With the development of society and the progress of technology,more and more ocean activities are carried out.It results in booming of deep-sea diving.The use of helium-oxygen mixture(as a kind of breathing gas)solves...With the development of society and the progress of technology,more and more ocean activities are carried out.It results in booming of deep-sea diving.The use of helium-oxygen mixture(as a kind of breathing gas)solves the physiological problems of divers in saturated diving,but it brings about the Heliumspeech voice communication problem,the drop of speech intelligibility.There is no doubt that the effective speech communication must be provided for supporting the life and work of divers in deep-sea.This paper describes the mechanism of forming heliumspeech,discusses the effects of pressure and helium environment on the speech spectrum,compares the pros and cons of the time-domain and frequency-domain unscrambling techniques,shows the challenges in heliumspeech communications.Finally,it briefly introduces the deep learning,and points out that deep learning/machine learning may be a perfectly unscrambling technique.展开更多
Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In th...Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In this study, we verified the effect of sex, temperature, time and flock size on the diving behavior of the Scaly-sided Merganser(Mergus squamatus).Methods: The study was conducted by means of focal animal sampling in the Wuyuan section of the Poyang Lake watershed in Jiangxi Province, China from December 2015 to March 2016. We used one-way ANOVA and LSD tests to investigate the differences among these factors. Pearson correlations were used to test the relation between pause duration and the previous or subsequent dive duration. The relations between these factors and dive/pause duration are illustrated using Spearman correlations.Results: Mean dive duration and mean time on the pause of males were significantly higher than those of females. With an increase in temperature, dive duration significantly increased. Along with the passage of time of year and daytime, dive duration significantly increased, while dive duration decreased significantly with the increase in flock size.Conclusions: Sex, temperature, time and flock size have an effect on the diving behavior of the wintering Scalysided Merganser. The difference of diving behavior between males and females is related to differences in body mass. The difference of diving behavior among various temperatures and time periods may be related to a low minimum rate of oxygen consumption, while the difference among various flock sizes may be caused by rising intraspecific competition.展开更多
This paper concentrates on the cross-range resolution of Synthetic Aperture Radar(SAR) based on diving model.In comparison to the azimuth resolution,the cross-range resolution can manifest the two-dimensional resoluti...This paper concentrates on the cross-range resolution of Synthetic Aperture Radar(SAR) based on diving model.In comparison to the azimuth resolution,the cross-range resolution can manifest the two-dimensional resolution ability of the imaging sensor SAR correctly.The diving model of SAR is an extended model from the conventional stripmap model,and the cross-range resolution expression is deduced from the equivalent linear frequency modulation pulses' compression.This expression points out that only the cross-range velocity component of the horizontal velocity contributes to the cross-range resolution.Also the cross-range resolution expressions and the performance of the conventional stripmap operation,squint side-look operation and beam circular-scanning operation are discussed.The cross-range resolution expression based on diving model will provide more general and more accurate reference.展开更多
Herein, we present the results of our experimental investigation of splashes formed by a frog diving into water from the ground or from a leaf and the accompanying sound generated by the impact of the frog on the wate...Herein, we present the results of our experimental investigation of splashes formed by a frog diving into water from the ground or from a leaf and the accompanying sound generated by the impact of the frog on the water. The experiments are performed by visualizing the flow with a high-speed camera. In addition, we used physical models comprising hydrophilic bodies made from hydrogel or acrylic resin to experimentally study how hydrophilicity affects the splash. In these experiments, we use the degree of swelling to define the hydrophilicity degree. The results show that different splashes are caused by the increase in water-film velocity upon an increase in hydrophilicity. For a body with strong hydrophilicity, at a relatively high film velocity, the water film forms when the body impacts the water surface separates from the body surface. In addition, an aircavity forms when the film separates from the body. We empirically examine the relation between the hydrophilicity degree and film velocity. The results indicate that increased hydrophilicity does not reduce the splash. Therefore, we conclude that reducing of the formation of water from the biomimetic point of view is related to the shape of body.展开更多
Based on our preceding studies on the aerodynamics of a falcoperegrinus in diving flight along a vertical dam it is known that even when the body shape of the bird is rather streamlined in V-shape some feathers tips m...Based on our preceding studies on the aerodynamics of a falcoperegrinus in diving flight along a vertical dam it is known that even when the body shape of the bird is rather streamlined in V-shape some feathers tips may elevate in certain regions of the body. These regions were identified in wind tunnel tests for typical diving flight conditions as regions of locally separated flow. A life-size model in V-shape of a falcoperegrinus with artificial feathers fixed along the body was studied in a wind tunnel to focus on the fluid-structure interaction of feathers located in this sector. The distal ends of the feathers show flow-induced vibrations at typical flight conditions which grow linear in amplitude with increasing angle of incidence until incipient separation. In light of the proven existence of vibration-sensitive mechanoreceptors in the follicles of secondary feathers in birds it is hypothesized that this linear amplitude response offers the bird to sense the angle of incidence during the diving flight using the vibration magnitude as sensory stimulus. Thus the bird in streamlined shape has still a good measure to control its attitude to be in the narrow window of safe angle of incidence. This might have implications also for other birds or technical applications of airfoil sensors regarding incipient separation detection.展开更多
The bistratified lobula giant type 1(BLG1) neuron is an identified looming-sensitive neuron in crab's visual brain that demonstrates special sensitivity to diving targets, or descending approaching motions. In thi...The bistratified lobula giant type 1(BLG1) neuron is an identified looming-sensitive neuron in crab's visual brain that demonstrates special sensitivity to diving targets, or descending approaching motions. In this paper, a novel neural model is proposed to shape such unique selectivity through incorporating a bio-plausible feedforward contrast inhibition synapse and a radially extending spatial enhancement distribution. Herein the synaptic connections and neuronal functions of this model are placed within a framework for matching and describing underlying biological findings. The systematic and comparative experiments have validated the proposed computational model that reconciles with the characteristics of BLG1 neurons in crab.展开更多
This paper reports the changes of the EEG of human bodies during saturation ex-posure at different depths to different mixed gases. The results of the research show thatthe most obvious on EEG was the appearance of di...This paper reports the changes of the EEG of human bodies during saturation ex-posure at different depths to different mixed gases. The results of the research show thatthe most obvious on EEG was the appearance of diffused slow waves, usually θ wavesof 4- 7 times/s, and δ waves of 2- 3 times/s within individual subjects. The EEG changesat 50 m were more obvious than those at 36 .5 m. With the prolonging of time under highpressure, the EEG had some improvements, for instance, the slow waves decreased andthe α waves increased. There was a certain relationship between these changes and thesymptoms which appeared in the human body. The chief factor of the EEG changes isdue to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. Inaddition, carbon dioxide retention under the high pressure is also a factor of the EEGchanges, because repeated inhaling of CO<sub>2</sub>-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could展开更多
SINCE she won the gold medal for thethree meters springboard dive at the ThirteenthAsian Games, Guo Jingjing has become anoutstanding star within China’s sporting circle.People take her as a leading figure after thel...SINCE she won the gold medal for thethree meters springboard dive at the ThirteenthAsian Games, Guo Jingjing has become anoutstanding star within China’s sporting circle.People take her as a leading figure after thelikes of Fu Mingxia and Tan Shuping, andplace great expectations on her. As soon as shefinishes a competition. reporters pursue her foranswers to their questions. A cheeky figure,her reply is often a non-committal,"I don’tknow".展开更多
AFTER winning two gold medals atthe 1996 Atlanta Olympic,theDiving Queen’Fu Mingxia quit her sportscareer and became a student at QinghuaUniversity,one of the best universities inChina.Recently,due to the less than i...AFTER winning two gold medals atthe 1996 Atlanta Olympic,theDiving Queen’Fu Mingxia quit her sportscareer and became a student at QinghuaUniversity,one of the best universities inChina.Recently,due to the less than idealstandard of the younger divers,sheresumed her training under the展开更多
A moving submarine can generate internal waves,as well as extremely small free surface waves,in a fluid with density stratification.In this study,the internal and free surface wave wakes caused by a moving submarine i...A moving submarine can generate internal waves,as well as extremely small free surface waves,in a fluid with density stratification.In this study,the internal and free surface wave wakes caused by a moving submarine in two layers of constant density fluid were studied numerically using the commercial software STAR-CCM+.The realizable k–εturbulence model was used to solve the Reynolds-averaged Navier–Stokes equation,and the volume of the fluid method was used to monitor the fluctuations of the internal interface and free surface.Different cases of a moving submarine with different cruising speeds and relative diving depths were studied.Results showed that the maximum fluctuation amplitude of the free surface increased as the speed of the submarine increased;however,the maximum fluctuation amplitude of the internal interface first decreased and then increased.When the submarine moved at the maximum cruising speed,the maximum fluctuation amplitude of the free surface decreased as the diving depth increased,while the wavelength of the free surface wave was basically the same.If the submarine moved at the minimum cruising speed,then the wave elevation in the free surface was extremely small,but the internal surface had obviously large-amplitude internal waves,and the relative diving depth had a great influence on internal waves.展开更多
An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously obs...An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.展开更多
The study deals with the observation of the changes in the electrical activities of 8 healthy divers in the 80 msw saturation-100 msw excursion heliox dive by DCG. Results showed significant changes in the 24 h of ave...The study deals with the observation of the changes in the electrical activities of 8 healthy divers in the 80 msw saturation-100 msw excursion heliox dive by DCG. Results showed significant changes in the 24 h of average heart rate, the decrease of heart rate at saturation storage depth and decompression periods being 15.5% and 19.7% respectively. Fortuitous supraventricular premature beats appeared in 8 divers and ventricular premature beats in 5 divers during exposure. Transient ischemic ST-T changes in 6 divers occurred repeatedly during diving operations. The discussion puts up the view that the ST-T changes were due to the stress reaction of the body induced by the combined effect of such stress factors as hyperbaric pressure per se, high partial pressure of oxgen, noise and the closed restricted chamber environment.展开更多
The Diver Gas Recovery Installation (DGRI) was evaluated at 80 msw saturation - 100 msw excursion diving on HeO2 in the Naval Medical Research Institute (NMRI) of China in April, 1995. The diving depth, lockout time, ...The Diver Gas Recovery Installation (DGRI) was evaluated at 80 msw saturation - 100 msw excursion diving on HeO2 in the Naval Medical Research Institute (NMRI) of China in April, 1995. The diving depth, lockout time, breathing gas flow rate and consumption, inspired oxygen partial pressure (PO2) and carbon dioxide partial pressure (PCO2) were monitored. The results indicated that PO2 was controlled to fluctuate from 64.3 to 84.0 kPa and PCO2 went up from 0.01 kPa up to O.I kPa during 4 hours excursion diving; recovery of breathing gas reached 95%; three divers felt well and breathed comfortably during simulating heavy work. The test showed that it met desired performance goals. The DGRI is a kind of important equipment for long duration deep dive. It enables the gases exhaled by the divers to be re-cycled, and therefore it has great social, military and economic significance for diving operation and submarine rescue.展开更多
Underwater robot technology has shown impressive results in applications such as underwater resource detection.For underwater applications that require extremely high flexibility,robots cannot replace skills that requ...Underwater robot technology has shown impressive results in applications such as underwater resource detection.For underwater applications that require extremely high flexibility,robots cannot replace skills that require human dexterity yet,and thus humans are often required to directly perform most underwater operations.Wearable robots(exoskeletons)have shown outstanding results in enhancing human movement on land.They are expected to have great potential to enhance human underwater movement.The purpose of this survey is to analyze the state-of-the-art of underwater exoskeletons for human enhancement,and the applications focused on movement assistance while excluding underwater robotic devices that help to keep the temperature and pressure in the range that people can withstand.This work discusses the challenges of existing exoskeletons for human underwater movement assistance,which mainly includes human underwater motion intention perception,underwater exoskeleton modeling and human-cooperative control.Future research should focus on developing novel wearable robotic structures for underwater motion assistance,exploiting advanced sensors and fusion algorithms for human underwater motion intention perception,building up a dynamic model of underwater exoskeletons and exploring human-in-theloop control for them.展开更多
BACKGROUND AND OBJECTIVE: Posterior tibialis tendon dysfunction (PTTD) is a progressive ailment of a lower limb that, if left untreated, can lead to irreversible changes in the structure and function. The authors of t...BACKGROUND AND OBJECTIVE: Posterior tibialis tendon dysfunction (PTTD) is a progressive ailment of a lower limb that, if left untreated, can lead to irreversible changes in the structure and function. The authors of the present study hypothesized the damages to the tibias tendon can be countered and reversed using electrical acupuncture and concurrent treatment of the associated muscle. INTERVENTION: The following study details a successful treatment of the early stage PTTD in a group of competitive athletes using a specific Electrical Intra Muscular Stimulation (EIMS) protocol developed and rooted in years of practice and the knowledge of the pathophysiology of the muscle and tendon tissues. Specifically, a combination the posterior and the original EIMS approach was used to stimulate the tendon and muscle concurrently at a frequency of 2 Hz. Analysis of the VAS scores showed a significant improvement following the treatment sessions. CONCLUSION: The success of this combined muscle/tendon stimulation protocol is given a strong correlation between the mechanism of tendon and muscle injury and recovery. The fast rate of healing and the simplicity of the materials required for the treatment offer a great potential for a wide-spread application. The authors extrapolate that the treatment method, with applicable modifications in needling locations, can be used for an array of common ailments involving tendons and muscles of the lower limb and foot, including the over-pronation, which is now common place due to the overweight problem in the general population.展开更多
Objectives: Due to presence of extensively fascinating coral reef ecosystem in the continental shelf of Andaman and Nicobar Islands, people from all over the world visit these islands of India to indulge in recreation...Objectives: Due to presence of extensively fascinating coral reef ecosystem in the continental shelf of Andaman and Nicobar Islands, people from all over the world visit these islands of India to indulge in recreational diving. An increased participation figure has also elevated the number of divers at risk for Decompression Sickness (DCS). Despite this, no scientific data are available on DCS incidents from India. Present study is aimed to evaluate the DCS incidents reported in these islands, treatment provided, and the outcome of the treatment. An attempt has also been made to calculate the approximate frequency of DCS in comparison to the participation figure. Methods: Study design is retrospective data analyses of a recompression chamber. Naval Diving Unit Port Blair has the only active decompression chamber available in the islands, and Govind Ballabh Pant Hospital Port Blair was used to collect information on DCS incidents that occurred during the mentioned period. Due to lack of authenticated generalized documents of divers’ health history and dive logs, the scanty information was gathered from the dive centres on the basis of personal interviews/communications among the SCUBA diving instructors. Results: A total of nine cases were reported during the span of last four and half years, and thus approximate frequency of DCS in Andamans was 0.2/10000 divers year. All of the patients recovered completely after receiving the Hyperbaric Oxygen Therapy (HBOT), with no residual symptoms. Conclusions: Incident rate of DCS in Andamans is lower than that in many other parts of the world;possible reason could be under-reporting of less severe DCS cases. During the study period, the number of DCS type II incidents presented for the treatment was higher than that of DCS type I incidents. HBOT proved a complete success in treating DCS cases in the island.展开更多
基金supported by National Natural Science Foundation of China(No.61871241,No.61771263)Science and Technology Program of Nantong(No.JC2018129,No.JC2018127)Fund of Nantong University-Nantong Joint Research Center for Intelligent Information Technology(No.KFKT2016A01,No.KFKT2017A05)。
文摘With the development of society and the progress of technology,more and more ocean activities are carried out.It results in booming of deep-sea diving.The use of helium-oxygen mixture(as a kind of breathing gas)solves the physiological problems of divers in saturated diving,but it brings about the Heliumspeech voice communication problem,the drop of speech intelligibility.There is no doubt that the effective speech communication must be provided for supporting the life and work of divers in deep-sea.This paper describes the mechanism of forming heliumspeech,discusses the effects of pressure and helium environment on the speech spectrum,compares the pros and cons of the time-domain and frequency-domain unscrambling techniques,shows the challenges in heliumspeech communications.Finally,it briefly introduces the deep learning,and points out that deep learning/machine learning may be a perfectly unscrambling technique.
基金supported by the National Natural Science Foundation of China(Grant No.31560597)
文摘Background: The foraging and diving behavior of waterfowl are affected by a number of important factors. Hence, learning more about these major factors is of great concern in order to protect endangered species. In this study, we verified the effect of sex, temperature, time and flock size on the diving behavior of the Scaly-sided Merganser(Mergus squamatus).Methods: The study was conducted by means of focal animal sampling in the Wuyuan section of the Poyang Lake watershed in Jiangxi Province, China from December 2015 to March 2016. We used one-way ANOVA and LSD tests to investigate the differences among these factors. Pearson correlations were used to test the relation between pause duration and the previous or subsequent dive duration. The relations between these factors and dive/pause duration are illustrated using Spearman correlations.Results: Mean dive duration and mean time on the pause of males were significantly higher than those of females. With an increase in temperature, dive duration significantly increased. Along with the passage of time of year and daytime, dive duration significantly increased, while dive duration decreased significantly with the increase in flock size.Conclusions: Sex, temperature, time and flock size have an effect on the diving behavior of the wintering Scalysided Merganser. The difference of diving behavior between males and females is related to differences in body mass. The difference of diving behavior among various temperatures and time periods may be related to a low minimum rate of oxygen consumption, while the difference among various flock sizes may be caused by rising intraspecific competition.
基金Supported by the Chinese Postdoctoral Science Foundation(No. 20080440300)the Fundamental Research Funds for the Central Universities
文摘This paper concentrates on the cross-range resolution of Synthetic Aperture Radar(SAR) based on diving model.In comparison to the azimuth resolution,the cross-range resolution can manifest the two-dimensional resolution ability of the imaging sensor SAR correctly.The diving model of SAR is an extended model from the conventional stripmap model,and the cross-range resolution expression is deduced from the equivalent linear frequency modulation pulses' compression.This expression points out that only the cross-range velocity component of the horizontal velocity contributes to the cross-range resolution.Also the cross-range resolution expressions and the performance of the conventional stripmap operation,squint side-look operation and beam circular-scanning operation are discussed.The cross-range resolution expression based on diving model will provide more general and more accurate reference.
文摘Herein, we present the results of our experimental investigation of splashes formed by a frog diving into water from the ground or from a leaf and the accompanying sound generated by the impact of the frog on the water. The experiments are performed by visualizing the flow with a high-speed camera. In addition, we used physical models comprising hydrophilic bodies made from hydrogel or acrylic resin to experimentally study how hydrophilicity affects the splash. In these experiments, we use the degree of swelling to define the hydrophilicity degree. The results show that different splashes are caused by the increase in water-film velocity upon an increase in hydrophilicity. For a body with strong hydrophilicity, at a relatively high film velocity, the water film forms when the body impacts the water surface separates from the body surface. In addition, an aircavity forms when the film separates from the body. We empirically examine the relation between the hydrophilicity degree and film velocity. The results indicate that increased hydrophilicity does not reduce the splash. Therefore, we conclude that reducing of the formation of water from the biomimetic point of view is related to the shape of body.
文摘Based on our preceding studies on the aerodynamics of a falcoperegrinus in diving flight along a vertical dam it is known that even when the body shape of the bird is rather streamlined in V-shape some feathers tips may elevate in certain regions of the body. These regions were identified in wind tunnel tests for typical diving flight conditions as regions of locally separated flow. A life-size model in V-shape of a falcoperegrinus with artificial feathers fixed along the body was studied in a wind tunnel to focus on the fluid-structure interaction of feathers located in this sector. The distal ends of the feathers show flow-induced vibrations at typical flight conditions which grow linear in amplitude with increasing angle of incidence until incipient separation. In light of the proven existence of vibration-sensitive mechanoreceptors in the follicles of secondary feathers in birds it is hypothesized that this linear amplitude response offers the bird to sense the angle of incidence during the diving flight using the vibration magnitude as sensory stimulus. Thus the bird in streamlined shape has still a good measure to control its attitude to be in the narrow window of safe angle of incidence. This might have implications also for other birds or technical applications of airfoil sensors regarding incipient separation detection.
基金supported by the National Natural Science Foundation of China (No.12031003)the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement (No.778062 ULTRACEPT)。
文摘The bistratified lobula giant type 1(BLG1) neuron is an identified looming-sensitive neuron in crab's visual brain that demonstrates special sensitivity to diving targets, or descending approaching motions. In this paper, a novel neural model is proposed to shape such unique selectivity through incorporating a bio-plausible feedforward contrast inhibition synapse and a radially extending spatial enhancement distribution. Herein the synaptic connections and neuronal functions of this model are placed within a framework for matching and describing underlying biological findings. The systematic and comparative experiments have validated the proposed computational model that reconciles with the characteristics of BLG1 neurons in crab.
文摘This paper reports the changes of the EEG of human bodies during saturation ex-posure at different depths to different mixed gases. The results of the research show thatthe most obvious on EEG was the appearance of diffused slow waves, usually θ wavesof 4- 7 times/s, and δ waves of 2- 3 times/s within individual subjects. The EEG changesat 50 m were more obvious than those at 36 .5 m. With the prolonging of time under highpressure, the EEG had some improvements, for instance, the slow waves decreased andthe α waves increased. There was a certain relationship between these changes and thesymptoms which appeared in the human body. The chief factor of the EEG changes isdue to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. Inaddition, carbon dioxide retention under the high pressure is also a factor of the EEGchanges, because repeated inhaling of CO<sub>2</sub>-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could
文摘SINCE she won the gold medal for thethree meters springboard dive at the ThirteenthAsian Games, Guo Jingjing has become anoutstanding star within China’s sporting circle.People take her as a leading figure after thelikes of Fu Mingxia and Tan Shuping, andplace great expectations on her. As soon as shefinishes a competition. reporters pursue her foranswers to their questions. A cheeky figure,her reply is often a non-committal,"I don’tknow".
文摘AFTER winning two gold medals atthe 1996 Atlanta Olympic,theDiving Queen’Fu Mingxia quit her sportscareer and became a student at QinghuaUniversity,one of the best universities inChina.Recently,due to the less than idealstandard of the younger divers,sheresumed her training under the
基金Supported by the Frontier Science Center for Extreme Marine Environmental Fluctuation FieldsHeilongjiang Touyan Innovation Team Program
文摘A moving submarine can generate internal waves,as well as extremely small free surface waves,in a fluid with density stratification.In this study,the internal and free surface wave wakes caused by a moving submarine in two layers of constant density fluid were studied numerically using the commercial software STAR-CCM+.The realizable k–εturbulence model was used to solve the Reynolds-averaged Navier–Stokes equation,and the volume of the fluid method was used to monitor the fluctuations of the internal interface and free surface.Different cases of a moving submarine with different cruising speeds and relative diving depths were studied.Results showed that the maximum fluctuation amplitude of the free surface increased as the speed of the submarine increased;however,the maximum fluctuation amplitude of the internal interface first decreased and then increased.When the submarine moved at the maximum cruising speed,the maximum fluctuation amplitude of the free surface decreased as the diving depth increased,while the wavelength of the free surface wave was basically the same.If the submarine moved at the minimum cruising speed,then the wave elevation in the free surface was extremely small,but the internal surface had obviously large-amplitude internal waves,and the relative diving depth had a great influence on internal waves.
文摘An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.
文摘The study deals with the observation of the changes in the electrical activities of 8 healthy divers in the 80 msw saturation-100 msw excursion heliox dive by DCG. Results showed significant changes in the 24 h of average heart rate, the decrease of heart rate at saturation storage depth and decompression periods being 15.5% and 19.7% respectively. Fortuitous supraventricular premature beats appeared in 8 divers and ventricular premature beats in 5 divers during exposure. Transient ischemic ST-T changes in 6 divers occurred repeatedly during diving operations. The discussion puts up the view that the ST-T changes were due to the stress reaction of the body induced by the combined effect of such stress factors as hyperbaric pressure per se, high partial pressure of oxgen, noise and the closed restricted chamber environment.
文摘The Diver Gas Recovery Installation (DGRI) was evaluated at 80 msw saturation - 100 msw excursion diving on HeO2 in the Naval Medical Research Institute (NMRI) of China in April, 1995. The diving depth, lockout time, breathing gas flow rate and consumption, inspired oxygen partial pressure (PO2) and carbon dioxide partial pressure (PCO2) were monitored. The results indicated that PO2 was controlled to fluctuate from 64.3 to 84.0 kPa and PCO2 went up from 0.01 kPa up to O.I kPa during 4 hours excursion diving; recovery of breathing gas reached 95%; three divers felt well and breathed comfortably during simulating heavy work. The test showed that it met desired performance goals. The DGRI is a kind of important equipment for long duration deep dive. It enables the gases exhaled by the divers to be re-cycled, and therefore it has great social, military and economic significance for diving operation and submarine rescue.
基金supported in part by the National Key Research and Development Program of China(2021YFF0501600)the National Natural Science Foundation of China(U1913601)+6 种基金the Major Science and Technology Projects of Anhui Province(202103a05020004)the China Postdoctoral Science Foundation(2021M693079)the Fundamental Research Funds for the Central Universities(WK2100000020)the State Key Laboratory of Mechanical System and Vibration(MSV202219)the Ministry of Science and Higher Education of the Russian Federation as Part of World-Class Research Center Program:Advanced Digital Technologies(075-15-2020-903)the Open Research Project of the State Key Laboratory of Industrial Control Technology,Zhejiang UniversityChina(ICT2022B42)。
文摘Underwater robot technology has shown impressive results in applications such as underwater resource detection.For underwater applications that require extremely high flexibility,robots cannot replace skills that require human dexterity yet,and thus humans are often required to directly perform most underwater operations.Wearable robots(exoskeletons)have shown outstanding results in enhancing human movement on land.They are expected to have great potential to enhance human underwater movement.The purpose of this survey is to analyze the state-of-the-art of underwater exoskeletons for human enhancement,and the applications focused on movement assistance while excluding underwater robotic devices that help to keep the temperature and pressure in the range that people can withstand.This work discusses the challenges of existing exoskeletons for human underwater movement assistance,which mainly includes human underwater motion intention perception,underwater exoskeleton modeling and human-cooperative control.Future research should focus on developing novel wearable robotic structures for underwater motion assistance,exploiting advanced sensors and fusion algorithms for human underwater motion intention perception,building up a dynamic model of underwater exoskeletons and exploring human-in-theloop control for them.
文摘BACKGROUND AND OBJECTIVE: Posterior tibialis tendon dysfunction (PTTD) is a progressive ailment of a lower limb that, if left untreated, can lead to irreversible changes in the structure and function. The authors of the present study hypothesized the damages to the tibias tendon can be countered and reversed using electrical acupuncture and concurrent treatment of the associated muscle. INTERVENTION: The following study details a successful treatment of the early stage PTTD in a group of competitive athletes using a specific Electrical Intra Muscular Stimulation (EIMS) protocol developed and rooted in years of practice and the knowledge of the pathophysiology of the muscle and tendon tissues. Specifically, a combination the posterior and the original EIMS approach was used to stimulate the tendon and muscle concurrently at a frequency of 2 Hz. Analysis of the VAS scores showed a significant improvement following the treatment sessions. CONCLUSION: The success of this combined muscle/tendon stimulation protocol is given a strong correlation between the mechanism of tendon and muscle injury and recovery. The fast rate of healing and the simplicity of the materials required for the treatment offer a great potential for a wide-spread application. The authors extrapolate that the treatment method, with applicable modifications in needling locations, can be used for an array of common ailments involving tendons and muscles of the lower limb and foot, including the over-pronation, which is now common place due to the overweight problem in the general population.
文摘Objectives: Due to presence of extensively fascinating coral reef ecosystem in the continental shelf of Andaman and Nicobar Islands, people from all over the world visit these islands of India to indulge in recreational diving. An increased participation figure has also elevated the number of divers at risk for Decompression Sickness (DCS). Despite this, no scientific data are available on DCS incidents from India. Present study is aimed to evaluate the DCS incidents reported in these islands, treatment provided, and the outcome of the treatment. An attempt has also been made to calculate the approximate frequency of DCS in comparison to the participation figure. Methods: Study design is retrospective data analyses of a recompression chamber. Naval Diving Unit Port Blair has the only active decompression chamber available in the islands, and Govind Ballabh Pant Hospital Port Blair was used to collect information on DCS incidents that occurred during the mentioned period. Due to lack of authenticated generalized documents of divers’ health history and dive logs, the scanty information was gathered from the dive centres on the basis of personal interviews/communications among the SCUBA diving instructors. Results: A total of nine cases were reported during the span of last four and half years, and thus approximate frequency of DCS in Andamans was 0.2/10000 divers year. All of the patients recovered completely after receiving the Hyperbaric Oxygen Therapy (HBOT), with no residual symptoms. Conclusions: Incident rate of DCS in Andamans is lower than that in many other parts of the world;possible reason could be under-reporting of less severe DCS cases. During the study period, the number of DCS type II incidents presented for the treatment was higher than that of DCS type I incidents. HBOT proved a complete success in treating DCS cases in the island.
