The presentation of clinical symptoms due to decompression during diving, varies significantly, as mainly minor disturbances for the gastrointestinal tract in particular have been reported. The following case debates ...The presentation of clinical symptoms due to decompression during diving, varies significantly, as mainly minor disturbances for the gastrointestinal tract in particular have been reported. The following case debates whether diving can cause severe symptoms from the gastrointestinal system. We describe a clinical case of ischemic colitis presented in a 27-year-old male, who manifested abdominal pain while in the process of scuba diving 20 meters undersea, followed by bloody diarrhoea as soon as he ascended to sea level. Taking into account his past medical history, the thorough, impeccable clinical and laboratory examinations and presence of no other factors predisposing to ischemia of the colon, we assume that a possible relationship between diving conditions and the pathogenesis of ischemic colitis may exist. This unusual case might represent a hematologic manifestation of decompression sickness, due to increased coagulability and/or transient air emboli, occurring during a routine scuba diving ascent to sea level.展开更多
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
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
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
-The chief purpose of the research was to understand the physiological function change regularity, performance and adaptability of the human body living and working under high pressure for prolonged time.In January 19...-The chief purpose of the research was to understand the physiological function change regularity, performance and adaptability of the human body living and working under high pressure for prolonged time.In January 1989, 4 naval divers entered the habital of NMRI's 500 msw saturation diving system after a series of adaptive diving training. The breathing mixture was helium-oxygen. After 55 h compression (including intermediate stages) the 350 msw depth was reached, where the divers lived and worked for 72 h 10 min. No sign of discomfort or significant HPNS was found in the 4 divers.The second and third day of the saturation exposure, the divers carried out 370 msw dry and wet chamber excursion diving 2 man-time each, the divers effectively carried out operational work under water, the total excursion time was 1 h each excursion dive.Saturation decompression started after 3-day storage exposure, the divers were gradually brought toward the surface 25 msw a day on the average by employing the linear steady rate of decompression. During decompression, no case of DCS occurred. Immediate post-dive medical check-ups shows that they were physically normal.More than 120 biomedical indices were monitored and measured on the divers at different period of the experiment. The organisms showed a good adaptability and certain operating capability, and both the compression and decompression profiles were proved to be satisfactory.The detailed experimental data obtained provided sound scientific basis for the practical application of future great depth open sea saturation diving.展开更多
The 300 msw Simulated Saturation Diving Chamber Complex was designed and built by ourselves. It was completed at the end of 1985. A 300 msw trimixed saturation diving experiment was successfully conducted in the compl...The 300 msw Simulated Saturation Diving Chamber Complex was designed and built by ourselves. It was completed at the end of 1985. A 300 msw trimixed saturation diving experiment was successfully conducted in the complex by Chinese Underwater Technology Institute(CUTI) from May 22 to June 12 of 1987. During the experiment, 4 divers habitated in the complex for 20 days, and they performed 16 person-time excursion dives and 8 other tests. The result of the experiment indicates that the complex is well designed, suitably configurated, wholly integrated and steadily run, as well as of low leakage. The main functions of the complex have approached to those of the same kind in the world. The complex can be used as a basic facility for serving the nation's saturation diving technology, underwater operation, personnel training, etc.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
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
Competitive diving is a popular sport that attracts numerous participants worldwide;unfortunately,competitive divers experience a notable frequency of injuries during training and competition.Despite this,injuries in ...Competitive diving is a popular sport that attracts numerous participants worldwide;unfortunately,competitive divers experience a notable frequency of injuries during training and competition.Despite this,injuries in diving often received less attention compared to those in other aquatic sports.The purpose of this study was to conduct a systematic review to update the scientific evidence on injury incidence in competitive divers to offer insights into the prevalent injury patterns and help develop injury prevention strategies.This involved analyzing injury data collected from the Injury Surveillance Programme(ISP)across various levels of competition events and assessing case reports involving a wide spectrum of diving injuries.Four online bibliographical databases were consulted:Google Scholar,PubMed,Scops,and Web of Science from their inception until December 6,2023.819 studies were initially identified,and 15 studies were finally included in this review.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISM)guidelines and PRISMA in Exercise,Rehabilitation,Sport Medicine,and Sport Science(PERSiST)were followed.Two independent reviewers evaluated the methodological quality of the studies.The majority of diving injuries are concentrated on the upper body/trunk,including the shoulder,spine,hand/wrist,head/face,and neck,with overuse injury being a main contribution.Regarding diving incidence,the actual injury rate in competitive athletes could be even higher than currently reported,primarily due to limitations in implementing injury surveillance protocol for diving athletes.The latest injury data for diving in big competition events is absent,and there is a strong expectation for more new injury surveillance data to be published in the future.Additionally,the specific injury pattern,prevention strategy,and rehabilitation training plan for diving injury are severely deficient in the current literature.展开更多
Ensuring accurate parameter identification and diving motion prediction of marine crafts is essential for safe navigation,optimized operational efficiency,and the advancement of marine exploration.Addressing this,this...Ensuring accurate parameter identification and diving motion prediction of marine crafts is essential for safe navigation,optimized operational efficiency,and the advancement of marine exploration.Addressing this,this paper proposes an instrumental variable-based least squares(IVLS)algorithm.Firstly,aiming to balance complexity with accuracy,a decoupled diving model is constructed,incorporating nonlinear actuator characteristics,inertia coefficients,and damping coefficients.Secondly,a discrete parameter identification matrix is designed based on this dedicated model,and then a IVLS algorithm is innovatively derived to reject measurement noise.Furthermore,the stability of the proposed algorithm is validated from a probabilistic point of view,providing a solid theoretical foundation.Finally,performance evaluation is conducted using four depth control datasets obtained from a piston-driven profiling float in Qiandao Lake,with desired depths of 30 m,40 m,50 m,and 60 m.Based on the diving dynamics identification results,the IVLS algorithm consistently shows superior performance when compared to recursive weighted least squares algorithm and least squares support vector machine algorithm across all depths,as evidenced by lower average absolute error(AVGAE),root mean square error(RMSE),and maximum absolute error values and higher determination coefficient(R2).Specifically,for desired depth of 60 m,the IVLS algorithm achieved an AVGAE of 0.553 m and RMSE of 0.655 m,significantly outperforming LSSVM with AVGAE and RMSE values of 8.782 m and 11.117 m,respectively.Moreover,the IVLS algorithm demonstrates a remarkable generalization capability with R2 values consistently above 0.95,indicating its robustness in handling varied diving dynamics.展开更多
In the mysterious depths of the ocean,robots glide between reefs and corals,avoid obstacles,navigate independently,and fulfil their tasks as if they had a vision that could penetrate the murkiness of the water.The Chi...In the mysterious depths of the ocean,robots glide between reefs and corals,avoid obstacles,navigate independently,and fulfil their tasks as if they had a vision that could penetrate the murkiness of the water.The Chinese company Chasing has developed a robot capable of diving to a depth of 350 metres.As an underwater photographer,lifeguard or swimming pool cleaner,it demonstrates the expertise the company has acquired over years of research and development work.展开更多
High-nickel ternary silicon-carbon lithium-ion batteries,which use silicon-carbon materials as anodes and high-nickel ternary materials as cathodes,have already been commercialized as power batteries.The increasing de...High-nickel ternary silicon-carbon lithium-ion batteries,which use silicon-carbon materials as anodes and high-nickel ternary materials as cathodes,have already been commercialized as power batteries.The increasing demand for high-energy density and rapid charging characteristics has heightened the urgency of improving their fast charging cycle performance while establishing degradation mechanisms.Based on a pouch battery design with an energy density of 285 Wh·kg^(-1),this work studied 3 Ah pouch batteries for fast charging cycles ranging from 0.5C to 3C.Non-destructive techniques,such as differential voltage,incremental capacity analysis,and electrochemical impedance spectroscopy,were employed to investigate the effects of charging rates on battery cycling performance and to establish the degradation mechanisms.The experimental results indicated that capacity diving was observed at all charging rates.However,at lower rates(0.5C-2C),more cycles were achieved,while at higher rates(2C-3C),the cycle life remained relatively stable.Computed tomography,electrochemical performance analysis,and physicochemical characterizations were obtained,using scanning electron microscopy with energy dispersive spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and inductively coupled plasma optical emission spectrometry.The mechanisms of capacity decrease during 3C fast charging cycles were investigated.It is proposed that the primary causes of capacity diving during 3C fast charging are the degradation of SiOx,anode polarization,and the simultaneous dissolution of metal ions in the cathode which were deposited at the anode,resulting the continuous growth and remodeling of the SEI membrane at the anode,thereby promoting more serious side reactions.展开更多
In this paper,we studied the wing root pivot joint’s radial load of a submersible airplane which imitates the locomotion of gannet’s Morus plunge-diving,by implementing a test device name Mimic-Gannet.The housing of...In this paper,we studied the wing root pivot joint’s radial load of a submersible airplane which imitates the locomotion of gannet’s Morus plunge-diving,by implementing a test device name Mimic-Gannet.The housing of the device was designed by mimicking the morphology of a living gannet,and the folding wings were realized by the mechanism of variable swept back wing.Then,the radial loads of the wing root were obtained under the conditions of different dropping heights,different sweptback angles and different water-entry inclination angles(i.e.,the angle between the longitudinal body axis and the water surface),and the relationships between the peak radial load and the above three parameters were analyzed and discussed respectively.In the studied areas,the minimum peak radial load of the pivot joint is 50.93 N,while the maximum reaches up to1135.00 N.The largest peak load would be generated for the situation of vertical water entry and zero wing sweptback angle.And it is of great significance to choose the three parameters properly to reduce the pivot joint’s radial load,i.e.,larger wing sweptback angle,smaller dropping height and water-entry inclination angle.It is also concluded that the peak radial load on the wing root is closely linear with the water-entry dropping height and the wing sweptback angle with a significant correlation.Eventually,the relationship between the wing load and the dropping height,water-entry inclination angle or wing sweptback angle,could be used to calculate the wing load about plunge-diving of a submersible aircraft,and the conclusions reveal the wing load characteristic of the gannet’s plunge process for the biologists.展开更多
Background It is very common for professional divers to have damage on the retinas.Severe retinal lesions can profoundly affect athletes＆#39; training efficacy and their daily lives.At present,it is not clear if ther...Background It is very common for professional divers to have damage on the retinas.Severe retinal lesions can profoundly affect athletes＆#39; training efficacy and their daily lives.At present,it is not clear if there is effective preventive action.Thus,in our study,we continuously tracked the ocular changes in athletes and closely monitored the risk factors associated with retinal detachment.Also,we analyzed possible interventions,their associated factors,and efficacies for timely preventions to protect the retina from damage in professional divers.Methods Between 2009 and 2012,a total of 39 professional divers enrolled in follow-up management.The conducted examinations included ocular examination,record screening on retinal lesion,monitoring best-corrected visual acuity,and checking intraocular pressure （lOP） and the scope of retinal lesion.The management included optimizing training methods,taking customized follow-up based on different retinal lesions,laser treatments for definite cases of retinal tear,retinal degeneration caused by retinal layer thinning or vitreous traction,and observing the changes in the scope of retinopathy.Results Every year,the percentage of divers who have various degrees of retinal lesions is between 43.3% and 56.2%.During the 4 years,there were no statistically significant differences in divers＆#39; best-corrected visual acuity and retinal lesions.There were also no statistically significant differences between male and female athletes.However,there were statistically significant differences in lOP during these years.Moreover there were statistically significant differences in IOP and the scope of retinal lesions between platform divers and springboard divers.Conclusions Our management of retinal lesions could be effective to prevent severe retinopathy in professional divers.At the same time,platform divers are more likely to have retinal lesions than springboard divers.展开更多
Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of bearing, earache daring compression. Ex...Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of bearing, earache daring compression. Examination showed that the threshold of tower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test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_2-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could improveabnormal EEGs. The main changes of the EEG during the helium-oxygen exposure at 302 mwere the increase of θ waves, and even of δ waves, the decrease in α rhythm and thedecline of amplitude of α waves. Increased θ index and decreased α index could be seenat the depth of 302 m. Under any of the above-mentioned pressure conditions when slowwaves characteristic of abnormal changes appeared in the EEGs, the EEGs could be tem-porarily improved by photic stimulation, i.e. slow waves disappeared and a waves reap-peared. When photic stimulation was over, α waves disappeared and slow waves reap-peared. It was indicated that abnormal changes of the EEG under high pressure were akind of temporary and reversible changes of the brain function.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
文摘The presentation of clinical symptoms due to decompression during diving, varies significantly, as mainly minor disturbances for the gastrointestinal tract in particular have been reported. The following case debates whether diving can cause severe symptoms from the gastrointestinal system. We describe a clinical case of ischemic colitis presented in a 27-year-old male, who manifested abdominal pain while in the process of scuba diving 20 meters undersea, followed by bloody diarrhoea as soon as he ascended to sea level. Taking into account his past medical history, the thorough, impeccable clinical and laboratory examinations and presence of no other factors predisposing to ischemia of the colon, we assume that a possible relationship between diving conditions and the pathogenesis of ischemic colitis may exist. This unusual case might represent a hematologic manifestation of decompression sickness, due to increased coagulability and/or transient air emboli, occurring during a routine scuba diving ascent to sea level.
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 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.
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.
文摘-The chief purpose of the research was to understand the physiological function change regularity, performance and adaptability of the human body living and working under high pressure for prolonged time.In January 1989, 4 naval divers entered the habital of NMRI's 500 msw saturation diving system after a series of adaptive diving training. The breathing mixture was helium-oxygen. After 55 h compression (including intermediate stages) the 350 msw depth was reached, where the divers lived and worked for 72 h 10 min. No sign of discomfort or significant HPNS was found in the 4 divers.The second and third day of the saturation exposure, the divers carried out 370 msw dry and wet chamber excursion diving 2 man-time each, the divers effectively carried out operational work under water, the total excursion time was 1 h each excursion dive.Saturation decompression started after 3-day storage exposure, the divers were gradually brought toward the surface 25 msw a day on the average by employing the linear steady rate of decompression. During decompression, no case of DCS occurred. Immediate post-dive medical check-ups shows that they were physically normal.More than 120 biomedical indices were monitored and measured on the divers at different period of the experiment. The organisms showed a good adaptability and certain operating capability, and both the compression and decompression profiles were proved to be satisfactory.The detailed experimental data obtained provided sound scientific basis for the practical application of future great depth open sea saturation diving.
文摘The 300 msw Simulated Saturation Diving Chamber Complex was designed and built by ourselves. It was completed at the end of 1985. A 300 msw trimixed saturation diving experiment was successfully conducted in the complex by Chinese Underwater Technology Institute(CUTI) from May 22 to June 12 of 1987. During the experiment, 4 divers habitated in the complex for 20 days, and they performed 16 person-time excursion dives and 8 other tests. The result of the experiment indicates that the complex is well designed, suitably configurated, wholly integrated and steadily run, as well as of low leakage. The main functions of the complex have approached to those of the same kind in the world. The complex can be used as a basic facility for serving the nation's saturation diving technology, underwater operation, personnel training, etc.
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.
文摘Competitive diving is a popular sport that attracts numerous participants worldwide;unfortunately,competitive divers experience a notable frequency of injuries during training and competition.Despite this,injuries in diving often received less attention compared to those in other aquatic sports.The purpose of this study was to conduct a systematic review to update the scientific evidence on injury incidence in competitive divers to offer insights into the prevalent injury patterns and help develop injury prevention strategies.This involved analyzing injury data collected from the Injury Surveillance Programme(ISP)across various levels of competition events and assessing case reports involving a wide spectrum of diving injuries.Four online bibliographical databases were consulted:Google Scholar,PubMed,Scops,and Web of Science from their inception until December 6,2023.819 studies were initially identified,and 15 studies were finally included in this review.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISM)guidelines and PRISMA in Exercise,Rehabilitation,Sport Medicine,and Sport Science(PERSiST)were followed.Two independent reviewers evaluated the methodological quality of the studies.The majority of diving injuries are concentrated on the upper body/trunk,including the shoulder,spine,hand/wrist,head/face,and neck,with overuse injury being a main contribution.Regarding diving incidence,the actual injury rate in competitive athletes could be even higher than currently reported,primarily due to limitations in implementing injury surveillance protocol for diving athletes.The latest injury data for diving in big competition events is absent,and there is a strong expectation for more new injury surveillance data to be published in the future.Additionally,the specific injury pattern,prevention strategy,and rehabilitation training plan for diving injury are severely deficient in the current literature.
基金supported in part by the National Natural Sci-ence Foundation of China under Grant 42376187in part by the National Key R&D Program of China under Grant 2023YFC2812800,in part by the Natural Science Foundation of Shanghai under Grant 22ZR1434600+2 种基金in part by the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University under Grant SL2022MS016in part by the Shanghai Jiao Tong University 2030 Initiative under Grant WH510244001in part by the Shanghai Underwater Robot En-gineering Technology Innovation Center under Grant 21DZ2221600.
文摘Ensuring accurate parameter identification and diving motion prediction of marine crafts is essential for safe navigation,optimized operational efficiency,and the advancement of marine exploration.Addressing this,this paper proposes an instrumental variable-based least squares(IVLS)algorithm.Firstly,aiming to balance complexity with accuracy,a decoupled diving model is constructed,incorporating nonlinear actuator characteristics,inertia coefficients,and damping coefficients.Secondly,a discrete parameter identification matrix is designed based on this dedicated model,and then a IVLS algorithm is innovatively derived to reject measurement noise.Furthermore,the stability of the proposed algorithm is validated from a probabilistic point of view,providing a solid theoretical foundation.Finally,performance evaluation is conducted using four depth control datasets obtained from a piston-driven profiling float in Qiandao Lake,with desired depths of 30 m,40 m,50 m,and 60 m.Based on the diving dynamics identification results,the IVLS algorithm consistently shows superior performance when compared to recursive weighted least squares algorithm and least squares support vector machine algorithm across all depths,as evidenced by lower average absolute error(AVGAE),root mean square error(RMSE),and maximum absolute error values and higher determination coefficient(R2).Specifically,for desired depth of 60 m,the IVLS algorithm achieved an AVGAE of 0.553 m and RMSE of 0.655 m,significantly outperforming LSSVM with AVGAE and RMSE values of 8.782 m and 11.117 m,respectively.Moreover,the IVLS algorithm demonstrates a remarkable generalization capability with R2 values consistently above 0.95,indicating its robustness in handling varied diving dynamics.
文摘In the mysterious depths of the ocean,robots glide between reefs and corals,avoid obstacles,navigate independently,and fulfil their tasks as if they had a vision that could penetrate the murkiness of the water.The Chinese company Chasing has developed a robot capable of diving to a depth of 350 metres.As an underwater photographer,lifeguard or swimming pool cleaner,it demonstrates the expertise the company has acquired over years of research and development work.
基金supported by the New Energy Vehicle Power Battery Life Cycle Testing and Verification Public Service Platform Project(No.2022-235-224).
文摘High-nickel ternary silicon-carbon lithium-ion batteries,which use silicon-carbon materials as anodes and high-nickel ternary materials as cathodes,have already been commercialized as power batteries.The increasing demand for high-energy density and rapid charging characteristics has heightened the urgency of improving their fast charging cycle performance while establishing degradation mechanisms.Based on a pouch battery design with an energy density of 285 Wh·kg^(-1),this work studied 3 Ah pouch batteries for fast charging cycles ranging from 0.5C to 3C.Non-destructive techniques,such as differential voltage,incremental capacity analysis,and electrochemical impedance spectroscopy,were employed to investigate the effects of charging rates on battery cycling performance and to establish the degradation mechanisms.The experimental results indicated that capacity diving was observed at all charging rates.However,at lower rates(0.5C-2C),more cycles were achieved,while at higher rates(2C-3C),the cycle life remained relatively stable.Computed tomography,electrochemical performance analysis,and physicochemical characterizations were obtained,using scanning electron microscopy with energy dispersive spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,and inductively coupled plasma optical emission spectrometry.The mechanisms of capacity decrease during 3C fast charging cycles were investigated.It is proposed that the primary causes of capacity diving during 3C fast charging are the degradation of SiOx,anode polarization,and the simultaneous dissolution of metal ions in the cathode which were deposited at the anode,resulting the continuous growth and remodeling of the SEI membrane at the anode,thereby promoting more serious side reactions.
基金supported by the National Natural Science Foundation of China(Grant No.51005008)
文摘In this paper,we studied the wing root pivot joint’s radial load of a submersible airplane which imitates the locomotion of gannet’s Morus plunge-diving,by implementing a test device name Mimic-Gannet.The housing of the device was designed by mimicking the morphology of a living gannet,and the folding wings were realized by the mechanism of variable swept back wing.Then,the radial loads of the wing root were obtained under the conditions of different dropping heights,different sweptback angles and different water-entry inclination angles(i.e.,the angle between the longitudinal body axis and the water surface),and the relationships between the peak radial load and the above three parameters were analyzed and discussed respectively.In the studied areas,the minimum peak radial load of the pivot joint is 50.93 N,while the maximum reaches up to1135.00 N.The largest peak load would be generated for the situation of vertical water entry and zero wing sweptback angle.And it is of great significance to choose the three parameters properly to reduce the pivot joint’s radial load,i.e.,larger wing sweptback angle,smaller dropping height and water-entry inclination angle.It is also concluded that the peak radial load on the wing root is closely linear with the water-entry dropping height and the wing sweptback angle with a significant correlation.Eventually,the relationship between the wing load and the dropping height,water-entry inclination angle or wing sweptback angle,could be used to calculate the wing load about plunge-diving of a submersible aircraft,and the conclusions reveal the wing load characteristic of the gannet’s plunge process for the biologists.
文摘Background It is very common for professional divers to have damage on the retinas.Severe retinal lesions can profoundly affect athletes＆#39; training efficacy and their daily lives.At present,it is not clear if there is effective preventive action.Thus,in our study,we continuously tracked the ocular changes in athletes and closely monitored the risk factors associated with retinal detachment.Also,we analyzed possible interventions,their associated factors,and efficacies for timely preventions to protect the retina from damage in professional divers.Methods Between 2009 and 2012,a total of 39 professional divers enrolled in follow-up management.The conducted examinations included ocular examination,record screening on retinal lesion,monitoring best-corrected visual acuity,and checking intraocular pressure （lOP） and the scope of retinal lesion.The management included optimizing training methods,taking customized follow-up based on different retinal lesions,laser treatments for definite cases of retinal tear,retinal degeneration caused by retinal layer thinning or vitreous traction,and observing the changes in the scope of retinopathy.Results Every year,the percentage of divers who have various degrees of retinal lesions is between 43.3% and 56.2%.During the 4 years,there were no statistically significant differences in divers＆#39; best-corrected visual acuity and retinal lesions.There were also no statistically significant differences between male and female athletes.However,there were statistically significant differences in lOP during these years.Moreover there were statistically significant differences in IOP and the scope of retinal lesions between platform divers and springboard divers.Conclusions Our management of retinal lesions could be effective to prevent severe retinopathy in professional divers.At the same time,platform divers are more likely to have retinal lesions than springboard divers.
文摘Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of bearing, earache daring compression. Examination showed that the threshold of tower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test
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_2-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could improveabnormal EEGs. The main changes of the EEG during the helium-oxygen exposure at 302 mwere the increase of θ waves, and even of δ waves, the decrease in α rhythm and thedecline of amplitude of α waves. Increased θ index and decreased α index could be seenat the depth of 302 m. Under any of the above-mentioned pressure conditions when slowwaves characteristic of abnormal changes appeared in the EEGs, the EEGs could be tem-porarily improved by photic stimulation, i.e. slow waves disappeared and a waves reap-peared. When photic stimulation was over, α waves disappeared and slow waves reap-peared. It was indicated that abnormal changes of the EEG under high pressure were akind of temporary and reversible changes of the brain function.
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".
