We develop a policy of observer-based dynamic event-triggered state feedback control for distributed parameter systems over a mobile sensor-plus-actuator network.It is assumed that the mobile sensing devices that prov...We develop a policy of observer-based dynamic event-triggered state feedback control for distributed parameter systems over a mobile sensor-plus-actuator network.It is assumed that the mobile sensing devices that provide spatially averaged state measurements can be used to improve state estimation in the network.For the purpose of decreasing the update frequency of controller and unnecessary sampled data transmission, an efficient dynamic event-triggered control policy is constructed.In an event-triggered system, when an error signal exceeds a specified time-varying threshold, it indicates the occurrence of a typical event.The global asymptotic stability of the event-triggered closed-loop system and the boundedness of the minimum inter-event time can be guaranteed.Based on the linear quadratic optimal regulator, the actuator selects the optimal displacement only when an event occurs.A simulation example is finally used to verify that the effectiveness of such a control strategy can enhance the system performance.展开更多
AIM: To investigate the mechanisms and effects of sphincter of Oddi(SO) motility on cholesterol gallbladder stone formation in guinea pigs.METHODS: Thirty-four adult male Hartley guinea pigs were divided randomly into...AIM: To investigate the mechanisms and effects of sphincter of Oddi(SO) motility on cholesterol gallbladder stone formation in guinea pigs.METHODS: Thirty-four adult male Hartley guinea pigs were divided randomly into two groups, the control group(n = 10) and the cholesterol gallstone group(n = 24), which was sequentially divided into four subgroups with six guinea pigs each according to time of sacrifice. The guinea pigs in the cholesterol gallstone group were fed a cholesterol lithogenic diet and sacrificed after 3, 6, 9, and 12 wk. SO manometry and recording of myoelectric activity were obtained by a multifunctional physiograph at each stage. Cholecystokinin-A receptor(CCKAR) expression levels in SO smooth muscle were detected by quantitative real-time PCR(q RT-PCR) and serum vasoactive intestinal peptide(VIP), gastrin, and cholecystokinin octapeptide(CCK-8) were detected by enzyme-linked immunosorbent assay at each stage in the process of cholesterol gallstone formation.RESULTS: The gallstone formation rate was 0%, 0%, 16.7%, and 83.3% in the 3, 6, 9, and 12 wk groups, respectively. The frequency of myoelectric activity in the 9 wk group, the amplitude of myoelectric activity in the 9 and 12 wk groups, and the amplitude and the frequency of SO in the 9 wk group were all significantly decreased compared to the control group. The SO basal pressure and common bile duct pressure increased markedly in the 12 wk group, and the CCKAR expression levels increased in the 6 and 12 wk groups compared to the control group. Serum VIP was elevated significantly in the 9 and 12 wk groups and gastrin decreased significantly in the 3 and 9 wk groups. There was no difference in serum CCK-8 between the groups.CONCLUSION: A cholesterol gallstone-causing diet can induce SO dysfunction. The increasing tension of the SO along with its decreasing activity may play an important role in cholesterol gallstone formation. Expression changes of CCKAR in SO smooth muscle and serum VIP and CCK-8 may be important causes of SO dysfunction.展开更多
An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classifica...An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.展开更多
Due to high ground stress and mining disturbance, the deformation and failure of deep soft rock roadway is serious, and invalidation of the anchor net-anchor cable supporting structure occurs. The failure characterist...Due to high ground stress and mining disturbance, the deformation and failure of deep soft rock roadway is serious, and invalidation of the anchor net-anchor cable supporting structure occurs. The failure characteristics of roadways revealed with the help of the ground pressure monitoring. Theoretical analysis was adopted to analyze the influence of mining disturbance on stress distribution in surrounding rock,and the change of stress was also calculated. Considering the change of stress in surrounding rock of bottom extraction roadway, the displacement, plastic zone and distribution law of principal stress difference under different support schemes were studied by means of FLAC3D. The supporting scheme of U-shaped steel was proposed for bottom extraction roadway that underwent mining disturbance. We carried out a similarity model test to verify the effect of support in dynamic pressure. Monitoring results demonstrated the change rules of deformation and stress of surrounding rock in different supporting schemes. The supporting scheme of U-shaped steel had an effective control on deformation of surrounding rock. The scheme was successfully applied in underground engineering practice, and achieved good technical and economic benefits.展开更多
A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyra- nosyl-(1→4)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyra-nosyl ester, was isolated fro...A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyra- nosyl-(1→4)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyra-nosyl ester, was isolated from the roots of Platycodon grandiflorum, together with three known saponins, including platycodin D, deapio platycoside E and platycoside E. The structure of the new compound, named 16-oxo-platycodin D, was elucidated on the basis of spectroscopic data.展开更多
The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debata...The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debatable. Fe-Ti oxide minerals are seldom used to study sediment provenance, expecially using scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). In this study, the provenance of Quaternary sediments in Yichang area, which is located to the east of the Yangtze Three Gorges, was investigated by using SEM and EDS to research Fe-Ti oxides. The Panzhihua vanadium titanomagnetite and Emeishan basalt outcrop are located to the west of the Three Gorges. Further, the materials from them are observed in the Quaternary sediments of Yichang area. Fe-Ti oxide minerals from the Huangling granite are observed in the Yunchi and Shanxiyao Formations, which were formed before 0.75 Ma B.P., whereas Fe-Ti oxide minerals from the Huangling granite, Panzhihua vanadium titanomagnetite, and Emeishan basalt are observed in the riverbed and fifth-terrace sediments of the Yangtze River, which were formed after 0.73 Ma B.P.. Thus, we can infer that the Three Gorges formed after the deposition of the Shanxi Formation and before the fifth-terrace; i.e., 0.75-0.73 Ma B.P..展开更多
We consider that the reserve of an insurance company follows a renewal risk process with interest and dividend. For this risk process, we derive integral equations and exact infinite series expressions for the Cerber-...We consider that the reserve of an insurance company follows a renewal risk process with interest and dividend. For this risk process, we derive integral equations and exact infinite series expressions for the Cerber-Shiu discounted penalty function. Then we give lower and upper bounds for the ruin probability. Finally, we present exact expressions for the ruin probability in a special case of renewal risk processes.展开更多
BACKGROUND There is a high annual incidence of acute,nonvariceal upper gastrointestinal bleeding in Chinese adults.Early endoscopic intervention can reduce rates of rebleeding,surgery,and mortality.The metal clip is t...BACKGROUND There is a high annual incidence of acute,nonvariceal upper gastrointestinal bleeding in Chinese adults.Early endoscopic intervention can reduce rates of rebleeding,surgery,and mortality.The metal clip is the most common method for establishing homeostasis;however,it possesses several limitations.In patients with bleeding secondary to large gastric ulcers,the clip will often fail to stop the bleeding.This article highlights the use of an elastic traction ring as a novel hemostatic method for patients with upper gastrointestinal bleeding.CASE SUMMARY An elderly male presented to the emergency room with complaints of hematemesis and melena.Endoscopic examination revealed an ulcer(Forrest IIa)in the lesser curvature of the gastric antrum.Six tissue clips and one elastic traction ring were inserted into the stomach cavity to suture the ulcer.The patient recovered quickly without postoperative gastrointestinal bleeding.Two months later,the patient's ulcer was significantly healed.CONCLUSION To our best knowledge,this is the first report to demonstrate the safety and efficacy of elastic traction rings for upper gastrointestinal bleeding.Elastic traction rings should be considered a routine therapeutic modality for patients with upper gastrointestinal bleeds.展开更多
Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction.In this work,tidal channels and road construction in the Yellow River Delta(YRD)were extracte...Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction.In this work,tidal channels and road construction in the Yellow River Delta(YRD)were extracted by visual interpretation methods so as to decipher impacts of tidal channel development and road construction on landscape patch change during 1989–2016.Spatial distribution history of three wetlands,which covered by Phragmites australis(freshwater marsh,FM),Suaeda salsa(salt marsh,SM),and mudflats(MD)were also established.Results indicated that tidal channel,number,frequency,and fractal dimension were all the maximum in 2003,and the minimum in 1998,respectively.Road length,number,and density showed increasing trend during 1989–2016.MD were the predominant landscape type,followed by FM and SM during 1989-2016.Principal component analysis implied two extracted factors,F1 and F2,which could represent 91.93% of the total variations.F1 mainly proxied tidal channel development,while F2 represented road construction.A multiple linear regression analysis showed positive effects of both F1 and F2 on FM patch numbers and negative impacts on SM patch areaes with R^2 values of 0.416 and 0.599,respectively.Tidal channels were negatively related to MD patch numbers,while roads were positively related to that.In any case,road construction showed larger impacts on landscape type shifting than that of tidal channel development in the YRD.展开更多
In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge be...In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge beam was replaced by a piece of steel plate which supports the weight of the traveling vehicle.All weights would be finally transferred into the tubes where four FBGs were attached and could record the weight-induced strains by shifting their Bragg wavelengths.The system identification algorithm based on parameters estimation was initiated.Over 40-ton load had been applied on the system and the experimental results showed a good repeatability and linearity.The system resolution had been achieved as low as 10 kg.Compared with other designs of fiber-optic WIM systems,this design is easy and reliable.展开更多
Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured ...Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.展开更多
Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endo-scopic sphincterotomy induced by barium examination. An a...Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endo-scopic sphincterotomy induced by barium examination. An adult male patient presented with epigastric pain was diagnosed as having choledocholithiasis by ultra-sonography. EST was performed and the stone was completely cleaned. Barium examination was done 3 d after EST and severe cholangitis appeared 4 h later. The patient was recovered after treated with tienam for 4 d. Barium examination may induce severe cholangitis in patients after EST, although rare, barium examination should be chosen cautiously. Cautions should be also used when EST is performed in patients younger than 50 years to avoid the damage to the sphincter of Oddi.展开更多
In most bacteria, plants and algae, fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase (FAS II) system. In the FAS II system, enoyl- acyl carrier ...In most bacteria, plants and algae, fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase (FAS II) system. In the FAS II system, enoyl- acyl carrier protein reductase (ENR) acts as a determinant for completing the cycles of fatty acid elongation. In this study, the cDNA sequence of ENR, designated as IgENR, was isolated from the microalga lsochrysis galbana CCMM5001. RACE (rapid amplification of cDNA ends) was used to isolate the full-length cDNA oflgENR (1 503 bp), which contains an open reading frame (ORF) of 1 044 bp and encodes a protein of 347 amino acids. The genomic DNA sequence oflgENR is interrupted by four introns. The putative amino acid sequence is homologous to the ENRs of seed plants and algae, and they contain common coenzyme- binding sites and active site motifs. Under different stress conditions, real-time quantitative polymerase chain reaction (RT-qPCR) showed the expression oflgENR was upregulated by high temperature (35℃), and downregulated by depleted nitrogen (0 mol/L). To clarify the mechanism of lipids accumulating lipids, other genes involved in lipids accumulation should be studied.展开更多
Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon (PS) using a simple vapour-solid (VS) growth method. A comparison of their morphologies is ...Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon (PS) using a simple vapour-solid (VS) growth method. A comparison of their morphologies is investigated by scanning electron microscopy (SEM). The transmission electron microscopy (TEM) confirms that ZnO nanobelts and nanorods are single crystalline with the growth direction of (0110) and (0001), respectively. Field emission tests indicate that the ZnO nanostructures on porous silicon have low turn-on field of about 3.6 V/μm (at 1.0μA/cm^2) and the threshold field of about 8.3 V/μm (at 1.0mA/cm^2), high emission site density (ESD) of approximately 104 cm^-2.展开更多
Receptor-like kinases(RLKs)are important for plant growth,development and defense responses.The S-receptor protein kinases(SRKs),which represent an RLK subfamily,control the selfincompatibility among Brassica species....Receptor-like kinases(RLKs)are important for plant growth,development and defense responses.The S-receptor protein kinases(SRKs),which represent an RLK subfamily,control the selfincompatibility among Brassica species.However,little information is available regarding SRK functions in rice.We identified a gene OsSRK1 encoding an atypical SRK.The transcript of OsSRK1 was induced by abscisic acid(ABA),salt and polyethylene glycol.OsSRK1 localized to the plasma membrane and cytoplasm.Leaf width was increased in OsSRK1-overexpression(OsSRK1-OX)transgenic rice plants,likely because of an increase in cell number per leaf.Furthermore,the expression levels of OsCYCA3-1 and OsCYCD2-1,which encode positive regulators of cell division,were up-regulated in leaf primordium of OsSRK1-OX rice plants relative to those in wild type.Meanwhile,the expression level of OsKRP1,which encodes cell cycle inhibitor,was down-regulated in the OsSRK1-OX plants.Therefore,it is deduced that OsSRK1 regulates leaf width by promoting cell division in the leaf primordium.Additionally,OsSRK1-OX plants exhibited enhanced ABA sensitivity and salt tolerance compared with wild type.These results suggest that OsSRK1 plays important roles in leaf development and salt responses in rice.展开更多
To further understand the generation and development of coinfection of Marek's disease virus (MDV) and reticuloendotheliosis virus (REV) in broiler breeders, and then find the method and optimal time of different...To further understand the generation and development of coinfection of Marek's disease virus (MDV) and reticuloendotheliosis virus (REV) in broiler breeders, and then find the method and optimal time of differential diagnosis for complex clinic multiple infection, the authors studied the pathohistological changes, apoptosis, immunohistochemistry (immunofluorescence), and ultrastructure of tumor tissues of broiler breeders inoculated with MDV and REV. The study showed that proliferation of small lymphocytes was seen in the main organs at the age of 1 week, then immature lymphocytes, all kinds of lymphocytes, primitive reticulum cells, and Marek's disease cells (MDCs) were observed at 2-9 weeks. Apoptosis of lymphocytes could not be seen until the age of 10 weeks in the immune system. Immunohistochemistry detection showed that the positive signs of MDV and REV antigen were observed in the main organs at 2 weeks of age. Multi-morphology lymphocytes, MDV, and REV, mitotic figures and apoptosis of lymphocytes were observed with the help of transmission electron microscopy. MDV cooperating with REV promotes the course of disease of coinfection. Differential diagnosis can be done by immunohistochemistry in the early stage (before 2 weeks), and histopathology in the late stage (post 4 weeks). MDCs, primitive reticulum cells, immature lymphocytes, and two kinds of virions can serve as a basis for bistopathology differential diagnosis.展开更多
Educational investment is the material basis for developing intelligence and educational cause and also an important factor for the development of economic and society.This paper argues that educational investment is ...Educational investment is the material basis for developing intelligence and educational cause and also an important factor for the development of economic and society.This paper argues that educational investment is an important strategy to solve the problem of disadvantaged groups in our country,and hopes that through the analysis of the structure and the trend for educational investment in developed countries,and it can provide reference and valuable suggestions for our country.展开更多
To analyze the influence of new compound admixture on shotcrete performance, the ordinary Portland cement pr425 was used as matrix components. The optimum proportion of admixture was obtained by analyzing the influenc...To analyze the influence of new compound admixture on shotcrete performance, the ordinary Portland cement pr425 was used as matrix components. The optimum proportion of admixture was obtained by analyzing the influence of content on cement setting time and compressive strength. The microstructure of cement test block and the mechanism of reducing dust of composite macromolecule admixture were analyzed by scanning electron microscopy and infrared spectroscopy. It was shown that the ratio of polyacrylic acid was 0.02%. The ratio of J85 accelerator was 5%. The ratio of bentonite was 4.5% in composite admixture. The most optimal content of admixture in the slurry was 7%. The compound coagulant formed by additive together with C3A, C4AF which provided nucleation for hydration and crystallization of C3S and C3S, and played an active role to promote the activity of the mineral admixture in cement, and increased the elastic modulus of C-S-H gel and accelerated the hydration process of portland cement. Bentonite and polyacrylic acid promote the wettability, cohesiveness and workability of cement paste in the process of hydration. The formation of cement test block gel was even. The interface between the matrix phase and the aggregate phase was not obvious which ensured the matching between the matrix and the aggregate phase. The addition of bentonite formed hydrogen bonds in cement paste and improved the cohesiveness of the system. The J-85 accelerator promoted the combination of aluminate and gypsum which hindered the formation of calcium carbide around the cement particles which made cement rapid condensation. Polyacrylic acid mainly changed the strength of hydroxyl absorption peak in cement paste to improve the initial strength of cement test block. The addition of new admixtures promoted the process of cement hydration to be more thorough and affected the later strength development of concrete by affecting the formation of calcium carbonate stone.展开更多
By means of different checks and measures, we obserced and analysed the microstructure of Fe-Al/ Al2O3 composite material, We found that not only intragranular nanostructure grains and rod-like crystals but also fine-...By means of different checks and measures, we obserced and analysed the microstructure of Fe-Al/ Al2O3 composite material, We found that not only intragranular nanostructure grains and rod-like crystals but also fine-grained structure of the composite material as well as the bridging of the Fe-Al intermetallics compound contribute to the material's strength and toughness, It is shoun that the strengthening and toughening of the Fe- Al/ Al2O3 composite is the joint effect of a multiplicute strengthening and tougheniug mechanism.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.62073045)。
文摘We develop a policy of observer-based dynamic event-triggered state feedback control for distributed parameter systems over a mobile sensor-plus-actuator network.It is assumed that the mobile sensing devices that provide spatially averaged state measurements can be used to improve state estimation in the network.For the purpose of decreasing the update frequency of controller and unnecessary sampled data transmission, an efficient dynamic event-triggered control policy is constructed.In an event-triggered system, when an error signal exceeds a specified time-varying threshold, it indicates the occurrence of a typical event.The global asymptotic stability of the event-triggered closed-loop system and the boundedness of the minimum inter-event time can be guaranteed.Based on the linear quadratic optimal regulator, the actuator selects the optimal displacement only when an event occurs.A simulation example is finally used to verify that the effectiveness of such a control strategy can enhance the system performance.
基金Supported by Natural Science Foundation of Shandong Province,China,No.ZR 2012 HM-079
文摘AIM: To investigate the mechanisms and effects of sphincter of Oddi(SO) motility on cholesterol gallbladder stone formation in guinea pigs.METHODS: Thirty-four adult male Hartley guinea pigs were divided randomly into two groups, the control group(n = 10) and the cholesterol gallstone group(n = 24), which was sequentially divided into four subgroups with six guinea pigs each according to time of sacrifice. The guinea pigs in the cholesterol gallstone group were fed a cholesterol lithogenic diet and sacrificed after 3, 6, 9, and 12 wk. SO manometry and recording of myoelectric activity were obtained by a multifunctional physiograph at each stage. Cholecystokinin-A receptor(CCKAR) expression levels in SO smooth muscle were detected by quantitative real-time PCR(q RT-PCR) and serum vasoactive intestinal peptide(VIP), gastrin, and cholecystokinin octapeptide(CCK-8) were detected by enzyme-linked immunosorbent assay at each stage in the process of cholesterol gallstone formation.RESULTS: The gallstone formation rate was 0%, 0%, 16.7%, and 83.3% in the 3, 6, 9, and 12 wk groups, respectively. The frequency of myoelectric activity in the 9 wk group, the amplitude of myoelectric activity in the 9 and 12 wk groups, and the amplitude and the frequency of SO in the 9 wk group were all significantly decreased compared to the control group. The SO basal pressure and common bile duct pressure increased markedly in the 12 wk group, and the CCKAR expression levels increased in the 6 and 12 wk groups compared to the control group. Serum VIP was elevated significantly in the 9 and 12 wk groups and gastrin decreased significantly in the 3 and 9 wk groups. There was no difference in serum CCK-8 between the groups.CONCLUSION: A cholesterol gallstone-causing diet can induce SO dysfunction. The increasing tension of the SO along with its decreasing activity may play an important role in cholesterol gallstone formation. Expression changes of CCKAR in SO smooth muscle and serum VIP and CCK-8 may be important causes of SO dysfunction.
基金Projects(51509147,51879153) supported by the National Natural Science Foundation of ChinaProjects(2017JC002,2017JC001) supported by the Fundamental Research Funds of Shandong University,China
文摘An attribute recognition model for safe thickness assessment between a concealed karst cave and a tunnel is established based on the attribute mathematic theory.The model can be applied to carrying out risk classification of the safe thickness between a concealed karst cave and a tunnel and to guarantee construction’s safety in tunnel engineering.Firstly,the assessment indicators and classification standard of safe thickness between a concealed karst cave and a tunnel are studied based on the perturbation method.Then some attribute measurement functions are constructed to compute the attribute measurement of each single index and synthetic attribute measurement.Finally,the identification and classification of risk assessment of safe thickness between a concealed karst cave and a tunnel are recognized by the confidence criterion.The results of two engineering application show that the evaluation results agree well with the site situations in construction.The results provide a good guidance for the tunnel construction.
基金financial assistance provided by the National Natural Science Foundation of China (Nos. 51322401, 51404262, 51579239, 51574223)Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals (Shandong University of Science and Technology) of China (No. CDPM2014KF03)+1 种基金China Postdoctoral Science Foundation (Nos. 2015M580493, 2014M551700, 2013M531424)the Natural Science Foundation of Jiangsu Province of China (No. BK20140213)
文摘Due to high ground stress and mining disturbance, the deformation and failure of deep soft rock roadway is serious, and invalidation of the anchor net-anchor cable supporting structure occurs. The failure characteristics of roadways revealed with the help of the ground pressure monitoring. Theoretical analysis was adopted to analyze the influence of mining disturbance on stress distribution in surrounding rock,and the change of stress was also calculated. Considering the change of stress in surrounding rock of bottom extraction roadway, the displacement, plastic zone and distribution law of principal stress difference under different support schemes were studied by means of FLAC3D. The supporting scheme of U-shaped steel was proposed for bottom extraction roadway that underwent mining disturbance. We carried out a similarity model test to verify the effect of support in dynamic pressure. Monitoring results demonstrated the change rules of deformation and stress of surrounding rock in different supporting schemes. The supporting scheme of U-shaped steel had an effective control on deformation of surrounding rock. The scheme was successfully applied in underground engineering practice, and achieved good technical and economic benefits.
文摘A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-(1 → 3)-β-D-xylopyra- nosyl-(1→4)-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyra-nosyl ester, was isolated from the roots of Platycodon grandiflorum, together with three known saponins, including platycodin D, deapio platycoside E and platycoside E. The structure of the new compound, named 16-oxo-platycodin D, was elucidated on the basis of spectroscopic data.
基金supported by the Project of the National Natural Science Foundation of China (Grant No. 41572093, 41072083, 40602011)the Open Foundation of Shangdong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Mineralthe Cultivating Program of Young and Middle-aged Backbone Teachers of Chengdu University of Technology
文摘The Three Gorges are considered to be critical to understand the formation of Yangtze River. Recent research results suggest that the Yangtze Three Gorges was created during the Quaternary but the exact time is debatable. Fe-Ti oxide minerals are seldom used to study sediment provenance, expecially using scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). In this study, the provenance of Quaternary sediments in Yichang area, which is located to the east of the Yangtze Three Gorges, was investigated by using SEM and EDS to research Fe-Ti oxides. The Panzhihua vanadium titanomagnetite and Emeishan basalt outcrop are located to the west of the Three Gorges. Further, the materials from them are observed in the Quaternary sediments of Yichang area. Fe-Ti oxide minerals from the Huangling granite are observed in the Yunchi and Shanxiyao Formations, which were formed before 0.75 Ma B.P., whereas Fe-Ti oxide minerals from the Huangling granite, Panzhihua vanadium titanomagnetite, and Emeishan basalt are observed in the riverbed and fifth-terrace sediments of the Yangtze River, which were formed after 0.73 Ma B.P.. Thus, we can infer that the Three Gorges formed after the deposition of the Shanxi Formation and before the fifth-terrace; i.e., 0.75-0.73 Ma B.P..
文摘We consider that the reserve of an insurance company follows a renewal risk process with interest and dividend. For this risk process, we derive integral equations and exact infinite series expressions for the Cerber-Shiu discounted penalty function. Then we give lower and upper bounds for the ruin probability. Finally, we present exact expressions for the ruin probability in a special case of renewal risk processes.
文摘BACKGROUND There is a high annual incidence of acute,nonvariceal upper gastrointestinal bleeding in Chinese adults.Early endoscopic intervention can reduce rates of rebleeding,surgery,and mortality.The metal clip is the most common method for establishing homeostasis;however,it possesses several limitations.In patients with bleeding secondary to large gastric ulcers,the clip will often fail to stop the bleeding.This article highlights the use of an elastic traction ring as a novel hemostatic method for patients with upper gastrointestinal bleeding.CASE SUMMARY An elderly male presented to the emergency room with complaints of hematemesis and melena.Endoscopic examination revealed an ulcer(Forrest IIa)in the lesser curvature of the gastric antrum.Six tissue clips and one elastic traction ring were inserted into the stomach cavity to suture the ulcer.The patient recovered quickly without postoperative gastrointestinal bleeding.Two months later,the patient's ulcer was significantly healed.CONCLUSION To our best knowledge,this is the first report to demonstrate the safety and efficacy of elastic traction rings for upper gastrointestinal bleeding.Elastic traction rings should be considered a routine therapeutic modality for patients with upper gastrointestinal bleeds.
基金Under the auspices of National Key Research and Development Project(No.2017YFC0505901)
文摘Landscape characters in estuarine regions generally controlled by tidal regimes and human activities like road construction.In this work,tidal channels and road construction in the Yellow River Delta(YRD)were extracted by visual interpretation methods so as to decipher impacts of tidal channel development and road construction on landscape patch change during 1989–2016.Spatial distribution history of three wetlands,which covered by Phragmites australis(freshwater marsh,FM),Suaeda salsa(salt marsh,SM),and mudflats(MD)were also established.Results indicated that tidal channel,number,frequency,and fractal dimension were all the maximum in 2003,and the minimum in 1998,respectively.Road length,number,and density showed increasing trend during 1989–2016.MD were the predominant landscape type,followed by FM and SM during 1989-2016.Principal component analysis implied two extracted factors,F1 and F2,which could represent 91.93% of the total variations.F1 mainly proxied tidal channel development,while F2 represented road construction.A multiple linear regression analysis showed positive effects of both F1 and F2 on FM patch numbers and negative impacts on SM patch areaes with R^2 values of 0.416 and 0.599,respectively.Tidal channels were negatively related to MD patch numbers,while roads were positively related to that.In any case,road construction showed larger impacts on landscape type shifting than that of tidal channel development in the YRD.
文摘In this weigh-in-motion(WIM)research,a novel fiber Bragg grating(FBG)-based weigh-in-motion(WIM)system was introduced.The design derived from the idea using in-service bridge abutments as the weigh scale.The bridge beam was replaced by a piece of steel plate which supports the weight of the traveling vehicle.All weights would be finally transferred into the tubes where four FBGs were attached and could record the weight-induced strains by shifting their Bragg wavelengths.The system identification algorithm based on parameters estimation was initiated.Over 40-ton load had been applied on the system and the experimental results showed a good repeatability and linearity.The system resolution had been achieved as low as 10 kg.Compared with other designs of fiber-optic WIM systems,this design is easy and reliable.
基金provided by the National Natural Science Foundation of China(Nos.51322401,51309222,51323004,51579239 and 51574223)the Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation(No.CDPM2014KF03)+2 种基金the State Key Laboratory for GeoMechanics Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and MitigationDeep Underground Engineering,China University of Mining&Technology(No.SKLGDUEK1305)China Postdoctoral Science Foundation(Nos.2014M551700and 2013M531424)
文摘Based on the safety coefficient method,which assigns rock failure criteria to calculate the rock mass unit,the safety coefficient contour of surrounding rock is plotted to judge the distribution form of the fractured zone in the roadway.This will provide the basis numerical simulation to calculate the surrounding rock fractured zone in a roadway.Using the single factor and multi-factor orthogonal test method,the evolution law of roadway surrounding rock displacements,plastic zone and stress distribution under different conditions is studied.It reveals the roadway surrounding rock burst evolution process,and obtains five kinds of failure modes in deep soft rock roadway.Using the fuzzy mathematics clustering analysis method,the deep soft surrounding rock failure model in Zhujixi mine can be classified and patterns recognized.Compared to the identification results and the results detected by geological radar of surrounding rock loose circle,the reliability of the results of the pattern recognition is verified and lays the foundations for the support design of deep soft rock roadways.
文摘Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endo-scopic sphincterotomy induced by barium examination. An adult male patient presented with epigastric pain was diagnosed as having choledocholithiasis by ultra-sonography. EST was performed and the stone was completely cleaned. Barium examination was done 3 d after EST and severe cholangitis appeared 4 h later. The patient was recovered after treated with tienam for 4 d. Barium examination may induce severe cholangitis in patients after EST, although rare, barium examination should be chosen cautiously. Cautions should be also used when EST is performed in patients younger than 50 years to avoid the damage to the sphincter of Oddi.
基金Supported by the National Natural Science Foundation of China(No.41106148)the Ocean Public Welfare Scientific Research Project(Nos.GHME2001SW02,200905019,200805039)the Science and Technology Development Program of Shandong Province(No.2011GHY11533)
文摘In most bacteria, plants and algae, fatty acid biosynthesis is catalyzed by a group of freely dissociable proteins known as the type II fatty acid synthase (FAS II) system. In the FAS II system, enoyl- acyl carrier protein reductase (ENR) acts as a determinant for completing the cycles of fatty acid elongation. In this study, the cDNA sequence of ENR, designated as IgENR, was isolated from the microalga lsochrysis galbana CCMM5001. RACE (rapid amplification of cDNA ends) was used to isolate the full-length cDNA oflgENR (1 503 bp), which contains an open reading frame (ORF) of 1 044 bp and encodes a protein of 347 amino acids. The genomic DNA sequence oflgENR is interrupted by four introns. The putative amino acid sequence is homologous to the ENRs of seed plants and algae, and they contain common coenzyme- binding sites and active site motifs. Under different stress conditions, real-time quantitative polymerase chain reaction (RT-qPCR) showed the expression oflgENR was upregulated by high temperature (35℃), and downregulated by depleted nitrogen (0 mol/L). To clarify the mechanism of lipids accumulating lipids, other genes involved in lipids accumulation should be studied.
基金Supported by the National Natural Science Foundation of China under Grant No 60476004, the Foundation of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing of Wuhan University of Technology under Grant No WUT2004 Z01, and GS of ECNU (No ECNU 2005).
文摘Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon (PS) using a simple vapour-solid (VS) growth method. A comparison of their morphologies is investigated by scanning electron microscopy (SEM). The transmission electron microscopy (TEM) confirms that ZnO nanobelts and nanorods are single crystalline with the growth direction of (0110) and (0001), respectively. Field emission tests indicate that the ZnO nanostructures on porous silicon have low turn-on field of about 3.6 V/μm (at 1.0μA/cm^2) and the threshold field of about 8.3 V/μm (at 1.0mA/cm^2), high emission site density (ESD) of approximately 104 cm^-2.
基金This work was supported by grants from Excellent Middle-Aged and Youth Scientist Award Foundation of Shandong Province(Grant No.BS2014SW029)the Shandong Natural Science Foundation(Grant Nos.ZR2016CB17 and ZR2018ZC08N2)Shandong Major Agricultural Applied Technological Innovation Projects(Grant No.2017.04-2020.04)in China.
文摘Receptor-like kinases(RLKs)are important for plant growth,development and defense responses.The S-receptor protein kinases(SRKs),which represent an RLK subfamily,control the selfincompatibility among Brassica species.However,little information is available regarding SRK functions in rice.We identified a gene OsSRK1 encoding an atypical SRK.The transcript of OsSRK1 was induced by abscisic acid(ABA),salt and polyethylene glycol.OsSRK1 localized to the plasma membrane and cytoplasm.Leaf width was increased in OsSRK1-overexpression(OsSRK1-OX)transgenic rice plants,likely because of an increase in cell number per leaf.Furthermore,the expression levels of OsCYCA3-1 and OsCYCD2-1,which encode positive regulators of cell division,were up-regulated in leaf primordium of OsSRK1-OX rice plants relative to those in wild type.Meanwhile,the expression level of OsKRP1,which encodes cell cycle inhibitor,was down-regulated in the OsSRK1-OX plants.Therefore,it is deduced that OsSRK1 regulates leaf width by promoting cell division in the leaf primordium.Additionally,OsSRK1-OX plants exhibited enhanced ABA sensitivity and salt tolerance compared with wild type.These results suggest that OsSRK1 plays important roles in leaf development and salt responses in rice.
基金supported by grants from the National Science Foundation for Post-Doctoral of China(2005038258)
文摘To further understand the generation and development of coinfection of Marek's disease virus (MDV) and reticuloendotheliosis virus (REV) in broiler breeders, and then find the method and optimal time of differential diagnosis for complex clinic multiple infection, the authors studied the pathohistological changes, apoptosis, immunohistochemistry (immunofluorescence), and ultrastructure of tumor tissues of broiler breeders inoculated with MDV and REV. The study showed that proliferation of small lymphocytes was seen in the main organs at the age of 1 week, then immature lymphocytes, all kinds of lymphocytes, primitive reticulum cells, and Marek's disease cells (MDCs) were observed at 2-9 weeks. Apoptosis of lymphocytes could not be seen until the age of 10 weeks in the immune system. Immunohistochemistry detection showed that the positive signs of MDV and REV antigen were observed in the main organs at 2 weeks of age. Multi-morphology lymphocytes, MDV, and REV, mitotic figures and apoptosis of lymphocytes were observed with the help of transmission electron microscopy. MDV cooperating with REV promotes the course of disease of coinfection. Differential diagnosis can be done by immunohistochemistry in the early stage (before 2 weeks), and histopathology in the late stage (post 4 weeks). MDCs, primitive reticulum cells, immature lymphocytes, and two kinds of virions can serve as a basis for bistopathology differential diagnosis.
文摘Educational investment is the material basis for developing intelligence and educational cause and also an important factor for the development of economic and society.This paper argues that educational investment is an important strategy to solve the problem of disadvantaged groups in our country,and hopes that through the analysis of the structure and the trend for educational investment in developed countries,and it can provide reference and valuable suggestions for our country.
基金Funded by the National Science Foundation of China(No.41472281)the National Science Foundation of Liaoning Province(No.20170540143)
文摘To analyze the influence of new compound admixture on shotcrete performance, the ordinary Portland cement pr425 was used as matrix components. The optimum proportion of admixture was obtained by analyzing the influence of content on cement setting time and compressive strength. The microstructure of cement test block and the mechanism of reducing dust of composite macromolecule admixture were analyzed by scanning electron microscopy and infrared spectroscopy. It was shown that the ratio of polyacrylic acid was 0.02%. The ratio of J85 accelerator was 5%. The ratio of bentonite was 4.5% in composite admixture. The most optimal content of admixture in the slurry was 7%. The compound coagulant formed by additive together with C3A, C4AF which provided nucleation for hydration and crystallization of C3S and C3S, and played an active role to promote the activity of the mineral admixture in cement, and increased the elastic modulus of C-S-H gel and accelerated the hydration process of portland cement. Bentonite and polyacrylic acid promote the wettability, cohesiveness and workability of cement paste in the process of hydration. The formation of cement test block gel was even. The interface between the matrix phase and the aggregate phase was not obvious which ensured the matching between the matrix and the aggregate phase. The addition of bentonite formed hydrogen bonds in cement paste and improved the cohesiveness of the system. The J-85 accelerator promoted the combination of aluminate and gypsum which hindered the formation of calcium carbide around the cement particles which made cement rapid condensation. Polyacrylic acid mainly changed the strength of hydroxyl absorption peak in cement paste to improve the initial strength of cement test block. The addition of new admixtures promoted the process of cement hydration to be more thorough and affected the later strength development of concrete by affecting the formation of calcium carbonate stone.
文摘By means of different checks and measures, we obserced and analysed the microstructure of Fe-Al/ Al2O3 composite material, We found that not only intragranular nanostructure grains and rod-like crystals but also fine-grained structure of the composite material as well as the bridging of the Fe-Al intermetallics compound contribute to the material's strength and toughness, It is shoun that the strengthening and toughening of the Fe- Al/ Al2O3 composite is the joint effect of a multiplicute strengthening and tougheniug mechanism.