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The thermal deformation behavior of a novel CrFeNiSi0.15medium entropy alloy (MEA) was studied via isothermal compression experiments, with the processing parameter range of 900–1200 °C and 0.001–1 s−1. According to experimental data, the modified constitutive equation had been obtained, which precisely predicted the flow behavior of CrFeNiSi0.15MEA during thermal deformation. At the same time, the processing map was established on the basis of the dynamic material model (DMM) theory. According to the map, the optimal processing parameters were determined at 1130–1200 °C/0.06–1 s−1, under which the power dissipation efficiency could reach above 34%. The peak efficiency was above 38%, which occurred at 1200 °C/1 s−1. In such parameter, complete dynamic recrystallization (DRX) also occurred. The flow instability of CrFeNiSi0.15MEA was estimated to occur at 900–985 °C/0.12–1 s−1, which was shown as grain boundaries cracking. Furthermore, both the continuous DRX (CDRX) and discontinuous DRX (DDRX) occurred simultaneously during thermal deformation. Meanwhile, some twins were also newly formed during DRX process, most of which were primary twins. The occurrence of twinning was beneficial to promote the development of DRX behavior.

Graphical abstract:

The influence of selective laser melting (SLM) process parameters on the microstructure and mechanical properties of a typical Ni-based superalloy was researched. The optimum parameters of P= 170 W, V= 0.8 m/s were determined, under which the SLMed samples exhibited both the largest relative density of 99.57% and the best mechanical properties, including the microhardness (329.3 ± 3.8 HV), yield strength (726 ± 8.1 MPa), ultimate tensile strength (900 ± 5.9 MPa) and elongation ((31.9 ± 0.24)%). The average grain size ranges of SLMed samples are from 15.2 to 17.4 μm, with a typical mixed grain structure. Owing to the high cooling rate and remelting during SLM process, a large number of low-angle grain boundaries (LAGBs), dislocations and sub-grains were formed, and the fraction of LAGBs reached above 65%. At the same time, the content of low-Σcoincidence site lattice (CSL) boundaries was mostly less than 1%, while there was almost no γ′ phase precipitated in the matrix. The texture of SLMed samples was weak, and there was no obvious preferred growth direction. Combining with the microstructure characterization, both grain refinement strengthening and dislocation strengthening were considered as the main strengthening mechanisms. Moreover, the fracture mechanism of the optimum sample belonged to ductile fracture.

Achieving high selectivity and production efficiency simultaneously in electrocatalytic H2O2production to replace the anthraquinone process via two-electron (2e−) oxygen reduction reaction (ORR) and 2e−water oxidation reaction (WOR) is a long-sought-after goal. However, sluggish kinetics and intrinsically unfavored thermodynamics make the electrochemical method still far from practical implementation. Herein, we experimentally demonstrate a high-efficiency two-side H2O2generation system (WOR//ORR coupling cell) based on an active and stable bifunctional plasma-induced defective TiO2-xnanocatalyst that exhibits dramatically boosted activity/selectivity for both 2e−ORR and 2e−WOR. Such a WOR-ORR coupling strategy enables the H2O2-producing cell to provide an ultrahigh H2O2yield rate of ∼20 mmol L−1h−1and a remarkable cell Faradaic efficiency of up to 134%. In situRaman spectroscopy results and density functional theory calculations together uncover that oxygen vacancies located at the inner atomic layer and surface distortion are responsible for enhanced 2e−ORR and 2e−WOR performance, respectively.

By compensating the irreversible loss of lithium ions during the first cycle, prelithiations can solve the issue of insufficient initial Coulombic efficiency for various anodes. Recently, the chemical prelithiation using organolithium compounds has attracted increasing attention because of its uniform and fast reaction, safety, and easily adjustable degree of prelithiation. However, the nature and activity of organolithium involved in chemical prelithiations have not been deeply explored yet. Here, by monitoring the electrical conductivity change in the lithiation solution in the duration of its formation, we have demonstrated the essential role of lithium radical anions for chemical prelithiation and compared the prelithiation activity of dissociated species and aggregates of lithium radical anions. The mechanistic understanding of the nature of the lithiation solution leads to controllable chemical prelithiation, as demonstrated in full cells of prelithiated hard carbon and LiFePO4.

The influence of induction heating on the grain boundary character distribution (GBCD) in near-surface regions of a cold-rolled Nickel-based superalloy was researched. After induction heating, most of low-Σcoincidence site lattice (CSL) boundaries were Σ3 boundaries, which were mainly formed via the growth accident model. Moreover, the grain structures evolution during induction heating had a great influence on the evolution of GBCD. At the low strain of 0.1, both the fraction of Σ3 boundaries and grain size increased with the increasing temperatures, while the former was closely related to the better development of grain-clusters at the higher temperature. In addition, the coherent Σ3 boundaries were easier to be formed at the higher temperature during induction heating, owing to their low interface energy and mobility. At the large strain of 0.5, the fraction of Σ3 boundaries also increased with the increasing temperatures, but the grain size exhibited the opposite trend, which was closely related to the well development of static recrystallization (SRX) behaviors. Meanwhile, there was a “symbiotic relationship” between the SRX grains and Σ3 boundaries during induction heating. Through the electrochemical corrosion tests, it was proved that induction heating can contribute to the improvement of corrosion properties of superalloys via increasing the fraction of Σ3 boundaries, while the best corrosion resistance appeared in the samples treated at 800 °C with the strain of 0.5. Moreover, the evolution of both Σ9 and Σ27 boundaries was also closely related to strains and induction heating temperatures, but their fractions were less than 4%.

In this study, a novel fine-grained AZ31 magnesium (Mg) alloy reinforced with sub-micron vanadium particles (VP) was prepared by powder metallurgy (P/M). It was found that VPcould accelerate the pile-up of dislocations and the refinement of Mg crystallite sizes during the milling process. The Mg matrix was refined to nanocrystalline scale after milling for 90 h, and the ultimate average crystallite size was only 25 nm. Meanwhile, a homogeneous distribution of the sub-micron VPin Mg matrix was achieved. After hot-extrusion process, the average grain size of Mg matrix was 3.08 μm, which reached fine-grained scale. Additionally, the AZ31-2.5 wt % VPcomposite exhibited competitive mechanical properties. Compared to the as-cast AZ31 Mg alloy, the microhardness, yield strength, ultimate tensile strength and elongation of AZ31-2.5 wt % VPcomposite increased by 102%, 128%, 59% and 10%, respectively. The grain boundary strengthening played a dominant role in improvement of strength. Simultaneously, the strengthening mechanisms of thermal mismatch, Orowan strengthening and load transfer also made a contribution. Besides that, the fracture mechanism of the AZ31-2.5 wt % VPcomposite included ductile and brittle fracture mode.

The active site amount of photocatalysts, being the key factors in photocatalytic reactions, directly affects the photocatalytic performance of the photocatalyst. Pristine graphitic carbon nitride (g-C3N4) exhibits moderate photocatalytic activity due to insufficient active sites. In this study, cyano-modified porous g-C3N4nanosheets (MCN-0.5) were synthesized through molecular self-assembly and alkali-assisted strategies. The cyano group acted as the active site of the photocatalytic reaction, because the good electron-withdrawing property of the cyano group promoted carrier separation. Benefiting from the effect of the active sites, MCN-0.5 exhibited significantly enhanced photocatalytic activity for CO2reduction under visible light irradiation. Notably, the photocatalytic activity of MCN-0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid (HCl) treatment, further verifying the role of cyano groups as active sites. The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction. Furthermore, the controlled experiments showed that g-C3N4grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity, which proved the versatility of the strategy for enhancing the activity of g-C3N4via cyano group modification. In situdiffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2reduction by cyano-modified g-C3N4. This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.

Personalized information retrieval is an effective tool to solve the problem of information overload. Along with the rapid development of emerging network technologies such as cloud computing, however, network servers are becoming more and more untrusted, resulting in a serious threat to user privacy of personalized information retrieval. In this paper, we propose a basic framework for the comprehensive protection of all kinds of user privacy in personalized information retrieval. Its basic idea is to construct and submit a group of well-designed dummy requests together with each user request to the server, to mix up the user requests and then cover up the user privacy behind the requests. Also, the framework includes a privacy model and its implementation algorithm. Finally, theoretical analysis and experimental evaluation demonstrate that the framework can comprehensively improve the security of all kinds of user privacy, without compromising the availability of personalized information retrieval.

The evolution of grain boundary character distribution in a cold-deformed nickel-based superalloy during the electropulsing treatment (EPT) was studied. The results revealed that both coherent Σ3 boundaries (Σ3c) and incoherent Σ3 boundaries (Σ3ic) were formed in the recrystallized structures mainly by growth accidents during EPT, while the fraction of Σ3icboundaries became much lower at the higher EPT temperatures. Meanwhile, the fraction of Σ3 boundaries increased with the increasing EPT temperatures till 850 °C, and decreased again at 900 °C. In addition, the high mobility of grain boundary during EPT could promote the formation of stacking errors at some locations of high angle grain boundaries (HAGBs), and thus promoting the nucleation of annealing twins. With the increasing EPT time, the fraction of Σ3 boundaries increased slightly, and the unstable Σ3icboundaries were transformed into stable Σ3cboundaries, in which intersecting migrating SRX fronts were easier to be extended. On the other hand, a lot of low-ΣCSL grain boundaries were formed in the pre-deformed alloy with the strain of 0.1 during EPT, which was mainly attributed to the development of large grain-clusters. As the strain was large enough, the energy supplied by electropulsing could enable the cold-rolled alloy to effectively utilize the stored energy on the formation of Σ3 boundaries. Besides that, the evolution of Σ9 and Σ27 boundaries was analyzed in detail as well as the corrosion resistance of the studied alloy after different treatments.

Cathode materials play a crucial role in determining the electrochemical properties and fabrication cost of Lithium-ion batteries (LIBs). Li2MnO3has garnered increasing attentions due to its high theoretical capacity, but it suffers from severe issues, such as structural deterioration and irreversible capacity loss. In this paper, we propose a novel strategy to synthesize Li2-xMnO3cathodes using MOF-derived manganese oxide via a simple solid-state reaction. When used as cathodes for LIBs, the MOF-Li2MnO3exhibits a high reversible capacity of 92.5 mAh g−1after 120 cycles at 25 mA g−1, as compared to pristine Li2MnO3(31.7 mAh g−1). Additionally, hybrid phases including orthorhombic-LiMnO2and cubic LiMn2O4are introduced into Li-deficient materials, which exhibit different electrochemical behaviors from MOF-Li2MnO3. The MOF-Li1.75MnO3delivers an unprecedented capacity of 151.9 mAh g−1after 120 cycles at 25 mA g−1. Overall, the synergistic effect of adopting MOF-derived precursor and inducing multiphase by tuning Li content is conducive to enhancing the electrochemical performance of Li2MnO3cathode.

Abstract

The California Department of Transportation (Caltrans) awarded a contractor a three-year contract to collect, analyze, and report pavement condition of the state highway system for 2018 and 2019 using automated pavement condition survey (APCS). The contract covers 12 Caltrans districts with roughly 52,000 lane miles of on-system roadways and 6,000 lane miles of off-system roadways. Before investing significant resources on statewide APCS data collection, Caltrans and the contractor initiated a pilot study. The purpose is to establish a workable process for data quality control (QC) and quality assurance (QA), making sure the data collected closely reflect the field condition. The pilot study was conducted on selected routes in Caltrans District 12. The study included a total of 113 lane miles of roadway, representing roughly 5% of the total lane miles in the district. Of these lane miles, 69 lane miles are asphalt pavements and 44 lane miles are jointed plain concrete pavements. The developed data QC/QA process functioned very well. With this process, the contractor was responsible for performing the QC of the APCS data before submitting to Caltrans. Caltrans performed data QA, which included data completeness check; image review; field review and office verification; data upload into Caltrans pavement management system, and year-by-year data consistency check. The joint effort has resolved many data inconsistency issues caused either by interpretation or software issues. The data quality was thus well improved. It is recommended that this QC/QA process be implemented for all APCS data collections in California.

Development of delithiation methods with cost-efficiency and highly kinetic effectivity is of great importance for the preparation of diversified intercalation materials, mechanistic study, and lithium extraction from spent lithium-ion batteries. Electrochemical delithiation in aqueous electrolytes is low-cost, straightforward, and fast, but has been plagued by incomplete delithiation. To address this issue, we propose to add oxidation reagents, usually applied in chemical delithation, to traditional aqueous delithiation electrolyte. As a demonstration, herein, a Na2SO4+ Na2S2O8composite aqueous electrolyte is used to obtain olivine FePO4from the electrochemical delithiation of LiFePO4, and compared with the similar delithiation in Na2SO4aqueous electrolyte. The delithiation goes completion in the composite electrolyte 79% faster than that in traditional electrolyte. The resulting olivine FePO4exhibits integrity in terms of structure and electrochemical properties, with discharge specific capacity of 157.1 mAh g−1at 0.1 C, constant voltage plateau of 3.37 V, and 98.8% capacity retention after 100 cycles, all comparable to the LiFePO4starting material. Mechanistic studies show that Na2S2O8promotes the electrochemical delithiation by providing acidic and chemically oxidative conditions.

Garnet-type Li7La3Zr2O12(LLZO) is one of the most promising solid-state electrolytes (SSEs). However, the application of LLZO is limited by structural instability, low ionic conductivity, and poor lithium stability. To obtain a garnet-type solid electrolyte with a stable structure and high ionic conductivity, a series of TaCe co-doping cubic Li6.4La3Zr1.4-xTa0.6CexO12(LLZTCO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.30) electrolytes were successfully synthesized through conventional solid-phase method. The Ta5+doping can introduce more lithium vacancies and effectively maintain the stability of the cubic phase. The Ce4+with a larger ionic radius is introduced into the lattice to widen the Li+migration bottleneck size, which significantly increased the ionic conductivity to 1.05 × 10−3S/cm. It also shows excellent stability to lithium metal by the optimization of Li+transport channel. Li||LLZTCO||Li symmetric cells can cycle stably for more than 6000 h at a current density of 0.1 mA/cm2without any surface modifications. The commercialization potential of LLZTCO samples in all solid-state lithium batteries (ASSLBs) is confirmed by the prepared LiFePO4||LLZTCO||Li cells with a capacity retention rate of 98 % after 100 cycles at 0.5 C. This new co-doping method presents a practical solution for the realization of high-performance ASSLBs.

In this paper, the microstructure evolution and thermal stability of nanocrystalline (NC) AZ31-2.5wt.%VPmagnesium matrix composites were studied, while the hardness was analyzed. The results showed that the NC AZ31-2.5wt.%VPstill kept NC scale after annealing at 300°C and 350°C. Even at 400°C and 450°C, the grain size of the annealed composite only grew to 113nm and 132nm, which was still in ultrafine grain scale, illustrating excellent thermal stability of NC AZ31-2.5wt.%VP. Furthermore, the V particles, which was uniformly distributed in the Mg matrix, had no obvious change in dimension after annealing, while it also had no new phase formed. The stabilization mechanism was expounded and found that the pinning effect of V particles effectively inhibited the grain growth of Mg matrix at high temperature. In addition, the grain growth kinetics equation (D6−D06=kt) was utilized to explain the grain growth behavior of NC AZ31-2.5wt.%VP, and the activation energy (Ea) of grain growth was calculated to be 130.9KJ/mol, which was much higher than that of pure Mg (92KJ/mol). Eventually, the hardness of NC AZ31-2.5wt.%VPwas contrastive studied and the hardness evolution curves at different temperatures were obtained. After annealing treatment was performed at 450°C for 180min, the hardness remained at 80HV, which was higher than that of as-cast AZ31 (53HV).

The California Department of Transportation (Caltrans) has been using scrap tire rubber in asphalt pavements since the 1970s in chip seals and the 1980s in rubberized hot mix asphalt(RHMA). Both the wet (field blend) and dry processes were used in early trials. Caltrans has also used rubber modified binders containing both crumb rubber modifier and polymer modifier that could be manufactured at a refinery facility, a terminal blend wet process. Since the beginning of this century, Caltrans increased the use of scrap tire rubber in paving projects and invested considerable resources in developing technically sound, cost effective, and environmentally friendly strategies for using scrap tire rubber in roadway applications. By the end of year 2010, approximately 31%of all hot mix asphalt (HMA) placed by Caltrans was rubberized HMA, roughly 1.2 million tons. Caltrans efforts in using asphalt rubber products were also demonstrated in its research and technology development. These included the construction of two full-scale field experiments, five warranty projects, and an accelerated pavement study using a heavy vehicle simulator. Additionally, terminal blend asphalt rubber and rubberized warm mix asphalts began to be experimented on trial basis. This paper provides a comprehensive review of Caltrans experience over four decades with asphalt rubber products. Current practices and future outlook are also discussed.

This paper presents a low damage inductively coupled plasma (ICP) etching process to define sub-100 nm platinum gate lines for III--V metal--oxide--semiconductor field-effect transistors (MOSFETs) fabrication. In this process, a negative resist etching mask patterned by electron beam lithography is used to define the high resolution platinum features using a combination of SF6and C4F8etch gases. Systematic investigation of the impact of various etch conditions, such as coil and platen power, gas composition, chamber pressure on etch rate and profile, resulted in a controllable etching process. Optical emission spectra of the ICP plasma have been checked for better understanding the etching mechanism. Etch induced damage of the underlying device channel of the III--V MOSFET materials has been evaluated through monitoring the sheet resistance variation of the materials at room temperature, which showed the process does not significantly degrade the electrical properties of the underlying device channel under optimized conditions.

Urothelium that lines almost the entire urinary tract performs important functions and is prone to assaults by urinary microbials, metabolites, and carcinogens. To improve our understanding of urothelial physiology and disease pathogenesis, we sought to develop two novel transgenic systems, one that would allow inducible and urothelium-specific gene expression, and another that would allow inducible and urothelium-specific knockout. Toward this end, we combined the ability of the mouse uroplakin II promoter (mUPII) to drive urothelium-specific gene expression with a versatile tetracycline-mediated inducible system. We found that, when constructed under the control of mUPII, only a modified, reverse tetracycline trans-activator (rtTA-M2), but not its original version (rtTA), could efficiently trans-activate reporter gene expression in mouse urothelium on doxycycline (Dox) induction. The mUPII/rtTA-M2-inducible system retained its strict urothelial specificity, had no background activity in the absence of Dox, and responded rapidly to Dox administration. Using a reporter gene whose expression was secondarily controlled by histone remodeling, we were able to identify, colocalize with 5-bromo-2-deoxyuridine incorporation, and semiquantify newly divided urothelial cells. Finally, we established that, when combined with a Cre recombinase under the control of the tetracycline operon, the mUPII-driven rtTA-M2 could inducibly inactivate any gene of interest in mouse urothelium. The establishment of these two new transgenic mouse systems enables the manipulation of gene expression and/or inactivation in adult mouse urothelium at any given time, thus minimizing potential compensatory effects due to gene overexpression or loss and allowing more accurate modeling of urothelial diseases than previously reported constitutive systems.

We describe the safety of the human papillomavirus (HPV)-6/11/16/18 vaccine using updated clinical trial data (median follow-up time of 3.6 years) and summarize up to 3 years of post-licensure surveillance.

To address issues associated with continual scaling of the International Technology Roadmap for Semiconductors (ITRS) [1] to follow Moore's Law, MOSFETs with high mobility channel materials are now being seriously considered. As a result, there has been a significant expansion in research into III-V MOSFETs as a potential n-channel device solution. For ultimate CMOS exploitation, self-aligned III-V MOSFETs with sub-20 nm critical dimensions will have to be realized using silicon compatible process flows. This paper reviews the current status of III-V MOSFET research from the perspective of silicon ULSI process compatibility.

To address issues associated with continual scaling of the International Technology Roadmap for Semiconductors (ITRS) (1) to follow Moore's Law, MOSFETs with high mobility channel materials are now being seriously considered. As a result, there has been a significant expansion in research into III-V MOSFETs as a potential n-channel device solution. A wide range of high electron mobility channel materials, device architectures and gate oxides are currently being considered, and in this review, key performance metrics of III-V MOSFETs will be compared.

In 2001, the California Department of Transportation (Caltrans) initiated a 3-year, $7 million project with MACTEC, Inc. The project included on-call flexible pavement consulting services to Caltrans in the areas of new products, asphalt rubber, modified binders, moisture sensitivity, failure investigations, independent quality assurance, training, laboratory testing, pavement maintenance, pavement rehabilitation, and asphalt recycling. One of the key tasks of the project was to develop a comprehensive guide and a detailed procedure to investigate flexible pavement distresses and develop cost-effective remedies and repair strategies. The emphasis of the procedure is on addressing premature distress and certain problems that might arise during pavement construction. The guide contains two manuals: (a) an office manual that describes the types of flexible pavement distress, identifies the factors that affect distress and performance, and provides tools that can be used to characterize distress condition, determine likely causes, and generate a corrective solution and (b) a field manual for use in the field by experienced engineers familiar with the new tools and requiring little instruction on its application. The principles presented in the guide are based on modern pavement engineering technology and are applicable to the practices of many federal, state, and local agencies. The process presented in the guide is summarized, and several of the new tools that have applicability to other agencies are described.

In 2001, the California Department of Transportation (Caltrans) initiated a 3-year, $7 million project with MACTEC, Inc. The project included on-call flexible pavement consulting services to Caltrans in the areas of new products, asphalt rubber, modified binders, moisture sensitivity, failure investigations, independent quality assurance, training, laboratory testing, pavement maintenance, pavement rehabilitation, and asphalt recycling. One of the key tasks of the project was to develop a comprehensive guide and a detailed procedure to investigate flexible pavement distresses and develop cost-effective remedies and repair strategies. The emphasis of the procedure is on addressing premature distress and certain problems that might arise during pavement construction. The guide contains two manuals: (a) an office manual that describes the types of flexible pavement distress, identifies the factors that affect distress and performance, and provides tools that can be used to characterize distress condition, determine likely causes, and generate a corrective solution and (b) a field manual for use in the field by experienced engineers familiar with the new tools and requiring little instruction on its application. The principles presented in the guide are based on modern pavement engineering technology and are applicable to the practices of many federal, state, and local agencies. The process presented in the guide is summarized, and several of the new tools that have applicability to other agencies are described.

The interpretation and use of deflection measurements on the prepared surfaces of the various pavement layers during construction are examined. Measurements were obtained from four asphalt concrete pavement test sections, two with unbound aggregate base and two with bituminous-treated base over an untreated aggregate base. Deflection basin measurements using a falling weight deflectometer were performed on the prepared surfaces of the subgrade, base layers, and asphalt concrete layers. The elastic moduli of each layer were computed using the EVERCALC backcalculation program. The primary finding from this investigation is that deflection measurements on the subgrade and base layers during construction can be used to control construction uniformity and provide checks on mechanistic-based pavement design assumptions. Also, subgrade uniformity has a profound impact on the entire pavement structure and subgrade variations affect total deflections and computed layer moduli of all successive layers. The backcalculated modulus is directly related to the stress state in the layer. For unbound aggregate bases, the backcalculated elastic modulus decreases with a decrease in the bulk stress, and for fine-grained subgrade soil, the backcalculated elastic modulus increased with a decrease in the deviator stress. As expected, a higher and more variable root-mean-square basin fit error value was obtained for measurements on unbound material as compared with measurements on bound material surfaces.

Collision of vehicles with fixed objects adjacent to the roadway has been a concern of traffic engineers for many years. One solution to prevent or reduce the number of accidents of this type is to install a traffic barrier to shield the objects from being hit directly. However, because the barrier itself is a fixed object, the question is whether a barrier is more effective at a particular location than no barrier at all. If a barrier is needed, where should it be located and what type of barrier would satisfy the design criteria? Issues of this nature are ill‐structured and difficult to address using normal computing technology since many factors contribute to the problem. For roadside safety, the primary factors are diverse and interrelated. This paper presents a demonstration prototype knowledge‐based expert system (Roadside) for roadside‐safety analysis. In particular, this system is developed to evaluate whether a traffic barrier is necessary for a particular site in analysis. Development of this demonstration prototype shows an expert‐system approach for roadside safety analysis is feasible. The artificial‐intelligence (AI) programming language Prolog is used for developing the system. The use of Prolog provides greater flexibility and adaptability in developing the system. However, much more programming time is required to develop the expert system.

The interpretation and use of deflection measurements on the prepared surfaces of the various pavement layers during construction are examined. Measurements were obtained from four asphalt concrete pavement test sections, two with unbound aggregate base and two with bituminous-treated base over an untreated aggregate base. Deflection basin measurements using a falling weight deflectometer were performed on the prepared surfaces of the subgrade, base layers, and asphalt concrete layers. The elastic moduli of each layer were computed using the EVERCALC backcalculation program. The primary finding from this investigation is that deflection measurements on the subgrade and base layers during construction can be used to control construction uniformity and provide checks on mechanistic-based pavement design assumptions. Also, subgrade uniformity has a profound impact on the entire pavement structure and subgrade variations affect total deflections and computed layer moduli of all successive layers. The backcalculated modulus is directly related to the stress state in the layer. For unbound aggregate bases, the backcalculated elastic modulus decreases with a decrease in the bulk stress, and for fine-grained subgrade soil, the backcalculated elastic modulus increased with a decrease in the deviator stress. As expected, a higher and more variable root-mean-square basin fit error value was obtained for measurements on unbound material as compared with measurements on bound material surfaces.

In this paper, the pavement maintenance and rehabilitation practices are presented based on the analysis of as-built data housed in PaveM—the pavement management system for the California Department of Transportation (Caltrans). A 35-year period of as-built data from 1983 to 2017 was analyzed, involving 37 treatment strategies with 17 for asphalt and 20 for Portland Cement Concrete (PCC) pavements. The top ten treatment strategies, geographical and temporal variation of treated mileage, together with treatment costs and corresponding network condition were presented. It was found that: (1) The top 10 strategies are, in descending order: “Chip Seal”, “Hot Mix Asphalt (HMA) Thin Overlay”, “HMA Medium Overlay”, “HMA Thick Overlay”, “Mill and Fill”, “Grind/Replace Slabs”, “Slab Replacement”, “Crack Seat and Overlay”, “HMA Lane Replacement”, and “PCC Lane Replacement”. The top 10 strategies accounted for about 84% of the total treated lane kilometers. (2) On average, about 12.4% of the total network inventory (both asphalt and concrete pavements) was treated each year. This is equivalent to treat the entire network once every eight years. (3) About 18.3% of AC and 35.1% of PCC rehabilitation mileage was found applied on a lane-by-lane basis, instead of across all lanes. This finding solidified the necessity of a lane-based pavement management system in California. (4) The average annual weighted maintenance and rehabilitation cost per lane kilometer is about $192,248 for asphalt and $366,804 for PCC pavements. Due to the lack of preventive types of treatments for PCC pavement, the per lane kilometer cost is almost twice as high as that for its asphalt counterpart. It is suggested that more preventive type of treatments be implemented for PCC pavements.

Coexistence of non-volatile and volatile resistive switching on the same device are of interest in memory devices for weight storage applications. In this work, stacked MoS2nanosheet thin film was modified using soft nitrogen plasma treatment (NPT). Compared to pristine MoS2-based counterparts, the fabricated Ag/NPT-MoS2/indium tin oxide (ITO) structure exhibited both an enhanced ratio of 104and lowered threshold voltage of 0.1 V. The distinction might be attributed to the introduced carbonitride between Ag and MoS2, where the conductive filaments and interface barrier altogether affect the switching. The observation suggested a possibility of programming on a single two-terminal device.

To address issues associated with continual scaling of the International Technology Roadmap for Semiconductors (ITRS) [1] to follow Moore's Law, MOSFETs with high mobility channel materials are now being seriously considered. As a result, there has been a significant expansion in research into III-V MOSFETs as a potential n-channel device solution. For ultimate CMOS exploitation, self-aligned III-V MOSFETs with sub-20 nm critical dimensions will have to be realized using silicon compatible process flows. This paper reviews the current status of III-V MOSFET research from the perspective of silicon ULSI process compatibility.

To address issues associated with continual scaling of the International Technology Roadmap for Semiconductors (ITRS) (1) to follow Moore's Law, MOSFETs with high mobility channel materials are now being seriously considered. As a result, there has been a significant expansion in research into III-V MOSFETs as a potential n-channel device solution. A wide range of high electron mobility channel materials, device architectures and gate oxides are currently being considered, and in this review, key performance metrics of III-V MOSFETs will be compared.