摘要：一些人士所称的移动广告世界末日终于到来了。从2021年4月26日起,苹果公司将实施新的隐私协议,从而使其平台上的应用程序更难通过收集用户数据来投放个性化的数字广告。此举将对应用程序的经济运行机制产生巨大影响,并改变一线系统平台、广告商和应用程序开发者之间的力量对比。但目前也正值科技行业面临紧要关口:在世界各国想方设法遏制大型科技公司曰益上升的主导地位之际,苹果此举可能会进一步增强科技巨头的实力,削弱较小的竞争对手。

摘要：分析了周界环境的防入侵需求,针对周界的物理入侵和传感网自身面临的安全威胁,提出了一种基于WIA-PA(wireless networks for industrial automation-process automation)网络的围界防入侵安全系统体系结构,设计了周界入侵检测系统的组网方案和安全机制,采用密钥管理、安全入网、基于预共享密钥的双向鉴别、周界安全检测及入侵行为记录等技术来保证传感网的安全,在此基础上,设计并实现了基于WIA-PA网络的周界防入侵安全系统。测试结果表明,该系统能够探测到周界的物理入侵,增加了网络安全机制,系统的安全性和可用性得到有效提高。

摘要：对于职业体育的粉丝来说,几乎不可能错过加密货币行业的宣传攻势:交易所和区块链公司的名字印在球队的球衣上,张贴在体育场里,还在中场休息的电视广告中亮相。那些拥有丰厚代言合同的明星球员也对他们大加吹捧。自去年以来,这些新兴企业采取了积极的行动,与啤酒品牌、汽车制造商、电信服务提供商和其他主要体育赞助商的广告投放力度不相上下。

摘要：随着城市的发展,各种污染的排放量也呈现出直线上升的现象,在诸多行业中,水污染问题也日益严重,造成了城市中水环境严重的破坏。而我国城市化发展进程较快,治理水平提升迅速。本文立于多中心治理的视角下,对城市水环境问题进行分析,并对水环境的治理进行探讨,以期为我国城市的水环境治理提供相应的依据。

摘要：横跨半个世纪的时尚摄影> 01 ICP(International Center of Photography)由即日起至9月6日举办一场名为"Avedon Fashion 1944-2000"的展览,是专门针对Richard Avedon的时尚摄影作品的展览。Richard Avedon的摄影风格深受匈牙利摄影师Martin Munkacsi影响,更以独有的美式风格撼动了战后欧洲呆板的时装摄影格局。他让模特们走出摄影棚,走上街头海滩,跳跃舞动欢笑。他抓拍行动中的模特并为定格为其招牌的"Avedon Blur"。

摘要：In photoelectrochemical （PEC） water splitting, charge separation and collection by the electric field in the photoactive material are the most important factors for improved conversion efficiency. Hence, ferroelectric oxides, in which electrons are the majority carriers, are considered promising photoanode materials because their high built-in potential, provided by their spontaneous polarization, can signifi＇canfly enhance the separation and drift of photogenerated carriers. In this regard, the PEC properties of BiFeO3 thin-film photoanodes with different crystallographic orientations and consequent ferroelectric domain structures are investigated. As the crystallographic orientation changes from （001）pc via （ll0）pc to （lll）p~, the ferroelastic domains in epitaxial BiFeO3 thin films become mono-variant and the spontaneous polarization levels increase to 110 btC/cm2. Consequent136 the photocurrent density at 0 V vs. Ag/AgC1 increases approximately 5.3-fold and the onset potential decreases by 0.180 V in the downward polarization state. It is further demonstrated that ferroelectric switching in the （lll）pc BiFeO3 thin-film photoanode leads to an approximate change of 8,000% in the photocurrent density and a 0.330 V shift in the onset potential. This study strongly suggests that domain-engineered ferroelectric materials can be used as effective charge separation and collection layers for efficient solar water-splitting photoanodes.

摘要：微电网中分布式发电可使微电网的电能质量增强,但线路阻抗不匹配时传统功率下垂控制方法不能保证负荷不对称功率的精确分配.针对此问题,提出了一种基于一致性和自适应虚拟阻抗的分布式负序功率均分控制方法.该方法通过引入负序虚拟阻抗使分布式发电单元按容量精确分配不对称负荷.设计了多智能体一致性算法,自适应调整负序虚拟阻抗,消除线路阻抗不匹配带来的影响,实现了不对称功率准确分配.仿真实验结果验证了该控制方案的正确性和有效性.

摘要：现有的精神疾病分类模型仅采用脑网络的静态指标作为特征,忽略了脑网络的空间动态信息,导致分类性能不高。为克服这一局限性,提升分类模型的性能,提出了基于功能脑连接空间动态的分类方法。通过高维模板对脑连接进行空间动态分析,提取脑连接空间动态特征。利用统计分析进行特征选择,构建基于静息态功能脑连接的分类模型。通过对抑郁症患者与正常被试的分类实验结果表明,脑连接空间动态特征的分类准确率(83.0%)比传统采用脑网络的静态指标特征的分类准确率(77.8%)高5.2个百分点。

摘要：Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.

摘要：世界上有这样的水果吗?无需用刀,用手便可轻松去皮。瞬间呈现诱人外表与芳香,口感更佳,柔软、香甜得仿佛巧克力。平时很难看见,若不是高级宾愴晚餐室,相信很难亲身体验——我们平曰能够吃到香蕉足以证明与西欧文化和物质的来往。所以,许多水果中只有香蕉才能得到人们高于其价值的认可。但随着当前运输手段及冷藏技术的发达,香蕉已成为极为常见水果,如果放在饭桌上,孩子们会不屑一顾。