Silt deposition occurs in the downstream approach channel of the tidal lock as in a closed channel or excavated dock basin. It is often difficult to calculate or predict siltation because of complex flow and sediment ...Silt deposition occurs in the downstream approach channel of the tidal lock as in a closed channel or excavated dock basin. It is often difficult to calculate or predict siltation because of complex flow and sediment conditions and many other affecting factors. In this paper, the characteristics of flow movement in the approach channel (including its mouth) of the tidal lock are analyzed, the basic laws of sediment movement and siltation mechanism are investigated, the conditions for three types of siltation (circumfluence siltation, density flow siltation and slow flow siltation) are discussed, and corresponding calculating formulas are proposed. A practical example shows that the difference between measured and calculated results is small, indicating that the present calculating methods could be used in design and management of practical engineering projects.展开更多
The variation of the amplitude of waves with varying incident angles when waves propagate through a typical approach channel is discussed by a numerical calculation method, the result of which shows that the influence...The variation of the amplitude of waves with varying incident angles when waves propagate through a typical approach channel is discussed by a numerical calculation method, the result of which shows that the influence of the channel on wave propagation is obvious. When the wave propagation direction is in coincidence with the channel axis, the wave amplitude ratio will decrease with the increase of propagation distance. When the incident angle is 15 - 30 , there appears an area of larger wave amplitude ratio on the side slope facing the waves, but at the another side, the wave amplitude ratio is generally small, indicating that the channel has a shielding effect. When waves propagate across the channel perpendicularly, the wave amplitude ratio can be calculated with the shallow water coefficient.展开更多
The Langevin approach has been applied to model the random open and closing dynamics of ion channels. It has long been known that the gate-based Langevin approach is not sufficiently accurate to reproduce the statisti...The Langevin approach has been applied to model the random open and closing dynamics of ion channels. It has long been known that the gate-based Langevin approach is not sufficiently accurate to reproduce the statistics of stochastic channel dynamics in Hodgkin–Huxley neurons. Here, we introduce a modified gate-based Langevin approach with rescaled noise strength to simulate stochastic channel dynamics. The rescaled independent gate and identical gate Langevin approaches improve the statistical results for the mean membrane voltage, inter-spike interval, and spike amplitude.展开更多
Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environme...Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environmental drivers were studied in the Kohelia channel, Bangladesh from summer 2014 to spring 2015.Samples were collected using net at a depth of 1 m. A total of 32 species belonged to 18 orders, 27 families and 15 taxonomic groups were identified. Of these species, 22 distributed in all four seasons of which 8 were dominant and highly contributing to the total communities. Species number peaked in summer next to winter and fall in spring while maximum abundance was in summer and minimum in spring. Multivariate analyses showed that there was a clear annual pattern in the zooplankton communities. Species diversity and evenness peaked in spring but fall in autumn while the high value of species richness was found in winter. Biological-environmental best matching（BIO-ENV） analyses conformed that community pattern of zooplankton was mainly driven by transparency salinity, and temperature individually or combined with water nutrients. These results demonstrate that annual pattern of the zooplankton community shaped by channel environmental factors in subtropical channel ecosystems, thus might be used for community-based subtropical coastal water bioassessment.展开更多
A semi-blind channel estimation algorithm based on subspace approach for orthogonal frequency division multiplexing（OFDM） systems over the frequency-selective channel is proposed. A linear preeoding is applied on ea...A semi-blind channel estimation algorithm based on subspace approach for orthogonal frequency division multiplexing（OFDM） systems over the frequency-selective channel is proposed. A linear preeoding is applied on each block before the IFFT operation and a low-rank structure is created in the received signal. Then subspace properties can be exploited to identify the channel up to a scalar ambiguity. The residual scalar ambiguities eliminated by inserting pilots into data stream. Simulation results illustrate the performance of the proposed semi-blind algorithm.展开更多
Background The retrograde approach allows to significantly increase the success rate of coronary chronic total occlusion（CTO） percutaneous intervention（PCI）. Epicardial collateral channels（CCs） remain an essenti...Background The retrograde approach allows to significantly increase the success rate of coronary chronic total occlusion（CTO） percutaneous intervention（PCI）. Epicardial collateral channels（CCs） remain an essential channel for retro-recanalization. But paucity of data in this area limits the use of epicardial CCs for retrograde canalization. The present study was to explore the feasibility and significance of coronary epicardial collaterals for the retrograde approach treatment of coronary CTO. Methods We retrospectively analyzed 347 CTO cases which the retrograde approach was attempted after reviewing the coronary angiograms of 1290 patients. And there were 89 retrograde approach PCI cases applying epicardial CCs. We collected the clinical and angiography data of those patents for analyzing the safety and usefulness of this technology. Results The study consisted of347 CTO PCI. Mean age was 60.8±10.4 and 60.3±10.2 years in epicardial CCs and septal CCs groups respectively. The total retrograde success rate was 79.8%. The success rate of retrograde approach applying epicardial CCs was not lower（82.0% vs. 79.1%, P=0.646） than that in cases applying septal CCs. There were 8 epicardial CCs injury cases（9.0%） and 3 cases resulted in cardiac tamponade and required emergency pericardiocentesis. Coils were used for all of them with success. No patients were dead in retrograde approach applying epicardial CCS.Conclusions Coronary epicardial collaterals can be used as an access for the retrograde approach in the percutaneous treatment of CTO, which is relative feasible, and has a high success rate. Epicardial CCs injury can be safety as long as it is treated timely.展开更多
Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cr...Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.展开更多
目的:分析双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗腰椎滑脱症的临床疗效。方法:回顾性分析2023年6月~2023年12月我科接受双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗的单节段腰椎滑脱症患者的临床资料共2...目的:分析双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗腰椎滑脱症的临床疗效。方法:回顾性分析2023年6月~2023年12月我科接受双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗的单节段腰椎滑脱症患者的临床资料共20例;其中退变性腰椎滑脱15例,峡部裂型腰椎滑脱5例;女7例,男13例;年龄49~72(59.95±7.16)岁;病程为2~120(35.15±42.10)个月。记录手术时间、术中出血量、住院时间及手术并发症,术前、术后1个月及末次随访时应用腰椎Oswestry功能障碍指数(Oswestry disability index,ODI)、腰痛及腿痛的视觉模拟评分(visual analog scale,VAS)评价疗效。对随访期间腰椎CT影像按照Bridwell标准判断椎间融合情况。结果:所有患者顺利完成镜下融合手术;手术时间为175~235min(201.75±24.40min)。所有病例随访时间为12~16(14.15±1.14)个月。术后1个月及末次随访时ODI、腰痛及腿痛VAS评分均较术前明显改善(P<0.05)。术中、术后及末次随访时均无严重并发症发生。随访期间20例复查腰椎CT,其中19例(95.0%)达到骨性融合。结论:双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术早期随访临床疗效令人满意,是治疗腰椎滑脱症的一种微创、安全、有效的术式选择。展开更多
A multiuser Ultra Wide Band (UWB) channel suffers seriously from realistic impairments. Among this, multipath fading and interferences, such as Multiple Access Interference (MAI) and Inter Symbol Interference (ISI), t...A multiuser Ultra Wide Band (UWB) channel suffers seriously from realistic impairments. Among this, multipath fading and interferences, such as Multiple Access Interference (MAI) and Inter Symbol Interference (ISI), that significantly degrade the system performance. In this paper, a polar coding technique, originally developed by Arikan, is suggested to enhance the BER performance of indoor UWB based Orthogonal Frequency Division Multiplexing (OFDM) communications. Moreover, Interleave Division Multiple Access (IDMA) scheme has been considered for multiuser detection depending on the turbo type Chip-By-Chip (CBC) iterative detection strategy. Three different models as Symmetric Alpha Stable (SαS), Laplace model and Gaussian Mixture Model (GMM), have been introduced for approximating the interferences which are more realistic for UWB system. The performance of the proposed Polar-coded IDMA OFDM-based UWB system is investigated under UWB channel models proposed by IEEE 802.15.3a working group and compared with Low Density Parity Check (LDPC)-coded IDMA OFDM-based UWB system in terms of BER performance and complexity under the studied noise models. Simulation results show that the complexity of the proposed polar-coded system is much lower than LDPC-coded system with minor performance degradation. Furthermore, the proposed polar-coded system is robust against noise and interferences in UWB indoor environment and gains a significant performance improvement by about 5 dB compared with un-coded IDMA-OFDM-UWB system under the studied noise models.展开更多
文摘Silt deposition occurs in the downstream approach channel of the tidal lock as in a closed channel or excavated dock basin. It is often difficult to calculate or predict siltation because of complex flow and sediment conditions and many other affecting factors. In this paper, the characteristics of flow movement in the approach channel (including its mouth) of the tidal lock are analyzed, the basic laws of sediment movement and siltation mechanism are investigated, the conditions for three types of siltation (circumfluence siltation, density flow siltation and slow flow siltation) are discussed, and corresponding calculating formulas are proposed. A practical example shows that the difference between measured and calculated results is small, indicating that the present calculating methods could be used in design and management of practical engineering projects.
文摘The variation of the amplitude of waves with varying incident angles when waves propagate through a typical approach channel is discussed by a numerical calculation method, the result of which shows that the influence of the channel on wave propagation is obvious. When the wave propagation direction is in coincidence with the channel axis, the wave amplitude ratio will decrease with the increase of propagation distance. When the incident angle is 15 - 30 , there appears an area of larger wave amplitude ratio on the side slope facing the waves, but at the another side, the wave amplitude ratio is generally small, indicating that the channel has a shielding effect. When waves propagate across the channel perpendicularly, the wave amplitude ratio can be calculated with the shallow water coefficient.
基金Project supported by the National Natural Science Foundation for Distinguished Young Scholars of China(Grant No.11125419)the National Natural Science Foundation of China(Grant No.10925525)+1 种基金the Funds for the Leading Talents of Fujian ProvinceChina
文摘The Langevin approach has been applied to model the random open and closing dynamics of ion channels. It has long been known that the gate-based Langevin approach is not sufficiently accurate to reproduce the statistics of stochastic channel dynamics in Hodgkin–Huxley neurons. Here, we introduce a modified gate-based Langevin approach with rescaled noise strength to simulate stochastic channel dynamics. The rescaled independent gate and identical gate Langevin approaches improve the statistical results for the mean membrane voltage, inter-spike interval, and spike amplitude.
基金The Bangladesh Nature Foundation(BNF),Cox’s Bazar(a Non-Governmental Organization)Chinese Scholarship Council(CSC No.2016GXY030)under Ministry of Eudcation for Excellent Master’s Scholarship Awards
文摘Zooplankton plays an important role in aquatic food webs by fluxing of energy from primary producer to subsequent trophic levels in the food chain. The annual pattern of zooplankton communities and potential environmental drivers were studied in the Kohelia channel, Bangladesh from summer 2014 to spring 2015.Samples were collected using net at a depth of 1 m. A total of 32 species belonged to 18 orders, 27 families and 15 taxonomic groups were identified. Of these species, 22 distributed in all four seasons of which 8 were dominant and highly contributing to the total communities. Species number peaked in summer next to winter and fall in spring while maximum abundance was in summer and minimum in spring. Multivariate analyses showed that there was a clear annual pattern in the zooplankton communities. Species diversity and evenness peaked in spring but fall in autumn while the high value of species richness was found in winter. Biological-environmental best matching（BIO-ENV） analyses conformed that community pattern of zooplankton was mainly driven by transparency salinity, and temperature individually or combined with water nutrients. These results demonstrate that annual pattern of the zooplankton community shaped by channel environmental factors in subtropical channel ecosystems, thus might be used for community-based subtropical coastal water bioassessment.
文摘A semi-blind channel estimation algorithm based on subspace approach for orthogonal frequency division multiplexing（OFDM） systems over the frequency-selective channel is proposed. A linear preeoding is applied on each block before the IFFT operation and a low-rank structure is created in the received signal. Then subspace properties can be exploited to identify the channel up to a scalar ambiguity. The residual scalar ambiguities eliminated by inserting pilots into data stream. Simulation results illustrate the performance of the proposed semi-blind algorithm.
基金supported by Science and Technology Planning Project of Guangdong Province(No.2016A020216022)
文摘Background The retrograde approach allows to significantly increase the success rate of coronary chronic total occlusion（CTO） percutaneous intervention（PCI）. Epicardial collateral channels（CCs） remain an essential channel for retro-recanalization. But paucity of data in this area limits the use of epicardial CCs for retrograde canalization. The present study was to explore the feasibility and significance of coronary epicardial collaterals for the retrograde approach treatment of coronary CTO. Methods We retrospectively analyzed 347 CTO cases which the retrograde approach was attempted after reviewing the coronary angiograms of 1290 patients. And there were 89 retrograde approach PCI cases applying epicardial CCs. We collected the clinical and angiography data of those patents for analyzing the safety and usefulness of this technology. Results The study consisted of347 CTO PCI. Mean age was 60.8±10.4 and 60.3±10.2 years in epicardial CCs and septal CCs groups respectively. The total retrograde success rate was 79.8%. The success rate of retrograde approach applying epicardial CCs was not lower（82.0% vs. 79.1%, P=0.646） than that in cases applying septal CCs. There were 8 epicardial CCs injury cases（9.0%） and 3 cases resulted in cardiac tamponade and required emergency pericardiocentesis. Coils were used for all of them with success. No patients were dead in retrograde approach applying epicardial CCS.Conclusions Coronary epicardial collaterals can be used as an access for the retrograde approach in the percutaneous treatment of CTO, which is relative feasible, and has a high success rate. Epicardial CCs injury can be safety as long as it is treated timely.
文摘Heat transfer experiments were conducted to investigate the thermal performance of air cooling through mini-channel heat sink with various configurations. Two types of channels have been used, one has a rectangular cross section area of 5 × 18 mm2 and the other is triangular with dimension of 5 × 9 mm2. Four channels of each configuration have been etched on copper block of 40 mm width,30 mm height, and 200 mm length. The measurements were performed in steady state with air flow rates of 0.002 - 0.005 m3/s, heating powers of 80 - 200 W and channel base temperatures of 48°C, 51°C, 55°C and 60°C. The results showed that the heat transfer to air stream is increased with increasing both of air mass flow rate and channel base temperature. The rectangular channels have better thermal performance than trian- gular ones at the same conditions. Analytical fin approach of 1-D and 2-D model were used to predict the heat transfer rate and outlet air temperature from channels heat sink. Theoretical results have been compared with experimental data. The predicted values for outlet air temperatures using the two models agree well with a deviation less than ±10%. But for the heat transfer data, the deviation is about +30% to –60% for 1-D model, and –5% to –80% for 2-D model. The global Nusselt number of the present experimental data is empirically correlated as with accuracy of ±20% for and compared with other literature correlations.
文摘目的:分析双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗腰椎滑脱症的临床疗效。方法:回顾性分析2023年6月~2023年12月我科接受双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术治疗的单节段腰椎滑脱症患者的临床资料共20例;其中退变性腰椎滑脱15例,峡部裂型腰椎滑脱5例;女7例,男13例;年龄49~72(59.95±7.16)岁;病程为2~120(35.15±42.10)个月。记录手术时间、术中出血量、住院时间及手术并发症,术前、术后1个月及末次随访时应用腰椎Oswestry功能障碍指数(Oswestry disability index,ODI)、腰痛及腿痛的视觉模拟评分(visual analog scale,VAS)评价疗效。对随访期间腰椎CT影像按照Bridwell标准判断椎间融合情况。结果:所有患者顺利完成镜下融合手术;手术时间为175~235min(201.75±24.40min)。所有病例随访时间为12~16(14.15±1.14)个月。术后1个月及末次随访时ODI、腰痛及腿痛VAS评分均较术前明显改善(P<0.05)。术中、术后及末次随访时均无严重并发症发生。随访期间20例复查腰椎CT,其中19例(95.0%)达到骨性融合。结论:双操作通道全内镜下远外侧经椎间孔入路腰椎椎间融合术早期随访临床疗效令人满意,是治疗腰椎滑脱症的一种微创、安全、有效的术式选择。
文摘A multiuser Ultra Wide Band (UWB) channel suffers seriously from realistic impairments. Among this, multipath fading and interferences, such as Multiple Access Interference (MAI) and Inter Symbol Interference (ISI), that significantly degrade the system performance. In this paper, a polar coding technique, originally developed by Arikan, is suggested to enhance the BER performance of indoor UWB based Orthogonal Frequency Division Multiplexing (OFDM) communications. Moreover, Interleave Division Multiple Access (IDMA) scheme has been considered for multiuser detection depending on the turbo type Chip-By-Chip (CBC) iterative detection strategy. Three different models as Symmetric Alpha Stable (SαS), Laplace model and Gaussian Mixture Model (GMM), have been introduced for approximating the interferences which are more realistic for UWB system. The performance of the proposed Polar-coded IDMA OFDM-based UWB system is investigated under UWB channel models proposed by IEEE 802.15.3a working group and compared with Low Density Parity Check (LDPC)-coded IDMA OFDM-based UWB system in terms of BER performance and complexity under the studied noise models. Simulation results show that the complexity of the proposed polar-coded system is much lower than LDPC-coded system with minor performance degradation. Furthermore, the proposed polar-coded system is robust against noise and interferences in UWB indoor environment and gains a significant performance improvement by about 5 dB compared with un-coded IDMA-OFDM-UWB system under the studied noise models.
