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Seahorses have a circum-global distribution in tropical to temperate coastal waters. Yet, seahorses show many adaptations for a sedentary, cryptic lifestyle: they require specific habitats, such as seagrass, kelp or coral reefs, lack pelvic and caudal fins, and give birth to directly developed offspring without pronounced pelagic larval stage, rendering long-range dispersal by conventional means inefficient. Here we investigate seahorses’ worldwide dispersal and biogeographic patterns based on a de novo genome assembly of Hippocampus erectus as well as 358 re-sequenced genomes from 21 species. Seahorses evolved in the late Oligocene and subsequent circum-global colonization routes are identified and linked to changing dynamics in ocean currents and paleo-temporal seaway openings. Furthermore, the genetic basis of the recurring “bony spines” adaptive phenotype is linked to independent substitutions in a key developmental gene. Analyses thus suggest that rafting via ocean currents compensates for poor dispersal and rapid adaptation facilitates colonizing new habitats., A new seahorse genome and the re-sequenced genomes of 21 other species shed new light on the evolutionary origin and global dispersal routes of seahorses, and show that bony spines—a key adaptation against predation—probably evolved multiple times via independent substitutions in the bmp3 gene.

We prove that u is constant if u is a bounded solution of $$\begin{aligned} A_{\alpha } u(x) = C_{n,\alpha } \text {P.V.} \int _{\mathbb {R}^n} \frac{a(x-y)(u(x)-u(y))}{|x-y|^{n+\alpha }} \mathrm{d}y=0, \;\; x \in \mathbb {R}^n, \end{aligned}$$ where the function $$a:\mathbb {R}^n \mapsto \mathbb {R}$$ be uniformly bounded and radial decreasing. This result can be regarded as the generalization of usual Liouville theorem. To get the proof, we establish a maximum principle involving the nonlocal operator $$ A_{\alpha }$$ for antisymmetric functions on any half space.

In this paper, we consider equations involving the fully nonlinear fractional order operator with homogeneous Dirichlet condition: \begin{document}$ \begin{cases} F_\alpha(u)(x) = f(x,u,\nabla u) \ \mbox{in} \ \Omega,\\ u>0, \ \mbox{in}\ \Omega; \ u\equiv0, \ \mbox{in}\ \mathbb R^n\backslash\Omega, \end{cases} $\end{document} where \begin{document}$ \Omega $\end{document} is a domain(bounded or unbounded) in \begin{document}$ \mathbb R^n $\end{document} which is convex in \begin{document}$ x_1- $\end{document} direction. By using some ideas of maximum principle, we prove that the solution is strictly increasing in \begin{document}$ x_1- $\end{document} direction in the left half of \begin{document}$ \Omega $\end{document} . Symmetry of solution is also proved. Meanwhile we obtain a Liouville type theorem on the half space \begin{document}$ \mathbb R^n_+ $\end{document} .

Microparticles with carbon microsphere (CMS) cores and poly(methyl methacrylate) (PMMA) shells were successfully synthesized through an aqueous-phase radical polymerization method. The morphologies...

Foodborne viruses are a global threat to food safety. Real-time reverse transcription polymerase chain reaction (RT-PCR) is the most commonly used method to detect viral RNA in food. Armored RNA (AR) prepared using the MS2 phage system is a successful positive control for detecting foodborne viruses and is an important quality control process when using real-time RT-PCR. In this study, we report a novel technology for preparing AR using bacteriophage Qβ and compare its stability with AR prepared using the MS2 phage system for packaging norovirus detection target RNA. AR could be successfully and efficiently produced using the developed bacteriophage Qβ system. Two types of AR–AR-QNoV prepared using the Qβ system and AR-MNoV prepared using the MS2 system—were stored at different temperatures for different durations. After incubating at − 20 °C for 360 days, the copy numbers of AR-QNoV and AR-MNoV decreased by 8.9% and 35.9%, respectively. After incubating at 4 °C for 60 days, the copy numbers of AR-QNoV and AR-MNoV decreased by 12.0% and 38.9%, respectively. After incubating at 45 °C, the copy numbers of AR-QNoV decreased by 71.8% after 5 days, whereas those of AR-MNoV decreased by 92.9% after only 4 days. After 5 days, AR-MNoV could not be detected using real-time RT-PCR. There was a significant difference in copy numbers decrease rate between AR-QNoV and AR-MNoV at three different temperatures (P

We study the Triebel–Lizorkin spaces associated with sections which are closely related to the Monge-Ampere equations and show that Monge-Ampere singular integral operators are bounded on these Tri...

The effect of grain boundary and crystallographic orientation on the stress corrosion behavior of an Al-4.5Zn-1.4Mg alloy was investigated by comparing the performance of constant load stress corrosion test (CLSCT) and tensile test of specimens parallel to the longitudinal and transverse directions of the extruded plate. The results revealed that the strength of the longitudinal and transverse specimens decreased by 9.68 and 18.13%, respectively, after 10-day CLSCT. The transverse specimens show poor resistance to stress corrosion cracking (SCC). The grain boundaries (GB) of the longitudinal section are less dense, and more of them are distributed along the extrusion direction compared with the cross section with selected areas of the same size. The SCC of all specimens starts from the side faces of the specimen, and it is dominated by intergranular cracking. But the corrosion of the transverse specimens was more serious. The cracks of all specimens tend to propagate along the GBs with misorientation of about 50°-60°, and the difference of Schmidt factor (SF) values of grains on both sides of the crack is significantly large. The crack of longitudinal specimens propagates relatively parallel to the tensile direction, while propagation of the crack in transverse specimens is more zigzag.

Perfluorooctanoic acid (PFOA), a persistent environmental contaminant, resists environmental degradation and bioaccumulates in food chains. Lots of literatures have proved that PFOA exposure could disrupt detoxifying function in a variety of organisms, however, it still remained poorly known about this in mollusk. Here, we examined physiological, transcriptomic, and metabolomic responses to PFOA in Mytilus edulis, a model organism frequently used in studies of aquatic pollution. We aimed to characterize PFOA-induced stress responses and detoxification mechanisms. PFOA exposure significantly altered antioxidant enzyme activity levels and the abundances of lipid peroxidation products. In addition, transcriptomic analysis indicated that several genes associated with oxidative stress and detoxication were differentially expressed after PFOA exposure. In combination, transcriptomic and metabolomic analyses showed that PFOA exposure disturbed several metabolic processes in M. edulis, including the lipid metabolism, amino acid metabolism, and carbohydrate metabolism etc. Molecular examination and enzymes assay of PFOA-exposed M. edulis after a 7-day depuration period still did not recover to control levels. The Pathway enrichment analysis proved that several pathways related to detoxification, such as c-Jun N-terminal kinase (JNK) and p38-dependent mitogen-activated protein kinase (MAPK) pathway, Peroxisome proliferator-activated receptor γ (PPARγ) pathway etc, were obviously affected. The present work verifies firstly PFOA disruption to molluscan detoxification and identifies the key pathways to understand the molecular mechanisms thereof. This study provides new insights into the detoxication disruption invoked in response to PFOA exposure in M. edulis.

A new species of grouper, Epinephelus tankahkeeisp. nov. is described from the South China Sea based on examination of morphological and molecular characteristics. This new species has been treated as, and is similar to, its congener E. chlorostigma. Epinephelus tankahkeeisp. nov. can be distinguished from E. chlorostigma by the following combination of characters: a convex anal fin; closer dark spots on the body; a lack of dark spots on the abdomen, cheek, and pectoral fin; the absence of a clear posterior white margin on the caudal fin. Molecular analyses of the mitochondrial COI sequence variation, genetic distances, and a phylogeny, all highly support E. tankahkeeisp. nov. as a distinct species. A key to E. tankahkeeisp. nov. and its most closely related species is provided.

The Thunnini, or tuna, comprise many species with very different commercial values. The principal raw tuna product on the market is sashimi, for which the species used is difficult to identify through conventional morphological analysis. The present study amplified the cytochrome b gene (Cytb) of 4 major tuna species used for preparing sashimi—yellowfin tuna (Thunnus albacares), southern bluefin tuna (Thunnus maccoyii), bigeye tuna (Thunnus obesus), and Atlantic bluefin tuna (Thunnus thynnus)—and 4 species commonly mislabeled as components of tuna sashimi—albacore tuna (Thunnus alalunga), skipjack tuna (Katsuwonus pelamis), striped marlin (Tetrapturus audax), and swordfish (Xiphias gladius). Polymerase chain reaction (PCR) amplicons were digested with 5 restriction enzymes—Eco147 I, Hinf I, Mbo I, Xag I, and Hind II—to obtain characteristic restriction maps of the above‐mentioned raw tuna species and the commonly mislabeled species. An identification method using PCR restriction fragment length polymorphism (PCR‐RFLP) was established and validated using 39 commercial tuna sashimi samples, which verified that this method provides results consistent with those obtained by classical sequencing. PCR‐RFLP has several advantages over classical sequencing, such as simplicity, speed and accuracy. This technique could support species identification for raw tuna and sashimi., Find out the restriction fragment length polymorphism in the Cyt b gene of most common kinds of tuna for sashimi preparation. Established a simply and accurate method for most common kinds of tuna identification. This method provides the technology needed to support the rapid identification of raw tuna species for quality inspections and scientific research.

The purpose of this study was to evaluate the effect of hot-etching surface treatment on the shear bond strength between zirconia ceramics and resin cement. Ceramic cylinders were divided randomly into 10 groups (n = 10) according to different surface treatments (blank control; airborne particle abrasion; hot-etching for 10 min; hot-etching for 30 min; hot-etching for 60 min) and whether or not performed thermal cycling fatigue test. Flat enamel surfaces, were prepared from human permanent incisors and were bonded to the zirconia discs. All specimens were subjected to shear bond strength test by a universal testing machine. All data were statistically analysed using one-way analysis of variance and multiple comparison least significant difference tests (α = 0.05). Hot-etching for 60 min treatment produced higher bond strengths than the other treatment. Surface treatment of zirconia with a hot-etching solution might enhance surface roughness and bond strength between zirconia and resin cement.

In this paper, we consider the following nonlinear Schrödinger system involving the fractional Laplacian operator: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \textstyle\begin{cases} (-\Delta)^{\frac{\alpha}{2}}u+au=f(v), \\ (-\Delta)^{\frac{\beta}{2}}v+bv=g(u), \end{cases}\displaystyle \quad \text{on } \Omega\subseteqq \mathbb{R}^{n}, $$\end{document}{(−Δ)α2u+au=f(v),(−Δ)β2v+bv=g(u),on Ω⫅Rn, where \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$a,b\geq0$\end{document}a,b≥0. When Ω is the unit ball or \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathbb{R}^{n}$\end{document}Rn, we prove that the solutions \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$(u,v)$\end{document}(u,v) are radially symmetric and decreasing. When Ω is the parabolic domain on \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathbb{R}^{n}$\end{document}Rn, we prove that the solutions \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$(u,v)$\end{document}(u,v) are increasing. Furthermore, if Ω is the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathbb{R}^{n}_{+}$\end{document}R+n, then we also derive the nonexistence of positive solutions to the system on the half-space. We assume that the nonlinear terms f, g and the solutions u, v satisfy some amenable conditions in different cases.

Based on the theory of variable exponents and atomic decomposition, we study the boundedness of $n$ -dimensional fractional Hardy operators on variable Herz and Herz-type Hardy spaces, where the three main indices are variable exponents. The corresponding boundedness for the $m$ th order commutators generated by the $n$ -dimensional fractional Hardy operators and bounded mean oscillation (BMO) function are also considered. We note that, even in the special case of $m=1$ , the obtained results are also new.

In recent years, there has been a surge of interests in interpretable graph reasoning methods. However, these models often suffer from limited performance when working on sparse and incomplete graphs, due to the lack of evidential paths that can reach target entities. Here we study open knowledge graph reasoning---a task that aims to reason for missing facts over a graph augmented by a background text corpus. A key challenge of the task is to filter out "irrelevant" facts extracted from corpus, in order to maintain an effective search space during path inference. We propose a novel reinforcement learning framework to train two collaborative agents jointly, i.e., a multi-hop graph reasoner and a fact extractor. The fact extraction agent generates fact triples from corpora to enrich the graph on the fly; while the reasoning agent provides feedback to the fact extractor and guides it towards promoting facts that are helpful for the interpretable reasoning. Experiments on two public datasets demonstrate the effectiveness of the proposed approach. Source code and datasets used in this paper can be downloaded at https://github.com/shanzhenren/CPL

We study the Besov spaces associated with a family of parabolic sections which are closely related to the parabolic Monge-Ampere equation. We demonstrate their duals under the doubling property only, and show an embedding theorem for these Besov spaces under the doubling property with a lower bound condition.

Sea ice leads promote mass and energy exchange between the atmosphere and the Arctic Ocean. The continuous thinning of sea ice and the enhanced sea ice mobility in the past decades can potentially change the seasonal cycle and interannual variability of lead distribution in the Arctic, especially during spring. However, the long-term trend in Arctic leads, associated with sea ice loss, remains inconclusive. Sequential lead distribution data from serial middle- or high- resolution satellite observations are needed to obtain realistic variation, trends, and lead characteristics on a regional or basin scale. This study proposed a modified algorithm to retrieve daily spring leads in the Beaufort Sea using temperature anomaly from Terra/MODIS thermal imagery. Our lead map was compared to existing lead datasets and validated by Landsat-8 images, showing that the modified method gave better results in identification of open water leads and refrozen leads covered by thin ice. The development and interannual trend for April leads were explored for the study period 2001–2020. We found a positive interannual trend in the April lead area of about 2612 ± 1245 km2/year (90% confidence). Higher increasing rate was identified in the early April, which would be 26.4– 29.2% lower if the influence from cloud variation was removed. Lead area presents a close correlation with the 11-day average of ice drift speed before lead detection, while the influence of regional pressure gradient and easterly wind on the lead area is limited to the synoptic scale and recedes within a week. In the years with anomalous large lead area, we found the detected lead area are closely related to enhanced ice motion driven by strengthening Beaufort High and persistent easterly wind.

A novel solid acid was prepared by impregnating trifluoromethanesulfonic acid (TFMSA) onto mesoporous ZrO 2 coated attapulgite (MPZCA) via one-pot synthesis method. Dibenzyl ether (DBE) was used as a coal-related model compound to evaluate the catalytic activity of TFMSA/MPZCA for cleaving C alk –O bridged bonds in low-rank coals. The results show that DBE conversion over TFMSA/MPZCA could reach 100% at 160 °C in C 2 H 5 OH without charging H 2 . TFMSA/MPZCA proved to be stable after 4 cycles with only slight loss in catalytic activity. Moreover, a H + transfer mechanism was proposed, which reasonably deduces possible pathways for DBE hydrocracking over TFMSA/MPZCA.

A novel solid acid was prepared by impregnating trifluoromethanesulfonic acid (TFMSA) onto attapulgite powder (AP). Benzyloxybenzene (BOB) was used as a lignite-related model compound to evaluate the catalytic activity of TFMSA/AP for cleaving C alk –O bridged bonds in lignites. The results show that BOB was mainly hydrocracked to toluene, phenol, and (ethoxymethyl)benzene over TFMSA/AP in ethanol without adding gaseous hydrogen. In addition, ethanol participated in and significantly facilitated BOB hydrocracking. Based on the kinetic investigation, BOB hydrocracking over TFMSA/AP is absent of mass transfer limitations with the apparent activation energy of only 19.4 kJ mol − 1 , which is far smaller than the dissociation energy (209.2 kJ mol − 1 ) of C alk –O bridged bond in BOB. The proton transfer directly from TFMSA/AP and/or via ethanol dehydrogenation to the oxygen atom of BOB could be the crucial step for BOB hydrocracking over TFMSA/AP.

Precipitate hardening through coherent particles is an important strengthening mechanism in Ni-based IN718 superalloy. The change of coherency state, e.g., loss of coherency, can affect the precipitation kinetics and the efficacy of precipitate hardening. In this work, we predict the critical size of $$ \gamma^{\prime\prime} $$ -Ni3Nb precipitates in IN718 to trigger coherency loss using the phase-field approach with available materials parameters from first-principles calculations and from the literature. The predicted critical size lies within the range of experimentally reported values. The effect of coherency loss on precipitate morphology and kinetics, as well as the aging time to reach this critical size during heat treatment, is also predicted and discussed. These predictions provide guidance in controlling the size of $$ \gamma^{\prime\prime} $$ precipitates and optimizing the strength of IN718 alloys.

BST2 is a single-pass type II transmembrane (TM) protein, which has a cytoplasmic domain, a transmembrane domain, and an extracellular domain, each domain is important for biologic function of BST2. BST2 is a host restriction factor that can effectively inhibit retrovirus release. Rhesus monkeys are considered as relevant natural animal models for studying AIDS in humans. In order to recognize rhesus BST2 (RhBST2) protein and detect its function accurately, we prepared a polyclonal antibody (pAb) especially for RhBST2. Meanwhile, we constructed RhBST2 proteins with the addition of an HA-tag at the N-terminus (RhBST2-NHA) or inside of the ectodomain (RhBST2-IHA) to compare the recognition ability of rabbit anti-RhBST2 pAb and anti-HA mAb. The results showed that the anti-HA mAb and rabbit anti-RhBST2 pAb had the same ability to identify RhBST2. RhBST2 demonstrated antiviral activity and the ability to activate NF-κB. Moreover, the N-glycosylation states, cell surface level and intracellular localization of RhBST2 were detected. However, HA tags relatively changed part of the biological function of RhBST2. These results show that the RhBST2 polyclonal antibody is more suitable for analyzing the properties and functions of RhBST2, and the natural domain of RhBST2 is very important for its function.

Accurate and high-resolution sea ice surface temperature (IST) data is of great importance for Arctic climate studies. However, the validation of high-resolution IST data using in situ measurements in polar sea ice regions is lacking. This study assesses the accuracy of three split-window (SW) and two single-channel (SC) methods, based on Landsat 8 thermal infrared imagery at 100 m resolution over Arctic sea ice regions. The SW methods are proposed by Jin et al. (2015) (SW-Jin), Jimenez-Munoz et al. (2014) (SW-JM), and Du et al. (2015) (SW-Du). The SC methods are proposed by Jimenez-Munoz et al. (2014) (SC-JM) and Barsi et al. (2003, 2005) (SC-Barsi). IST data derived from 58 scenes of the Landsat 8 images were compared with coincident in situ ice skin temperatures and near-surface air temperatures, as measured by a combination of Ice Mass Balance (IMB) buoys, Snow and Ice Mass Balance Array (SIMBA) buoys, and automatic weather stations. SW-Du offers the best accuracy when compared with the skin temperature (bias: −1.06 K; root mean square error (RMSE): 2.08 K) and near-surface air temperature (bias: -0.98 K; RMSE: 2.17 K). SC-Barsi ranks second, with a bias of −1.55 K and RMSE of 2.40 K for the skin temperature. As for precision, IST from the Moderate Resolution Imaging Spectrometer (MODIS) has best performance (standard deviation (STD): 1.69 K), followed by SW-Du, SW-JM, and SC-Barsi (STD: 1.80 K, 1.82 K, and 1.85 K, respectively). The Landsat IST outperforms the MODIS IST in narrow lead areas, owing to its better spatial resolution, and SW-JM and SC-Barsi methods agree best with the MODIS IST in leads and marginal ice zone scenes, respectively. As all three SW methods are constrained by banding effects with different degrees in a lead scene, they are not recommended to be applied on an image scene with severe banding artifacts. The small bias (1.26 K) and high correlation (0.99) between skin temperature and near-surface air temperature prove the capability of using near-surface air temperature as a substitute for validating a satellite IST data if skin temperature data are not available.

In recent years, much attention has been paid to the behavior of passive microwave sea ice concentration (SIC) products for marginal ice zones. Based on the definition of ice edges from ship observations, we identified pseudo-ship observations (PSO) and generated PSO ice edges from twelve cloud-free moderate-resolution imaging spectroradiometer (MODIS) images. Two SIC products of the advanced microwave scanning radiometer 2 (AMSR2) were compared at the PSO ice edges: ARTIST (arctic radiation and turbulence interaction study) sea ice (ASI-SIC) and bootstrap (BST-SIC). The mean values of ASI-SIC pixels located at ice edges were 10.5% and 10.3% for the Arctic and the Antarctic, respectively, and are below the commonly applied 15% threshold, whereas the mean values of corresponding BST-SIC pixels were 23.6% and 27.3%, respectively. The mean values of both ASI-SIC and BST-SIC were lower in summer than in winter. The spatial gaps among the 15% ASI-SIC ice edge, the 15% BST-SIC ice edge and the PSO ice edge were mostly within 35 km, whereas the 15% ASI-SIC ice edge matched better with the PSO ice edge. Results also show that the ice edges were located in the thin ice region, with a mean ice thickness of around 5–8 cm. We conclude that the 15% threshold well determines the ice edge from passive microwave SIC in both the Arctic and the Antarctic.

The rapid development of knowledge graphs (KGs), such as Freebase and WordNet, has changed the paradigm for AI-related applications. However, even though these KGs are impressively large, most of them are suffering from incompleteness, which leads to performance degradation of AI applications. Most existing researches are focusing on knowledge graph embedding (KGE) models. Nevertheless, those models simply embed entities and relations into latent vectors without leveraging the rich information from the relation structure. Indeed, relations in KGs conform to a three-layer hierarchical relation structure (HRS), i.e., semantically similar relations can make up relation clusters and some relations can be further split into several fine-grained sub-relations. Relation clusters, relations and sub-relations can fit in the top, the middle and the bottom layer of three-layer HRS respectively. To this end, in this paper, we extend existing KGE models TransE, TransH and DistMult, to learn knowledge representations by leveraging the information from the HRS. Particularly, our approach is capable to extend other KGE models. Finally, the experiment results clearly validate the effectiveness of the proposed approach against baselines.

Groupers (family Epinephelidae) are an assemblage of coral reef fishes comprising more than 160 species in 16 genera, many of which are both environmentally and economically valuable. Because of their similar morphology, variable color patterns, and tendency for interspecies hybridization, morphological identification of groupers usually leads to taxonomic confusion. To find an effective method for identifying different grouper species and hybrids, evaluate genetic diversity and uncover any synonymous or cryptic species, we sampled a total of 221 specimens representing 57 species in 9 genera in the China Seas. Both mitochondrial (mt) cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 2 (ND2) were found to be effective barcoding genes. We also developed an efficient protocol for identifying hybrid groupers using mt markers and the nuclear RYR3 gene and found the first record of wide interspecies hybridization in genus Epinephelus. This barcoding study revealed high genetic divergence in many widespread species and possible synonyms. In addition to providing a molecular method for identifying grouper species, this study offers important resources for the further study of grouper conservation genetics, speciation, hybridization and other evolutionary traits.

Highly nanoporous surfaces were observed on the underside of Ni splats. Experiments varying process parameters and substrate treatments were performed to determine the mechanism of pore formation. A theory of impact-induced bubble nucleation and freezing into pores is presented, and calculations are compared with experimental results. Pore formation and morphology is strongly dependent on substrate (a) thermal properties as they affect time for bubble growth before solidification into pores and (b) roughness as submicron scratches enhance nucleation by providing heterogeneous sites and several micron grooves reduce the driving force for nucleation. Splat pull-off experiments are shown that suggest bubble nucleation and pore formation strongly affect adhesion, and represent a strong contribution to the effectiveness of surface roughening. Finally, this observation shows the potential for the manufacturing of high-surface area materials using thermal spray.

In this note, we prove that the fractional integral operators from Herz spaces with variable exponent $\dot{K}^{\alpha}_{p(\cdot), q}$ to Lipschitz-type spaces are bounded provided $p(\cdot)$ is locally log-Holder continuous and log-Holder continuous at infinity.

By decomposing functions, we establish some boundedness results for some rough singular integrals on the homogeneous Morrey-Herz spaces $M\dot{K}_{q, p(\cdot)}^{\alpha(\cdot),\lambda}({\Bbb{ R}}^{n})$ , where the two main indices are variable. The corresponding results as regards their commutators are also considered.