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To meet the demand of various high-speed data rate services as well as serving an exponential increment of mobile devices, millimeter-Wave (mmWave) communication in ultra-dense networks (UDNs) has been considered as a promising technology for future wireless communication systems. By deploying multiple small-cell base stations (SBSs), the dense topology combining high frequency mmWave is expected to grow not only the users (UEs) throughput but also the energy efficiency (EE) of the whole networks. Exploiting the benefits from mmWave and UDNs, in this paper, we introduce a new approach for jointly optimizing SBS-UE association and power allocation to maximize the system EE while guaranteeing the quality of service (QoS) constraints for each UE. Specifically, the throughput fairness among UEs is also taken into account by formulating UE throughput maxmin problem. Unfortunately, such SBS-UE association problem poses a new challenge since it reflects as a complex mixed-integer non-convex problem. On the other hand, the power allocation problem is in nonconvexity structure, which is impossible to handle with the association problem concurrently. Tackling those issues, an alternating descent method is proposed to separate the primal optimization problem into two subproblems and handle one-by-one at each iteration. In particular, the SBS-UE association problem is reformulated using the penalty approach. Then, successive convex programming is developed to convert non-convex problem into the simple convex quadratic functions at each iteration. Numerical results are provided to demonstrate the convergence and low-complexity of our proposed schemes, where the increment of the objective function is guaranteed at each iteration. [ABSTRACT FROM AUTHOR]

Although seafloor massive sulfide (SMS) deposits are crucially important metal resources that contain high‐grade metals such as copper, lead, and zinc, their internal structures and generation mechanisms remain unclear. This study obtained detailed near‐seafloor images of electrical resistivity in a hydrothermal field off Okinawa, southwestern Japan, using deep‐towed marine electrical resistivity tomography. The image clarified a semi‐layered resistivity structure, interpreted as SMS deposits exposed on the seafloor, and another deep‐seated SMS layer at about 40‐m depth below the seafloor. The images reinforce our inference of a new mechanism of SMS evolution: Upwelling hydrothermal fluid is trapped under less‐permeable cap rock. The deeper embedded SMS accumulates there. Then hydrothermal fluids expelled on the seafloor form exposed SMS deposits. Plain Language Summary: Hydrothermal circulation of seawater through the permeable ocean crust engenders formation of seafloor massive sulfide (SMS) deposits, which present high potential for metal mining. Geophysical surveys using modes such as electrical and electromagnetic methods have revealed that SMS deposits exhibit lower resistivity than the surrounding host rock. However, because detailed geophysical images of internal structures of SMS deposits are lacking, the spatial distribution of SMS deposits and the evolutionary processes of SMS deposits remain unclear. For this study, we applied a deep‐towed marine electrical resistivity tomography (ERT) system to capture detailed images of electrical resistivity structures of SMS deposits in the Iheya North hydrothermal field, Okinawa Trough, southwestern Japan. An optimal sub‐seafloor resistivity section reveals a semi‐layered structure consisting of double low‐resistivity SMS layers: exposed and deep‐seated ones. Between the SMS layers, a cap rock layer is recognized as a moderately resistive zone. This detailed structure offers an explanation of how the SMS deposits accumulate: Hydrothermal fluids upwelling from the deep crust are trapped by less‐permeable cap rock, which results in the precipitation and accumulation of SMS deposits below the cap rock. Then fluids passing through the cap rock to the seafloor produce SMS deposits on the seafloor. Key Points: Deep‐towed marine electrical resistivity tomography revealed massive sulfide deposits on the seafloor as low‐resistivity zonesLow‐resistivity zones are semi‐layered with deposits exposed on the seafloor and other deposits at 40‐m depth below the seafloorDetailed near‐seafloor images of electrical resistivity offer an explanation of how the SMS deposits accumulate [ABSTRACT FROM AUTHOR]

Single-pancake coils having different winding turns are fabricated. The bobbin material used for the coils is a Dyneema fiber-reinforced plastic (DFRP), which has a thermal expansion property during cooling. The influence of the DFRP's expansion on thermal strains of the coil during cooling is experimentally estimated. In the experiment, the thermal strains on the superconducting tape of the outermost turns in the coils are measured. The dependence of epoxy impregnation on the thermal strain of the coil is also experimentally estimated. According to the experimental data, the combination of impregnation and the bobbin's expansion effectively decreases thermal contraction of the outermost tape. [ABSTRACT FROM PUBLISHER]

The purpose of this study is to identify the underlying differences between patients with white matter lesions (WMLs) who manifested gait disturbance suggestive of vascular parkinsonism (VaP) and those who did not, using the PET scan. Fourteen patients with extensive WMLs, as determined by MRI, were divided into two groups – 7 with gait disturbance and 7 without it. Neuronal integrity was evaluated with a PET scan using [11C]flumazenil (FMZ) by calculating the distribution volume of FMZ (FMZ-Vd) in various regions of interest by non-linear curve fitting. Additionally, tracer kinetic analysis was applied for voxel-by-voxel quantification of FMZ-Vd and data analysis was performed using statistical parametric mapping. The striatal FMZ-Vd values were inversely correlated with the motor UPDRS scores ( r = 0.70, p < 0.005), and their reductions were associated with the presence of gait disturbance. Therefore, differences in neuronal integrity in the striatum may determine whether patients with WMLs develop VaP or not. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor on aggregation behaviors of AB-type brush-block-brush amphiphilic copolymers in aqueous media.

Presents a letter to the editor on the architecture of shell-crosslinked polymer nanoparticles via a living radical mechanism and modification to hollow nanocapsules.

The article informs that comb copolymers with densely grafted side chains in a good solvent can adopt a worm-like cylindrical brush conformation, in which the side chains are stretched in the direction normal to the backbone owing to the excluded volume interaction. Polymerizations of macromonomers provide regular multi-branched polymers with dense branching. Since both degree of polymerization and the length of branches are varied, poly-macromonomers, often so-called "polymer brushes," are interesting models for the study of branched polymers. Free-radical copolymerization of binary macro-monomers will form copolymers with not only comb-shaped but also hetero-armed structures.

focuses on the architecture of nanocylinders with hyperbranched polymer side groups via living radical mechanism. Synthetic strategy of nanocylinders with hyperbranched polymer side groups; Formation of the anchor groups of the polymer by hyperbranched structures; Removal of nanocylinder polymer from the copolymerization product; Characteristics of nanocylinders.

The X-band and Q-band ESR spectra of Mn(II) ion in Chinese limnetic pearls have been studied. No ESR signal of melanin-like radical has been detected. A method of theoretical treatment on ESR spectrum of Mn(II) ion has been modified. Using it, the parameters of zero field splitting D=224 Gs, E=74 Gs and E/D=0.33 for Chinese limnetic pearls with bright pearlite colour have been calculated. The computer simulation has been done using experimental ESR spectra parameters, and satisfactory results have been obtained. [ABSTRACT FROM AUTHOR]

Vinylbenzyl-terminated polystyrene (PS) macromonomers were prepared by the direct reaction of living PS anions with p-chloro-methylstyrene (CMS). The propagation rate constant (k p) was obtained from free-radical polymerization of PS macromonomers in the presence of 1-buten-3-ol as a degradative chain transfer agent by using gel permeation chromatography (GPC) analysis. In this condition, the polymer radicals were terminated by a unimoiecular mechanism. Subsequently, we studied the radical propagation step of vinylbenzyl-terminated diblock poly[styrene (S)-b-isoprene (I)] and poly[S-b-2-vinylpyridine (2VP)] macromonomers in benzene. The vinylbenzyl groups at the terminal ends of diblock macromonomers apparently take the concentrated state in micelles. These results are discussed from the point of view of polymer-polymer reactions. [ABSTRACT FROM PUBLISHER]