The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(M...The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(MLS),which is inherently nonlinear and unstable system.The proposal is to deploy discrete optimal pole-zero approximation method for realization of digital fractional order controller.An approach of phase shaping by slope cancellation of asymptotic phase plots for zeros and poles within given bandwidth is explored.The controller parameters are tuned using dynamic particle swarm optimization(d PSO)technique.Effectiveness of the proposed control scheme is verified by simulation and experimental results.The performance of realized digital FO-PID controller has been compared with that of the integer order PID controllers.It is observed that effort required in fractional order control is smaller as compared with its integer counterpart for obtaining the same system performance.展开更多
Highly accurate positioning is a crucial prerequisite of multi Unmanned Aerial Vehicle close-formation flight for target tracking,formation keeping,and collision avoidance.Although the position of a UAV can be obtaine...Highly accurate positioning is a crucial prerequisite of multi Unmanned Aerial Vehicle close-formation flight for target tracking,formation keeping,and collision avoidance.Although the position of a UAV can be obtained through the Global Positioning System(GPS),it is difficult for a UAV to obtain highly accurate positioning data in a GPS-denied environment(e.g.,a GPS jamming area,suburb,urban canyon,or mountain area);this may cause it to miss a tracking target or collide with another UAV.In particular,UAV close-formation control in GPS-denied environments faces difficulties owing to the low-accuracy position,close distance between vehicles,and nonholonomic dynamics of a UAV.In this paper,on the one hand,we develop an innovative UAV formation localization method to address the formation localization issues in GPS-denied environments;on the other hand,we design a novel reinforcement learning based algorithm to achieve the high-efficiency and robust performance of the controller.First,a novel Lidar-based localization algorithm is developed to measure the localization of each aircraft in the formation flight.In our solution,each UAV is equipped with Lidar as the position measurement sensor instead of the GPS module.The k-means algorithm is implemented to calculate the center point position of UAV.A novel formation position vector matching method is proposed to match center points with UAVs in the formation and estimate their position information.Second,a reinforcement learning based UAV formation control algorithm is developed by selecting the optimal policy to control UAV swarm to start and keep flying in a close formation of a specific geometry.Third,the innovative collision risk evaluation module is proposed to address the collision-free issues in the formation group.Finally,a novel experience replay method is also provided in this paper to enhance the learning efficiency.Experimental results validate the accuracy,effectiveness,and robustness of the proposed scheme.展开更多
Objective:To analyse the laboratory surveillance data from 2004 till 2008 to examine the changing trend of rubella cases in Malaysia.Methods:Samples for this study were either received through the measles case based s...Objective:To analyse the laboratory surveillance data from 2004 till 2008 to examine the changing trend of rubella cases in Malaysia.Methods:Samples for this study were either received through the measles case based surveillance program or were hospital cases received for sero-diagnosis of congenital rubella syndrome(CRS). Specific rubella IgM antibody test was carried out on all samples that were negative for measles IgM antibody and for sero-diagnosis of CRS.Results:Through the surveillance program for measles,the samples received for rubella had increased five fold from 365 in 2004 to 1 522 in 2007.Positive rubella cases detected had also increased from 4.1%in 2004 to 33.2%in 2007.The age group 11 to 20 years accounted for 73.6%of rubella cases confirmed in 2008,with a higher incidence among males than females.Positive rubella IgM was detected in 25 CRS cases during the 6 year period between January 2003 and December 2008.Conclusion:The measles elimination program had contributed to significant progress in the control of rubella,with the majority of rubella cases detected through this strategy.Since rubella is not notifiable in Malaysia,this integrated measles and rubella surveillance should be continued.However,to enhance the progress,specific targets should also be established in the national program to eliminate rubella and CRS.展开更多
During well-killing operations for the workover of low-pressure gas wells,formation pressure should be balanced so as to guarantee well control safety by preventing natural gas overflow.In this paper,a laboratory eval...During well-killing operations for the workover of low-pressure gas wells,formation pressure should be balanced so as to guarantee well control safety by preventing natural gas overflow.In this paper,a laboratory evaluation was conducted with fuzzy-ball fluids as killing fluids.The results show that,the fuzzy-ball fluid,with a density of 0.5e1.5 g/cm^(3) and a viscosity up to 78,50,000 mPa$s at a low shear rate,realizes controllable performance and forms piston-like plugging slugs of solid-free high structural strength on natural gas wellbore after bonding.During well workover,multiple fluid column pressures were set up by injecting fuzzy-ball fluids with different densities at various rates.Owing to high structural strength of the fluids at a low shear rate,natural gas breaks through only inside the piston-like slug and cannot flow upwards to the ground,so the pathways of natural gas in the wellbore are isolated from the ground surface.Moreover,the fluid can wholly move up and down like a piston-like plug,with the change of formation pressures or the tripping of pipe strings.Like the conventional operations,the production can be restored after the workover,so long as the fluid in wellbore is cleaned by means of gas lift.In a natural gas field in NW China,where the formation pressure coefficient dropped to 0.60e0.82,three wells were fully filled with fuzzy-ball workover fluids for 7 days and another three wells were treated with the piston-like plugs of fuzzy-ball workover fluids for only 3 days.They all presented better technical results.The technology provides a new way for low-pressure gas well workover.展开更多
This paper presents a model and analysis for a flexible link with non-collocations of sensors and actuators. It shows the changes in the system dynamics and the appearance of zeroes in the right-plan complex, turning ...This paper presents a model and analysis for a flexible link with non-collocations of sensors and actuators. It shows the changes in the system dynamics and the appearance of zeroes in the right-plan complex, turning the system a non-minimum phase system. The performance of the PID （proportional-integral-derivative） and LQR （linear quadratic regulator） controller are discussed considering the zero dynamics of the system in three points of special interest： （I） the collocated case, when the sensor is in the base of the link; （2） the critical case, where the system starts to present zeroes in the right-plan complex and （3） the limit case, when the sensors are in the end point of the flexible link. Investigation for a simple rigid-flexible model with one mode, in the three cases, the PID and LQR controller performance are damage. To deal with this kind of problem, new control techniques should be developed.展开更多
In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the con...In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the construction of the high performance computer （HPC） system, the plasma configuration real-time reconstruction with EFIT code, the immigration of plasma simulation codes, the improvement of the poloidal field control system with circulating current, the design of the new data acquiring device with higher anti-disturbing power, the new software on soft X-ray spectrum measurement providing the multi-channel Te evolution, the upgrade to the HL-2A data storage system and experimental net. On the other hand, according to the arrangement of HL-2A modification project, a series of designs such as new plasma configuration, poloidal field coils distribution and plasma shape and position control system are on the processing.展开更多
An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This ...An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.展开更多
BACKGROUND Seek highly effective treatment measures for improving mood and sleep.AIM To explore the effects of mood and depression in patients with endometrial cancer after cognitive behavioral therapy(CBT)and mindful...BACKGROUND Seek highly effective treatment measures for improving mood and sleep.AIM To explore the effects of mood and depression in patients with endometrial cancer after cognitive behavioral therapy(CBT)and mindfulness-based stress reduction.METHODS In a prospective study,90 patients with diabetes,endometrial cancer,and depression were selected from January 2023 to January 2024 in our hospital.There were 45 patients in the control group and 45 patients in the observation group.In addition to the conventional treatment,the control group received cognitive behavioral treatment,and the observation group:Control group was given to compare changes in mood state and sleep quality before and after the intervention.Follow-up was performed3 months after treatment completion.RESULTS Before treatment,the mood and sleep quality scores between the two groups(P>0.05);in the observation group,the 5 negative mood scores were lower and lower than the control group;the 2 positive mood scores were higher than in the control group,and the difference was statistically significant(P<0.05);compared with before treatment,the 7 sleep quality scores and Pittsburgh sleep quality index scale total score in the observation group and lower in the control group(P<0.05).CONCLUSION In patients with diabetes and endometrial cancer,mood state and sleep quality significantly improved after CBT and breathing relaxation.These findings provide new and effective treatment strategies in clinical practice.展开更多
Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic congestion.However,little has ...Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic congestion.However,little has been done on the optimization of air route network in the fragmented airspace caused by prohibited,restricted,and dangerous areas（PRDs）.In this paper,an air route network optimization model is developed with the total operational cost as the objective function while airspace restriction,air route network capacity,and non-straight-line factors（NSLF） are taken as major constraints.A square grid cellular space,Moore neighbors,a fixed boundary,together with a set of rules for solving the route network optimization model are designed based on cellular automata.The empirical traffic of airports with the largest traffic volume in each of the 9 flight information regions in China's Mainland is collected as the origin-destination（OD） airport pair demands.Based on traffic patterns,the model generates 35 air routes which successfully avoids 144 PRDs.Compared with the current air route network structure,the number of nodes decreases by 41.67%,while the total length of flight segments and air routes drop by 32.03% and 5.82% respectively.The NSLF decreases by 5.82% with changes in the total length of the air route network.More importantly,the total operational cost of the whole network decreases by 6.22%.The computational results show the potential benefits of the model and the advantage of the algorithm.Optimization of air route network can significantly reduce operational cost while ensuring operation safety.展开更多
In this work. phenol and oxalic acid （OA） degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe3 ＋/TiO2 catalyst. The ferrioxalate complex formed between Fe3＋ and oxalate ...In this work. phenol and oxalic acid （OA） degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe3 ＋/TiO2 catalyst. The ferrioxalate complex formed between Fe3＋ and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of-OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe3＋/TiO2 catalyzed processes, because Fe＋ was greatly reduced but not regenerated in many cases. The synergetic effect was found to be highly related with the property of the target pollutants. Fe3 ＋/TiO2 catalyzed system showed the highest ability to destroy organics, but the TiO2 catalyzed system showed little higher synergy.展开更多
To assess the knowledge, attitudes, and practices(KAP) on Zika virus infection among pregnant women in Brunei Darussalam by a cross-sectional survey. Methods: Between February and June 2017, we recruited 234 pregnant ...To assess the knowledge, attitudes, and practices(KAP) on Zika virus infection among pregnant women in Brunei Darussalam by a cross-sectional survey. Methods: Between February and June 2017, we recruited 234 pregnant women from all government healthcare centres at Brunei-Muara district, using a modified systematic sampling approach. A pre-tested and self-administered questionnaire was used and data analysis was conducted using descriptive statistics and multiple logistic regression analyses. Results: The study participants were mainly Malay(87.2%) and their mean age was 28.0 years. The median knowledge score was 13, out of a possible score of 28. Most participants(92.7%) knew that Zika virus was transmitted by mosquito bites whereas some(34.6%) knew that sexual transmission was also possible. Media(radio, television or newspapers) was the preferred source of updated information on Zika virus, followed by healthcare workers(44.0%), government announcements(43.2%), and social media(38.0%). Pregnant women who were 25 years old or older [Adj. OR=3.62(95% CI: 1.57, 9.51)], not Malays [Adj. OR=3.32(95% CI: 1.35, 8.55)], and had an average monthly household income of more than BND $3 000 [Adj. OR=4.06(95% CI: 1.81, 19.44)] were more likely to score higher for knowledge on Zika virus. The median prevention practice score was 23, out of a possible score of 36. Most participants reported wearing covering clothes(98.3%) and kept their living surroundings clean(99.6%). Most participants(88.0%) agreed that Zika is an important issue in their community. Conclusion: We found a lack of knowledge on Zika virus infection among pregnant women attending government maternal and child healthcare centres in Brunei Darussalam, in particular that Zika virus can be sexually transmitted. Such information could be well disseminated at the healthcare centre level. Health literacy studies should be conducted to understand the facilitators and barriers of KAP on Zika virus infection among pregnant women.展开更多
The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuatio...The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuation Analysis(DFA) during the lockdown period(March 24–April 20, 2020) and the corresponding period during the previous two years(i.e., 2018 and 2019). The analysis suggests the anticipated impact of confinement on the PMand NOconcentration in urban cities, causing low concentrations. It is observed that the original PMand NOconcentration time series is persistent but filtering the time series by fitting the autoregressive process of order 1 on the actual time series and subtracting it changes the persistence property significantly. It indicates the presence of linear correlations in the PMand NOconcentrations. Hurst exponent of the PMand NOconcentration during the lockdown period and previous two years shows that the inherent temporal characteristics of the short-term air pollutant concentrations(APCs) time series do not change even after withholding the emissions. The meteorological variations also do not change over the three time periods. The finding helps in developing the prediction models for future policy decisions to improve urban air quality across cities.展开更多
Objective:To determine the prevalence and risk factors associated with tuberculosis mortality in Brunei Darussalam and to explore its underlying causes.Methods:A retrospective cohort study was conducted where data on ...Objective:To determine the prevalence and risk factors associated with tuberculosis mortality in Brunei Darussalam and to explore its underlying causes.Methods:A retrospective cohort study was conducted where data on socio-demographics,clinical characteristics and treatment outcomes of all tuberculosis patients registered at the National tuberculosis Coordinating Centre between 2013 and 2017 were collected.Overall tuberculosis mortality and the proportion of tuberculosis-related deaths were calculated.Logistic regression analysis was used to determine the risk factors of tuberculosis mortality when compared to those who are cured and/or completed tuberculosis treatment.Results:Of 1107 tuberculosis cases,99 died,giving an overall tuberculosis mortality rate of 8.9%(95%CI 7.4%-10.8%).Significant risk factors associated with tuberculosis mortality were age≥40 years(adjusted OR for 40-59 years was 3.89;95%CI 1.13-1.69;adjusted OR for≥60 years was 22.3;95%CI 7.27-91.9,using 20-39 years as reference),female sex(adjusted OR 1.74;95%CI 1.09-2.79),having renal disease(adjusted OR 25.7;95%CI 2.82-191.50)and having any cancers(adjusted OR 3.61;95%CI 1.26-10.00).The majority(75.8%)of the recorded deaths were not related to tuberculosis.Conclusions:Tuberculosis patients who were older than 40 years,female,and having renal disease and any cancer will need close monitoring in their management program to prevent tuberculosis mortality.Clinicians should also focus on other non-tuberculosis aspects of the patient’s medical history.展开更多
Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only syste...Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only system parameters, such as configuration, hazard rate, coverage, repair rate, etc. along with periodic proof-tests （or inspection）. Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants, chemical plants, etc. In this paper, a basic model of IEC 61508 is used. The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test. A new safety index, probability of failure on actual demand （PFAD） based on extended model and demand rate is proposed. Periodic proof-test makes the model semi-Markovian, so a piece-wise continuous time Markov chain （CTMC） based method is used to derive mean state probabilities of elementary or aggregated state. Method to determine probability of failure on demand （PFD） （IEC 61508） and PFAD based on these state probabilities are described. In example, safety indices of PFD and PFAD are compared.展开更多
In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including r...In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including reaction pH, DA concentration and enzyme concentration, a central composite response surface method was applied. The optimal condition was determined as p H value of 5.92, laccase concentration of 0.25 mg mL^(-1) and DA concentration of 12.74 mg mL^(-1), under which a high enzyme activity recovery of 88.17% was obtained.By comparing with free laccase, the stabilities of immobilized laccase towards p H, thermostability, storage were enhanced significantly.Approximately 60% of relative activity for immobilized laccase was remained after being incubated for 6 h at 50℃, but the free laccase only remained 25%. After 40 days of storage at 4℃, the laccase immobilized by DA kept about 89% of its original activity, but the free laccase only retained 48%. After recycled 10 times, the relative activity of immobilized laccase still retained 70%. The immobilized laccase was then applied to catalyze the degradation of 4-chlorophenol(4-CP), 86% percentage of 4-CP was removed within 2 h. After degraded 10 times, the relative activity of immobilized laccase still remained 64% of its initial activity, which exhibits an excellent reusability and operational stability.展开更多
To investigate the prevalence of drug-resistance mutations,resistance to antiretroviral drugs,and the subsequent virological response to therapy in treatment-naive and antiretroviral-treated patients infected with HIV...To investigate the prevalence of drug-resistance mutations,resistance to antiretroviral drugs,and the subsequent virological response to therapy in treatment-naive and antiretroviral-treated patients infected with HIV/AIDS in Henan,China,a total of 431 plasma samples were collected in Queshan county between 2003 and 2004,from patients undergoing the antiretroviral regimen Zidovudine + Didanosine + Nevirapine(Azt+Ddi+Nvp).Personal information was collected by face to face interview.Viral load and genotypic drug resistance were tested.Drug resistance mutation data were obtained by analyzing patient-derived sequences through the HIVdb Program(http://hivdb.stanford.edu).Overall,38.5% of treatment-naive patients had undetectable plasma viral load(VL),the rate significantly increased to 61.9% in 0 to 6 months treatment patients(mean 3 months)(P<0.005)but again significantly decrease to 38.6% in 6 to 12 months treatment patients(mean 9 months)(P<0.001)and 40.0% in patients receiving more than 12 months treatment(mean 16 months)(P<0.005).The prevalence of drug resistance in patients who had a detectable VL and available sequences were 7.0%,48.6%,70.8%,72.3% in treatment-na?ve,0 to 6 months treatment,6 to 12 months treatment,and treatment for greater than 12 months patients,respectively.No mutation associated with resistance to Protease inhibitor(PI)was detected in this study.Nucleoside RT inhibitor(NRTI)mutations always emerged after non-nucleoside RT inhibitor(NNRTI)mutations,and were only found in patients treated for more than 6 months,with a frequency less than 5%,with the exception of mutation T215Y(12.8%,6/47)which occurred in patients treated for more than 12 months.NNRTI mutations emerged quickly after therapy begun,and increased significantly in patients treated for more than 6 months(P<0.005),and the most frequent mutations were K103N,V106A,Y181C,G190A.There had been optimal viral suppression in patients undergoing treatment for less than 6 months in Queshan,Henan.The drug resistance strains were highly prevalent in antiretroviral-treated patients,and increased with the continuation of therapy,with many patients encountering virological failure after 6 months therapy.展开更多
Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach t...Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride （NaF） on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin （IL）-1β, matrix metalloproteinase 9 （MMP9）, and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL （receptor activator of nuclear factor KB ligand） and macrophage colony-stimulating factor （M-CSF）. The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells （NFAT） cl was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATcl, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.展开更多
Objective:To determine the potential effect of environment variables on cutaneous leishmaniasis occurrence using time-series models and compare the predictive ability of seasonal autoregressive integrated moving avera...Objective:To determine the potential effect of environment variables on cutaneous leishmaniasis occurrence using time-series models and compare the predictive ability of seasonal autoregressive integrated moving average(SARIMA)models and Markov switching model(MSM).Methods:This descriptive study employed yearly and monthly data of 49364 parasitologically-confirmed cases of cutaneous leishmaniasis in Isfahan province,located in the center of Iran from January 2000 to December 2019.The data were provided by the leishmaniasis national surveillance system,the meteorological organization of Isfahan province,and Iranian Space Agency for vegetation information.The SARIMA and MSM models were implemented to examine the environmental factors of cutaneous leishmaniasis epidemics.Results:The minimum relative humidity,maximum relative humidity,minimum wind speed,and maximum wind speed were significantly associated with cutaneous leishmaniasis epidemics in different lags(P<0.05).Comparing SARIMA and MSM,Akaikes information criterion(AIC),and mean absolute percentage error(MAPE)in MSM were much smaller than SARIMA models(MSM:AIC=0.95,MAPE=3.5%;SARIMA:AIC=158.93,MAPE:11.45%).Conclusions:SARIMA and MSM can be a useful tool for predicting cutaneous leishmaniasis in Isfahan province.Since cutaneous leishmaniasis falls into one of two states of epidemic and non-epidemic,the use of MSM(dynamic)is recommended,which can provide more information compared to models that use a single distribution for all observations(Box-Jenkins SARIMA model).展开更多
Commercial production of unconventional oil and gas resources will not be easily achieved without large-scale engineering measures,let alone the additional operation cost,increasingly stricter requirement for safety a...Commercial production of unconventional oil and gas resources will not be easily achieved without large-scale engineering measures,let alone the additional operation cost,increasingly stricter requirement for safety and environment,fluctuating low oil and gas prices,etc.,defeating the confidence of those investors.Therefore,unconventional measures are urgently needed to guide the exploration and exploitation of unconventional oil and gas resources.Thus,we put forward the concept of joint exploration and development by integrating research methodologies and operating techniques for a variety of oil and gas resources to simultaneously achieve analysis,construction,gathering and exploitation of multiple hydrocarbon sources.In this way,the annoying interference between the produced mixture of hydrocarbon flow resulting in the reduction of single-well flowrate will be possibly turned into a dynamic mutual force to enhance the well's flowrate.We also point out that the inevitability of joint exploration and development is determined by the occurrence conditions of oil and gas resources,its feasibility relies on the advancement of technologies,and its arduous and long-term nature is attributed to the current energy market and environment.In spite of various problems and difficulties,we believe that joint exploration and development will be a feasible option to achieve both cost reduction and production&benefit enhancement,boost investors'confidence,raise energy comprehensive utilization,and enhance energy supply efficiency.In conclusion,the advantages of joint exploration and development outweigh its disadvantages for both countries and enterprises.展开更多
基金supported by the Board of Research in Nuclear Sciences of the Department of Atomic Energy,India(2012/36/69-BRNS/2012)
文摘The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(MLS),which is inherently nonlinear and unstable system.The proposal is to deploy discrete optimal pole-zero approximation method for realization of digital fractional order controller.An approach of phase shaping by slope cancellation of asymptotic phase plots for zeros and poles within given bandwidth is explored.The controller parameters are tuned using dynamic particle swarm optimization(d PSO)technique.Effectiveness of the proposed control scheme is verified by simulation and experimental results.The performance of realized digital FO-PID controller has been compared with that of the integer order PID controllers.It is observed that effort required in fractional order control is smaller as compared with its integer counterpart for obtaining the same system performance.
基金This work was co-funded by the National Natural Science Foundation of China(No.52072309)Key Research and Development Program of Shaanxi,China(No.2019ZDLGY14-02-01)+5 种基金Shenzhen Fundamental Research Program,China(No.JCYJ20190806152203506)Aeronautical Science Foundation of China(No.ASFC-2018ZC53026)Funding Project with Beijing Institute of Spacecraft System Engineering,China(No.JSZL2020203B004)the Basic Research Program of Taicang,China(No.TC2021JC09)the Natural Science Foundation of Shaanxi Province,China(No.2023-JC-QN-0003)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China(No.CX2021033).
文摘Highly accurate positioning is a crucial prerequisite of multi Unmanned Aerial Vehicle close-formation flight for target tracking,formation keeping,and collision avoidance.Although the position of a UAV can be obtained through the Global Positioning System(GPS),it is difficult for a UAV to obtain highly accurate positioning data in a GPS-denied environment(e.g.,a GPS jamming area,suburb,urban canyon,or mountain area);this may cause it to miss a tracking target or collide with another UAV.In particular,UAV close-formation control in GPS-denied environments faces difficulties owing to the low-accuracy position,close distance between vehicles,and nonholonomic dynamics of a UAV.In this paper,on the one hand,we develop an innovative UAV formation localization method to address the formation localization issues in GPS-denied environments;on the other hand,we design a novel reinforcement learning based algorithm to achieve the high-efficiency and robust performance of the controller.First,a novel Lidar-based localization algorithm is developed to measure the localization of each aircraft in the formation flight.In our solution,each UAV is equipped with Lidar as the position measurement sensor instead of the GPS module.The k-means algorithm is implemented to calculate the center point position of UAV.A novel formation position vector matching method is proposed to match center points with UAVs in the formation and estimate their position information.Second,a reinforcement learning based UAV formation control algorithm is developed by selecting the optimal policy to control UAV swarm to start and keep flying in a close formation of a specific geometry.Third,the innovative collision risk evaluation module is proposed to address the collision-free issues in the formation group.Finally,a novel experience replay method is also provided in this paper to enhance the learning efficiency.Experimental results validate the accuracy,effectiveness,and robustness of the proposed scheme.
文摘Objective:To analyse the laboratory surveillance data from 2004 till 2008 to examine the changing trend of rubella cases in Malaysia.Methods:Samples for this study were either received through the measles case based surveillance program or were hospital cases received for sero-diagnosis of congenital rubella syndrome(CRS). Specific rubella IgM antibody test was carried out on all samples that were negative for measles IgM antibody and for sero-diagnosis of CRS.Results:Through the surveillance program for measles,the samples received for rubella had increased five fold from 365 in 2004 to 1 522 in 2007.Positive rubella cases detected had also increased from 4.1%in 2004 to 33.2%in 2007.The age group 11 to 20 years accounted for 73.6%of rubella cases confirmed in 2008,with a higher incidence among males than females.Positive rubella IgM was detected in 25 CRS cases during the 6 year period between January 2003 and December 2008.Conclusion:The measles elimination program had contributed to significant progress in the control of rubella,with the majority of rubella cases detected through this strategy.Since rubella is not notifiable in Malaysia,this integrated measles and rubella surveillance should be continued.However,to enhance the progress,specific targets should also be established in the national program to eliminate rubella and CRS.
文摘During well-killing operations for the workover of low-pressure gas wells,formation pressure should be balanced so as to guarantee well control safety by preventing natural gas overflow.In this paper,a laboratory evaluation was conducted with fuzzy-ball fluids as killing fluids.The results show that,the fuzzy-ball fluid,with a density of 0.5e1.5 g/cm^(3) and a viscosity up to 78,50,000 mPa$s at a low shear rate,realizes controllable performance and forms piston-like plugging slugs of solid-free high structural strength on natural gas wellbore after bonding.During well workover,multiple fluid column pressures were set up by injecting fuzzy-ball fluids with different densities at various rates.Owing to high structural strength of the fluids at a low shear rate,natural gas breaks through only inside the piston-like slug and cannot flow upwards to the ground,so the pathways of natural gas in the wellbore are isolated from the ground surface.Moreover,the fluid can wholly move up and down like a piston-like plug,with the change of formation pressures or the tripping of pipe strings.Like the conventional operations,the production can be restored after the workover,so long as the fluid in wellbore is cleaned by means of gas lift.In a natural gas field in NW China,where the formation pressure coefficient dropped to 0.60e0.82,three wells were fully filled with fuzzy-ball workover fluids for 7 days and another three wells were treated with the piston-like plugs of fuzzy-ball workover fluids for only 3 days.They all presented better technical results.The technology provides a new way for low-pressure gas well workover.
文摘This paper presents a model and analysis for a flexible link with non-collocations of sensors and actuators. It shows the changes in the system dynamics and the appearance of zeroes in the right-plan complex, turning the system a non-minimum phase system. The performance of the PID （proportional-integral-derivative） and LQR （linear quadratic regulator） controller are discussed considering the zero dynamics of the system in three points of special interest： （I） the collocated case, when the sensor is in the base of the link; （2） the critical case, where the system starts to present zeroes in the right-plan complex and （3） the limit case, when the sensors are in the end point of the flexible link. Investigation for a simple rigid-flexible model with one mode, in the three cases, the PID and LQR controller performance are damage. To deal with this kind of problem, new control techniques should be developed.
文摘In 2006, except the basic improvement on HL-2A tokamak control system, data acquisition and processing system, a series of research activities have been developed in computer and control division. They include the construction of the high performance computer （HPC） system, the plasma configuration real-time reconstruction with EFIT code, the immigration of plasma simulation codes, the improvement of the poloidal field control system with circulating current, the design of the new data acquiring device with higher anti-disturbing power, the new software on soft X-ray spectrum measurement providing the multi-channel Te evolution, the upgrade to the HL-2A data storage system and experimental net. On the other hand, according to the arrangement of HL-2A modification project, a series of designs such as new plasma configuration, poloidal field coils distribution and plasma shape and position control system are on the processing.
基金supported in part by the Aeronautical Science Foundation of China under Grant 2022Z005057001the Joint Research Fund of Shanghai Commercial Aircraft System Engineering Science and Technology Innovation Center under CASEF-2023-M19.
文摘An aileron is a crucial control surface for rolling.Any jitter or shaking caused by the aileron mechatronics could have catastrophic consequences for the aircraft’s stability,maneuverability,safety,and lifespan.This paper presents a robust solution in the form of a fast flutter suppression digital control logic of edge computing aileron mechatronics(ECAM).We have effectively eliminated passive and active oscillating response biases by integrating nonlinear functional parameters and an antiphase hysteresis Schmitt trigger.Our findings demonstrate that self-tuning nonlinear parameters can optimize stability,robustness,and accuracy.At the same time,the antiphase hysteresis Schmitt trigger effectively rejects flutters without the need for collaborative navigation and guidance.Our hardware-in-the-loop simulation results confirm that this approach can eliminate aircraft jitter and shaking while ensuring expected stability and maneuverability.In conclusion,this nonlinear aileron mechatronics with a Schmitt positive feedback mechanism is a highly effective solution for distributed flight control and active flutter rejection.
基金Supported by Wuxi Municipal Health Commission Maternal and Child Health Research Project,No.FYKY202301。
文摘BACKGROUND Seek highly effective treatment measures for improving mood and sleep.AIM To explore the effects of mood and depression in patients with endometrial cancer after cognitive behavioral therapy(CBT)and mindfulness-based stress reduction.METHODS In a prospective study,90 patients with diabetes,endometrial cancer,and depression were selected from January 2023 to January 2024 in our hospital.There were 45 patients in the control group and 45 patients in the observation group.In addition to the conventional treatment,the control group received cognitive behavioral treatment,and the observation group:Control group was given to compare changes in mood state and sleep quality before and after the intervention.Follow-up was performed3 months after treatment completion.RESULTS Before treatment,the mood and sleep quality scores between the two groups(P>0.05);in the observation group,the 5 negative mood scores were lower and lower than the control group;the 2 positive mood scores were higher than in the control group,and the difference was statistically significant(P<0.05);compared with before treatment,the 7 sleep quality scores and Pittsburgh sleep quality index scale total score in the observation group and lower in the control group(P<0.05).CONCLUSION In patients with diabetes and endometrial cancer,mood state and sleep quality significantly improved after CBT and breathing relaxation.These findings provide new and effective treatment strategies in clinical practice.
基金co-supported by the National Natural Science Foundation of China(No.61304190)the Natural Science Foundation of Jiangsu Province(No.BK20130818)the Fundamental Research Funds for the Central Universities of China(No.NJ20150030)
文摘Air route network optimization,one of the essential parts of the airspace planning,is an effective way to optimize airspace resources,increase airspace capacity,and alleviate air traffic congestion.However,little has been done on the optimization of air route network in the fragmented airspace caused by prohibited,restricted,and dangerous areas（PRDs）.In this paper,an air route network optimization model is developed with the total operational cost as the objective function while airspace restriction,air route network capacity,and non-straight-line factors（NSLF） are taken as major constraints.A square grid cellular space,Moore neighbors,a fixed boundary,together with a set of rules for solving the route network optimization model are designed based on cellular automata.The empirical traffic of airports with the largest traffic volume in each of the 9 flight information regions in China's Mainland is collected as the origin-destination（OD） airport pair demands.Based on traffic patterns,the model generates 35 air routes which successfully avoids 144 PRDs.Compared with the current air route network structure,the number of nodes decreases by 41.67%,while the total length of flight segments and air routes drop by 32.03% and 5.82% respectively.The NSLF decreases by 5.82% with changes in the total length of the air route network.More importantly,the total operational cost of the whole network decreases by 6.22%.The computational results show the potential benefits of the model and the advantage of the algorithm.Optimization of air route network can significantly reduce operational cost while ensuring operation safety.
基金Supported by the Natural Science Foundation of Beijing City(8172043)the National Science Fund for Distinguished Young Scholars(51425405)National Natural Science Foundation of China(51378487)
文摘In this work. phenol and oxalic acid （OA） degradation in an ozone and photocatalysis integrated process was intensively conducted with Fe3 ＋/TiO2 catalyst. The ferrioxalate complex formed between Fe3＋ and oxalate accelerated the removal of OA in the ozonation, photolysis and photocatalytic ozonation process, for its high reactivity with ozone and UV. Phenol was degraded in ozonation and photolysis with limited TOC removal rates, but much higher TOC removal was achieved in photocatalytic ozonation due to the generation of-OH. The sequence of UV light and ozone in the sequential process also influences the TOC removal, and ozone is very powerful to oxidize intermediates catechol and hydroquinone to maleic acid. Fenton or photo-Fenton reactions only played a small part in Fe3＋/TiO2 catalyzed processes, because Fe＋ was greatly reduced but not regenerated in many cases. The synergetic effect was found to be highly related with the property of the target pollutants. Fe3 ＋/TiO2 catalyzed system showed the highest ability to destroy organics, but the TiO2 catalyzed system showed little higher synergy.
文摘To assess the knowledge, attitudes, and practices(KAP) on Zika virus infection among pregnant women in Brunei Darussalam by a cross-sectional survey. Methods: Between February and June 2017, we recruited 234 pregnant women from all government healthcare centres at Brunei-Muara district, using a modified systematic sampling approach. A pre-tested and self-administered questionnaire was used and data analysis was conducted using descriptive statistics and multiple logistic regression analyses. Results: The study participants were mainly Malay(87.2%) and their mean age was 28.0 years. The median knowledge score was 13, out of a possible score of 28. Most participants(92.7%) knew that Zika virus was transmitted by mosquito bites whereas some(34.6%) knew that sexual transmission was also possible. Media(radio, television or newspapers) was the preferred source of updated information on Zika virus, followed by healthcare workers(44.0%), government announcements(43.2%), and social media(38.0%). Pregnant women who were 25 years old or older [Adj. OR=3.62(95% CI: 1.57, 9.51)], not Malays [Adj. OR=3.32(95% CI: 1.35, 8.55)], and had an average monthly household income of more than BND $3 000 [Adj. OR=4.06(95% CI: 1.81, 19.44)] were more likely to score higher for knowledge on Zika virus. The median prevention practice score was 23, out of a possible score of 36. Most participants reported wearing covering clothes(98.3%) and kept their living surroundings clean(99.6%). Most participants(88.0%) agreed that Zika is an important issue in their community. Conclusion: We found a lack of knowledge on Zika virus infection among pregnant women attending government maternal and child healthcare centres in Brunei Darussalam, in particular that Zika virus can be sexually transmitted. Such information could be well disseminated at the healthcare centre level. Health literacy studies should be conducted to understand the facilitators and barriers of KAP on Zika virus infection among pregnant women.
文摘The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuation Analysis(DFA) during the lockdown period(March 24–April 20, 2020) and the corresponding period during the previous two years(i.e., 2018 and 2019). The analysis suggests the anticipated impact of confinement on the PMand NOconcentration in urban cities, causing low concentrations. It is observed that the original PMand NOconcentration time series is persistent but filtering the time series by fitting the autoregressive process of order 1 on the actual time series and subtracting it changes the persistence property significantly. It indicates the presence of linear correlations in the PMand NOconcentrations. Hurst exponent of the PMand NOconcentration during the lockdown period and previous two years shows that the inherent temporal characteristics of the short-term air pollutant concentrations(APCs) time series do not change even after withholding the emissions. The meteorological variations also do not change over the three time periods. The finding helps in developing the prediction models for future policy decisions to improve urban air quality across cities.
基金Universiti Brunei Darussalam’s University Research Grant(Ref:UBD/RSCH/URC/RG(b)/2019/011)。
文摘Objective:To determine the prevalence and risk factors associated with tuberculosis mortality in Brunei Darussalam and to explore its underlying causes.Methods:A retrospective cohort study was conducted where data on socio-demographics,clinical characteristics and treatment outcomes of all tuberculosis patients registered at the National tuberculosis Coordinating Centre between 2013 and 2017 were collected.Overall tuberculosis mortality and the proportion of tuberculosis-related deaths were calculated.Logistic regression analysis was used to determine the risk factors of tuberculosis mortality when compared to those who are cured and/or completed tuberculosis treatment.Results:Of 1107 tuberculosis cases,99 died,giving an overall tuberculosis mortality rate of 8.9%(95%CI 7.4%-10.8%).Significant risk factors associated with tuberculosis mortality were age≥40 years(adjusted OR for 40-59 years was 3.89;95%CI 1.13-1.69;adjusted OR for≥60 years was 22.3;95%CI 7.27-91.9,using 20-39 years as reference),female sex(adjusted OR 1.74;95%CI 1.09-2.79),having renal disease(adjusted OR 25.7;95%CI 2.82-191.50)and having any cancers(adjusted OR 3.61;95%CI 1.26-10.00).The majority(75.8%)of the recorded deaths were not related to tuberculosis.Conclusions:Tuberculosis patients who were older than 40 years,female,and having renal disease and any cancer will need close monitoring in their management program to prevent tuberculosis mortality.Clinicians should also focus on other non-tuberculosis aspects of the patient’s medical history.
文摘Quantitative safety assessment of safety systems plays an important role in decision making at all stages of system lifecycle, i.e., design, deployment and phase out. Most safety assessment methods consider only system parameters, such as configuration, hazard rate, coverage, repair rate, etc. along with periodic proof-tests （or inspection）. Not considering demand rate will give a pessimistic safety estimate for an application with low demand rate such as nuclear power plants, chemical plants, etc. In this paper, a basic model of IEC 61508 is used. The basic model is extended to incorporate process demand and behavior of electronic- and/or computer-based system following diagnosis or proof-test. A new safety index, probability of failure on actual demand （PFAD） based on extended model and demand rate is proposed. Periodic proof-test makes the model semi-Markovian, so a piece-wise continuous time Markov chain （CTMC） based method is used to derive mean state probabilities of elementary or aggregated state. Method to determine probability of failure on demand （PFD） （IEC 61508） and PFAD based on these state probabilities are described. In example, safety indices of PFD and PFAD are compared.
基金support from the National Natural Science Foundation of China(Grant Nos.51378487,51425405,21376249,21336010)Youth Innovation Promotion Association,CAS(2014037)973 Program(2013CB733604)
文摘In this work, a new immobilization method based on dopamine(DA) self-polymerization was developed for laccase immobilization on magnetic nanoparticles(Fe_3O_4 NPs). To optimize the immobilization condition including reaction pH, DA concentration and enzyme concentration, a central composite response surface method was applied. The optimal condition was determined as p H value of 5.92, laccase concentration of 0.25 mg mL^(-1) and DA concentration of 12.74 mg mL^(-1), under which a high enzyme activity recovery of 88.17% was obtained.By comparing with free laccase, the stabilities of immobilized laccase towards p H, thermostability, storage were enhanced significantly.Approximately 60% of relative activity for immobilized laccase was remained after being incubated for 6 h at 50℃, but the free laccase only remained 25%. After 40 days of storage at 4℃, the laccase immobilized by DA kept about 89% of its original activity, but the free laccase only retained 48%. After recycled 10 times, the relative activity of immobilized laccase still retained 70%. The immobilized laccase was then applied to catalyze the degradation of 4-chlorophenol(4-CP), 86% percentage of 4-CP was removed within 2 h. After degraded 10 times, the relative activity of immobilized laccase still remained 64% of its initial activity, which exhibits an excellent reusability and operational stability.
基金Molecular epidemiology research of HIV-1 Drug resistance in China sponsored by the 973 program (2005CB523103) Molecular epidemiology research and new technologies in HIV surveillance in China sponsored by the 863 program (2006AA02Z418).
文摘To investigate the prevalence of drug-resistance mutations,resistance to antiretroviral drugs,and the subsequent virological response to therapy in treatment-naive and antiretroviral-treated patients infected with HIV/AIDS in Henan,China,a total of 431 plasma samples were collected in Queshan county between 2003 and 2004,from patients undergoing the antiretroviral regimen Zidovudine + Didanosine + Nevirapine(Azt+Ddi+Nvp).Personal information was collected by face to face interview.Viral load and genotypic drug resistance were tested.Drug resistance mutation data were obtained by analyzing patient-derived sequences through the HIVdb Program(http://hivdb.stanford.edu).Overall,38.5% of treatment-naive patients had undetectable plasma viral load(VL),the rate significantly increased to 61.9% in 0 to 6 months treatment patients(mean 3 months)(P<0.005)but again significantly decrease to 38.6% in 6 to 12 months treatment patients(mean 9 months)(P<0.001)and 40.0% in patients receiving more than 12 months treatment(mean 16 months)(P<0.005).The prevalence of drug resistance in patients who had a detectable VL and available sequences were 7.0%,48.6%,70.8%,72.3% in treatment-na?ve,0 to 6 months treatment,6 to 12 months treatment,and treatment for greater than 12 months patients,respectively.No mutation associated with resistance to Protease inhibitor(PI)was detected in this study.Nucleoside RT inhibitor(NRTI)mutations always emerged after non-nucleoside RT inhibitor(NNRTI)mutations,and were only found in patients treated for more than 6 months,with a frequency less than 5%,with the exception of mutation T215Y(12.8%,6/47)which occurred in patients treated for more than 12 months.NNRTI mutations emerged quickly after therapy begun,and increased significantly in patients treated for more than 6 months(P<0.005),and the most frequent mutations were K103N,V106A,Y181C,G190A.There had been optimal viral suppression in patients undergoing treatment for less than 6 months in Queshan,Henan.The drug resistance strains were highly prevalent in antiretroviral-treated patients,and increased with the continuation of therapy,with many patients encountering virological failure after 6 months therapy.
文摘Osteoclasts are bone-specific multinucleated cells generated by the differentiation of monocyte/macrophage lineage precursors. Regulation of osteoclast differentiation is considered an effective therapeutic approach to the treatment of bone-lytic diseases. Periodontitis is an inflammatory disease characterized by extensive bone resorption. In this study, we investigated the effects of sodium fluoride （NaF） on osteoclastogenesis induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of cathepsin K, interleukin （IL）-1β, matrix metalloproteinase 9 （MMP9）, and tartrate-resistant acid phosphatase, which were up-regulated during P. gingivalis-induced osteoclastogenesis. Consistent with the in vivo anti-osteoclastogenic effect, NaF inhibited osteoclast formation caused by the differentiation factor RANKL （receptor activator of nuclear factor KB ligand） and macrophage colony-stimulating factor （M-CSF）. The RANKL-stimulated induction of the transcription factor nuclear factor of activated T cells （NFAT） cl was also abrogated by NaF. Taken together, our data demonstrate that NaF inhibits RANKL-induced osteoclastogenesis by reducing the induction of NFATcl, ultimately leading to the suppressed expression of cathepsin K and MMP9. The in vivo effect of NaF on the inhibition of P. gingivalis-induced osteoclastogenesis strengthens the potential usefulness of NaF for treating periodontal diseases.
文摘Objective:To determine the potential effect of environment variables on cutaneous leishmaniasis occurrence using time-series models and compare the predictive ability of seasonal autoregressive integrated moving average(SARIMA)models and Markov switching model(MSM).Methods:This descriptive study employed yearly and monthly data of 49364 parasitologically-confirmed cases of cutaneous leishmaniasis in Isfahan province,located in the center of Iran from January 2000 to December 2019.The data were provided by the leishmaniasis national surveillance system,the meteorological organization of Isfahan province,and Iranian Space Agency for vegetation information.The SARIMA and MSM models were implemented to examine the environmental factors of cutaneous leishmaniasis epidemics.Results:The minimum relative humidity,maximum relative humidity,minimum wind speed,and maximum wind speed were significantly associated with cutaneous leishmaniasis epidemics in different lags(P<0.05).Comparing SARIMA and MSM,Akaikes information criterion(AIC),and mean absolute percentage error(MAPE)in MSM were much smaller than SARIMA models(MSM:AIC=0.95,MAPE=3.5%;SARIMA:AIC=158.93,MAPE:11.45%).Conclusions:SARIMA and MSM can be a useful tool for predicting cutaneous leishmaniasis in Isfahan province.Since cutaneous leishmaniasis falls into one of two states of epidemic and non-epidemic,the use of MSM(dynamic)is recommended,which can provide more information compared to models that use a single distribution for all observations(Box-Jenkins SARIMA model).
文摘Commercial production of unconventional oil and gas resources will not be easily achieved without large-scale engineering measures,let alone the additional operation cost,increasingly stricter requirement for safety and environment,fluctuating low oil and gas prices,etc.,defeating the confidence of those investors.Therefore,unconventional measures are urgently needed to guide the exploration and exploitation of unconventional oil and gas resources.Thus,we put forward the concept of joint exploration and development by integrating research methodologies and operating techniques for a variety of oil and gas resources to simultaneously achieve analysis,construction,gathering and exploitation of multiple hydrocarbon sources.In this way,the annoying interference between the produced mixture of hydrocarbon flow resulting in the reduction of single-well flowrate will be possibly turned into a dynamic mutual force to enhance the well's flowrate.We also point out that the inevitability of joint exploration and development is determined by the occurrence conditions of oil and gas resources,its feasibility relies on the advancement of technologies,and its arduous and long-term nature is attributed to the current energy market and environment.In spite of various problems and difficulties,we believe that joint exploration and development will be a feasible option to achieve both cost reduction and production&benefit enhancement,boost investors'confidence,raise energy comprehensive utilization,and enhance energy supply efficiency.In conclusion,the advantages of joint exploration and development outweigh its disadvantages for both countries and enterprises.
