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Oases and deserts generally act as a landscape matrix and mosaic in arid/semiarid regions. The significant difference of thermal and dynamic characteristics between oasis and desert surface will result in oasis-desert interaction. That is, the interaction between oasis and desert system through the exchange of momentum, energy, water and carbon, which can lead to a series of microclimate effects that affect the structure of the atmospheric boundary layer, changes of carbon sources/sinks in oasis and the local ecological environment. Therefore, studying water, heat and carbon exchange is significant for achieving the goals of carbon peaking and carbon neutrality in oasis-desert areas and supporting the ecological security and sustainable development of oases. To monitor energy, water vapor and carbon exchange between the land surface and atmosphere, a land surface process integrated observatory was established in the oasis-desert area in the middle and lower reaches of the Heihe River Basin, the 2nd largest endorheic basin in China. In this study, we present a suite of observational datasets in artificial and natural oases-desert systems, which consist of long-term energy, water vapor, carbon/methane fluxes, and auxiliary data involving hydrometeorology, vegetation and soil parameters from 2012 to 2021. Half-hourly turbulent flux data were acquired by an eddy covariance system and scintillometer. The hydrometeorological data, including radiation, soil heat flux and soil temperature profile, gradient of air temperature/humidity and wind speed/direction, air pressure, precipitation and soil moisture profiles, were observed from automatic weather stations with a 10-minute average period as well as the groundwater table data. Moreover, vegetation and soil parameters were also supplemented in the datasets. Careful data processing and quality control are implemented during data production, including data collection, processing, archiving and sharing. The current datasets can be used to explore the water-heat-carbon process and its influence mechanism, calibrate and validate related remote sensing products, simulate energy, water vapor and carbon exchange in oasis and desert areas, and provide references and representatives for other similar artificial and natural oases along the Silk Road. The datasets are available from the National Tibetan Plateau Third Pole Environment.

The traditional Thevenin equivalent Modular Multilevel Converter (MMC) model has poor versatility for the two working conditions of pre-charging and DC-side faults. In this paper, an improved Thevenin equivalent MMC model considering pre-charge conditions and DC side fault conditions is proposed. The model divides the pre-charging condition into a Controllable charging stage and an Uncontrollable charging stage. The DC-side fault condition is divided into the pre-blocking and post-blocking conditions of the converter. The circuit characteristics are analyzed, and the equivalent model topology is comprehensively improved to make it suitable for full-condition simulation, and a control strategy suitable for the equivalent model is proposed. The detailed model and the proposed improved equivalent model were built in PSCAD/EMTDC for comparison and analysis. The simulation results shows that the improved equivalent model can be applied to various working conditions, and the versatility of the traditional Thevenin equivalent model is improved.

Constructing a heterojunction photocatalyst is a significant method to enhance photocatalytic activity because it can promote the separation of photogenerated carriers. Herein, amorphous/crystalline contact Bi2S3/Bi4O7 heterostructure was successfully synthesized by in-situ sulfidation of Bi4O7. The amorphous Bi2S3 is diffused on the surface of Bi4O7 rod, enhancing the visible light response and improving the transport of photogenerated carriers. Various characterizations confirm that the rapid separation of photogenerated carriers leads to increased photocatalytic performance. The optimized Bi2S3/Bi4O7 heterostructure photocatalyst (BiS-0.15) exhibits the highest Cr(VI) reduction (0.01350 min−1) and RhB oxidation (0.08011 min−1) activity, which is much higher than that of pure Bi4O7 and Bi2S3/Bi4O7 mixture under visible light irradiation. This work provides new insights into the construction of efficient novel photocatalysts.

Tao Jiang,1,* Qianyun Li,1,* Jinmei Qiu,2 Jing Chen,1 Shuang Du,2 Xiang Xu,1 Zihan Wu,1 Xiaofan Yang,1 Zhenbing Chen,1 Tongkai Chen2 1Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China; 2Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Zhenbing Chen, Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Ave, Wuhan, 430022, People’s Republic of China, Tel +86 13871103730, Email zbchen@hust.edu.cn Tongkai Chen, Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, 12 Jichang Road, Guangzhou, 510405, People’s Republic of China, Tel +86 20 36585707, Email chentongkai@gzucm.edu.cnAbstract: Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.Keywords: nanobiotechnology, chronic wound healing, scaffold systems, cell-carrying systems, stimuli-responsive systems

Additional file 1: Table S1. The sequences of siRNAs.

Additional file 1: Figure S1. Compressive behavior of GelMA/PEGDA hydrogel. Figure S2. SEM images of hydrogel after concentrated. Scale bar = 200 ��m (a, b, c, g, h, i), scale bar = 100 ��m (d, e, f, j, k, l). Figure S3. Biocompatibility of the degradation products of GelMA/PEGDA hydrogel. a Survival ratio of fibroblasts, HUVECs, HaCAT treated with the degradation products of GelMA/PEGDA hydrogel after 7, 14 days, scale bar: 100 ��m. b Cell viability was determined by CCK8 assay. *p

Groundwater-surface water (GW-SW) interaction, as a key component in the cold region hydrologic cycle, is extremely sensitive to seasonal and climate change. Specifically, the dynamic change of snow cover and frozen soil bring additional challenges in observing and simulating hydrologic processes under GW-SW interactions in cold regions. Integrated hydrologic models are promising tools to simulate such complex processes and study the system behaviours as well as its responses to perturbations. The cold region integrated hydrologic models should be physically representative and fully considering the thermal-hydrologic processes under snow cover variations, freeze-thaw cycles in frozen soils and GW-SW interactions. Benchmarking and integration with scarce field observations are also critical in developing cold region integrated hydrologic models. This review summarizes the current status of hydrologic models suitable for cold environment, including distributed hydrologic models, cryo-hydrogeologic models, and fully-coupled cold region GW-SW models, with a specific focus on their concepts, numerical methods, benchmarking, and applications across scales. The current research can provide implications for cold region hydrologic model development and advance our understanding of altered environments in cold regions disturbed by climate change, such as permafrost degradation, early snow melt and water shortage.

Superatomic crystal is a class of hierarchical materials composed of atomically precise clusters assembled via van der Waals or covalent-like interactions. AuTe$_2$Se$_{4/3}$, an all-inorganic superatomic superconductor exhibiting superatomic-charge-density-wave (S-CDW), provides a first platform to study the response of their collectively quantum phenomenon to the external pressure in superatomic crystals. We reveal a competition between S-CDW and superconductivity using cutting-edge measurements on thin flakes at low pressures. Prominently, the pressure modulation of S-CDW ordering is 1$\sim$2 order of magnitudes (0.1 GPa) lower than that of conventional atomic superconductors. As pressure increases to 2.5 GPa, the $T_{\mathrm{CDW}}$ is suppressed and the superconducting transition temperature ($T_{\mathrm{c}}$) is firstly enhanced, and reaches the maximum then quenches with increasing pressure. Above 7.3 GPa, a second superconducting phase emerges, and then a three-fold enhancement in the transition temperature ($T_{\mathrm{c}}$) happens. Analyses of the crystal structure and theoretical calculations suggest a pressure-mediated switch of the conduction channel from the $a$- to the $b$-axis occur, followed by a dimensional crossover of conductivity and the Fermi surface from 2D to 3D., 6 pages, 4 figures

Chengqi Yan,1 Jing Chen,1 Xiaofan Yang,1 Wenqing Li,2 Renqun Mao,2 Zhenbing Chen1 1Department of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, People’s Republic of China; 2Department of Hand and Foot Surgery, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, Guangdong, People’s Republic of ChinaCorrespondence: Zhenbing ChenDepartment of Hand Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, People’s Republic of ChinaTel +86 13871103730Fax +86 2785351628Email zbchen@hust.edu.cnAbstract: Diabetes mellitus is one of the most widespread metabolic diseases in the world, and diabetic foot ulcer (DFU), as one of its chronic complications, not only causes a large amount of physiological and psychological pain to patients but also places a tremendous burden on the entire economy and society. Despite significant advances in knowledge on the mechanism and in the treatment of DFU, clinical practice is still not satisfactory, and our understanding of its cellular and molecular pathogenesis is far from complete. Fortunately, progress in studying the roles of long non-coding RNAs (lncRNAs), which play important regulatory roles in the expression of genes at multiple levels, suggests that we can apply them in the early diagnosis and potential targeted intervention of DFU. In this review, we briefly summarize the current knowledge regarding the functional roles and potential mechanisms of reported lncRNAs in regulating DFU.Keywords: diabetic foot ulcer, long non-coding RNAs, diabetes mellitus, wound healing

Additional file 1: Table S1–S4. Primers used for real-time polymerase chain reaction. Table S5. Sequences of mimics and inhibitors.

Additional file 2: Figure S1. This figure illustrated the negative results of Fig. 7. The selected mRNAs, lncRNAs and circRNAs without significant difference by PCR analyses were shown in (A, B). (C, D) The correlation analysis found the expression level of miR-145-5p was not significantly correlated with the expression levels of LOC102723591 and hsa_circ_0092630.

International audience; Certains composants structuraux en acier situés dans la partie secondaire des centrales nucléaires REP (Réacteurs à Eau Pressurisée) sont soumis à un phénomène de corrosion atmosphérique en milieu confiné affectant leur fond par la surface externe. Pour l'un d'entre eux (il s'agit d'une bâche), plusieurs campagnes de mesures d'épaisseur du fond de la bâche sont disponibles au cours du temps sur une population de points de mesure. Il est possible d'évaluer, à partir de ces mesures, une distribution de cinétique de perte d'épaisseur et, en chaque point de mesure, une distribution d'épaisseur résiduelle au cours du temps, et un risque de sous-épaisseur. En cumulant ces risques individuels, on obtient un risque global de sous-épaisseur au cours du temps. En imposant une limite à ce risque, on en déduit un nombre de points à réparer (patcher). C'est cette approche probabiliste prévisionnelle pour la maintenance qui est détaillée dans cet article, tant sur le plan méthodologique qu'industriel.

The effect of ceria abrasive compound with zirconia and silica on polishing performance of SiO2 dielectric was studied. The results show that adding zirconia and silica to the ceria slurry can improve the polishing performance of SiO2 dielectric. When the mass ratio of ceria and zirconia is 4:3, the material removal rate (MRR) of SiO2 dielectric is increased to 218.6 nm min−1 at pH 3. Meanwhile, under the same pH, when the ratio of ceria to silica is 2:1, the MRR of SiO2 dielectric is 228.8 nm min−1. But the MRR reaches the highest at pH 5, the MRR of SiO2 dielectric reached 477.7 nm min−1 after the combination of ceria and zirconia, and 538.2 nm min−1 after the composite of ceria and silica. With the increase of the average particle size of silica, the MRR of SiO2 dielectric increases gradually. When the silica particle size is 80 nm, the MRR of SiO2 dielectric is the highest of 538.2 nm min−1. When using PL-3 instead of alkaline silica to verify the polishing rate of TEOS dielectric and Si3N4, the removal rate of TEOS dielectric reached 1080.6 nm min−1, the removal rate of Si3N4 was only 91.9 nm min−1, and the removal rate selectivity was 11.75:1. At the same time, the surface roughness of SiO2 dielectric is also decreased after the abrasive mixture.

Jamming identification is the precondition of taking targeted anti-jamming measures, and it is very important to improve the adaptability of electronic information system to electromagnetic environment. The traditional recognition method of jamming is based on the feature extraction based on expert knowledge, but due to the jamming pattern diversity and different parameter, in practice it is difficult to determine the appropriate feature set. Therefore, this paper introduces a deep learning approach, which automatically extracts features from the original data to identify the jamming factors of electronic information system. In order to demonstrate the effectiveness and practicability of this approach, the noise jamming factor identification of the superheterodyne receiver is introduced.

Background: The cellular form of the prion protein (PrPC) is implicated in Alzheimer disease as a receptor for amyloid-β (Aβ). Results: An assay was developed capable of identifying inhibitors of Aβ binding to PrPC. Conclusion: Chicago Sky Blue inhibits Aβ binding to PrPC. Significance: This is the first small molecule shown to disrupt the binding of Aβ to PrPC., The prion protein (PrP) has been implicated both in prion diseases such as Creutzfeldt-Jakob disease, where its monomeric cellular isoform (PrPC) is recruited into pathogenic self-propagating polymers of misfolded protein, and in Alzheimer disease, where PrPC may act as a receptor for synaptotoxic oligomeric forms of amyloid-β (Aβ). There has been considerable interest in identification of compounds that bind to PrPC, stabilizing its native fold and thereby acting as pharmacological chaperones to block prion propagation and pathogenesis. However, compounds binding PrPC could also inhibit the binding of toxic Aβ species and may have a role in treating Alzheimer disease, a highly prevalent dementia for which there are currently no disease-modifying treatments. However, the absence of a unitary, readily measurable, physiological function of PrP makes screening for ligands challenging, and the highly heterogeneous nature of Aβ oligomer preparations makes conventional competition binding assays difficult to interpret. We have therefore developed a high-throughput screen that utilizes site-specifically fluorescently labeled protein to identify compounds that bind to PrP and inhibit both Aβ binding and prion propagation. Following a screen of 1,200 approved drugs, we identified Chicago Sky Blue 6B as the first small molecule PrP ligand capable of inhibiting Aβ binding, demonstrating the feasibility of development of drugs to block this interaction. The interaction of Chicago Sky Blue 6B was characterized by isothermal titration calorimetry, and its ability to inhibit Aβ binding and reduce prion levels was established in cell-based assays.

This paper addresses the issue of suppressing a rumor using the truth in a cost-effective way. First, an individual-level dynamical model capturing the rumor-truth mixed spreading processes is proposed. On this basis, the cost-effective rumor-containing problem is modeled as an optimization problem. Extensive experiments show that finding a cost-effective rumor-containing strategy boils down to enhancing the first truth-spreading rate until the cost effectiveness of the rumor-containing strategy reaches the first turning point. This finding greatly reduces the time spent for solving the optimization problem. The influences of different factors on the optimal cost effectiveness of a rumor-containing strategy are examined through computer simulations. We believe our findings help suppress rumors in a cost-effective way. To our knowledge, this is the first time the rumor-containing problem is treated this way.

The new cyber attack pattern of advanced persistent threat (APT) has posed a serious threat to modern society. This paper addresses the APT defense problem, i.e., the problem of how to effectively defend against an APT campaign. Based on a novel APT attack-defense model, the effectiveness of an APT defense strategy is quantified. Thereby, the APT defense problem is modeled as an optimal control problem, in which an optimal control stands for a most effective APT defense strategy. The existence of an optimal control is proved, and an optimality system is derived. Consequently, an optimal control can be figured out by solving the optimality system. Some examples of the optimal control are given. Finally, the influence of some factors on the effectiveness of an optimal control is examined through computer experiments. These findings help organizations to work out policies of defending against APTs.

This paper addressed the issue of estimating the damage caused by a computer virus. First, an individual-level delayed SIR model capturing the spreading process of a digital virus is derived. Second, the damage inflicted by the virus is modeled as the sum of the economic losses and the cost for developing the antivirus. Next, the impact of different factors, including the delay and the network structure, on the damage is explored by means of computer simulations. Thereby some measures of reducing the damage of a virus are recommended. To our knowledge, this is the first time the antivirus-developing cost is taken into account when estimating the damage of a virus.

Spreading truths and blocking rumors are two typical strategies for inhibiting rumors. In practice, a tradeoff between the two strategies, which is known as the TSRB strategy, may achieve a better cost-effectiveness. This paper is devoted to assessing the effectiveness of the TSRB strategy. For that purpose, an individual-level spreading model (the generic URQT model) capturing the interaction between a rumor and the truth is established. Under the model, a set of criteria for the dying out of a rumor is presented. These criteria capture the combined influence of the basic parameters and the network structures on the effectiveness of the TSRB strategy. Experimental results show that, when the rumor dies out, the dynamics of a simplified URQT model (the linear URQT model) fits well with the actual rumor-truth interacting process. Therefore, the generic URQT model and sometimes the linear URQT model provide a proper basis for assessing the effectiveness of the TSRB strategy., rumor spreading, truth-spreading/rumor-blocking strategy, effectiveness, individual-level spreading model, qualitative analysis of dynamical system, network structure. arXiv admin note: substantial text overlap with arXiv:1705.06604; text overlap with arXiv:1705.04818

The decentralized patch distribution mechanism holds significant promise as an alternative to its centralized counterpart. For the purpose of accurately evaluating the performance of the decentralized patch distribution mechanism and based on the exact SIPS model that accurately captures the average dynamics of the interaction between viruses and patches, a new virus-patch interacting model, which is known as the generic SIPS model, is proposed. This model subsumes the linear SIPS model. The dynamics of the generic SIPS model is studied comprehensively. In particular, a set of criteria for the final extinction or/and long-term survival of viruses or/and patches are presented. Some conditions for the linear SIPS model to accurately capture the average dynamics of the virus-patch interaction are empirically found. As a consequence, the linear SIPS model can be adopted as a standard model for assessing the performance of the distributed patch distribution mechanism, provided the proper conditions are satisfied.

As compared to the traditional advertising, the word-of-mouth (WOM) communications have striking advantages such as significantly lower cost and rapid delivery; this is especially the case with the popularity of online social networks. This paper addresses the issue of maximizing the overall profit of a WOM marketing campaign. A marketing process with both positive and negative WOM is modeled as a dynamical model knwn as the SIPNS model, and the profit maximization problem is modeled as a constrained optimization problem. The influence of different factors on the dynamics of the SIPNS model is revealed experimentally. Also, the impact of different factors on the expected overall profit of a WOM marketing campaign is uncovered experimentally. On this basis, some promotion strategies are suggested. To our knowledge, this is the first time a WOM marketing campaign is treated this way.

Based on the orthogonal experiment, the influences of grinding depth (a p), the workpiece feeding rate (v w) and the transverse regrinding value (C r) on two side-direction burr of 40Cr steel large-plane grind-hardening workpiece were investigated. The results show that, under the coupling of heat and force in the grind-hardening process, the surface metal of the workpiece metal flows toward the unconstrained direction on both sides, resulting in the formation of the burr. The grinding depth and the workpiece feeding rate become leading factors affecting the size of the burr. Moreover, the significance of three factors to the size of the burrs is as follows: the grinding depth (a p) > the workpiece feeding rate (v w) > the transverse regrinding value (C r). The result showed that the maximum size of the first-pass and the second-pass burr would increase with the increasing of the grinding depth and the transverse regrinding value in grind-hardening processes, but it decreases with the workpiece feeding rate. The optimal process parameters are a p=0.1mm, v w=0.8m/min, and C r=1mm under the experiment conditions.

Spreading truths is recognized as a feasible strategy for inhibiting rumors. This paper is devoted to assessing the effectiveness of the truth-spreading strategy. An individual-level rumor-truth spreading model (the generic URTU model) is derived. Under the model, two criteria for the termination of a rumor are presented. These criteria capture the influence of the network structures on the effectiveness of the truth-spreading strategy. Extensive simulations show that, when the rumor or the truth terminates, the dynamics of a simplified URTU model (the linear URTU model) fits well with the actual rumor-truth interplay process. Therefore, the generic URTU model forms a theoretical basis for assessing the effectiveness of the truth-spreading strategy for restraining rumors., Comment: arXiv admin note: text overlap with arXiv:1705.04818

This paper addresses the discount pricing in word-of-mouth (WOM) marketing. A new discount strategy known as the Infection-Based Discount (IBD) strategy is proposed. The basic idea of the IBD strategy lies in that each customer enjoys a discount that is linearly proportional to his/her influence in the WOM network. To evaluate the performance of the IBD strategy, the WOM spreading process is modeled as a dynamic model known as the DPA model, and the performance of the IBD strategy is modeled as a function of the basic discount. Next, the influence of different factors, including the basic discount and the WOM network, on the dynamics of the DPA model is revealed experimentally. Finally, the influence of different factors on the performance of the IBD strategy is uncovered experimentally. On this basis, some promotional measures are recommended., Comment: word-of-mouth marketing, discount strategy, marketing profit, dynamic model

As a new type of cyber attacks, advanced persistent threats (APTs) pose a severe threat to modern society. This paper focuses on the assessment of the risk of APTs. Based on a dynamic model characterizing the time evolution of the state of an organization, the organization's risk is defined as its maximum possible expected loss, and the risk assessment problem is modeled as a constrained optimization problem. The influence of different factors on an organization's risk is uncovered through theoretical analysis. Based on extensive experiments, we speculate that the attack strategy obtained by applying the hill-climbing method to the proposed optimization problem, which we call the HC strategy, always leads to the maximum possible expected loss. We then present a set of five heuristic attack strategies and, through comparative experiments, show that the HC strategy causes a higher risk than all these heuristic strategies do, which supports our conjecture. Finally, the impact of two factors on the attacker's HC cost profit is determined through computer simulations. These findings help understand the risk of APTs in a quantitative manner., Comment: advanced persistent threat, risk assessment, expected loss, attack strategy, constrained optimization

This paper is devoted to measuring the security of cyber networks under advanced persistent threats (APTs). First, an APT-based cyber attack-defense process is modeled as an individual-level dynamical system. Second, the dynamic model is shown to exhibit the global stability. On this basis, a new security metric of cyber networks, which is known as the limit security, is defined as the limit expected fraction of compromised nodes in the networks. Next, the influence of different factors on the limit security is illuminated through theoretical analysis and computer simulation. This work helps understand the security of cyber networks under APTs.

We prepared two superconducting phases, which are called “low-Tc phase” and “high-Tc phase” of (NH3)yNaxFeSe showing Tc’s of 35 and 44 K, respectively, at ambient pressure, and studied the superconducting behavior and structure of each phase under pressure. The Tc of the 35 K at ambient pressure rapidly decreases with increasing pressure up to 10 GPa, and it remains unchanged up to 22 GPa. Finally, superconductivity was not observed down to 1.4 K at 29 GPa, i.e., Tc < 1.4K. The Tc of the 44 K phase also shows a monotonic decrease up to 15 GPa and it weakly decreases up to 25 GPa. These behaviors suggest no pressure-driven high-Tc phase (called “SC-II”) between 0 and 25 GPa for the low-Tc and high-Tc phases of (NH3)yNaxFeSe, differing from the behavior of (NH3)yCsxFeSe,which has a pressure-driven high-Tc phase (SC-II) in addition to the superconducting phase (SC-I) observed at ambient and low pressures. The Tc-c phase diagram for both low-Tc and high-Tc phases shows that the Tc can be linearly scaled with c (or FeSe plane spacing), where c is a lattice constant. The reason why a pressure-driven high-Tc phase (SC-II) was found for neither low-Tc nor high-Tc phases of (NH3)yNaxFeSe is fully discussed, suggesting a critical c value as the key to forming the pressure-driven high-Tc phase (SC-II). Finally, the precise Tc-c phase diagram is depicted using the data obtained thus far from FeSe codoped with a metal and NH3 or amine, indicating two distinct Tc-c lines below c = 17.5A° .

We investigated the pressure dependence of electric transport and crystal structure of Ag-doped Bi2Se3. In the sample prepared by Ag doping of Bi2Se3, the Bi atom was partially replaced by Ag, i.e., Ag0.05Bi1.95Se3. X-ray diffraction patterns of Ag0.05Bi1.95Se3 measured at 0–30 GPa showed three different structural phases, with rhombohedral, monoclinic, and tetragonal structures forming in turn as pressure increased, and structural phase transitions at 8.8 and 24 GPa. Ag0.05Bi1.95Se3 showed no superconductivity down to 2.0 K at 0 GPa, but under pressure, superconductivity suddenly appeared at 11 GPa. The magnetic field (H) dependence of the superconducting transition temperature Tc was measured at 11 and 20.5 GPa, in order to investigate whether the pressure-induced superconducting phase is explained by either p-wave polar model or s-wave model.

This master thesis is an empirical investigation project that has been carried out in cooperation with Trustweaver AB. The purpose is to identify the key factors that influence the adoption of electronic invoicing in Chinese enterprises. A background study on global e-invoicing adoption and current e-invoicing development in China is conducted. A research model integrated by the diffusion of innovation theory, the technology, organization, and environment framework and Iacovou et al. (1995) model is postulated.The research model consists of three constructs which are technological context, organizational context and environmental and external context. Key factors that are analyzed in the research are perceived benefits and barriers, leader’s attitude, technology and financial readiness, top management support, partner and competitive pressure, government pressure, and regulatory concern. Based on the research model and the theoretical basis for each of the explanatory variables, nine hypotheses stating the relationships between the key factors and enterprises’ e-invoicing adoption intention are proposed.An online survey has been conducted and 72 responses have been collected from management of Chinese enterprises. Descriptive statistics and paired-samples T test are used to describe the values distribution and test the difference between the variables. Factor analysis and reliability test are performed to evaluate the validity of variables and assess the stability of constructs. Linear regression analysis is employed in order to examine six proposed hypotheses, i.e. the relationships between technological and organizational characteristics and enterprises’ adoption of e-invoicing.The results generally offer support for the research model and eight of the hypotheses hold while one rejects. Analysis has shown that perceived barriers, management attitude and support, technology and financial readiness are the determinant factors of e-invoicing adoption. Results also indicate that environmental and external factors strongly influence enterprises’ adoption decision, whereby government pressure and policy support have the most significant effect. The findings could be taken account to improve e-invoicing diffusion in China. Some strategies are developed in the study to promote enterprises’ adoption of e-invoicing.

Twisted hypercube-like networks (THLNs) are an important class of interconnection networks for parallel computing systems, which include most popular variants of the hypercubes, such as crossed cubes, M\"obius cubes, twisted cubes and locally twisted cubes. This paper deals with the fault-tolerant hamiltonian connectivity of THLNs under the large fault model. Let $G$ be an $n$-dimensional THLN and $F \subseteq V(G)\bigcup E(G)$, where $n \geq 7$ and $|F| \leq 2n - 10$. We prove that for any two nodes $u,v \in V(G - F)$ satisfying a simple necessary condition on neighbors of $u$ and $v$, there exists a hamiltonian or near-hamiltonian path between $u$ and $v$ in $G-F$. The result extends further the fault-tolerant graph embedding capability of THLNs., Comment: 22 pages, 26 figures, Submitted to IEEE TPDS

Molybdenum-bearing alloys are widely used in industry because of their excellent corrosion resistance. However, the role of molybdenum in passivation is a subject which has been a matter for discussion and controversy for many years. In the previous work carried out in this laboratory, Professor Castle and Dr Qiu suggested that molybdenum oxide might provide the nuclei for formation of the passive film. This hypothesis is the basis of the present work. In order to find out the evidence for the existence of the molybdenum oxide nuclei, furthermore, to establish a model of passivation for the molybdenum-bearing alloys, the passivation of molybdenum-bearing alloys are investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), especially in-situ AFM, in conjunction with SEM and TEM. During the passivation study, it was found that the chemical composition on anodically polarised surfaces varied with potential. For 516 alloy, the peak value of molybdenum in the surface is at the low potential of the passive region close to the Flade potential. Therefore, molybdenum exerts its greatest function in this potential region. A further AFM study at this potential revealed, surprisingly, that a platelet layer formed on the passivation surface. The dendritic structure on the surface of the platelets presented under the high resolution of STM, which shows the crystallization property of the platelets. These platelets are mainly composed of chromium and molybdenum oxides and they are only found in the passivation of the molybdenum-bearing alloy, so the formation of the platelets may be associated with molybdenum nucleation in passivation. The in-situ AFM studies provide the evidence for the formation and disappearance of the platelets during the passivation of molybdenum-bearing alloys, i.e. the platelets form at the early stage of passivation and they gradually merge into the passive film if they are not disturbed by the environment. Based on the above finding, the role of molybdenum in passivation is proposed as following: molybdenum oxide precipitated on the surface seeds chromium oxide to form platelets at the early stage of passivation and the formed platelet layer prohibits the dissolution of the passive species from the metal. By this way, molybdenum facilitates the formation of the passive film on alloys. Using Fe-Cr-Mo duplex stainless steels, the corrosion of molybdenum-bearing alloys are studied in HCl and the kinetics of the corrosion are traced by in-situ AFM. During corrosion, it was observed that the ferritic phase in duplex stainless steel dissolves more rapidly than the austenitic phase and the dissolution occurs on the austenite preferentially along grain boundaries, sub-grain boundaries and the planes with high energy. By switching the electrochemical condition from active dissolution to passivation and then changing it back, it is found that under the passivation condition after the active dissolution, the corrosion changes from selective dissolution of the crystallographic feature to general corrosion. This situation persists even though the electrochemical condition changes back to the active condition from the passivation condition. Since AFM is a new technique and this is one of the first attempts at applying it to a corrosion study, an in-depth explanation of the images obtained from a corroded rough surface is an important topic on which so far little work has been reported. In this study, therefore, the artifacts and the reality of the structure in AFM images obtained in the corrosion study are discussed.

In this paper, we study the behavior of positive solutions of the system of difference equations xn=A+yn−1xn−pyn−q,yn=A+xn−1xn−ryn−s,n=1,2,…, where p⩾2, q⩾2, r⩾2, s⩾2, A is a positive constant, and x1−max{p,r},x2−max{p,r},…,x0,y1−max{q,s},y2−max{q,s},…,y0 are positive real numbers.

In this paper, we study the boundedness, persistence, and global asymptotic stability of positive solutions of the system of two difference equations xn+1=A+yn−mxn,yn+1=A+xn−myn,n=0,1,…, where A>0.