Mathematica在物理化学公式可视化中的应用

随着计算机技术的快速发展,软件工具在化学教学和研究中的作用日益凸显。本文以Mathematica软件为例,探讨了其在物理化学公式可视化中的应用。借助几个典型的例子,如范德华状态方程、原子轨道与电子云形状以及化学反应速率方程的可视化,为物理化学的教学和研究提供新的视角和方法。通过互动式的学习模式,学生不仅能够通过直观的图形来观察和理解理论背后的物理意义,还能激发他们的兴趣,增强学生学习的主动性和创造性。

报国赤心·守正创新·倾心育新——电动势法测定化学反应热力学函数实验的课程思政设计

课程思政的有效融入是教学质量提升和高素质人才培养的关键。我们以“电动势法测定化学反应的热力学函数”这一实验项目为例,构建了一次深入的实验探究与思政教育相结合的教学实践活动。通过对电动势测定原理和方法的探讨以及反应热力学量的导出,学生们不仅深化了对相关基础理论知识的理解,提升了他们解决实际问题的实验技能和创新能力;同时强化了学生的家国情怀以及责任担当意识。

Analysis and Application of Endogenous Wireless Security Principle for Key Generation

The open and broadcast nature of wireless channels leads to the inherent security problem of information leakage in wireless communication.We can utilize endogenous security functions to resolve this problem.The fundamental solution is channel-based mechanisms,like physical layer secret keys.Unfortunately,current investigations have not fully exploited the randomness of wireless channels,making secret key rates not high.Consequently,user data can be encrypted by reducing the data rate to match the secret key rate.Based on the analysis of the endogenous wireless security principle,we proposed that the channel-based endogenous secret key rate can nearly match the maximum data rate in the fast-fading environments.After that,we validated the proposition in an instantiation system with multiple phase shift keying(MPSK)inputs from the perspectives of both theoretical analysis and simulation experiments.The results indicate that it is possible to accomplish the onetime pad without decreasing the data rate via channelbased endogenous keys.Besides,we can realize highspeed endogenously secure transmission by introducing independent channels in the domains of frequency,space,or time.The conclusions derived provide a new idea for wireless security and promote the application of the endogenous security theory.

Metastable-phaseβ-Fe_(2)O_(3) photoanodes for solar water splitting with durability exceeding 100 h

Planar films of pure and Ti^(4+)-dopedβ-Fe_(2)O_(3)were prepared by a spray pyrolysis method.X-ray diffraction patterns and Raman spectra of the metastableβ-Fe_(2)O_(3)film showed that its thermal stability was significantly improved because of covalent bonds in the interfaces between the film and substrate,while only weak Van der Waals bonds existed at the interfaces within the particle-assembledβ-Fe_(2)O_(3)film prepared by electrophoretic deposition.The as-prepared planar films were thus able to withstand higher annealing temperature and stronger laser irradiation power in comparison with theβ-Fe_(2)O_(3)particle-assembly.Ti^(4+)doping was used to increase the concentration of carriers in the metastableβ-Fe_(2)O_(3)film.Compared with pureβ-Fe_(2)O_(3)photoanodes,the highest saturated photocurrent for water splitting over the Ti^(4+)-dopedβ-Fe_(2)O_(3)photoanode was increased by a factor of approximately three.Theβ-Fe_(2)O_(3)photoanode exhibited photochemical stability for water splitting for a duration exceeding 100 h,which indicates its important potential application in solar energy conversion.

A Physical Layer Authentication Mechanism for IoT Devices

When Internet of Things(IoT)nodes access the network through wireless channels,the network is vulnerable to spoofing attacks and the Sybil attack.However,the connection of massive devices in IoT makes it difficult to manage and distribute keys,thus limiting the application of traditional high-level authentication schemes.Compared with the high-level authentication scheme,the physical layer authentication scheme realizes the lightweight authentication of users by comparing the wireless channel characteristics of adjacent packets.However,traditional physical layer authentication schemes still adopt the one-to-one authentication method,which will consume numerous network resources in the face of large-scale IoT node access authentication.In order to realize the secure access authentication of IoT nodes and regional intrusion detection with low resource consumption,we propose a physical layer authentication mechanism based on convolution neural network(CNN),which uses the deep characteristics of channel state information(CSI)to identify sending nodes in different locations.Specifically,we obtain the instantaneous CSI data of IoT sending nodes at different locations in the pre-set area,and then feed them into CNN for training to procure a model for IoT node authentication.With its powerful ability of data analysis and feature extraction,CNN can extract deep Spatio-temporal environment features of CSI data and bind them with node identities.Accordingly,an authentication mechanism which can distinguish the identity types of IoT nodes located in different positions is established to authenticate the identity of unknown nodes when they break into the pre-set area.Experimental results show that this authentication mechanism can still achieve 94.7%authentication accuracy in the case of a low signalto-noise ratio(SNR)of 0 dB,which means a significant improvement in authentication accuracy and robustness.

A multi-objective train-scheduling optimization model considering locomotive assignment and segment emission constraints for energy saving

Energy saving and emission reduction for railway systems should not only be studied from a technical perspective but should also be focused on management and economics. On the basis of relevant trainscheduling models for train operation management, in this paper we introduce an extended multi-objective trainscheduling optimization model considering locomotive assignment and segment emission constraints for energy saving. The objective of setting up this model is to reduce the energy and emission cost as well as total passenger- time. The decision variables include continuous variables such as train arrival and departure time, and binary vari- ables such as locomotive assignment and segment occu- pancy. The constraints are concerned with train movement, trip time, headway, and segment emission, etc. To obtain a non-dominated satisfactory solution on these objectives, a fuzzy multi-objective optimization algorithm is employed to solve the model. Finally, a numerical example is performed and used to compare the proposed model with the existing model. The results show that the proposed model can reduce the energy consumption, meet exhausts emission demands effectively by optimal locomotive assignment, and its solution methodology is effective.

Secure Spectral-Energy Efficiency Tradeoff in RandomCognitive Relay Networks

Spectral efficiency(SE) and energy efficiency(EE) in secure communications is of primary importance due to the fact that 5 G wireless networks aim to achieve high throughput,low power consumption and high level of security.Nevertheless,maximizing SE and EE are not achievable simultaneously.In this paper,we investigate the SE and EE tradeoff for secure transmission in cognitive relay networks where all nodes are randomly distributed.We first introduce the opportunistic relay selection policy,where each primary transmitter communicates with the primary receiver with the help of a secondary user as a relay.Then,we evaluate the secure SE and secure EE of the primary network based on the outage probabilities analysis.Thirdly,by applying a unified SE-EE tradeoff metric,the secure SE and EE tradeoff problem is formulated as the joint secure SE and EE maximization problem.Considering the non-concave feature of the objective function,an iterative algorithm is proposed to improve secure SE and EE tradeoff.Numerical results show that the opportunistic relay selection policy is always superior to random relay selection policy.Furthermore,the opportunistic relay selection policy outperforms conventional direct transmission policy when faced with small security threat(i.e.,for smaller eavesdropper density).

Amphotericin B release rate is the link between drug status in the liposomal bilayer and toxicity

Amphotericin B(AmB)is an amphiphilic drug commonly formulated in liposomes and administered intravenously to treat systemic fungal infections.Recent studies on the liposomal drug product have shed light on the AmB aggregation status in the bilayer,which heat treatment(curing)modifies.Although toxicity was found related to aggregation status-loose aggregates significantly more toxic than tight aggregates-the precise mechanism linking aggregation and toxicitywas notwell understood.This study directlymeasured drug release rate fromvarious AmB liposomal preparations made with modified curing protocols to evaluate correlations among drug aggregation state,drug release,and in vitro toxicity.UV–Vis spectroscopy of these products detected unique curing-induced changes in the UV spectral features:a∼25nm blue-shift of the main absorption peak(λ_(max))in aqueous buffer and a decrease in the OD_(346)/OD_(322) ratio upon thermal curing,reflecting tighter aggregation.In vitro release testing(IVRT)data showed,by applying and fitting first-order release kinetic models for one or two pools,that curing impacts two significant changes:a 3–5-fold drop in the overall drug release rate and a ten-fold decrease in the ratio between the loosely aggregated and the tightly aggregated,more thermodynamically stable drug pool.The kinetic data thus corroborated the trend independently deduced from the UV–Vis spectral data.The in vitro toxicity assay indicated a decreased toxicity with curing,as shown by the significantly increased concentration,causing half-maximal potassium release(TC50).The data suggest that the release of AmB requires dissociation of the tight complexes within the bilayer and that the reduced toxicity relates to this slower rate of dissociation.This study demonstrates the relationship between AmB aggregation status within the lipid bilayer and drug release(directly measured rate constants),providing a mechanistic link between aggregation status and in vitro toxicity in the liposomal formulations.

Application of teleseismic tomography to the study of shallow structure beneath Shizigou in the western Qaidam basin

Teleseismic body wave traveltime tomography is used to inverse the three-dimensional seismic velocity structure beneath Shizigou in the western Qaidam basin. The travel time are picked from the continuous observation data on a small seismic array of stations deployed during 2004-2007. The tomographic results obtained indicate that a NW-trending low velocity anomaly just beneath the target region insert northeastwards with a high dip angle. In the north, northeast and east of the low velocity anomaly, some high-velocity anomalies distribute with the same strike and coverage as those of Shizigou anticline.

Physical-Layer Key Generation Based on Multipath Channel Diversity Using Dynamic Metasurface Antennas

Physical layer key generation(PKG)technology leverages the reciprocal channel randomness to generate the shared secret keys.The low secret key capacity of the existing PKG schemes is due to the reduction in degree-of-freedom from multipath fading channels to multipath combined channels.To improve the wireless key generation rate,we propose a multipath channel diversity-based PKG scheme.Assisted by dynamic metasurface antennas(DMA),a two-stage multipath channel parameter estimation algorithm is proposed to efficiently realize super-resolution multipath parameter estimation.The proposed algorithm first estimates the angle of arrival(AOA)based on the reconfigurable radiation pattern of DMA,and then utilizes the results to design the training beamforming and receive beamforming to improve the estimation accuracy of the path gain.After multipath separation and parameter estimation,multi-dimensional independent path gains are utilized for generating secret keys.Finally,we analyze the security and complexity of the proposed scheme and give an upper bound on the secret key capacity in the high signal-to-noise ratio(SNR)region.The simulation results demonstrate that the proposed scheme can greatly improve the secret key capacity compared with the existing schemes.

A new scheme of climate-vegetation regionalization in the Hengduan Mountains Region

The Hengduan Mountains Region(HMR) is essential for the future ecological protection, clean energy production,Sichuan-Xizang and Yunnan-Xizang railways, and other major infrastructure projects in China. The distributions of climate and vegetation exhibit significant regional differentiation and vertical zonality due to the rugged longitudinal ranges and gorges and the complex disaster-prone environments in HMR. Therefore, it is urgent to develop the climate-vegetation regionalization in HMR to effectively satisfy the national requirements such as agricultural production and ecological protection, mountain disaster risk prevention, and major project construction. We here develop a new scheme of climate-vegetation regionalization with the latest demarcation outcome of HMR, the ground observation from 122 meteorological stations in HMR and its surrounding areas during 1990–2019, and the high-precision remote sensing data of land cover types. The new scheme first constructs the regionalization index system, fully considering the extraordinarily complicated geomorphic pattern of mountains and valleys, the scarcity of meteorological observations, and the remarkable differentiation of climate and vegetation in HMR. The system consists of three primary regionalization indices(i.e., days with daily average temperature steady above 10°C, aridity index, and main vegetation types, dividing the temperature zones, moisture regions, and vegetation subregions, respectively) and three auxiliary indices of the accumulated temperature above 10°C, and the temperatures in January and July. Then, the HMR is divided into five temperature zones, 20 moisture regions, and 55 vegetation subregions. Compared with previous regionalization schemes, the new scheme optimizes the climate spatial interpolation model of thin plate smoothing spline suitable for the unique terrain in HMR. Moreover, the disputed division index threshold between different climatic zones(regions) is scientifically clarified using geographical detectors. Specifically, the stepwise downscaling pane division method is initially proposed to determine the zoning boundary, alleviating the excessive dependence of the traditional zoning method on subjective experience.Besides, the scheme considers the typical regional characteristics of the complex underlying surface and the high gradient zone of climate-vegetation distribution types in HMR. Consequently, the transition zone with quick climate changes between the plateau temperate and mid-subtropical zones is divided into mountainous subtropics, taking into account the spatial distribution characteristics of climate-vegetation regionalization indices. The regionalization scheme will provide practically theoretical support for agricultural production, ecological protection, major project construction, disaster prevention and relief efforts, and other socioeconomic activities in HMR, serving as a classic case of climate-vegetation regionalization for the alpine and canyon regions with intricate underlying surface, striking regional differences, and lack of ground observations.

Composite Braking Control Strategy for Electromechanical-Hydraulic Vehicles

Short driving ranges and low braking energy recovery efficiencies are two recognized technical bottlenecks to be overcome in electric vehicles. In this paper, a novel electromechanical-hydraulic coupling system is proposed and integrated as a powertrain for electric vehicles, which can assist the electric vehicle to fully utilize its braking energy. The hydraulic regenerative braking force and electric regenerative braking force can provide all the braking needs using the medium and small braking intensities. Furthermore, an improved compound brake control strategy based on the braking force distribution is proposed and simulated. The results show that under the premise of ensuring braking stability, the electromechanical-hydraulic coupling driving electric vehicle can adapt to various working conditions with excellent energy-saving results. The hydraulic accumulator recovery efficiency is above 99%, and the state of charge consumption rate of the battery pack can be reduced by more than 9%. More importantly, the proposed hybrid power system can significantly improve the driving range and energy efficiency, as well as reduce the consumers' mileage anxiety in electric vehicles.

Global status and trends in hepatitis B virus DNA mutation research from 2003 to 2022:A comprehensive bibliometric view

Aims:Hepatitis B virus(HBV)is an enveloped DNA virus belonging to the Hepadnaviridae family.It is a significant contributor to the prevalence of chronic liver disease on a global scale.Mutations in HBV DNA can affect the diagnosis,treatment,and prognosis of patients with chronic hepatitis B.Although numerous studies on HBV DNA mutations have been conducted,few bibliometric studies have been performed to date.This study aimed to analyze changes in scientific output to gain a better understanding of the current research status and identify potential new research directions in the field of HBV DNA mutation.Methods:Relevant studies published between 2003 and 2022 were retrieved from the Web of Science Core Collection database.CiteSpace version 6.1.R6 was used to construct network maps to evaluate collaborations among countries,institutions,authors,journals,and keywords.Results:In total,1508 publications over the past 20 years were obtained,mainly from China,the United States,and Japan.The major research institutions in China included the University of Hong Kong,Fudan University,and Peking University.Lai Ching Lung was the most productive author,whereas Anna Suk-Fong Lok was the most frequently co-cited author.The keyword“HBsAg”was the strongest burst keyword in recent years,indicating possible future study trends.Conclusions:This bibliometric analysis intuitively revealed the overall research status of HBV DNA mutations,providing valuable information for researchers,funding agencies,and policymakers to explore the current research status,research hotspots,and new directions for future research.

A Novel Algorithm for Streamlining Diagnosis of Advanced Liver Fibrosis in CHB Patients with Concurrent Hepatic Steatosis

Citation of this article:Xu X,Rui F,Ni W,Wu C,Shi J,Li J.A Novel Algorithm for Streamlining Diagnosis of Advanced Liver Fibrosis in CHB Patients with Concurrent Hepatic Steatosis.J Clin Transl Hepatol 2024;12(2):222–226.doi:10.14218/JCTH.2023.00362.Chronic hepatitis B(CHB)with concurrent hepatic steatosis(HS)is a growing challenge for public health globally.

6G无线内生安全理念与构想

6G开放融合、异构共存、智能互联的网络特点将引发更多未知复杂安全威胁,目前安全滞后于通信发展的格局必然难以应对,6G时代必须打破思维定势,催生真正具有代际效应的标志性技术.内生安全从无线网络内源性缺陷产生的共性和本源安全问题出发,通过结构导向的解决方法,具有抵御未知安全威胁的能力和通信/安全/服务内源性融合的能力.本文对6G无线网络内生安全问题、理念进行了探讨,并提出内生安全在6G超高速宽带通信、超大连接超低时延、天地一体化全域覆盖等典型场景中的应用构想,给出了若干潜在关键技术和解决方案.

Simulation of permafrost changes on the Qinghai–Tibet Plateau, China, over the past three decades

Permafrost is one of the largest elements of the terrestrial cryosphere and is extremely sensitive to climate change.Based on mean annual ground temperature(MAGT)data from 189 boreholes on the Qinghai–Tibet Plateau(QTP),terrain factors,and climate data from China Meteorological Forcing Dataset,we propose a new mean annual ground air temperature(MAGAT)statistical model between meteorological parameters with subsurface temperatures to simulate permafrost distribution and variation of MAGT on the QTP over the past three decades(1981–2010).Validation of the model with MAGT data from 13 boreholes and permafrost maps of the QTP indicated that the MAGAT model is applicable to simulate the distribution and evolution of permafrost on the QTP.Simulation results show that the spatiotemporal MAGT of permafrost significantly increased by 0.37℃,or 0.25℃/10 yr,and the total area of permafrost decreased by 2.48×10^(5)km^(2) on the QTP over the past three decades.Regionally,the changes of permafrost in the southwestern QTP were greater than other regions of the QTP.

H_(2)预处理增强CuO_(x)/CeO_(2)协同等离子体催化氧化CO的作用机制

一氧化碳(CO)对公众健康和环境都会造成严重危害,低温工况下CO的催化氧化是目前的研究热点之一.低温等离子体(non-thermal plasma,NTP)催化技术在该领域具备独特优势.本研究采用等体积浸渍法制备了CuO_(x)/CeO_(2)催化剂,并对催化剂进行了H_(2)预处理,比较研究了不同湿度条件下NTP催化体系中各类铜铈催化剂催化氧化CO的性能,并探讨了氢气预处理对催化剂的影响及作用机制.结果表明,H_(2)预处理可以增加CuO_(x)/CeO_(2)催化剂NTP氧化CO的活性,同时抑制副产物O_(3)和NO_(x)的排放;其作用机制与催化剂表面Cu^(+)活性位点与氧空位的增加有关.本研究揭示了氢气预处理对NTP协同CuO_(x)/CeO_(2)催化氧化CO的影响,对开发低温等离子体催化系统下多功能催化剂具有一定的参考价值.

Development background of Mesozoic high-quality source rocks: Evidence from microfossils in North Carnarvon Basin, Australia

Based on numerous microfossils in Mesozoic of North Carnarvon Basin in Australia,the Mesozoic paleoclimate and paleoenvironment were analyzed,the paleogeographic background and development model of Mesozoic high-quality source rocks were investigated and discussed.Variation of microfossil species and their relative contents in Mesozoic different intervals indicates changes of paleoclimate and paleoenvironment.The paleoclimate shows a cycle variation of aridehumidearidehumid,the regression occurred in the Early TriassiceLate Triassic and the transgression occurred in the Late TriassiceLate Cretaceous.Four sedimentary facieses including delta facies,littoral facies,restricted sea facies and open sea facies were developed in the Mesozoic.The open sea was mainly developed in the Early Triassic,the delta was distributed in the MiddleeLate Triassic,the restricted sea was especially well developed in the Jurassic,and the restricted sea and open sea were mainly distributed in the Cretaceous.Characteristics of microfossil assemblage in these four sedimentary facies are dramatically different.From the delta facies,littoral facies,restricted sea facies to open sea facies,content of pollen gradually decreases,but content of the dinoflagellate+acritarch gradually increases.The delta facies and littoral facies are dominated by the pollen.In the restricted sea facies,content of the pollen is equivalent to that of the dinoflagellate+acritarch.The open sea facies is dominated by the dinoflagellate and acritarch.Supply of sediment and formation of organic matter are influenced by the paleoclimate and paleoenvironment,and type of organic matter is controlled by the microfossil assemblage.Based on the palaeogeographic background,paleoclimatic condition and microfossil assemblage,two developmental models of the Mesozoic source rocks such as the development model of terrestrial organic matter under the background of large delta and the development model of mixed organic matter under the background of the restricted sea,were proposed.

Some Properties of Tracially Quasidiagonal Extensions

Suppose that 0→ I→ A→ A/I→ 0 is a tracially quasidiagonal extension of C*-algebras. In this paper, the authors give two descriptions of the K_0, K_1 index maps which are induced by the above extension and show that for any ∈ > 0, any τ in the tracial state space of A/I and any projection p ∈ A/I(any unitary u ∈ A/I), there exists a projection p ∈ A(a unitary u ∈ A) such that |τ(p)-τ(π(p))| < ∈(|τ(u)-τ(π(u))| < ∈).

Porous yolk-shell structured Na_(3)(VO)_(2)(PO_(4))_(2)F microspheres with enhanced Na-ion storage properties

Na_(3)(VO)_(2)(PO_(4))_(2)F(NVPOF)has been considered as one potential candidate for sodium-ion batteries because of its high operating voltage and theoretical capacity.However,the poor intrinsic electronic conductivity significantly restricts its widespread application.In response to this drawback,we adopt the optimization strategy of tuning the morphology and structure to boost the electrical conductivity and mitigate the capacity fading.In this paper,NVPOF microspheres with unique porous yolk-shell structure were fabricated via a facile one-step solvothermal method for the first time.By monitoring the morphological evolution with time-dependent experiments,the self-sacrifice and Ostwald ripening mechanism from rough spheres to yolk-shell structure was revealed.Benefited from the favorable interwoven nanosheets shell,inner cavity and porous core structure,the resulting NVPOF electrode exhibits superior rate capability of 63 m A h g^(-1)at 20 C as well as outstanding long-cycling performance with the capacity retention up to 92.1%over 1000 cycles at 5 C.