满足严格Avalanche标准的布尔函数的性质

本文讨论了满足严格Ａｖａｌａｎｃｈｅ标准的布尔函数的一个必要条件；对满足（ｎ—３）阶严格的Ａｖａｌａｎｃｈｅ标准（ＳＡＣ）的布尔函数，和所有次数不超过二次的满足任意阶严格Ａｖｌａｎｃｈｅ标准的布尔函数，本文给出了它们的布尔多项式特征．ＷａｎｇＪｉａｎｙｕ（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＮａｎｋａｉＵｎｉｖｅｒｓｉｔｙ，Ｔｉａｎｊｉｎ３０００７１）是ｎ元布尔函数，则易证明ｆ（ｘ）满足ＳＡＣ的充要条件是每一个ｆｉ（ｘ）均满足ＳＡＣ（１≤ｉ≤ｍ）。定义２称ｆ满足ｍ阶严格Ａｖａｌａｎｃｈｅ标准（ＳＡＣ）（１≤ｍ≤ｎ－２），如果ｆ满足：任意选择ｆ的任意ｍ个变元的值后所得到的函数是满足ＳＡＣ的布尔函数。显然不可能存在满足（ｎ－ｌ）阶ＳＡＣ的函数，因为任意确定ｆ的任意确定（ｎ－１）个变元的取值以后所得到的函数是仿射函数，它不可能满足ＳＡＣ因此次数最高的ＳＡＣ是（ｎ－２）阶ＳＡＣ。实际上，文献［３］给出了所有满足（ｎ－２）阶ＳＡＣ的布尔函数的形式。定理１设，满足阶为（ｎ－２）的ＳＡＣ的充要条件是：里ａｉεＺ２，ｉ＝０，１，…，ｎ。因此ｆ是（ｎ－２）阶ＳＡＣ的布尔函数的充要条件是ｆ的次数为２，且二次项的系数均为１。下面将给出满足?

Numerical simulation for the initial state of avalanche in polydisperse particle systems

Numerical simulation is employed to investigate the initial state of avalanche in polydisperse particle systems.Nucleation and propagation processes are illustrated for pentadisperse and triadisperse particle systems,respectively.In these processes,particles involved in the avalanche grow slowly in the early stage and explosively in the later stage,which is clearly different from the continuous and steady growth trend in the monodisperse system.By examining the avalanche propagation,the number growth of particles involved in the avalanche and the slope of the number growth,the initial state can be divided into three stages:T1(nucleation stage),T2(propagation stage),T3(overall avalanche stage).We focus on the characteristics of the avalanche in the T2 stage,and find that propagation distances increase almost linearly in both axial and radial directions in polydisperse systems.We also consider the distribution characteristics of the average coordination number and average velocity for the moving particles.The results support that the polydisperse particle systems are more stable in the T2 stage.

Dynamic Characteristics of the Long Runout Rock-ice Avalanche at High Altitude——A Case from the Zelongnong Basin,Eastern Himalayan Syntaxis,China

Rock-ice avalanches have frequently occurred in the Eastern Himalayan Syntaxis region due to climate change and active tectonic movements.These events commonly trigger catastrophic geohazard chains,including debris flows,river blockages,and floods.This study focuses on the Zelongnong Basin,analyzing the geomorphic and dynamic characteristics of high-altitude disasters.The basin exhibits typical vertical zonation,with disaster sources initiating at elevations exceeding 4000 m and runout distances reaching up to 10 km.The disaster chain movement involves complex dynamic effects,including impact disintegration,soil-rock mixture arching,dynamic erosion,and debris deposition,enhancing understanding of the flow behavior and dynamic characteristics of rock-ice avalanches.The presence of ice significantly increases mobility due to lubrication and frictional melting.In the disaster event of September 10,2020,the maximum flow velocity and thickness reached 40 m/s and 43 m,respectively.Furthermore,continuous deformation of the Zelongnong glacier moraine was observed,with maximum cumulative deformations of 44.68 m in the distance direction and 25.96 m in the azimuth direction from March 25,2022,to August 25,2022.In the future,the risk of rock-ice avalanches in the Eastern Himalayan Syntaxis region will remain extremely high,necessitating a focus on early warning and risk mitigation strategies for such basin disasters.

Evidence of ancient rock-ice avalanches along the China-Bhutan Chomolhari Range,and their implications for demise of the summit

Large-scale rock-ice avalanches resulting from the interaction of tectonics and climate are characterized with high mobility,huge volumes of sediment,and rapid denudation,being a major agent of landscape evolution in high altitude mountainous regions.Specifically,the extreme glaciated slope failures often transform into extraordinarily large and mobile debris flows,resulting in disastrous consequences such as sedimentation and desertification.Due to a dearth of on-site observation data and experimental data collection,our comprehension of the geomorphic and kinematic characteristics of rock-ice avalanches remains poor.Here we report a cluster of ancient rock-ice avalanches spreading along the Chomolhari range of the China-Bhutan Himalayas.By integrating remote sensing image interpretation with detailed field investigations,we demonstrate the geomorphic and sedimentary characteristics of four events among the avalanches.The estimated volumes of the four are 23.73 Mm³,39.69 Mm³,38.43 Mm³,and 38.25 Mm³,respectively.The presence of pre-existing moraines or alluvial fans constrained their movement,resulting in deposition features such as marginal digitated lobes at higher elevations and large depressed areas in the interior.Applying the Savage-Hutter theory,we calculate the basal friction angle and travel angle of these ancient rock-ice avalanches that are both less than 10°,affirming the similarity of these avalanches in the study area to those occurring in other regions.Our study significantly contributes to understanding the geomorphic and kinematic characteristics of rock-ice avalanches in high-altitude mountainous regions,providing valuable insights into their response to the disproportionate growth of Himalayan peaks.

Mantle avalanches in a Venus-like stagnant lid planet

Stagnant lid planets are characterized by a globe-encircling,conducting lid that is thick and strong,which leads to reduced global surface heat flows.Consequently,the mantles of such planets can have warmer interiors than Earth,and interestingly,a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose,2002;Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014;Dannberg et al,2022).Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite,at pressures corresponding to 410 km and 520 km depth in Earth,respectively,it instead transforms into a mineral assemblage of wadsleyite,majorite,and ferropericlase(WMF),and then to majorite+ferropericlase(MF),before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014).Convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips)forming within the mobile rheological sublayer under the rigid lid.Using ASPECT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo,we show that under certain conditions,the small drips can pond atop the WMF-MF mineral phase transition.The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni,2022).Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al.,2022;Li RP et al.,2024),the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle.Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed 1900 K,the smaller,cold drips from the lid continue to pile up until enough of them have coalesced that they collectively avalanche as a larger instability into the deeper interior.

Advances in ice avalanches on the Tibetan Plateau

As some of the greatest natural disasters in the cryosphere,ice avalanches(IAs)seriously threaten lives and cause catastrophic damage to the resource environment,but a comprehensive overview of the state of knowledge on IAs remains lacking.We summarized 63 IAs on the Tibetan Plateau(TP)since the 20th century,of which,over 20 IAs occurred after the 21st century.The distributions of IAs are mainly concentrated in the southeastern and northwestern TP,and the occurrence time of IAs is mostly concentrated from July to September.We highlight recent advances in mechanical properties and genetic mechanisms of IAs and emphasize that temperature,rainfall,and seismicity are the inducing factors.The failure modes of IAs are summarized into 6 categories by examples:slip pulling type,slip toppling type,slip breaking type,water level collapse type,cave roof collapse type,and wedge failure type.Finally,we deliver recommendations concerning the risk assessment and prediction of IAs.The results provide important scientific value for addressing climate change and resisting glacier-related hazards.

Research on the correlation between the dual diffusion behavior of zinc in InGaAs/InP single-photon avalanche photodiodes and device performance

The development of InGaAs/InP single-photon avalanche photodiodes(SPADs)necessitates the utiliza-tion of a two-element diffusion technique to achieve accurate manipulation of the multiplication width and the dis-tribution of its electric field.Regarding the issue of accurately predicting the depth of diffusion in InGaAs/InP SPAD,simulation analysis and device development were carried out,focusing on the dual diffusion behavior of zinc atoms.A formula of X_(j)=k√t-t_(0)+c to quantitatively predict the diffusion depth is obtained by fitting the simulated twice-diffusion depths based on a two-dimensional(2D)model.The 2D impurity morphologies and the one-dimensional impurity profiles for the dual-diffused region are characterized by using scanning electron micros-copy and secondary ion mass spectrometry as a function of the diffusion depth,respectively.InGaAs/InP SPAD devices with different dual-diffusion conditions are also fabricated,which show breakdown behaviors well consis-tent with the simulated results under the same junction geometries.The dark count rate(DCR)of the device de-creased as the multiplication width increased,as indicated by the results.DCRs of 2×10^(6),1×10^(5),4×10^(4),and 2×10^(4) were achieved at temperatures of 300 K,273 K,263 K,and 253 K,respectively,with a bias voltage of 3 V,when the multiplication width was 1.5µm.These results demonstrate an effective prediction route for accu-rately controlling the dual-diffused zinc junction geometry in InP-based planar device processing.

Topographic seismic effects and avalanche hazard:A case study of Mount Siella(L’Aquila,Central Italy)

In mountainous areas,snow avalanches could be triggered by the shaking produced by earthquakes.The forces induced by the earthquake can cause an irregular increase of shear strength load down the slope,for the presence of complex surface and buried morphologies.Topographic irregularities generate maximum effects of waves amplification linked to wavelengths comparable to the horizontal dimension of the topographic feature.For this reason,the selected time-histories represent an appropriate input for the two-dimensional numerical response analyses when a dynamic phenomenon produce the resonant motion of a whole mountain.This represents an important earthquake-induced hazard in snow-covered mountain areas with high probability of seismic events.Some valleys are located in regions with scare ground motion data and investments on infrastructures are not always accompanied by adequate protection against earthquake-induced avalanches.The paper points out a simple deterministic approach for selecting a set of real accelerograms applied to a real case of Siella Mountain(Central Italy)where a large avalanche destroying a tourist facility of Rigopiano resort on 18 January 2017.The selected time histories were used as input for the two-dimensional numerical model of the subsoil to evaluate the topographic seismic amplification in ridge and compare it with the results of other authors.These methods suggest that morphology-related inertial effects should be considered as an overload action on snow layers when controlling multi-hazard studies and spatial planning.

Protective effect of retaining wall on rock avalanche:A case study of Nayong rock avalanche in China

Rock avalanches are generally difficult to prevent and control due to their high velocities and the extensive destruction they cause.However,barrier structures constructed along the path of a rock avalanche can partially mitigate the magnitudes and consequences of such catastrophic events.We selected a rock avalanche in Nayong County,Guizhou Province,China as a case to study the effect of the location and height of a retaining wall on the dynamic characteristics of rock avalanche by using both actual terrain-based laboratory-model tests and coupled PFC3D-FLAC3D numerical simulations.Our findings demonstrate that a retaining wall can largely block a rock avalanche and its protective efficacy is significantly influenced by the integrity of the retaining wall.Coupled numerical simulation can serve as a powerful tool for analyzing the interaction between a rock avalanche and a retaining wall,facilitating precise observations of its deformation and destruction.The impact-curve characteristics of the retaining wall depend upon whether or not the rock avalanche-induced destruction is taken into account.The location of the retaining wall exerts a greater influence on the outcome compared to the height and materials of the retaining wall,while implementing a stepped retaining-wall pattern in accordance with the terrain demonstrates optimal efficacy in controlling rock avalanche.

基于RAMMS-AVALANCHE模型的雪崩模拟参数敏感性分析

以巩乃斯大陆性气候雪崩危险区为研究背景,建立三维数字地形模型对雪崩运动过程进行模拟。研究RAMMS雪崩数值模拟结果的影响因素,分析计算网格分辨率、雪层断裂深度、摩擦系数3种参数值对模拟结果的影响程度及敏感性。通过单因素分析法对比不同参数下模拟结果进而得出3种参数的影响程度,采用灰色关联法分析参数对模拟结果的敏感性。结果表明:选择合适的计算网格分辨率能提高模拟结果的准确性;雪层断裂深度每减少10%,流动高度变化率在5%~7%;流动速度变化率在1%~2%;冲击力变化率在2%~3%;而摩擦系数的大小主要对堆积区特征值和雪崩停止时间产生较大影响,对运动过程中的特征值影响较小。在此基础上进行敏感度计算,根据计算结果确定各特征值最大影响性时参数的主次关系。研究结果明晰了雪崩模拟各输入参数的敏感性,可有效提高雪崩数值模拟参数选取的合理性和计算结果的准确性,为雪崩灾害危险程度分析提供依据。

地方气象标准体系构成浅析——以吉林省为例

气象标准体系是气象标准化工作的规划和指引,标准构成分析可直观了解气象标准化工作现状。本文以吉林省气象标准体系为例,对照《气象高质量发展纲要(2022-2035年)》要求,浅析地方气象标准体系的具体构成特点,明确气象服务保障是目前气象标准化工作的突出领域,数值天气预报、资源开发利用、专业气象服务、气象灾害监测预警和重大突发事件保障等是目前气象标准化工作的重点方向,提出各业务领域全面加强标准化培训工作以及标准化管理工作需求和建议,以期为各地方气象标准体系建设及标准化工作发展提供科学参考。

大型综合医院《住院患者深静脉血栓栓塞症》防治团体标准推广应用研究

目的探讨《中国医院质量安全管理》团体标准“第2-25部分患者服务:住院患者深静脉血栓栓塞症防治”标准(简称VTE)在某大型综合医院的宣贯和应用。方法结合中国医院协会VTE标准,通过标准实施设计、试点遴选、标准实施、评价改进四个阶段,找出存在问题并提出改进建议。结果通过TOPSIS法对试点单位和非试点单位进行比较分析,发现试点单位VTE综合防治质量远高于非试点单位。结论应用VTE团体标准可有效提高VTE防治能力,规范VTE诊疗操作流程,减少VTE误诊、漏诊和死亡发生,保障患者安全,可为同类医院提供借鉴。

听力学工作中的标准化要求

听力学工作的标准化要求日益提高。本文介绍了目前我国听力学检测和干预方法、测听设备、测听环境、听力干预设备、职业听力损伤和听力防护等方面的标准化现状,介绍我国听力学标准化面临的任务和需求。

煤岩气:概念、内涵与分类标准

近年来,准噶尔、鄂尔多斯等盆地深层煤岩储层中的天然气勘探开发取得重大突破。针对目前工业界和学术界对这种新类型非常规天然气表述不一致的现状,在前人研究的基础上定义了“煤岩气”概念,并系统对比剖析其赋存状态、运储形式、差异聚集和开发规律。在地质上,煤岩气不同于传统意义上的煤层气,具有游离气与吸附气并存、富含游离气,自生自储-微距运移并可有他源的聚集,煤岩割理裂缝发育、游离气差异富集等特点,埋深超过2000m的深层煤岩气具有“高压力、高温度、高含气、高饱和、高游离”的“5高”地质特征;在开发上,与页岩气、致密气特征相似,人工改善储层连通性后,无需排水降压,高势能游离气弹性驱动产出、压降后吸附气解吸接替,可依靠地层自然能量开采,游离气与吸附气连续接力长周期产气。按照埋深、煤阶、压力系数、储量规模、储量丰度和气井产量等,提出了煤岩气的分类标准和资源/储量估算方法。初步估算埋深超过2 000 m的中国煤岩气地质资源量超过30×1012m3,是国家重要的战略资源。提出鄂尔多斯、四川、准噶尔和渤海湾等盆地是煤岩气的规模富集有利区,梳理了技术与管理挑战并指出攻关方向,为中国煤岩气管理与勘探开发奠定理论、评价和生产实践基础。

复杂系统视角下数字领域“smart”概念的国际标准化共识构建及应用

进入数字时代,伴随大数据和人工智能技术快速发展和普遍应用,带有“smart”的指称不断涌现,然而关于“smart”概念的认知尚缺少跨领域和跨国际标准组织的标准化共识构建研究。采用ISO 704:2022的概念构建原则和方法,基于复杂系统论视角,对数字领域国际标准定义中涉及“smart”的概念特征进行了识别。基于跨领域国际标准组织专家的研讨、问卷调查和国际共识构建,提出了适应于复杂系统数字领域“smart”的通用概念,并将其用于指导《智慧城市城市智能服务体系构建指南》国家标准的制定过程。该研究对推进国家标准和国际标准兼容具有重要战略意义。

司法实践中“证据标准”之评析

“证据标准”是我国近年刑事司法实践中发展出的一个区别于“证明标准”的独特概念,其核心是指某类犯罪定罪量刑所需的基本证据,另外还包括收集各类证据应遵循的程序性规范和技术性规范。“统一证据标准”不应作为“以审判为中心”诉讼制度改革的核心,因为“统一证据标准”不仅无助于庭审实质化的实现,还会妨碍法官对证据的主观判断。“证据标准”并非一种法定证据制度,但由于它本身具有一些违反诉讼证明原理之处,所以仍会给我国的刑事证明带来一些消极影响,包括强化诉讼证明偏重客观化的倾向、抹杀不同类型案件证明路径的差异性、使控方在收集和审查证据中侧重于指控有罪的心理偏差更为严重。“证据标准”对侦查取证环节可以发挥一定的积极作用,有利于指引和规范侦查取证,也有利于过程证据、辅助证据的收集。总体上看,“证据标准”弊大于利,并非我国刑事诉讼程序和证据制度完善所必需,可以予以舍弃;即便要继续运用,也应将其限于侦查取证阶段,并将其改造为一种指导性、全面性的取证指南,才能使其在合理范围内发挥作用。

新一代通用视频编码标准H.266/VVC:现状与发展

相比于上一代标准,新一代通用视频编码标准(H.266/VVC)在同等质量下能够节省大约50%的码率,且适用于多种多样的视频应用场景。论文从H.266/VVC的关键技术出发,对标准的现状、实现和应用发展进行深入探讨。H.266/VVC沿用既往标准中的双层码流体系和混合编码框架,针对帧内预测、帧间预测、变换、量化、环路滤波等所有主要编码模块进行了技术革新,并为屏幕内容视频等应用提供了高效的专用编码工具。H.266/VVC标准目前已处于实用化阶段,官方参考软件VTM和开源编解码器VVenC/VVdeC是目前最具代表性的软件编解码实现。对H.266/VVC的性能分析可以看出:H.266/VVC针对高分辨率视频取得的编码增益更为突出;主要编码工具对性能的贡献通常以复杂度为代价,但也有部分编码工具在提升编码性能的同时可降低整体编码复杂度。H.266/VVC的硬件实现面临诸多挑战,发展明显滞后于软件实现,现有研究主要集中在对具体编码模块的硬件加速方面。H.266/VVC标准发布之后,下一代视频编码标准的发展目前仍围绕混合编码框架进行探索,聚焦在两大方向:超越VVC的增强压缩关注更为先进的、非神经网络的编码工具,基于神经网络的视频编码则探索采用神经网络的编码工具。除此之外,部分或完全跳出现有混合编码框架的端到端视频编码也在飞速发展,未来视频编码标准与神经网络结合成为趋势,但面临着计算资源依赖和稳定结构两方面的考验。

《超说明书用药标准》制订与解析

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