development Project of Science and Technology of Traditional Chinese Medicine of Shandong Province(No.2013ZDZK-083)Development Project of Medicine and Health Science Technology of Shandong Province(No.2013WS0251)
文摘AIMTo compare the efficacy of intravitreal ranibizumab (IVR) alone or in combination with photodynamic therapy (PDT) vs PDT in patients with symptomatic polypoidal choroidal vasculopathy (PCV).METHODSA systematic search of a wide range of databases (including PubMed, EMBASE, Cochrane Library and Web of Science) was searched to identify relevant studies. Both randomized controlled trials (RCTs) and non-RCT studies were included. Methodological quality of included literatures was evaluated according to the Newcastle-Ottawa Scale. RevMan 5.2.7 software was used to do the Meta-analysis.RESULTSThree RCTs and 6 retrospective studies were included. The results showed that PDT monotherapy had a significantly higher proportion in patients who achieved complete regression of polyps than IVR monotherapy at months 3, 6, and 12 (All P≤0.01), respectively. However, IVR had a tendency to be more effective in improving vision on the basis of RCTs. The proportion of patients who gained complete regression of polyps revealed that there was no significant difference between the combination treatment and PDT monotherapy. The mean change of best-corrected visual acuity (BCVA) from baseline showed that the combination treatment had significant superiority in improving vision vs PDT monotherapy at months 3, 6 and 24 (All P<0.05), respectively. In the mean time, this comparison result was also significant at month 12 (P<0.01) after removal of a heterogeneous study.CONCLUSIONIVR has non-inferiority compare with PDT either in stabilizing or in improving vision, although it can hardly promote the regression of polyps. The combination treatment of PDT and IVR can exert a synergistic effect on regressing polyps and on maintaining or improving visual acuity. Thus, it can be the first-line therapy for PCV.
文摘AIM:To assess the effects of the fixed combination of0.005% latanoprost and 0.5% timolol(FCLT) vs their individual components for primary open angle glaucoma(POAG) and ocular hypertension(OHT).· METHODS:After searched PubMed, EMBASE, the Cochrane Library and SCI, all randomized controlled clinical trials(RCTs) and cross-over studies were included. The control groups were the monotherapy or the concomitant therapy of latanoprost and timolol. The outcomes were visual field defect, optic atrophy, mean intraocular pressure(IOP) and IOP fluctuation. The analysis was carried out in RevMan version 5.1 software.RESULTS:Thepost-interventionmeanIOPofFCLTwas significantly lower compared to timolol [mean difference(MD)-2.92, 95%CI-3.28 to-2.55, P 【0.00001] and latanoprost(MD-1.11, 95%CI-1.51 to-0.72, P 【0.00001). The postintervention IOP fluctuation was also significantly lower compared to timolol(MD-0.88, 95%CI-1.23 to-0.53, P 【0. 00001) and latanoprost( MD- 0. 63, 95 % CI- 1. 04to-0.22, P =0.002). The mean IOP was higher in FCLT morning dose group than the one in unfixed combination of 0.005% latanoprost and 0.5% timolol(UFCLT)(MD1.10, 95% CI 0.81 to 1.39, P 【0.00001). Otherwise, there was no difference between FCLT evening dose group and UFCLT(MD 0.34, 95% CI-0.01 to 0.69, P =0.06).There was no statistical difference for the incidence ofvisual field defect and optic atrophy between FCLT and the monotherapy of components.CONCLUSION:A better IOP lowering effect has been demonstrated for FCLT compared to the monotherapy of components. The IOP lowering effect was worse for FCLT morning dose and almost same for FCLT evening dose compared to the UFCLT. We need more long-term high quality RCTs to demonstrate the outcomes of visual field defect and optic atrophy.visual field defect and optic atrophy between FCLT and the monotherapy of components.CONCLUSION:A better IOP lowering effect has been demonstrated for FCLT compared to the monotherapy of components. The IOP lowering effect was worse for FCLT morning dose and almost same for FCLT evening dose compared to the UFCLT. We need more long-term high quality RCTs to demonstrate the outcomes of visual field defect and optic atrophy.
文摘To screen out the rapeseed(Brassica napus) combinations that are suitable for the production of both oilseed and vegetable, we carried out a field experiment for 11 new combinations(hybrids) of rapeseed and then performed grey relation analysis and cluster analysis on 12 traits including the yield and quality of young stem,seed yield, and several agronomic traits after harvesting of young stem. The results showed that A11, A7, and A4 had higher main stalk yield than other combinations.The young stem/leaf ratios of A11, A5, A7, A4, A3, and A1 were in line with the quality requirements for young stem commodity. The soluble sugar content of A2,A8, and A10 was higher than that of CK(Fengyou 737), and the seed yields of A4,A3, A2, A1, A5, and A6 were higher than that of CK. The 11 rapeseed combinations were classified into 3 grades by grey relation analysis and cluster analysis. Two combinations, A4(Y20A×95C4R) and A11(3194A×09-5R), showed the weighted relation degrees higher than 0.95, which were clustered into grade I by cluster analysis. They had good agronomic traits and good performance as both oilseed and vegetable. A8, A5, A3, A7, A2, A10, A6, and A1 were clustered into grade Ⅱ and A9 into grade Ⅲ. In this study, the oilseed and vegetable dual-purpose rapeseed combinations were screened out based on grey relation analysis and cluster analysis,which can provide reference for the breeding of oilseed and vegetable dual-purpose rapeseed combinations.
基金National Natural Science Foundation of China Youth Program(No.81804095)Project of Collaborative Innovation Center for Traditional Chinese Medicine Health Services in Shanghai(No.ZYJKFW201701002)
文摘Objective: To test the therapeutic effect of integrated traditional Chinese and western medicine on venous ulcer of lower limbs by Meta analysis method, and then to propose the best clinical treatment scheme. Methods: Domestic databases in the past 20 years (January 1999-December 2019) were searched by computer, including China Journal Full-text Database (CNKI), VIP, Wanfang and CBM. Literature was screened according to inclusion and exclusion criteria. Cochrane risk assessment tool was used to evaluate the quality of the included literature. Two-classification method was used to extract data. RevMan 5.3 software was used to make statistical analysis of the data. Results: Eleven articles were finally included, totaling 1,576 patients, 804 cases in the treatment group and 772 cases in the control group. Meta-analysis results show that there is no difference in heterogeneity and bias among the included literatures. The total effective rate (risk ratio [RR]=1.12, 95% confidence interval [CI]=1.09-1.15) of integrated traditional Chinese and western medicine in treating venous ulcer of lower limbs is higher, which is obviously better than that of western medicine alone. Conclusion: Through data analysis, it is concluded that in the study population, the treatment of integrated traditional Chinese and western medicine has a significant effect on venous ulcer of lower limbs. Make up for the deficiency of simple western medicine treatment, improve the cure rate and reduce the recurrence rate. However, there is currently a lack of relevant high-quality literature, so a large sample size, rigorous and standardized experimental design and randomized double-blind clinical study are needed to further test the conclusions.
文摘Quick, simple to perform, and cheap biomarkers were combined in a rapid assessment approach to measure the effects of metal pollutants, Cu, Cd, Pb and Zn in meadow burozem on wheat. Analysis of orthogonal design showed that the significant zinc factor indicated both the inhibition rate of shoot mass and that of root elongation were affected by zinc(P<0.05 and P<0.01, respectively). The first toxicity canonical variable (TOXI), formed from the toxicity data set, explained 49% of the total variance in the toxicity data set; the first biological canonical variable(BIOL) explained 42% of the total variation in the biological data set. The correlation between the first canonical variables TOXI and BIOL (canonical correlation) was 0.94 (P<0.0001). Therefore, it is reliable and feasible to use the achievement to assess toxicity of heavy metal combined polluted soil using canonical analysis. Toxicity of soil combined polluted by heavy metals to plant community was estimated by comparing the IC 50 values describing the concentration needed to cause 50% decrease with grow rate compared to no metal addition. Environmental quality standard for soils prescribe that all these tested concentration of heavy metals in soil should not cause hazard and pollution ultimately, whereas it indicated that the soils in second grade cause more or less than 50% inhibition rates of wheat growth. So environmental quality standard for soils can be modified to include other features.
基金supported by University of Kashan(Grant No.158426/5)
文摘Thermodynamic analysis was applied to study combined partial oxidation and carbon dioxide reforming of methane in view of carbon formation. The equilibrium calculations employing the Gibbs energy minimization were performed upon wide ranges of pressure （1-25 atm）, temperature （600-1300 K）, carbon dioxide to methane ratio （0-2） and oxygen to methane ratio （0-1）. The thermodynamic results were compared with the results obtained over a Ru supported catalyst. The results revealed that by increasing the reaction pressure methane conversion decreased. Also it was found that the atmospheric pressure is the preferable pressure for both dry reforming and partial oxidation of methane and increasing the temperature caused increases in both activity of carbon and conversion of methane. The results clearly showed that the addition of O2 to the feed mixture could lead to a reduction of carbon deposition.
基金Supported by Tianjin Institute of Urban Construction(03046)
文摘Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produced from capturing the pressure energy has been calculated. Based on the comprehensive thermodynamic analysis, two systems have been proposed to capture pressure energy of natural gas to generate electricity. In this study, the expression of exergy is given which can be used in evaluating purposes. A problem with this multidisciplinary study is the complicated boundary condition. In conclusion, a technical prospect on recoverable natural gas pressure energy has been presented based on total energy system theory.
基金Heilongjiang Provincial Natural Science Foundation of China (LH2021F009)。
文摘Anti-jamming performance evaluation has recently received significant attention. For Link-16, the anti-jamming performance evaluation and selection of the optimal anti-jamming technologies are urgent problems to be solved. A comprehensive evaluation method is proposed, which combines grey relational analysis (GRA) and cloud model, to evaluate the anti-jamming performances of Link-16. Firstly, on the basis of establishing the anti-jamming performance evaluation indicator system of Link-16, the linear combination of analytic hierarchy process(AHP) and entropy weight method (EWM) are used to calculate the combined weight. Secondly, the qualitative and quantitative concept transformation model, i.e., the cloud model, is introduced to evaluate the anti-jamming abilities of Link-16 under each jamming scheme. In addition, GRA calculates the correlation degree between evaluation indicators and the anti-jamming performance of Link-16, and assesses the best anti-jamming technology. Finally, simulation results prove that the proposed evaluation model can achieve the objective of feasible and practical evaluation, which opens up a novel way for the research of anti-jamming performance evaluations of Link-16.
基金supported by the National Natural Science Foundation of China (Grant No.51705145, 51779092)the National Key Research and Development Program of China (Grant No.2016YFC0300502 and No.2017YFC0307501)+1 种基金Natural Science Foundation of Hunan Province of China (Grant No.2019JJ50182)Research Foundation of Education Bureau of Hunan Province (Grant No.18B205)
文摘For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.
文摘Diffusions of multiple components have numerous applications such as underground water flow, pollutant movement, stratospheric warming, and food processing. Particularly, liquid hydrogen is used in the cooling process of the aeroplane. Further, liquid nitrogen can find applications in cooling equipment or electronic devices, i.e., high temperature superconducting(HTS) cables. So, herein, we have analysed the entropy generation(EG), nonlinear thermal radiation and unsteady(time-dependent) nature of the flow on quadratic combined convective flow over a permeable slender cylinder with diffusions of liquid hydrogen and nitrogen. The governing equations for flow and heat transfer characteristics are expressed in terms of nonlinear coupled partial differential equations. The solutions of these equations are attempted numerically by employing the quasilinearization technique with the implicit finite difference approximation. It is found that EG is minimum for double diffusion(liquid hydrogen and heat diffusion)than triple diffusion(diffusion of liquid hydrogen, nitrogen and heat). The enhancing values of the radiation parameter R_(d) and temperature ratio θ_(w) augment the fluid temperature for steady and unsteady cases as well as the local Nusselt number. Because, the fluid absorbs the heat energy released due to radiation, and in turn releases the heat energy from the cylinder to the surrounding surface.
基金supported by the National Natural Science Foundation of China(42174003)the Gansu Provincial Department of Education:Innovation Fund Project for College Teachers(2023A-035)+1 种基金Gansu Provincial Science and Technology Program(Joint Research Fund),24JRRA856the Lanzhou Talent Innovation Project,2023-RC-31.
文摘Cycle slip detection and repair is one of the key technologies for GNSS high-precision positioning.We introduce an enhanced methodology for detecting and repairing BDS four-frequency cycle slips,utilizing fuzzy clustering analysis.Firstly,based on fuzzy clustering analysis,the optimal combinations for the BDS four-frequency,including extra-wide lane(EWL),wide lane(WL),and narrow lane(NL),were selected.Secondly,the feasibility of this method was verified using actual static and dynamic observation data,and different types of cycle slips were simulated for further validation.Meanwhile,the proposed method was compared with the classical Turbo-Edit method through experiments.Finally,cycle slips were repaired using the least squares method.According to the experimental results,the optimal geometry-free phase combinations(-2,2,1,-1),(1,-1,1,-1),(3,2,-2,-3),and the pseudo-range phase combination(-1,1,1,-1),selected based on fuzzy clustering analysis,were used for cycle slip detection.The proposed method accurately detected small,large,and specific cycle slips simulated in the actual data.Compared with the Turbo-Edit method,the proposed methodwas able to detect specific cycle slips that Turbo-Edit could not.It is worth noting that during the repair process,the coefficients of the combined observation values are integers,preserving the integer cycle characteristic of the observation values,which allows cycle slips to be fixed directly,eliminating the need for complex searching procedures.Consequently,by enhancing the precision and reliability of the detection of BDS four-frequency cycle slips,our proposed method provides the support for the high-precision localization of BDS multi-frequency observations.
