The DFI-1 submarine pipeline was investigated using a dual-frequency side-scan sonar and a swath sounder system. More than a hundred scour pits under the pipeline were found, most of which have caused the span of the ...The DFI-1 submarine pipeline was investigated using a dual-frequency side-scan sonar and a swath sounder system. More than a hundred scour pits under the pipeline were found, most of which have caused the span of the pipeline to increase and threatened its safety. The maximum allowable free span length （MAFSL） of the pipeline was determined through the limitations re- garding maximum allowable stress under static or quasi-static loads and the onset of Vortex Induced Vibrations （VIV） under different hydrodynamic actions. The results show that the MAFSL under static conditions is 56m. However, the MAFSLs are 30m and 20m under ordinary weather conditions and hurricane-induced currents for the 100-year return period, respectively, to avoid VIV as cal- culated by using the highest safety class factor. It is suggested that spanning pipelines longer than 20 m should be supported. Addi- tionally, eight successive spans which may also threaten the pipeline were proposed. The most hazardous scour pits are along the pipeline section from KP42 to KP51.展开更多
Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the probl...Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.展开更多
The aim of this paper is to determine the maximum values of the track length (Lmax) of alpha particles in Nuclear Track Detector (type CR-39) using a new method by taking the relation between the etching time and the ...The aim of this paper is to determine the maximum values of the track length (Lmax) of alpha particles in Nuclear Track Detector (type CR-39) using a new method by taking the relation between the etching time and the diameter square of alpha particle with different energies at constant bulk etch rate VB (1.45 μm/hr) by using TRACK_TEST program from Brun et al. function and Yu et al. function. Using the new equation, the maximum values of the track lengths of alpha particles measured in CR-39 detector have been found to be in a good agreement with the values measured by using Brun et al. function and Yu et al. function in TRACK_TEST program.展开更多
The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limi...The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limited amount of information. Its applications to the wave group properties show the effectiveness of the maximum entropy distribution. FFF filtering method is employed to obtain the wave envelope fast and efficiently. Comparisons of both the maximum entropy distribution and the distribution of Longuet-Higgins （1984） with the laboratory wind-wave data show that the former gives a better fit.展开更多
Objective: To study the relationship between internal anal sphincter function and length of remaining rectum after resecting rectal carcinoma. Methods: Preoperatively, 21 patients were evaluated via patients' clin...Objective: To study the relationship between internal anal sphincter function and length of remaining rectum after resecting rectal carcinoma. Methods: Preoperatively, 21 patients were evaluated via patients' clinical date, including anal resting pressure (resting pressure) assay. Six months postoperatively, repeated manometric studies and clinical evaluations were performed to assess the level of continence . The formula use for calculating post operative resting pressure is as follows: postoperative resting pressure=0.42×preoperative resting pressure+1.56×length of remaining recturm+12.37(R 2=0.58; P <0.01).Degree of continence was graded based on severity of the dysfunction and grade of the continence score. Results: It was demonstrated the patients with low postoperative resting pressures (<4.0 Kpa) had incontinence, and those with high postoperative resting pressures (>4.7 Kpa) were continent. There were significant correlations between length of the remaining rectum and ratio of the decrease in maximum resting pressure (postoperative/preoperative maximum resting pressure;r=0.62; P <0.01). Conclusion: Continence of rectum is influenced by maximum resting pressure of function of the internal anal sphincter, length of remaining rectum is shorter, the more damage to the internal anal sphincter. It is able to foretell stool incontinence by using the postoperative resting pressure formula, and to determine the length of the remaining rectum.展开更多
目的探讨CT血管造影(CTA)升主动脉长度与最大直径对主动脉夹层预测价值。方法回顾性分析2017年4月-2021年4月期间南京医科大学第一附属医院放射科进行检查的急性A型主动脉夹层(acute type A aortic dissection,ATAAD)66例患者的影像学...目的探讨CT血管造影(CTA)升主动脉长度与最大直径对主动脉夹层预测价值。方法回顾性分析2017年4月-2021年4月期间南京医科大学第一附属医院放射科进行检查的急性A型主动脉夹层(acute type A aortic dissection,ATAAD)66例患者的影像学资料。患者均进行CTA,将ATAAD发病的13例设为试验组;升主动脉最大直径≥40mm的14例患者设为对照一组;升主动脉最大直径<40mm的39例患者设为对照二组。对三组的升主动脉长度、最大直径进行对比同时进行ROC曲线的评估,通过对数据的分析升主动脉长度和最大直径对主动脉夹层的相关性和对疾病预测效果。结果分析三组患者的升主动脉最大直径数据发现,对照二组患者的数据明显小于对照一组和试验组,数据存在明显的差异>有统计学意义(P<0.05)。对三组患者的升主动脉长度数据进行对比分析,对照二组<对照一组<试验组,对照一组、对照二组以及试验组两两之间均存在明显的差异,均有统计学意义(P<0.05)。计算ROC曲线下面积发现,升主动脉长度ROC曲线面积为0.887,升主动脉最大直径ROC曲线面积为0.821,选取55mm点预测主动脉夹层阳性率发现用升主动脉长度阳性率为75.8%,用升主动脉最大直径阳性率为24.6%,从数据上可知晓通过升主动脉长度能更提高ATAAD阳性预测率。结论从本次研究的数据分析可知,升主动脉长度和最大直径均对主动脉夹层有一定的预测可行性,相关之间存在一定的关联,且升主动脉长度预测主动脉夹层疾病的阳性率更高、更准确,能一定程度上帮助临床医师判断患者的疾病。展开更多
Most of multimedia schemes employ variable-length codes （VLCs） like Huffman code as core components in obtaining high compression rates. However VLC methods are very sensitive to channel noise. The goal of this pape...Most of multimedia schemes employ variable-length codes （VLCs） like Huffman code as core components in obtaining high compression rates. However VLC methods are very sensitive to channel noise. The goal of this paper is to salvage as many data from the damaged packets as possible for higher audiovisual quality. This paper proposes an integrated joint source-channel decoder （I-JSCD） at a symbol-level using three-dimensional （3-D） trellis representation for first-order Markov sources encoded with VLC source code and convolutional channel code. This method combines source code and channel code state-spaces and bit-lengths to construct a two-dimensional （2-D） state-space, and then develops a 3-D trellis and a maximum a-posterior （MAP） algorithm to estimate the source sequence symbol by symbol. Experiment results demonstrate that our method results in significant improvement in decoding performance, it can salvage at least half of （50%） data in any channel error rate, and can provide additional error resilience to VLC stream like image, audio, video stream over high error rate links.展开更多
基金supported by the National Basic Research Program of China (973 Program) (Grant No.2005CB422304)the Ocean University of China Scientific Research Start-up Funds Project for Introduced Talents
文摘The DFI-1 submarine pipeline was investigated using a dual-frequency side-scan sonar and a swath sounder system. More than a hundred scour pits under the pipeline were found, most of which have caused the span of the pipeline to increase and threatened its safety. The maximum allowable free span length （MAFSL） of the pipeline was determined through the limitations re- garding maximum allowable stress under static or quasi-static loads and the onset of Vortex Induced Vibrations （VIV） under different hydrodynamic actions. The results show that the MAFSL under static conditions is 56m. However, the MAFSLs are 30m and 20m under ordinary weather conditions and hurricane-induced currents for the 100-year return period, respectively, to avoid VIV as cal- culated by using the highest safety class factor. It is suggested that spanning pipelines longer than 20 m should be supported. Addi- tionally, eight successive spans which may also threaten the pipeline were proposed. The most hazardous scour pits are along the pipeline section from KP42 to KP51.
基金Supported by the Fundamental Research Funds for the Central Universities under Grant No ZYGX2009X008
文摘Based on the generalized uncertainty principle with maximum momentum arid minimal length, we discuss the equation of state of ideal ultra-relativistic Fermi gases at zero temperature. Maximum momentum avoids the problem that the Fermi degenerate pressure blows up since the increase of the Fermi energy is not limited. Applying this equation of state to the Tolman-Oppenheimer Volkoff （TOV） equation, the quantum gravitational effects on the cores of compact stars are discussed. In the center of compact stars, we obtain the singularity-free solution of the metric component, gtt ～-（1 ＋ 0.2185×r^2）. By numerically solving the TOV equation, we find that quantum gravity plays an important role in the region r～10^4α0（△x）min. Current observed masses of neutron stars indicate that the dimensionless parameter α0 cannot exceed 10^19.
文摘The aim of this paper is to determine the maximum values of the track length (Lmax) of alpha particles in Nuclear Track Detector (type CR-39) using a new method by taking the relation between the etching time and the diameter square of alpha particle with different energies at constant bulk etch rate VB (1.45 μm/hr) by using TRACK_TEST program from Brun et al. function and Yu et al. function. Using the new equation, the maximum values of the track lengths of alpha particles measured in CR-39 detector have been found to be in a good agreement with the values measured by using Brun et al. function and Yu et al. function in TRACK_TEST program.
基金This work was financially supported by the National Natural Science Foundation of China (Grant No50479028)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No20060423009)
文摘The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limited amount of information. Its applications to the wave group properties show the effectiveness of the maximum entropy distribution. FFF filtering method is employed to obtain the wave envelope fast and efficiently. Comparisons of both the maximum entropy distribution and the distribution of Longuet-Higgins （1984） with the laboratory wind-wave data show that the former gives a better fit.
文摘Objective: To study the relationship between internal anal sphincter function and length of remaining rectum after resecting rectal carcinoma. Methods: Preoperatively, 21 patients were evaluated via patients' clinical date, including anal resting pressure (resting pressure) assay. Six months postoperatively, repeated manometric studies and clinical evaluations were performed to assess the level of continence . The formula use for calculating post operative resting pressure is as follows: postoperative resting pressure=0.42×preoperative resting pressure+1.56×length of remaining recturm+12.37(R 2=0.58; P <0.01).Degree of continence was graded based on severity of the dysfunction and grade of the continence score. Results: It was demonstrated the patients with low postoperative resting pressures (<4.0 Kpa) had incontinence, and those with high postoperative resting pressures (>4.7 Kpa) were continent. There were significant correlations between length of the remaining rectum and ratio of the decrease in maximum resting pressure (postoperative/preoperative maximum resting pressure;r=0.62; P <0.01). Conclusion: Continence of rectum is influenced by maximum resting pressure of function of the internal anal sphincter, length of remaining rectum is shorter, the more damage to the internal anal sphincter. It is able to foretell stool incontinence by using the postoperative resting pressure formula, and to determine the length of the remaining rectum.
文摘目的探讨CT血管造影(CTA)升主动脉长度与最大直径对主动脉夹层预测价值。方法回顾性分析2017年4月-2021年4月期间南京医科大学第一附属医院放射科进行检查的急性A型主动脉夹层(acute type A aortic dissection,ATAAD)66例患者的影像学资料。患者均进行CTA,将ATAAD发病的13例设为试验组;升主动脉最大直径≥40mm的14例患者设为对照一组;升主动脉最大直径<40mm的39例患者设为对照二组。对三组的升主动脉长度、最大直径进行对比同时进行ROC曲线的评估,通过对数据的分析升主动脉长度和最大直径对主动脉夹层的相关性和对疾病预测效果。结果分析三组患者的升主动脉最大直径数据发现,对照二组患者的数据明显小于对照一组和试验组,数据存在明显的差异>有统计学意义(P<0.05)。对三组患者的升主动脉长度数据进行对比分析,对照二组<对照一组<试验组,对照一组、对照二组以及试验组两两之间均存在明显的差异,均有统计学意义(P<0.05)。计算ROC曲线下面积发现,升主动脉长度ROC曲线面积为0.887,升主动脉最大直径ROC曲线面积为0.821,选取55mm点预测主动脉夹层阳性率发现用升主动脉长度阳性率为75.8%,用升主动脉最大直径阳性率为24.6%,从数据上可知晓通过升主动脉长度能更提高ATAAD阳性预测率。结论从本次研究的数据分析可知,升主动脉长度和最大直径均对主动脉夹层有一定的预测可行性,相关之间存在一定的关联,且升主动脉长度预测主动脉夹层疾病的阳性率更高、更准确,能一定程度上帮助临床医师判断患者的疾病。
基金Supported by the Foundation of Ministry of Education of China (211CERS10)
文摘Most of multimedia schemes employ variable-length codes （VLCs） like Huffman code as core components in obtaining high compression rates. However VLC methods are very sensitive to channel noise. The goal of this paper is to salvage as many data from the damaged packets as possible for higher audiovisual quality. This paper proposes an integrated joint source-channel decoder （I-JSCD） at a symbol-level using three-dimensional （3-D） trellis representation for first-order Markov sources encoded with VLC source code and convolutional channel code. This method combines source code and channel code state-spaces and bit-lengths to construct a two-dimensional （2-D） state-space, and then develops a 3-D trellis and a maximum a-posterior （MAP） algorithm to estimate the source sequence symbol by symbol. Experiment results demonstrate that our method results in significant improvement in decoding performance, it can salvage at least half of （50%） data in any channel error rate, and can provide additional error resilience to VLC stream like image, audio, video stream over high error rate links.
