Designing ultrastable P2/O3-type layered oxides for sodium ion batteries by regulating Na distribution and oxygen redox chemistry

P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs.

Spatial Distribution of Soil Total Nutrients of Farmland in Liaoning Province

[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was used to analyze the spatial distribution characteristics of total C,total N,total P and total K for different soil layers in Liaoning Province. [Result]The results showed that the content of total C,total N,total P decrease from east to west,but the content of total K was high in north district of Liaoning Province. The content of total C,total N,total P and total K was higher in soil surface （0-20 cm） than the lower （20-40 cm）. Total K varied less with soil depth,and its mean content was respectively 17.64 g/kg and 17.08 g/kg for soil surface and soil lower layer. [Conclusion]The results of the distribution of soil total nutrients in different soil layers supplied a theory basis for farmland management.

基于电磁时间反演P范数判据的配电网故障定位

目前电磁时间反演(electromagnetic time reversal,EMTR)多应用在单一线路故障定位,且现有判据在高阻抗接地情况下效果不理想。针对上述问题,基于EMTR故障定位原理和均匀传输线理论推导了传播过程中线路故障信号与测量信号的传递函数,根据传递函数的相关性提出了P范数判据。利用ATP-EMTP搭建10 kV配电网线路,对比了2范数与P范数判据在复杂配电网中的定位性能,并验证了所提判据在混合配电网线路的适用性。最后,分析了配电网发生低阻抗及高阻抗接地故障下P范数判据的鲁棒性。仿真结果表明,该方法在过渡电阻高达3 kΩ的情况下能准确定位,且定位精度高,受噪声、故障类型和采样频率的影响小。

高压管汇材料疲劳性能测试及P-S-N模型曲线的拟合

高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命的准确描述问题,以某国产高压管汇材料为例,进行了一系列疲劳试验,并基于试验数据,采用多种分布模型和不同S-N模型进行拟合分析,得出综合评价拟合能力最强的P-S-N模型。结果表明,该材料在中长疲劳寿命区,Weibull三参数模型在7级应力水平下综合评价能力最好;在存活率分别为50%、90%、99%、99.9%时,指数S-N模型的拟合系数均大于0.98,拟合能力最好。得出的P-S-N模型曲线可以为高压管汇的疲劳寿命以及安全设计提供依据。

采用非稳相偏振滤波的DAS-VSP数据P/S波分离方法及其应用

分布式光纤声学传感(DAS)因成本低、易布设以及高密度采样等优势正成为重要的地震观测技术,尤其是越来越多地与垂直地震剖面(VSP)结合,用于主动地震勘探或被动地震监测.DAS传感器通过感知弹性波场产生的轴向应变或应变速率来观测地震波场振动.然而,目前单分量DAS-VSP数据未完整地记录地下弹性波场的三维矢量振动信号,因此如何从中分离出P波或S波用于后续地震成像与参数反演是重要且很有挑战的课题.以弹性波传播理论为基础,本文根据P波和S波的频散关系估算接收点处各自的偏振方向,通过随频率和空间位置变化的偏振滤波实现DAS-VSP数据的P/S波分离.理论模型合成数据与东海实际DAS-VSP数据实验结果表明,该方法能有效地将P波和S波信号从单分量DAS-VSP数据中分离出来,可为后续纵横波速度反演、PP与PS波成像提供关键的数据预条件处理.

通过基体晶粒和颗粒分布异质结构的调控协同提升AlN_(p)/Al复合材料的强度-塑性

为了获得优异的强塑性能,采用液固反应结合后续的热机械处理方法制备了3种具有不同微观组织构型的异构AlNp/Al复合材料,详细研究了AlN颗粒分布和基体晶粒组织构型对拉伸强度和塑性的影响。结果表明,复合材料的强度和塑性同时提高。其中,具有较弥散颗粒分布的Uniformed-AlNp/Al复合材料表现出优异的极限抗拉强度(~387 MPa)和断裂伸长率(~9.1%)。与其他文献报道的颗粒增强铝基复合材料相比,该复合材料具有较好的比强度和延展性组合。此外,计算了异质变形诱导(HDI)应力。结果表明,在Uniformed-AlNp/Al复合材料中,HDI应力显著增加。揭示了HDI应力在提高AlNp/Al复合材料的强度和塑性中起着至关重要的作用。

The Limitations of Polygenic Hypothesis and Theorizing about Dual Multiple Factors and Three Normal Distributions

The original data of Nilsson-Ehle experiment in wheat were analyzed with existent genetic knowledge. It indicated that the core of polygenic hypothesis from this experiment was that a character similarity produced by additive effect of multiple genes was the basis of continuous variation. Its precondition was for effective genes to have equal effect, to show merodominance and binomial distribution and to inherit independently. In fact, quantitative characters were determined by many genes with different property, effect and behavior. So it was difficult to solve all problems of continuous variation by the aid of polygenic hypothesis. The researchers should seek new ways. With Mendelian group as research object and by means of Lyapunov central limit theorem it was proved that both genotypic value G and the environmental effect in a niche E were subordinated to the normal distribution and respectively. According to additivity of the normal distribution the phenotype P = G + E also obeyed the normal distribution P = G + E ~ and quantitative characters showed continuous variation, whether or not the linkage was presented, whether or not every gene effect was equal, whether or not there were dominance and what kind of dominance between alleles. Moreover it was discussed that the quantitative characters in self-fertilized organism and clone were submitted to the normal distribution and presented continuous variation too.

Analysis of the characteristics of snow drop size distribution in the Qilian Mountains

Under the Watershed Allied Telemetry Experimental Research （WATER） project, a significant amount of snow size data was collected from March to April 2008. However, because of limited observation data for the Qinghai-Tibet Plateau, the modeling behavior was not satisfactory. This paper demonstrates characteristics of the snow drop size distribution （SSD） in this region. The experimental area is located in the northeastern part of the Qinghai-Tibet Plateau. The Heihe River Basin, which is the second largest interior river basin in China and is located on the northern slopes of the Qilian Mountains, was selected as the simulation region. This basin ranges from approximately 5,000 m to 1,000 m in elevation. A new generation Parsivel disdrometer, the OTT Parsivel, was used for measurements. Four data sets were compiled to determine the average distributions for four different snowfall rates. The characteristics of the snow particle size distribution in the mountainous area were analyzed. Similar to the raindrop distribution, there was a multi-peak structure. Most peaks appear in the D 〈 2 mm region （D： diameter of the snow drop size）. An M-P distribution and a Г distribution were developed based on the precipitation data observed in Qilian mountainous area. We found that the Г distribution has a better fit than the M-P distribution for the actual distribution. In addition, we observed that the intercept parameter （N0） and the slope parameter （Λ） correlate well with the shape parameter （μ）. The disdrometer data can also be used to model the reflectivity factor （ZH） and differential reflectivity factor （ZDR）. The radar reflectivity （ZHH, ZVV） and differential reflectivity （ZDR） were modeled in order to facilitate understanding of the connections between radar and ground measurements, and were used to support work for the improvement of rainfall estimates by polarimetric radar. Rain rate estimation using radar measurements was based on empirical models, such as the Z-R relationship and R（ZH, ZDR） in the Qilian mountainous areas. The relationship of R=0.017×100.079×ZH-0.022×ZDR is better than R=0.019×100.078×ZH for estimating R （melted snow）. The normalized errors （NE） of R（ZH） and R（ZH, ZDR） are 13.22% and 5.20%, respectively.

Root Sprouts of Domesticated Phaseolus coccineus L. Overwinter Plants and the Environment at Its Collection Sites

Buds emerge from the roots of domesticated runner bean plants (Phaseolus coccineus L.) as sprouts and give the crop its persistence. This particularity of the species seems to be associated with the environment where the species was cultivated during long time. Data on regrowth traits were recorded on 70 accessions of domesticated P. coccineus after overwintering at a site in the central highlands of Mexico. The characteristics recorded included fresh weight of vegetative regrowth, root length, root crown diameter, and diameter of the main root. Most accessions that sprout the following spring, after the grain harvest of the previous year, come from temperate and semi-cold sites with cambisol and andosol soils in mixed Quercus pine forest and high mountain fir trees. Those that do not sprout are from sites of semiarid temperate climate, haplic phaeozem soil in shrub grasslands with deciduous broadleaved trees, and semiwarm subhumid climate, eutrophic regosol soil in deciduous broadleaved forest. Two types of roots were differentiated: branched and thickened taproots, also associated with a different climate, and the type of soil of the collection sites.

Distribution, Function and Polymorphism Characteristics of Microsatellites in Pyropia yezoensis Transcriptome

The distribution, putative function and polymorphism characteristics of simple sequence repeats(SSRs) in P. yezoensis transcriptome were analyzed in this study. In total, 3076 SSRs were detected among 2681 unigenes. Trinucleotide types were dominant, constituting 91.87% of all the microsatellites. The most abundant SSR was CCG(71.03%) and the second abundant one was AGC(234, 7.61%). A total of 111(3.61%) dinucleotide types were found and the most abundant one was AC(51, 1.66%) which was followed by CG(34, 1.11%). SSRs identified showed a GC bases preference;GC bases constituted 89.73% of all the SSR bases. SSRs occurrence number decreased as repetitions increased. Annotation results exhibited that the majority of SSRs-containing unigenes have the functions of ‘metabolic process’,‘binding’ and ‘catalytic activity’ and existed as the forms of ‘cell’,‘cell component’ and ‘organelle’. The dominant amino acids that SSRs coded were Ala(28.59%), Arg(26.02%), Gly(14.35%) and Pro(13.65%). Amplification results showed that 3 out 23 SSRs from transcriptome(13.04%) and 8 out 77 SSRs from genome(10.39%) were polymorphic.

Content subscribing mechanism in P2P streaming based on gamma distribution prediction

P2P systems are categorized into tree-based and mesh-based systems according to their topologies. Mesh-based systems are considered more suitable for large-scale lnternet applications, but require optimization on latency issue. This paper proposes a content subscribing mechanism （CSM） to eliminate unnecessary time delays during data relaying. A node can send content data to its neighbors as soon as it receives the data segment. No additional time is taken during the interactive stages prior to data segment transmission of streaming content. CSM consists of three steps. First, every node records its historical segments latency, and adopts gamma distribution, which possesses powerful expression ability, to express latency statistics. Second, a node predicts subscribing success ratio of every neighbor by comparing the gamma distribution parameters of the node and its neighbors before selecting a neighbor node to subscribe a data segment. The above steps would not increase latency as they are executed before the data segments are ready at the neighbor nodes. Finally, the node, which was subscribed to, sends the subscribed data segment to the subscriber immediately when it has the data segment. Experiments show that CSM significantly reduces the content data transmission latency.

Hybrid ants-like search algorithms for P2P media streaming distribution in ad hoc networks

Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks.

Auto Distribution of Tag Table in P2P Control System

In control system, tag table is like a dictionary mapping tagname to address. Therefore, applications on workstation may use tagname to access different data in system. Normally tag table generated by configuration software will transfer to other workstation in system manually after system configuration, which is inconvenient and failible. The development of peer-to-peer （P2P） network technology and the realization of control system based on P2P network make the auto distn＇bution of tag table possible. In this paper based on file sharing technology the presented method realizes the auto distn＇bution of tag table.

P-adic空间上测度的Hausdorff维数和局部维数

研究了d-维P-adic向量空间Q_(p)^(d)上的Borel集Ω的Hausdorff维数与支撑在Ω上的概率测度μ的局部维数之间的关系.研究结果将欧氏空间Q^(d)上的质量分布原理推广到非阿基米德空间Q_(p)^(d)上去.

偏p-范分布的几何曲率及其应用

本文研究了偏p-范分布的几何曲率及其在假设检验过程中的应用.首先通过引入偏态参数λ,在p-范分布的基础上提出了偏p-范分布.接着推导了偏p-范分布的几何曲率并通过计.算得到了偏p=1.4-范分布的显著性水平值.最后利用这些显著性水平值分析加拿大ALGO测站的GPS数据,得到了该数据服从p=1.4的p-范分布..

A new quantum mechanical photon counting distribution formula

By virtue of the density operator＇s P-representation in the coherent state representation, we derive a new quantum mechanical photon counting distribution formula. As its application, we calculate photon counting distributions for some given light fields. It is found that the pure squeezed state＇s photon counting distribution is related to the Legendre function, which is a new result.

P值的显式表达式及其概率分布性质

针对几个常见的假设检验问题,首先给出检验P值的显式表达式,然后推导出P值作为一个随机变量的概率分布,接着证明P值在满足如下三个条件下服从均匀分布:真实参数为最接近对立假设的原假设参数值、检验统计量的相应零分布被正确指定、该零分布的分布函数可逆.

心电图P波离散度和红细胞分布宽度与冠状动脉慢血流现象的关系研究

目的:探讨心电图P波离散度(Pd)和红细胞分布宽度(RDW)与冠状动脉慢血流(CSF)的关系。方法:选取医院收治并经冠状动脉造影提示为CSF的103例患者纳入观察组,同时选择同期冠状动脉造影正常的58例患者纳入正常组,测定两组RDW与心电图Pd变化,并分析比较两组生化指标、Pd及RDW与冠状动脉平均血流帧数(TFC)差异。采用Pearson相关性分析Pd、RDW与冠状动脉心肌梗死溶栓试验(TIMI)的TFC值的相关性,采用受试者工作特征(ROC)曲线评估Pd、RDW对CSF发生的诊断价值,采用多因素Logistic回归分析CSF发生的影响因素。结果:观察组患者Pd、RDW均高于正常组,差异有统计学意义(t=7.353,t=8.770;P<0.05);LAD、LCX及RCA的TFC值以及平均TFC值均高于正常组,差异有统计学意义(t=15.162,t=11.680,t=13.663,t=13.296;P<0.05);Pd与LAD、LCX及RCA的TFC值以及平均TFC值均呈正相关(r=0.620,r=0.541,r=0.452,r=0.515;P<0.05);RDW与LAD、LCX及RCA的TFC值以及平均TFC值均呈正相关(r=0.352,r=0.417,r=0.510,r=0.462;P<0.05);Pd预测CSF的ROC曲线下面积(AUC)、灵敏度和特异度分别为0.789、85.2%和88.9%;RDW预测CSF的AUC、灵敏度和特异度分别为0.778、83.7%和90.6%。多因素Logistic回归分析,Pd和RDW均为影响CSF发生的危险因素(OR=3.50,OR=3.93;P<0.05)。结论:CSF患者心电图Pd增大,RDW水平升高,并且Pd、RDW与冠状动脉TIMI的TFC值呈正相关,二者可作为预测CSF发生的有效生物标志物。

基于TSP纵波的隧道地质异常体快速识别方法

在隧道超前地质预报中,TSP隧道预报系统广泛应用于探测隧道施工掌子面前方地质异常体,并取得较好的应用效果,其数据处理软件包能较好地完成数据采集、处理及结果评估。但是,TSP系统数据存储未采用SEG统一标准格式,也未公开数据格式,用户针对TSP数据处理开发的软件较少。针对这种情况,提出基于纵波资料的隧洞前方地质异常体的快速识别方法:采用小波变换对纵波信号进行时变高截滤波,消除时变的高频干扰;利用剪切波变换较好的时频聚集性和方向表征性来分离有效波,利用基于多道最大熵魏格纳-威尔分布改进方法获取TSP纵波资料高精度时频谱;对高精度时频谱提取各采样点的振幅对数衰减梯度,实现掌子面前方地质异常体的快速识别。识别方法在岩体较完整的花岗岩段开展预报应用,其结果显示存在频率异常峰值,与隧道开挖揭示花岗岩富水张性节理发育一致,说明识别方法简单有效,值得进一步推广。

青海东部农区引进燕麦品种各器官C、N、P生态化学计量学特征变化研究

以4个引种燕麦(Avena sativa)为典型代表,对其不同生育时期根、茎、叶中的C、N、P含量及其化学计量学特征进行测定,探讨不同生育时期燕麦C、N、P元素含量及其化学计量比的变化规律,为燕麦饲草的科学收获提供理论依据。结果表明:燕麦全株C、N、P含量分别为322.30~333.97、17.42~75.62、2.74~5.42 mg·g^(-1),燕麦根C、N、P含量分别为298.42~317.92、11.47~73.71、2.82~3.42 mg·g^(-1),燕麦茎C、N、P含量分别为311.25~338.86、10.15~75.16、2.44~5.06 mg·g^(-1),燕麦叶C、N、P含量分别为330.80~372.47、30.64~113.80、2.59~8.65 mg·g^(-1);各器官间C、N、P含量表现为叶>茎>根。此外,燕麦各器官C、N、P含量的积累过程具有一定季节特征,C含量积累过程受生育时期影响较小,表现出较强的稳定性;而N和P含量的积累过程受生育时期影响较大,其在拔节期~抽穗期均高于开花期~乳熟期。燕麦各器官C∶N、C∶P和N∶P分别为4.42~24.44、70.72~124.56和6.56~17.28,其中C∶N、C∶P在开花期~乳熟期均高于拔节期~抽穗期;N∶P则规律相反。