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Layered transition-metal oxides have served as the mainstream cathode materials for high-energy batteries due to their large theoretical capacity (≈280mAh/g),However, the actual usable capacity is much lower than the promised theoretical value. Additional, poor cycling performance and the first-cycle Coulombic efficiency, for which Mn(II)-dissolution, its immobilization in solid electrolyte interface (SEI), oxidation of electrolytes by Ni, and other parasitic process thereat have been held responsible, weight against their applications.. Here we report a significant enhancement of cathode capacity utilization through a novel concept of material design. By embedding Li(Ni0.5Co0.2Mn0.3)O2 in single wall carbon nanotube (CNT) network, a high charge/discharge reversible capacity up to about 250 mAh/g was obtained between 3.0-4.8V. Furthermore, to maintain this high capacity in long-term cycling, we proposes a unique “pre-lithiation process”, which brought the cathode to low potentials before regular cycling and led to an interphase that is normally formed only on anode surfaces. The complete coverage of cathode surface by this ~40 nm-thick interphase effectively prevented Mn(II) dissolution and minimized the side reactions of Ni, Co and Mn at the NMC interface during the subsequent cycling process. More importantly, such “pre-lithiation” process activated a structure containing two Li layers near the surface of NMC532 particles, as verified by XRD and first principle calculation. Hence, a new cathode material of both high capacity with depolarized structure; and excellent cycling performance was generated.

Well logs are indispensable sources of subsurface information in exploration, appraisal, and development. The term “advanced logs” here refers to well logs other than the conventional quad combo. They involve, but are not limited to, nuclear magnetic resonance (NMR), image, nuclear, spectroscopy

Traditional fracture-height and/or proppant-placement evaluation following a hydraulic fracture stimulation treatment has relied on the detection of radioactive (R/A) tracers pumped downhole with the proppant. While this technique has proven useful, it raises environmental, safety, and regulatory concerns and issues. In some areas of the world, transport and use of R/A tracers is prohibited. The proppant placement determination method described in this paper eliminates the downhole placement of R/A materials. A high thermal neutron capture compound (HTNCC) is incorporated into a ceramic proppant during manufacturing in sufficiently low concentration that it does not affect proppant strength or conductivity. Proppant is then detected using standard compensated or pulsed neutron tools, with detection based on the high thermal neutron capture of the compound relative to the surrounding downhole constituents. Two detection methods use a comparison of before-frac log-count rates and after-frac count rates, with reduced after-frac count rates observed in zones containing proppant. Another detection method, especially useful when formation gas saturations change, involves only the after-frac log. This paper will describe the methodology and results of an application of the new detectable proppant in the T sand of the Villeta and Caballos formations of Juanambú field in the Putumayo basin of Colombia. The results obtained from this novel technology provided the operator an improved understanding of the geomechanical characteristics of the formations and the achieved fracture dimensions. Additionally, this information will help improve future stimulation treatments. This paper should be beneficial to all completion engineers looking for methods to determine fracture height and/or proppant placement in an environmentally acceptable manner.

Cation exchange (CX) in the nonfluorescent ZnS nanocrystal clusters (NCCs) was employed to detect trace biomolecules with immunoassays. The NCCs were porous and allowed fast cation exchange reaction to release an ultralarge number of Zn(2+) from each cluster that turned on the Zn-responsive dyes for fluorescence detection. The ZnS NCCs were highly stable in biological buffers and more biocompatible than quantum dots. Zn(2+) release efficiency and target binding by NCCs with average diameters of 44 nm, 86 nm, and 144 nm were investigated. The smallest NCCs exhibited the highest CX efficiency because of its larger surface area and bigger pores inside the cluster structure, and 71.0% of the enclosed Zn(2+) were freed by CX with 2-min microwave irradiation. They also experienced the least space hindrance and the fastest rate when binding to target molecules immobilized on surface. When the 44-nm NCCs were used to detect IgE in a sandwich assay, the limit of detection (LOD) was 5 pg/mL (33 fM), 1,000 times better than that of ELISA. Our results well demonstrate that CX in the ZnS NCCs is superior to the conventional signaling strategies in its high amplification efficiency, robustness, and biocompatibility.

Abstract A new technique is discussed and tested in this work for proppant placement determination. A high thermal neutron capture compound (HTNCC) is inseparably incorporated into a ceramic proppant during manufacturing in sufficiently low concentration that it does not affect proppant properties. Proppant is detected using standard compensated neutron tools or pulsed neutron tools, with detection based on the high thermal neutron absorptive properties of the compound relative to downhole constituents. Compared to the traditional radioactive tracer (RA) techniques, the new detectable proppant is not radioactive so there are no HSE or regulatory issues. Additionally, since the high thermal neutron absorbing compound is placed in the proppant during the process of manufacturing, there is no requirement for special handling or mixing processes at the well site. Specifically, proppant is detected using after-frac compensated neutron logs combined with corresponding before-frac logs. Increased thermal neutron absorption by the compound reduces count rates in the near and far detectors, with approximately the same percentage reduction observed in each detector, leaving the near-to-far detector count ratio (N/F) unchanged. One detection method utilizes a comparison of before-frac log count rates and after-frac count rates, with reduced after-frac count rates observed in zones containing proppant. A second detection method, especially useful when formation gas saturations change, involves only the after-frac log. Since the near to far detector count ratio is unaffected by proppant, after-frac count rates predicted from the ratio will also be unaffected. These computed/synthetic count rates will be greater than the observed after-frac count rates in intervals containing proppant. Nuclear Monte Carlo modeling was performed to demonstrate the validation of this technique employing both compensated neutron logging tool (CNT) and pulsed neutron capture (PNC) logging tools. Two field examples from China are illustrated in this paper. The final interpreted locations of proppant are shown in the field examples. Introduction Hydraulic fracturing has been frequently used to increase hydrocarbon production especially in formations with low porosity and/or low permeability. Hydraulic fracturing operations can be conducted in horizontal, deviated, and vertical boreholes, and in open-hole wells or cased wells through perforations. The description below focuses on frac applications in cased boreholes in generally vertical wells, however analogous concepts are generally applicable to most frac situations. In hydraulic fracturing, the high-pressured, sometimes viscous, frac fluids exit the borehole via perforations through casing and cement, and cause the formation to fracture. At the same time, the high-pressured frac fluid carries proppant, such as sand, resin coated sand or ceramic proppant and places them in the fracture. Generally, the induced fracture extends laterally a considerable distance out from the wellbore into the surrounding formations, and extends vertically until the fracture reaches a formation that is not easily fractured above/below the desired frac interval. The direction of the least principal stress within the formation determines the azimuthal orientation of the induced fractures. In the case of viscous gelled frac fluids, gel "breakers" are added in the fluid slurry to reduce the viscosity of frac fluid after a desired time delay. This can enable fracturing fluid to be removed from the fractures and formation during production and leave the proppant in place to keep the induced fractures from closing.

Reconfiguring a VLSI array with faults is to construct a maximum logical sub-array (target array). A large target array implies a good harvest of the corresponding reconfiguration algorithm. Thus, a tight upper bound of the harvest can be directly used to evaluate the performance of the reconfiguration algorithm. This paper presents a new approach to calculate the upper bound of the harvest for the VLSI arrays with clustered faults. Simulation results show that the upper bound is reduced up to 20% on 256 × 256 array with clustered faults.

Nanoparticles that respond to various chemical and physical stimuli form the basis for various conceivable applications including sensors, chemical logic, biomedical imaging, and therapies. In this work, we demonstrate that the electrostatic and chemical (complexing and gold-thiol bonding) interactions existing in a gold nanoparticle/Zn(2+)/dithiothreitol-based ternary chemical system is "programmable" and can be utilized to regulate the aggregation and dispersion of nanoparticles via XOR and INHIBIT logics. The resulting solutions alter their colors according to different input combinations because of the well-controlled aggregation or dispersion of plasmonic gold nanoparticles, opening up new possibilities for the developments of advanced sensors and nanobiomedical devices based on the coupling, gating, and signaling of different chemical stimuli.

The need for an accurate representation of the detector response functions (DRFs) for sodium iodide (NaI), bismuth germinate (BGO), etc., arises in the oilwell logging business, especially important for spectral logging tools such as a geochemical logging tool. While Monte Carlo models predict the photon spectra incidents on these detectors, the DRFs are used to generate the pulse-height spectra. A Monte Carlo-based γ-ray detector response function code (GAMDRF) was developed to meet the requirements based on complete photon physics.

The goal of this paper is to develop some modeling capabilities that are missing in the current MCNP code. Those missing capabilities can greatly help for some certain nuclear tools designs, such as a nuclear lithology/mineralogy spectroscopy tool. The new capabilities to be developed in this paper include the following: zone tally, neutron interaction tally, gamma rays index tally and enhanced pulse-height tally. The patched MCNP code also can be used to compute neutron slowing-down length and thermal neutron diffusion length.

For the requirements of large-scale real-time vehicle GPS data map matching in application, this paper proposes a parallel algorithm for road matching based on multi-core and MPI(Massage Passing Interface). Several basic questions for road matching are discussed, such as maps storage structure, matching elements, and alternative road chain searching. Then, based on multi-core and MPI computing platform, the parallel algorithm for road matching is implemented, with actual road network and floating car data. The validation results show that the algorithm not only has high speedup rate and efficiency, but also the matching results are credible.

Information overload on the Internet is becoming more and more insufferable. The accurate representation of user interests is crucial to a successful information filtering system that are used to solve the issue of information overload. To model the users' interests more effectively, this paper investigate how to collect user tags from folksonomy and map them onto an existing domain ontology. The experiment that integrates our user interest profile model to a Web Search Engine shows that our approach can accurately capture user's multiple interests at the semantic level, and thus the personalized search performance is significantly improved compared with the state-of-the-art approaches.

The assessment of reservoir productivity and subsurface hydrocarbon can be significantly enhanced through an understanding of formation mineralogy and organic carbon. Such information allows petrophysicists to resolve ambiguities in their predictions of reservoir hydrocarbon potential. While core samples are a prime source for exact formation mineralogy, excellent results can also be derived in a timely and cost-efficient manner from in-situ log chemistry measurements of the rock. A direct measurement of the formation's elemental concentrations is achieved using a gamma ray scintillation sensor in combination with a 14-MeV pulsed-neutron generator. The most important element measured is carbon, as it may provide a direct indication of reservoir hydrocarbons. This paper presents a method for determining the amount of organic carbon in subsurface formations using a pulsed-neutron mineralogy tool and a natural gamma ray spectroscopy tool. The natural, inelastic, and capture gamma ray energy spectra from these instruments are used to extract the chemistry of the subsurface formation being investigated. The elemental concentrations measured include Al, C, Ca, Fe, Gd, K, Mg, S, Si, Th, Ti, and U. Carbon is very difficult to measure without the inelastic spectrum generated from a pulsed-neutron source. An interpretation process, based upon the geochemistry of petroleum-bearing formations, is employed to derive the lithology and mineralogy which leads to the interpretation of the carbon measurement. The oil saturation can be computed in conventional reservoirs, assuming that the amount of carbon in excess of that required for the inorganic matrix mineralogy is part of the pore fluid as hydrocarbon. The direct carbon measurement is also important in laminated shaly sands or in low-salinity reservoirs, where oil saturation determination from indirect measurements, such as resistivity, is not compatible with the environment. In other formations the carbon can be determined to be a component of the rock matrix as kerogen or coal, both of which are uniquely identified with this logging system. Kerogen becomes extremely important in the evaluation of shale gas formations. Field examples are presented to illustrate the effectiveness of the carbon measurement.

One of the most promising approaches for massive production of transparent conducting electrodes (TCE) is roll-to-roll printing of graphene flakes solution. However, graphene flakes inevitably contain structural defects like grain boundaries and dislocations, together with macroscopic defects such as wrinkles and cracks during transfer. In addition, the printed flakes can’t align with each other perfectly. All these defects and the gaps between detached flakes hinder electrical transport and limit the mechanical strength and reliability of the graphene. Here we report a technique to electrically heal and connect graphene flakes via selective atomic layer deposition (ALD) of conductive materials. We have demonstrated selective growth of ALD aluminum-doped zinc oxide, ruthenium and platinum on pristine graphene surface prepared from exfoliated highly ordered pyrolytic graphite (HOPG). ALD materials nucleate on graphene cracks and edges but exhibit a significant nucleation barrier on intact basal planes due to the chemical inertness from delocalized π-orbitals. We also present a high-throughput fabrication method to create graphene patterns via metal shadow mask and O2 plasma. This model system of patterned CVD graphene islands demonstrates electrical connection of separated graphnene flakes by selective ALD processes. In addition, shadow-mask-patterned CVD graphene field effect transistors (FETs) are used to monitor graphene carrier density and mobility variation after ALD growth. We found considerable carrier density and conductivity increase of a single graphene flake after V2O5 ALD, which can be explained by p-doping of graphene due to the high work function V2O5.

Reconfiguring a very large scale integration (VLSI) array with faults is to construct a maximum logical sub-array (target array) without faults. A large target array implies a good harvest of the corresponding reconfiguration algorithm. Thus, a tight upper bound of the harvest can be directly used to evaluate the performance of the reconfiguration algorithm. This paper presents a new approach to calculate the upper bound of the harvest for the VLSI arrays with clustered faults. The latest upper bound is successfully reduced and the proposed technique to calculate the upper bound is bound into a reconfiguration algorithm cited in this paper. Simulation results show that the upper bound is reduced up to 20% on 256 × 256 array with clustered faults, and the corresponding reconfiguration process is significantly accelerated over 30%, without loss of harvest.

Accelerator-based neutron source have been considered to be practical for boron neutron capture therapy (BNCT). Based on experience with a parameters of the Brookhaven National Laboratory BMRR reactor neutron source, which has been used in treatment experiments, the future accelerator-based neutron source for BNCT should have the properties of low energy distribution (< 100 keV) and high flux (about 10(9) neutrons per second per square centimeter) in the patient zone. Using protons to bombard thick 7Li targets, generating neutrons via the 7Li(p,n)7Be reaction, is one of the optimal choices for this kind of neutron source. Neutron yield data versus incident energy are necessary in order to select the proper incident energy and for estimating how high the incident proton current should be. The required proton beam current intensity is one of the key parameters for an accelerator useful for BNCT. In the present work, neutron yields of the 7Li(p,n)7Be reaction with a thick lithium target and incident energies of 1.885 and 1.9 MeV were measured at 0 degree with respect to the incident beam direction. The results are (3.08 +/- 0.17) x 10(12) and (5.71 +/- 0.32) x 10(12) neutrons/C sr, respectively. Neutron yield angular distribution measurements at 2 MeV incident energy were also performed. The proton beams were generated by the Peking University 4.5 MV electrostatic accelerator. The emitted neutrons from these reactions have the advantages of low energy distribution and forward angular distribution, which are requirements for a BNCT neutron source. The data obtained in this work can be used as a reference to study the accelerator-based neutron sources for BNCT.

A new openhole logging service, RockViewSM, has been developed which provides lithological and quantitative mineralogical information for accurate formation evaluation. The assessment begins with elemental formation weights and follows with an interpretation of lithology and mineralogy. Lithologies are divided into general categories including sand, shale, coal, carbonates, and evaporites. Potentially identifiable minerals are quartz, potassium-feldspar, albite, calcite, dolomite, siderite, anhydrite, illite/smectite, kaolinite, glauconite, chlorite, pyrite, and others. The logging system utilizes an electronic pulsed source to send high energy neutrons into the surrounding formation1-8. These neutrons quickly lose energy as a result of scattering, after which they are absorbed by the various atoms within the ambient environment. The scattered as well as the absorbed neutrons cause the atoms of the various elements to emit gamma rays with characteristic energies. These are measured with a scintillation detector, resulting in both inelastic and capture gamma ray energy spectra. A matrix inversion spectral fit algorithm is used to analyze these spectra in order to separate the total response into its individual elemental components. The prominent measured elements associated with subsurface rock formations include calcium, silicon, magnesium, carbon, sulfur, aluminum, and iron. Potassium, thorium, and uranium are measured separately with a natural gamma ray spectroscopy instrument9-11. The tool response is characterized for each individual element by placing it into formations of known chemical composition. Interpretation of the data begins with an assessment of the elemental formation weights, which then leads to a determination of lithology and mineralogy. Each step in the process is guided by the examination of ternary plots containing selected elements. Magnesium is an extremely important part of the interpretation process since it distinguishes dolomite from calcite and helps to identify various types of clay. Data from field examples is presented in order to illustrate the effectiveness of this technology.

Introduction The safety concern of Li-ion batteries due to the potential leakage and the flammability of the electrolyte severely hinders applications. The emergence of all-solid-state batteries, consisting of solid state electrodes and solid state ionic conductor electrolyte, will solve this safety problem because it eliminates the problematic liquid electrolytes. One key issue that needs to be addressed in constructing such a battery is the contact between electrode and electrolyte. Different from liquid electrolytes that can submerge the cathodes, it is difficult for solid state electrolyte to have a sufficient touch with electrodes. A common cathode-side fabrication method is to mix the electrolyte powder with cathode powder and electronically conductive materials, yielding a point-to-point contact. This contact configuration limits the number of effective pathways of li-ion diffusion, therefore hurts the performance of the battery. solves the aforementioned problems. Starting with precursor solutions, reactants are homogenously mixed at a molecular level, and are much easier to get into the scaffold than powders. Additionally, in-situ synthesis allows the high voltage cathode material to adhere to the surface of the electrolyte scaffold, yielding a face-to-face contact. This enlarges contact area, creating more pathways for Li-ion diffusion and improves the conductivity between the cathode and the electrolyte. Experimental Methods The high voltage cathode Li2FeMn3O8 (LFMO) is synthesized by glycine-nitrate combustion. Precursor solution containing metal nitrates and glycine with an optimized ratio is infiltrated into the porous garnet electrolyte scaffold. After drying at 300℃ combustion takes place. The pellet is subsequently annealed at 700℃ to achieve the desired LFMO phase. Finally, carbon nanotube ink is infiltrated to the scaffold to form a conductive network over the cathode. Results Fig. 1a shows a schematic of the cathode. With the conductive network and improved contact of cathode and electrolyte, it is expected to have an improved performance. As is shown in Fig. 1b, the cathode adheres to the surface of the scaffold, forming a face-to-face contact. The LFMO cathode has been tested in LFMO/Li coin cell with LiPF6/ FEC electrolyte. Fig.2 a) gives the XRD spectrum of the cathode prepared by glycine-nitride combustion method. The spectrum matches with JCPDS#48-0258, indicating a Li2FeMn3O8 phase. Fig.2 b) shows the cycling performance of the cathode. It can be seen from the voltage profile of the tested cell that LFMO has two plateaus at around 4.1V and 4.9V, with capacity being 104mAh/g.

Introduction Solid state batteries offer increased safety, high voltage stability, and simpler electrolyte chemistry than organic electrolytes. Their inherent protection from dendrite growth gives the capability to use metallic lithium anodes. Recent advances have improved conductivity to within an order of magnitude of organic electrolytes at room temperature. However, interfacial resistance between electrodes and the electrolyte remains a pressing concern. In a typical planar battery, this high resistance per area is magnified by low interfacial surface area. Elemental composition has a significant effect on the conductivity of a garnet electrolyte. The conductivity of the garnet fluctuates an order of magnitude based on a lithium stoichiometry of 6 to 7 in the Li7-xLa3Zr2-xTaxO12series. It has also been demonstrated that aluminium composition at the grain boundaries associated with higher temperature sintering increases conductivity. It stands to reason lithium activity extremes at the electrode interfaces effects would cause local variations in electrolyte composition and affect the conductivity. This study aims to address some of these concerns using a systematic study of the anode-electrolyte interface and the cathode-electrolyte interface. We investigate the elemental composition of the interface, as well as the effect of greatly increased surface area through a highly microporous electrolyte scaffold containing the cathode and anode material. Experimental Procedure Li7La3Zr2O12 garnet was produced in a conventional solid state method. 10% excess LiOH-H2O and stoichiometric amounts of La2O3 and ZrO2were ball milled in ethanol for 24 hours. The milled materials were added to an alumina crucible, calcined at 900 ºC for 4 hours, and milled again. A colloidal deposition of this slurry is prepared with polyvinyl butyral (PVB), benzyl butyl phthalate (BBP), and Solsperse dispersant in ethanol. Calcined powder is added to toluene and ethanol solvents with a binder system containing PVB, BBP, and menhaden fish oil as a dispersant. This preparation is milled for two days, then degassed in preparation for tape-casting. After tape-casting, tapes are drop-coated with the colloidal slurry and another tape is applied on top. This structure is held at 500ºC for 1 hour to burn off binders then heated to 1100 ºC for 1 hour. This produces a three layer porous-dense-porous scaffold of electrolyte that will maintain electronic isolation between electrodes. Symmetric cells with two cathodes are produced by infiltrating a glycine/metal-nitrate solution into the pores of each side and combusting. For two-anode symmetric cells, lithium is lightly pressed into both sides at 350 ºC. Electrochemical impedance spectroscopy was performed between room temperature and 300 ºC using a 10 mV amplitude between 10 MHz and 100 mHz. Electron energy loss spectroscopy was performed on a 2100F TEM equipped with a Gatan Tridiem post-it column energy filter. Results Figure 1 shows a cross section of a lithium-penetrated Li-garnet scaffold showing the fracture plane of the garnet(light) fully coated by the lithium (dark). Figure 2 shows the Nyquist plot of a full cell made with a lithium-penetrated scaffold. The bulk conductivity shown in the inset is fairly low at 20 Ω compared to the 1000 Ω overall cell impedance.

A pair of DNA tweezers are constructed, which are capable of capturing, holding and releasing a DNA object by playing with the open and close actions of the tweezers assisted by pH switchings. The object is captured between the tweezers' arms at pH 5.0 through Hoogsteen hydrogen bonding and can be stably held even when the pH is increased to 5.7 after the tweezers are closed. Upon introducing a DNA unlocker strand, the tweezers are opened and the object gets released. This capture-hold-release process can be easily cycled without losing much of its efficiency.

Paper, as an inexpensive substrate for flexible electronics and energy devices, has garnered great attention because of its abundance, biodegradability, renewability and sustainability. However, the intrinsic opacity and higher roughness of regular paper greatly restricts further applications. One promising method is to use cellulose nanofibers (CNs) to fabricate nanopaper with a high optical transmittance and excellent smoothness, but there are still some challenges facing nanopaper substrates, such as high-energy consumption to extract nanofibers and the time-consuming process to prepare nanopaper. We design a bilayer hybrid paper using unbeaten wood fibers and CNs with a papermaking technique, which achieves a high optical transmittance and superior smoothness while remaining less expensive than nanopaper and useful as a writable surface. The first transparent paper touchscreen with an excellent anti-glare effect in bright environments is demonstrated using our novel transparent and conductive hybrid paper as the flexible electrode.