针对传统硬件描述语言(Verilog/VHDL)实现密码算法时代码复杂性高、开发周期长且调试困难等问题,本文提出了一种基于Chisel语言的轻量级分组密码算法LBlock的硬件实现方案。利用Chisel的高级硬件构建能力,通过模块化设计和有限状态机控...针对传统硬件描述语言(Verilog/VHDL)实现密码算法时代码复杂性高、开发周期长且调试困难等问题,本文提出了一种基于Chisel语言的轻量级分组密码算法LBlock的硬件实现方案。利用Chisel的高级硬件构建能力,通过模块化设计和有限状态机控制,高效地实现了密钥扩展、加密和解密核心模块。通过在Xilinx ISE Design Suite 14.7上综合后,结果表明,基于Chisel的LBlock算法实现方案在逻辑资源消耗和工作频率上均表现出优势。最高工作频率达到250.197MHz,加密吞吐率为485.815 Mbps,与传统的Verilog实现相比,本设计在显著降低代码量的同时,吞吐率提升了55.7%,为资源受限环境下的密码硬件实现提供了一种更敏捷、高效的设计思路。展开更多
In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in...In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in the EBL after Mg-preflow treatment,effectively alleviating the commonly observed efficiency collapse and electrons overflowing at cryogenic temperatures.However,unexpected decline in quantum efficiency is observed after Mg-preflow treatment at room temperature.Our conclusions are drawn such that the efficiency decline is probably the result of different emission positions.Higher Mg doping concentration in the EBL after Mg-preflow treatment will make it easier for a hole to be injected into multiple quantum wells with emission closer to pGaN side through the（8-plane rather than the V-shape pits,which is not favorable to luminous efficiency due to the preferred occurrence of accumulated strain relaxation and structural defects in upper QWs closer to p-GaN.Within this framework,apparently disparate experimental observations regarding electroluminescence properties,in this work,are well reconciled.展开更多
Multiple instances of the Late Cretaceous granodiorites within the Anglonggangri region of the northwestern Lhasa Block were identified,their petrogenesis were explored and mineralization potential were assessed.The z...Multiple instances of the Late Cretaceous granodiorites within the Anglonggangri region of the northwestern Lhasa Block were identified,their petrogenesis were explored and mineralization potential were assessed.The zircon U-Pb dating of the Anglonggangri granodiorites revealed ages of 82.8 and 80.8 Ma.Granodiorite samples have SiO2 contents of 64.36-68.33 wt%,with high Sr/Y(55-95)and A/CNK ratios(0.99-1.06).Zirconε_(Hf)(t)values range from−0.3 to+16.2.Two granodiorite samples have(^(87)Sr/^(86)Sr)i values of 0.7034 and 0.7043 and positiveɛNd(t)values of 3.51 and 3.83.These geochemical properties indicate that they are adakitic rocks formed by partial melting of the juvenile thickened lower crust,slightly contaminated with material from the mantle due to the small-scale delamination of the lower crust.The zircons in the granodiorites have moderate Ce/Nd(2.5-43),logfO2(−20.0 to−9.6),andΔFMQ(−1.28 to+4.00)values;low(Ce/Nd)/Y(0.001-0.049)ratios;and high Dy/Yb(0.17-1.16)ratios,which indicate that these granodiorites exhibit moderate oxygen fugacity and lower magma water content than the Miocene Gangdese porphyry copper deposits associated with high-Sr/Y granites.Their ability to create porphyry-type copper deposits could have been hampered by their low magma water content and moderate oxygen fugacity.展开更多
BACKGROUND Abdominal aortic aneurysm(AAA)repair often involves significant postoperative pain,traditionally managed with systemic opioids,which can cause undesirable side effects.This case report explores the novel us...BACKGROUND Abdominal aortic aneurysm(AAA)repair often involves significant postoperative pain,traditionally managed with systemic opioids,which can cause undesirable side effects.This case report explores the novel use of a surgically-initiated rectus sheath block with a catheter-over-needle assembly for pain management in AAA repair.CASE SUMMARY A 67-year-old female with hypertension and previous aortic dissection underwent elective open repair of an infrarenal AAA,which had grown from 3.4 cm to 4.3 cm over 14 months.A rectus sheath block was initiated surgically for postoperative pain control.The patient reported low pain scores and did not require systemic intravenous opioids,enabling early ambulation and discharge on postoperative day seven without complications.By preventing complications of systemic opi-oids,the method indicating a promising direction for postoperative pain management in major vascular surgeries.CONCLUSION Surgically-initiated rectus sheath block as a valuable tool for managing postoperative pain in AAA repair.展开更多
For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G)...For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).展开更多
This paper explores the recovery of block sparse signals in frame-based settings using the l_(2)/l_(q)-synthesis technique(0<q≤1).We propose a new null space property,referred to as block D-NSP_(q),which is based ...This paper explores the recovery of block sparse signals in frame-based settings using the l_(2)/l_(q)-synthesis technique(0<q≤1).We propose a new null space property,referred to as block D-NSP_(q),which is based on the dictionary D.We establish that matrices adhering to the block D-NSP_(q)condition are both necessary and sufficient for the exact recovery of block sparse signals via l_(2)/l_(q)-synthesis.Additionally,this condition is essential for the stable recovery of signals that are block-compressible with respect to D.This D-NSP_(q)property is identified as the first complete condition for successful signal recovery using l_(2)/l_(q)-synthesis.Furthermore,we assess the theoretical efficacy of the l2/lq-synthesis method under conditions of measurement noise.展开更多
Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic re...Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic resin and n-octanol were used to synthesize the main agent SCA-2.Hexamethylenetetramine and vinyl carbonate were selected to prepare the curing agent YGA-1,which was then compounded with SCA-2 to develop a sand fixation and water plugging system.Firstly,single-factor experiments were conducted to determine the optimal concentrations of SCA-2 and YGA-1,subsequently,the system’s sand fixation and water blocking performance were evaluated.Finally,a pilot test was carried out in the mining site.Experimental results showed that the optimal formula composition of the system was 10%SCA-2+5%YGA-1.The gelation time of the system was 180 minutes and the viscosity after gelation could reach 108.4 mPa·s.When the dosage of the drug system was 0.6 PV,the sand production rate remained below 0.08%.Dual-tube parallel experiments showed that the sand fixation and water plugging system had a water flow channel plugging rate of 87.5%,while the oil flow channel plugging rate was only 11.3%,indicating minimal damage to the oil-bearing reservoir.The field test showed that after the measures taken in Well M of X oilfield,the sand free oil recovery period exceeded 360 days,the water content decreased by 5.0%and the cumulative oil production increased by 7092 m^(3).This study provides new ideas for efficient development of loose sandstone reservoirs.展开更多
A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and...A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.展开更多
Ballet is one of the finalists of the block cipher project in the 2019 National Cryptographic Algorithm Design Competition.This study aims to conduct a comprehensive security evaluation of Ballet from the perspective ...Ballet is one of the finalists of the block cipher project in the 2019 National Cryptographic Algorithm Design Competition.This study aims to conduct a comprehensive security evaluation of Ballet from the perspective of differential-linear(DL)cryptanalysis.Specifically,we present an automated search for the DL distinguishers of Ballet based on MILP/MIQCP.For the versions with block sizes of 128 and 256 bits,we obtain 16 and 22 rounds distinguishers with estimated correlations of 2^(-59.89)and 2^(-116.80),both of which are the publicly longest distinguishers.In addition,this study incorporates the complexity information of key-recovery attacks into the automated model,to search for the optimal key-recovery attack structures based on DL distinguishers.As a result,we mount the key-recovery attacks on 16-round Ballet-128/128,17-round Ballet-128/256,and 21-round Ballet-256/256.The data/time complexities for these attacks are 2^(108.36)/2^(120.36),2^(115.90)/2^(192),and 2^(227.62)/2^(240.67),respectively.展开更多
Based on the coalbed methane(CBM)/coal-rock gas(CRG)geological,geophysical,and experimental testing data from the Daji block in the Ordos Basin,the coal-forming and hydrocarbon generation&accumulation characterist...Based on the coalbed methane(CBM)/coal-rock gas(CRG)geological,geophysical,and experimental testing data from the Daji block in the Ordos Basin,the coal-forming and hydrocarbon generation&accumulation characteristics across different zones were dissected,and the key factors controlling the differential CBM/CRG enrichment were identified.The No.8 coal seam of the Carboniferous Benxi Formation in the Daji block is 8-10 m thick,typically overlain by limestone.The primary hydrocarbon generation phase occurred during the Early Cretaceous.Based on the differences in tectonic evolution and CRG occurrence,and with the maximum vitrinite reflectance of 2.0%and burial depth of 1800 m as boundaries,the study area is divided into deeply buried and deeply preserved,deeply buried and shallowly preserved,and shallowly buried and shallowly preserved zones.The deeply buried and deeply preserved zone contains gas content of 22-35 m^(3)/t,adsorbed gas saturation of 95%-100%,and formation water with total dissolved solid(TDS)higher than 50000 mg/L.This zone features structural stability and strong sealing capacity,with high gas production rates.The deeply buried and shallowly preserved zone contains gas content of 16-20 m^(3)/t,adsorbed gas saturation of 80%-95%,and formation water with TDS of 5000-50000 mg/L.This zone exhibits localized structural modification and hydrodynamic sealing,with moderate gas production rate.The shallowly buried and shallowly preserved zone contains gas content of 8-16 m^(3)/t,adsorbed gas saturation of 50%-70%,and formation water with TDS lower than 5000 mg/L.This zone experienced intense uplift,resulting in poor sealing and secondary alteration of the primary gas reservoir,with partial adsorbed gas loss,and low gas production rate.A depositional unification and structural divergence model is proposed,that is,although coal seams across the basin experienced broadly similar depositional and tectonic histories,differences in tectonic intensity have led to spatial heterogeneity in the maximum burial depth(i.e.,thermal maturity of coal)and current burial depth and occurrence of CRG(i.e.,gas content and occurrence state).The research results provide valuable guidance for advancing the theoretical understanding of CBM/CRG enrichment and for improving exploration and development practices.展开更多
The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to ca...The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.展开更多
To improve the heat transfer rate and thermal performance of the solar air heater due to low efficiency,new techniques,such as artificial roughness,barriers,and obstacles,should be used to increase the heat exchange b...To improve the heat transfer rate and thermal performance of the solar air heater due to low efficiency,new techniques,such as artificial roughness,barriers,and obstacles,should be used to increase the heat exchange between the fluid and the absorber.In this research,perforated V-shaped blockages with new geometric shapes,which are circular,hexagonal,square,rectangular,and triangular,were used.They were fixed on the absorber plate inside the channel with dimensions of 1.5 m×0.5 m×0.05 m,which increased the exit temperature of the air passing through the channel.The experimental work consists of six cases that were carried out during November in Baghdad,Iraq,to obtain an optimal result.These cases included using barriers that have holes with different geometric shapes for the barriers inside the solar air heater in addition to the reference case without any barriers.A comparison ismade between the cases under the same conditions and limits to reach the optimal case.The range of mass flow rate was from 0.0098 to 0.049 kg/s,and the range of Re was from 2000 to 10,000.Another goal of the comparison was to maximize Nu and minimize the friction factor.TheNu value improved by 1.77 and the fraction factor by 1.75 for the hexagonal perforated,which had the best performance.As for the triangle perforated,Nu improved by 1.58 and the fraction factor by 3.84,which had the worst performance.The Nu value improved by 1.39,1.22,and 1.4,and the fraction factor improved by 1.967,1.28,and 2.33 for square,circular,and rectangular,respectively.The thermal efficiency is evaluated by analyzing the heat losses from convection with the surrounding air and long-wave radiation exchange with the atmosphere.The experimental results indicated that using barriers with hexagonal holes is the best performance.展开更多
文摘针对传统硬件描述语言(Verilog/VHDL)实现密码算法时代码复杂性高、开发周期长且调试困难等问题,本文提出了一种基于Chisel语言的轻量级分组密码算法LBlock的硬件实现方案。利用Chisel的高级硬件构建能力,通过模块化设计和有限状态机控制,高效地实现了密钥扩展、加密和解密核心模块。通过在Xilinx ISE Design Suite 14.7上综合后,结果表明,基于Chisel的LBlock算法实现方案在逻辑资源消耗和工作频率上均表现出优势。最高工作频率达到250.197MHz,加密吞吐率为485.815 Mbps,与传统的Verilog实现相比,本设计在显著降低代码量的同时,吞吐率提升了55.7%,为资源受限环境下的密码硬件实现提供了一种更敏捷、高效的设计思路。
基金Supported by the National Key R&D Program of China under Grant Nos 2016YFB0400600 and 2016YFB0400601the State Key Program of the National Natural Science of China under Grant No 61334001+2 种基金the Key R&D Program of Jiangxi Province under Grant No 20165ABC28007the Natural Science Foundation of Jiangxi Province under Grant No 20151BAB207053the National Natural Science Foundation of China under Grant No 21405076
文摘In GaN-based green light-emitting diodes（LEDs） with and without Mg-preflow before the growth of p-Al GaN electron blocking layer（EBL） are investigated experimentally.A higher Mg doping concentration is achieved in the EBL after Mg-preflow treatment,effectively alleviating the commonly observed efficiency collapse and electrons overflowing at cryogenic temperatures.However,unexpected decline in quantum efficiency is observed after Mg-preflow treatment at room temperature.Our conclusions are drawn such that the efficiency decline is probably the result of different emission positions.Higher Mg doping concentration in the EBL after Mg-preflow treatment will make it easier for a hole to be injected into multiple quantum wells with emission closer to pGaN side through the（8-plane rather than the V-shape pits,which is not favorable to luminous efficiency due to the preferred occurrence of accumulated strain relaxation and structural defects in upper QWs closer to p-GaN.Within this framework,apparently disparate experimental observations regarding electroluminescence properties,in this work,are well reconciled.
基金jointly supported by the National Key Research&Development Program of China(2021YFC2900100)the Basic Research Fund of the Chinese Academy of Geological Sciences(KK2306)+1 种基金the Geological Survey Project(DD20230360,DD20243483)the Sichuan Provincial Natural Science Foundation(2023NSFSC0798).
文摘Multiple instances of the Late Cretaceous granodiorites within the Anglonggangri region of the northwestern Lhasa Block were identified,their petrogenesis were explored and mineralization potential were assessed.The zircon U-Pb dating of the Anglonggangri granodiorites revealed ages of 82.8 and 80.8 Ma.Granodiorite samples have SiO2 contents of 64.36-68.33 wt%,with high Sr/Y(55-95)and A/CNK ratios(0.99-1.06).Zirconε_(Hf)(t)values range from−0.3 to+16.2.Two granodiorite samples have(^(87)Sr/^(86)Sr)i values of 0.7034 and 0.7043 and positiveɛNd(t)values of 3.51 and 3.83.These geochemical properties indicate that they are adakitic rocks formed by partial melting of the juvenile thickened lower crust,slightly contaminated with material from the mantle due to the small-scale delamination of the lower crust.The zircons in the granodiorites have moderate Ce/Nd(2.5-43),logfO2(−20.0 to−9.6),andΔFMQ(−1.28 to+4.00)values;low(Ce/Nd)/Y(0.001-0.049)ratios;and high Dy/Yb(0.17-1.16)ratios,which indicate that these granodiorites exhibit moderate oxygen fugacity and lower magma water content than the Miocene Gangdese porphyry copper deposits associated with high-Sr/Y granites.Their ability to create porphyry-type copper deposits could have been hampered by their low magma water content and moderate oxygen fugacity.
基金Supported by the Taichung Veterans General Hospital,No.TCVGH-1125401B.
文摘BACKGROUND Abdominal aortic aneurysm(AAA)repair often involves significant postoperative pain,traditionally managed with systemic opioids,which can cause undesirable side effects.This case report explores the novel use of a surgically-initiated rectus sheath block with a catheter-over-needle assembly for pain management in AAA repair.CASE SUMMARY A 67-year-old female with hypertension and previous aortic dissection underwent elective open repair of an infrarenal AAA,which had grown from 3.4 cm to 4.3 cm over 14 months.A rectus sheath block was initiated surgically for postoperative pain control.The patient reported low pain scores and did not require systemic intravenous opioids,enabling early ambulation and discharge on postoperative day seven without complications.By preventing complications of systemic opi-oids,the method indicating a promising direction for postoperative pain management in major vascular surgeries.CONCLUSION Surgically-initiated rectus sheath block as a valuable tool for managing postoperative pain in AAA repair.
基金Supported by NSFC (Nos.12171089,12271235)NSF of Jiangsu (No.BK20190919)NSF of Fujian (No.2021J02048)。
文摘For a simple graph G,let A(G)and D(G)be the adjacency matrix and the diagonal degree matrix of G,respectively.[Appl.Anal.Discrete Math.,2017,11(1):81-107]defined the matrix A_(α)(G)of G as A_(α)(G)=αD(G)(1-α)A(G),α∈[0,1].The Aa-spectral radius is the largest eigenvalue of A_(α)(G).Let G_(n,β) be the set graphs with order n and dissociation numberβ.In this paper,we identify the b with maximal A_(α)-spectral radius among all graphs in G_(n,β).
基金Supported by The Featured Innovation Projects of the General University of Guangdong Province(2023KTSCX096)The Special Projects in Key Areas of Guangdong Province(ZDZX1088)Research Team Project of Guangdong University of Education(2024KYCXTD018)。
文摘This paper explores the recovery of block sparse signals in frame-based settings using the l_(2)/l_(q)-synthesis technique(0<q≤1).We propose a new null space property,referred to as block D-NSP_(q),which is based on the dictionary D.We establish that matrices adhering to the block D-NSP_(q)condition are both necessary and sufficient for the exact recovery of block sparse signals via l_(2)/l_(q)-synthesis.Additionally,this condition is essential for the stable recovery of signals that are block-compressible with respect to D.This D-NSP_(q)property is identified as the first complete condition for successful signal recovery using l_(2)/l_(q)-synthesis.Furthermore,we assess the theoretical efficacy of the l2/lq-synthesis method under conditions of measurement noise.
文摘Sand production and high water content in oil wells are two major challenges that restrict high and stable production in loose sandstone reservoirs.In this paper,nano SiO_(2),coupling agent triethoxysilane,phenolic resin and n-octanol were used to synthesize the main agent SCA-2.Hexamethylenetetramine and vinyl carbonate were selected to prepare the curing agent YGA-1,which was then compounded with SCA-2 to develop a sand fixation and water plugging system.Firstly,single-factor experiments were conducted to determine the optimal concentrations of SCA-2 and YGA-1,subsequently,the system’s sand fixation and water blocking performance were evaluated.Finally,a pilot test was carried out in the mining site.Experimental results showed that the optimal formula composition of the system was 10%SCA-2+5%YGA-1.The gelation time of the system was 180 minutes and the viscosity after gelation could reach 108.4 mPa·s.When the dosage of the drug system was 0.6 PV,the sand production rate remained below 0.08%.Dual-tube parallel experiments showed that the sand fixation and water plugging system had a water flow channel plugging rate of 87.5%,while the oil flow channel plugging rate was only 11.3%,indicating minimal damage to the oil-bearing reservoir.The field test showed that after the measures taken in Well M of X oilfield,the sand free oil recovery period exceeded 360 days,the water content decreased by 5.0%and the cumulative oil production increased by 7092 m^(3).This study provides new ideas for efficient development of loose sandstone reservoirs.
基金supported by the National Natural Science Foundation of China(Grant Nos.42150204 and 2288101)supported by the China National Postdoctoral Program for Innovative Talents(BX20230045)the China Postdoctoral Science Foundation(2023M730279)。
文摘A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.
基金National Natural Science Foundation of China(62272147,12471492,62072161,12401687)Shandong Provincial Natural Science Foundation(ZR2024QA205)+1 种基金Science and Technology on Communication Security Laboratory Foundation(6142103012207)Innovation Group Project of the Natural Science Foundation of Hubei Province of China(2023AFA021)。
文摘Ballet is one of the finalists of the block cipher project in the 2019 National Cryptographic Algorithm Design Competition.This study aims to conduct a comprehensive security evaluation of Ballet from the perspective of differential-linear(DL)cryptanalysis.Specifically,we present an automated search for the DL distinguishers of Ballet based on MILP/MIQCP.For the versions with block sizes of 128 and 256 bits,we obtain 16 and 22 rounds distinguishers with estimated correlations of 2^(-59.89)and 2^(-116.80),both of which are the publicly longest distinguishers.In addition,this study incorporates the complexity information of key-recovery attacks into the automated model,to search for the optimal key-recovery attack structures based on DL distinguishers.As a result,we mount the key-recovery attacks on 16-round Ballet-128/128,17-round Ballet-128/256,and 21-round Ballet-256/256.The data/time complexities for these attacks are 2^(108.36)/2^(120.36),2^(115.90)/2^(192),and 2^(227.62)/2^(240.67),respectively.
基金Supported by the China National Science and Technology Major Project(2025ZD1405700)CNPC Science and Technology Project(2023YQX20117).
文摘Based on the coalbed methane(CBM)/coal-rock gas(CRG)geological,geophysical,and experimental testing data from the Daji block in the Ordos Basin,the coal-forming and hydrocarbon generation&accumulation characteristics across different zones were dissected,and the key factors controlling the differential CBM/CRG enrichment were identified.The No.8 coal seam of the Carboniferous Benxi Formation in the Daji block is 8-10 m thick,typically overlain by limestone.The primary hydrocarbon generation phase occurred during the Early Cretaceous.Based on the differences in tectonic evolution and CRG occurrence,and with the maximum vitrinite reflectance of 2.0%and burial depth of 1800 m as boundaries,the study area is divided into deeply buried and deeply preserved,deeply buried and shallowly preserved,and shallowly buried and shallowly preserved zones.The deeply buried and deeply preserved zone contains gas content of 22-35 m^(3)/t,adsorbed gas saturation of 95%-100%,and formation water with total dissolved solid(TDS)higher than 50000 mg/L.This zone features structural stability and strong sealing capacity,with high gas production rates.The deeply buried and shallowly preserved zone contains gas content of 16-20 m^(3)/t,adsorbed gas saturation of 80%-95%,and formation water with TDS of 5000-50000 mg/L.This zone exhibits localized structural modification and hydrodynamic sealing,with moderate gas production rate.The shallowly buried and shallowly preserved zone contains gas content of 8-16 m^(3)/t,adsorbed gas saturation of 50%-70%,and formation water with TDS lower than 5000 mg/L.This zone experienced intense uplift,resulting in poor sealing and secondary alteration of the primary gas reservoir,with partial adsorbed gas loss,and low gas production rate.A depositional unification and structural divergence model is proposed,that is,although coal seams across the basin experienced broadly similar depositional and tectonic histories,differences in tectonic intensity have led to spatial heterogeneity in the maximum burial depth(i.e.,thermal maturity of coal)and current burial depth and occurrence of CRG(i.e.,gas content and occurrence state).The research results provide valuable guidance for advancing the theoretical understanding of CBM/CRG enrichment and for improving exploration and development practices.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3080200)。
文摘The identification and characterization of concealed in-situ rock blocks on high-steep slope exposures are critical in rock engineering,but remain challenging.This study employs advanced UAV-based photogrammetry to capture high-resolution discontinuity data and develops a fully automated rock block extraction method consisting of three steps:(1)determination of free face and non-free fracture intersections,(2)surface search for rock blocks on free face.and(3)extraction and analysis of rock blocks.This approach simplifies the determination of discontinuity intersections while maintaining high accuracy.By incorporating all types of discontinuities contributing to rock block formation,the method enables precise in-situ rock block identification and extraction.Application to a rock slope in China,produced results consistent with the rock blocks observed in the 3D model,highlighting its accuracy and practical value.
文摘To improve the heat transfer rate and thermal performance of the solar air heater due to low efficiency,new techniques,such as artificial roughness,barriers,and obstacles,should be used to increase the heat exchange between the fluid and the absorber.In this research,perforated V-shaped blockages with new geometric shapes,which are circular,hexagonal,square,rectangular,and triangular,were used.They were fixed on the absorber plate inside the channel with dimensions of 1.5 m×0.5 m×0.05 m,which increased the exit temperature of the air passing through the channel.The experimental work consists of six cases that were carried out during November in Baghdad,Iraq,to obtain an optimal result.These cases included using barriers that have holes with different geometric shapes for the barriers inside the solar air heater in addition to the reference case without any barriers.A comparison ismade between the cases under the same conditions and limits to reach the optimal case.The range of mass flow rate was from 0.0098 to 0.049 kg/s,and the range of Re was from 2000 to 10,000.Another goal of the comparison was to maximize Nu and minimize the friction factor.TheNu value improved by 1.77 and the fraction factor by 1.75 for the hexagonal perforated,which had the best performance.As for the triangle perforated,Nu improved by 1.58 and the fraction factor by 3.84,which had the worst performance.The Nu value improved by 1.39,1.22,and 1.4,and the fraction factor improved by 1.967,1.28,and 2.33 for square,circular,and rectangular,respectively.The thermal efficiency is evaluated by analyzing the heat losses from convection with the surrounding air and long-wave radiation exchange with the atmosphere.The experimental results indicated that using barriers with hexagonal holes is the best performance.
