Differential variational-hemivariational inequalities: existence, uniqueness, stability, and convergence

The goal of this paper is to study a comprehensive systemcalled differential variational–hemivariational inequality which is com-posed of a nonlinear evolution equation and a time-dependentvariational–hemivariational inequality in Banach spaces. Under the gen-eral functional framework, a generalized existence theorem for differ-ential variational–hemivariational inequality is established by employ-ing KKM principle, Minty’s technique, theory of multivalued analysis,the properties of Clarke’s subgradient. Furthermore, we explore a well-posedness result for the system, including the existence, uniqueness, andstability of the solution in mild sense. Finally, using penalty methods tothe inequality, we consider a penalized problem-associated differentialvariational–hemivariational inequality, and examine the convergence re-sult that the solution to the original problem can be approached, as aparameter converges to zero, by the solution of the penalized problem

Spatio-Temporal Change of LakeWater Extent in Wuhan Urban Agglomeration Based on Landsat Images from 1987 to 2015

Urban lakes play an important role in urban development and environmental protection for the Wuhan urban agglomeration. Under the impacts of urbanization and climate change, understanding urban lake-water extent dynamics is significant. However, few studies on the lake-water extent changes for the Wuhan urban agglomeration exist. This research employed 1375 seasonally continuous Landsat TM/ETM+/OLI data scenes to evaluate the lake-water extent changes from 1987 to 2015. The random forest model was used to extract water bodies based on eleven feature variables, including six remote-sensing spectral bands and five spectral indices. An accuracy assessment yielded a mean classification accuracy of 93.11%, with a standard deviation of 2.26%. The calculated results revealed the following: (1) The average maximum lake-water area of the Wuhan urban agglomeration was 2262.17 km2 from 1987 to 2002, and it decreased to 2020.78 km2 from 2005 to 2015, with a loss of 241.39 km2 (10.67%). (2) The lake-water areas of loss of Wuhan, Huanggang, Xianning, and Xiaogan cities, were 114.83 km2, 44.40 km2, 45.39 km2, and 31.18 km2, respectively, with percentages of loss of 14.30%, 11.83%, 13.16%, and 23.05%, respectively. (3) The lake-water areas in the Wuhan urban agglomeration were 226.29 km2, 322.71 km2, 460.35 km2, 400.79 km2, 535.51 km2, and 635.42 km2 under water inundation frequencies of 5%–10%, 10%–20%, 20%–40%, 40%–60%, 60%–80%, and 80%–100%, respectively. The Wuhan urban agglomeration was approved as the pilot area for national comprehensive reform, for promoting resource-saving and environmentally friendly developments. This study could be used as guidance for lake protection and water resource management

DNA barcoding of marine fish species in the waters surrounding Hainan Island, northern South China Sea

IntroductionHainan Island is encompassed within the shallow waters of the tropical continental shelf in China, which is recognized as a significant hotspot for fish biodiversity. Despite extensive research conducted on marine fish taxonomy surrounding Hainan Island, there remains a substantial gap between our current understanding and the actual fish diversity within this oceanic area.MethodsIn this study, we employed DNA barcoding and molecular identification approaches to explore the species diversity and distribution pattern of marine fish in both the northern and southern sea areas of Hainan Island in the northern South China Sea.ResultsA total of 186 sequences were obtained from the collected marine fish samples in the two sea areas surrounding Hainan Island. Through DNA identification, it was confirmed that all 186 sequences corresponded to typical fish species found in the northern South China Sea, all sequences represented a total of 56 species, 47 genera, 34 families, and 17 orders. The average Kimura 2-parameter (K2P) distances within species, genus, family, order and class were 0.15%, 6.53%, 13.17%, 16.95% and 24.81%, respectively.DiscussionOur investigation in the northern sea areas of Hainan Islands identified a total of 33 distinct species, while the southern sea areas exhibited 29 distinct species, with only 5 species found to be shared between both regions. These findings clearly indicate a significant disparity in the species composition of fish communities between the northern and southern sea regions

Spatio-Temporal Change of LakeWater Extent in Wuhan Urban Agglomeration Based on Landsat Images from 1987 to 2015

Urban lakes play an important role in urban development and environmental protection for the Wuhan urban agglomeration. Under the impacts of urbanization and climate change, understanding urban lake-water extent dynamics is significant. However, few studies on the lake-water extent changes for the Wuhan urban agglomeration exist. This research employed 1375 seasonally continuous Landsat TM/ETM+/OLI data scenes to evaluate the lake-water extent changes from 1987 to 2015. The random forest model was used to extract water bodies based on eleven feature variables, including six remote-sensing spectral bands and five spectral indices. An accuracy assessment yielded a mean classification accuracy of 93.11%, with a standard deviation of 2.26%. The calculated results revealed the following: (1) The average maximum lake-water area of the Wuhan urban agglomeration was 2262.17 km2 from 1987 to 2002, and it decreased to 2020.78 km2 from 2005 to 2015, with a loss of 241.39 km2 (10.67%). (2) The lake-water areas of loss of Wuhan, Huanggang, Xianning, and Xiaogan cities, were 114.83 km2, 44.40 km2, 45.39 km2, and 31.18 km2, respectively, with percentages of loss of 14.30%, 11.83%, 13.16%, and 23.05%, respectively. (3) The lake-water areas in the Wuhan urban agglomeration were 226.29 km2, 322.71 km2, 460.35 km2, 400.79 km2, 535.51 km2, and 635.42 km2 under water inundation frequencies of 5%–10%, 10%–20%, 20%–40%, 40%–60%, 60%–80%, and 80%–100%, respectively. The Wuhan urban agglomeration was approved as the pilot area for national comprehensive reform, for promoting resource-saving and environmentally friendly developments. This study could be used as guidance for lake protection and water resource management

Electronic and Optical Properties of Low-Dimensional B2CN Nanomaterials from First Principles

National Science Foundation of China [21133007, 20873105]; Ministry of Science and Technology [2011CB808504]The structures and electronic and optical properties of B2CN sheet and single-walled B2CN nanotubes were investigated by the first-principles density functional calculations. By rolling up the planar low-energy B2CN nanosheets along various chiral vectors, four types of zigzag and armchair B2CN nanotubes were constructed. The present calculations show that the structural and electronic properties of B-rich B2CN nanotubes strongly depend on their sizes and chiralities. The zigzag and armchair B2CN nanotubes with the small diameter generally are semiconductors, and their band gaps decrease as the tube-radius increases. When the diameter of tubes is large enough, the four kinds of nanotubes may produce the electronic behavior transitions from semiconductor to metal. Owing to the electronic affinity difference among B, C, and N atoms, there are remarkable charge transfers from B to C and N atoms in B2CN nanostructures. The predicted dielectric and optical properties show that the zigzag and armchair B2CN nanotubes are the optical anisotropy with respect to light polarization, and their absorption spectra are sensitive to the chirality of tube

Offline/Online Outsourced Attribute-Based Encryption with Partial Policy Hidden for the Internet of Things

In the Internet of Things (IoT) environment, the intelligent devices collect and share large-scale sensitive personal data for a wide range of application. However, the power of storage and computing of IoT devices is limited, so the mass perceived data will be encrypted and transmitted to a cloud platform-interconnected IoT devices. Therefore, the concern how to save the encryption/decryption cost and preserve the privacy of the sensitive data in IoT environment is an issue that deserves research. To mitigate these issues, an offline/online attribute-based encryption scheme that supports partial policy hidden and outsourcing decryption will be proposed. This scheme adopts offline/online attribute-based encryption algorithms; then, the key generation algorithm and encryption algorithm are divided into two stages: offline stage and online stage. Meanwhile, in order to solve the problem of policy disclosure under the cloud platform, the policy hidden is supported, that is, the attribute is divided into the attribute value and the attribute name. For the pairing operation involved in decryption process, a verifiable outsourced decryption is implemented. Our scheme is constructed based on composite bilinear groups, which meets full security under the standard model. Finally, by comparing with other schemes in terms of functionality and computational overhead, it is shown that the proposed scheme is more efficient and applicable to the mobile devices with limited computing and storage functions in the Internet of Things environment

On the well-posedness of differential quasi-variational-hemivariational inequalities

The goal of this paper is to discuss the well-posedness and the generalized well-posedness of a new kind of differential quasi-variational-hemivariational inequality (DQHVI) in Hilbert spaces. Employing these concepts, we explore the essential relation between metric characterizations and the well-posedness of DQHVI. Moreover, the compactness of the set of solutions for DQHVI is delivered, when problem DQHVI is well-posed in the generalized sense

A Facile Approach for the Preparation of Nano-size Zinc Oxide in Water/Glycerol with Extremely Concentrated Zinc Sources

Abstract A facile process to prepare zinc oxide (ZnO) nanoparticles from an aqueous zinc chloride (ZnCl2) solution and an aqueous hydroxide solution under a glycerol stabilizer at room temperature was developed. ZnCl2 aqueous solutions as concentrated as 65–80 wt% were used as the concentrated zinc source. The concentration of ZnCl2 solutions and the molar ratio of glycerol to Zn2+ had obvious effects on the sizes and shapes of the ZnO nanoparticles. The shape of ZnO nanoparticles changed from rods approximately 50–120 nm long and 30–70 nm in diameter to globular with diameters of approximately 20 nm with the increasing of the concentration of the ZnCl2 solution and the mole ratio of glycerol to Zn2+. Glycerol, as a stabilizer, played an important role in the formation of ZnO nanostructures at room temperature, even for a highly concentrated zinc source

Effects of Dodonaea viscosa Afforestation on Soil Nutrients and Aggregate Stability in Karst Graben Basin

Dodonaea viscosa is widely cultivated in the karst graben basin and is crucial for recovering land after rocky desertification. However, the effect of long–time D. viscosa afforestation on changes in the quality of soil remains unclear. Soil nutrients and aggregate composition can be used to evaluate the beneficial effects of afforestation of D. viscosa in improving soil functional stability. In this study, soil nutrients and aggregate stability were investigated using cropland, 10–year, 20–year, and 40–year D. viscosa afforestation and secondary succession shrub. Compared to the cropland, D. viscosa afforestation significantly increased the soil water content (WC), soil organic carbon (SOC), and total nitrogen (TN) contents, with an enhanced effect observed with prolonged afforestation. Soil nutrient contents under D. viscosa afforestation rapidly reached the level of the shrub. Dodonaea viscosa afforestation promoted the formation of >2 mm aggregates and decreased the ratio of 0.053–0.25 mm aggregates, which varied with afforestation years. Compared to the cropland, the content of >0.25 mm water–stable aggregates (R>0.25), mean weight diameter (MWD), and geometric mean weight diameter (GMD) of soil increased exponentially. However, soil erodibility factor (K) and unstable aggregates index (EIt) decreased exponentially with prolonged D. viscosa afforestation, and the latter two indicators did not reach the level of the shrub. These results indicated that soil nutrients, aggregate stability, and erosion resistance increased with prolonged D. viscosa afforestation. However, the aggregate stability and erosion resistance exhibited by D. viscosa could not reach the level of secondary shrub for a long time

Electronic and Optical Properties of Low-Dimensional B(2)CN Nanomaterials from First Principles

The structures and electronic and optical properties of B(2)CN sheet and single-walled B(2)CN nanotubes were investigated by the first-principles density functional calculations. By rolling up the planar low-energy B(2)CN nanosheets along various chiral vectors, four types of zigzag and armchair B(2)CN nanotubes were constructed. The present calculations show that the structural and electronic properties of B-rich B(2)CN nanotubes strongly depend on their sizes and chiralities. The zigzag and armchair B(2)CN nanotubes with the small diameter generally are semiconductors, and their band gaps decrease as the tube-radius increases. When the diameter of tubes is large enough, the four kinds of nanotubes may produce the electronic behavior transitions from semiconductor to metal. Owing to the electronic affinity difference among B, C, and N atoms, there are remarkable charge transfers from B to C and N atoms in B(2)CN nanostructures. The predicted dielectric and optical properties show that the zigzag and armchair B(2)CN nanotubes are the optical anisotropy with respect to light polarization, and their absorption spectra are sensitive to the chirality of tube.National Science Foundation of China[21133007, 20873105]; Ministry of Science and Technology[2011CB808504