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A near-infrared fluorescent nanoprobe based on semiconducting polymer nanoparticles with lysosome locating capacity for the detection and visualization of senescence-associated β-gal in living cells is developed.

Ionic diodes, referring to fluidic devices with ion rectifying properties, have recently received considerable attention from the nanofluidics community due to their promising applications particularly in promoting clean energy. The past ionic diodes were realized with nanometer-scale pores, but those nanofluidic devices suffer from high resistance and high fabrication cost, thus limiting their practical applications. Here we report a simple strategy to fabricate a robust mesoscale ionic diode by electrokinetic functionalization of single conical mesoscale pores (700–800 nm tip diameter) with high molecular weight poly-L-lysine. Experiments show that the mesoscale ionic diode exploited can still function in mild neutral and 10 mM salt solution, under conditions at which the pore size is over 200-fold larger than the Debye length. The findings are supported by our simulation that attributes the mesoscale rectification to the effect of ion concentration polarization induced by the coating of highly space-charged polyelectrolytes. The application of the exploited mesoscale ionic diode in osmotic energy harvesting is also demonstrated, which achieves a power up to 254 pW at “neutral” pH and a 1000-fold salinity gradient, 5 times more than that of all the state-of-the-art single nanopore-based devices reported under the same testing conditions.

The preservation of traditional rural landscape and community is affected not only by exogenous driving factors such as top-down policy and tourism industry, but by endogenous driving factors deriv...

Electrochemical conversion reaction based electrodes offer a high sodium storage capacity in rechargeable batteries by utilizing the variable valence states of transition metals. Thus, transition metal chalcogenides (TMCs) as such materials have been intensively investigated in recent years to explore the possibilities of practical application in rechargeable sodium-ion batteries; however, it is hindered by poor rate performance and a high-cost preparation method. In addition, some issues in regards to conversion reactions remain poorly understood, including incomplete reversible reaction processes, polarization, and hysteresis. Herein, a novel cagelike CoSe2@N-doped carbon aerogels hybrid composite was designed and prepared by a facile and high-efficiency sol-gel technology. Benefiting from the surface engineering optimization, high charge transfer, and low-energy diffusion barrier, the CoSe2@N-doped carbon aerogels exhibit a high pseudocapacitive property. Most importantly, the CoSe2 anode has been carefully investigated at different discharge/charge states by X-ray absorption near edge spectroscopy technologies and density functional theory (DFT) simulations, which deeply reveal the capacity fading mechanism and phase transition behavior.

Lithium-sulfur batteries have been considered as one of the most promising energy storage devices due to their high theoretical capacity and low cost. They go through complicated multistep electrochemical reactions from solid (sulfur)-liquid (soluble polysulfide) to liquid (soluble polysulfide)-solid (Li2S) during the discharge process. Actually, during this process, the transition from liquid phase (Li2S4) to solid phase (Li2S) at 2.1 V plateau is a difficult step with sluggish kinetics, thus leading to low sulfur utilization and discharge capacity. To promote the transition processes and enhance the sulfur utilization, CoS2@multichannel carbon nanofiber composites (CoS2@MCNFs) serving as sulfur host were successfully synthesized. Herein, CoS2 catalysts are proven to be beneficial not only for enhancing the phase-transition kinetics but also for adsorbing soluble polysulfide. Besides, unlike other carbon materials, MCNFs have plenty of hollow channels and thus enhance sulfur loading and conductivity. Accordingly, the discharge capacity increases 32% more than that of electrode without CoS2. And a very low capacity fade rate of 0.03% per cycle (over 450 cycles) is obtained at a 0.5C rate. This work has opened up new ideas for enhancing sulfur utilization for high sulfur-loading electrode.

Magneto-optical (MO) properties of the bilayed Au/BIG and trilayered Au/BIG/Au magneto-plasmonic crystals (MPCs) were analyzed by the finite-difference time-domain method. In contrast to the low deflection angle and transmission of the smooth thin film, all the heterostructures with perforated holes in the top Au film displayed a similar trend with two strong resonant bands in Faraday rotation and transmittance in the near infrared wavelength range. The bands and electric distribution relative to the component and hole structure were revealed. The MPC with plasmonic hexagonal holes was found to own superior Faraday effects with distinctive anisotropy. The evolution of the resonant bands with the size and period of hexagonal holes, the thickness of different layers, and the incident light polarization was illustrated. The Faraday rotation of the optimized bilayed and trilayered hexagonal MPCs was improved 15.3 and 17.5 times, and the transmittance was enhanced 12.1 and 11.1 folds respectively at the resonant wavelength in comparison to the continuous Au/BIG film, indicating that the systems might find potential application in MO devices.

Sparse code multiple access (SCMA) is one of the most intensively investigated non-orthogonal multiple access (NOMA) techniques for the fifth generation communication (5G) system. In this paper, a new multi-stage optimization approach for codebook design is proposed for the uplink SCMA system. The proposed schemes includes two parts: i) multi-dimensional mother constellation design ii) mapping matrix design. Firstly, the multi-dimensional complex mother constellation design is implemented by a series of two-dimensional real constellations which can be obtained by the lattice theory and the symbol switch algorithm (SSA). The Secondly, we construct user-specific mapping matrix by optimizing the phase rotation of the user constellation to effectively reduce the interference between the multi-user codewords superimposed on every single time-domain resource elements (REs). Finally, the multi-user codebooks are generated by combining the multi-dimensional mother constellation and the user-specific mapping matrix. The simulation results demonstrate that the proposed codebooks can greatly decrease bit error rate (BER) value compared to the existing codebooks under different channels, different codebook sizes and different overloading ratios, and the performance is also improved for the large-scale SCMA codebook. More importantly, in order to verify the proposed codebook applicability, two different message passing algorithm (MPA) are used to simulate the SCMA system with different codebook sizes, both of which obtain faster convergence speed and better BER performance than other existing codebooks.

Tips of multi-walled carbon nanotube of dissimilar shapes with/without gold nanoparticles are irradiated under electron beam. The tips become meta-stable and cause reduction in lengths of tubes under a high intense uniform electron beam by their smaller radius of curvature when the diffusion and evaporation of carbon atoms are activated. Meanwhile, normal-tube-tips and volcano-tube-tips with/without gold nanoparticles present dissimilar changes in their diameters. The gold nanoparticles with size ≥ 3 nm not only slow down length reduction process in the normal-tube-tips and increase tips diameters but also increase their size on the normal-tube-tip by the interaction and growth, while gold nanoparticles with size ≤ 1.5 nm retard the length reduction process in volcano-tube-tips without any change in the tips diameters. Furthermore, they also activate formation of carbon shells over their surface and keep their positions fixed on the volcano-tube-tip. This abnormal interaction of gold nanoparticles with the unstable tips is elucidated in terms of irradiation-induced activation of the graphitic layers, diffusion of Au atoms and bonding between adjacent large (≥ 3 nm) Au NPs, and catalytic effects of small (≤ 1.5 nm) Au NPs. The method can be employed to modify nanotubes with almost atomic precision and to create a predefined pattern of metal nanoparticles on tube tips and surface.

Innocuous hydrogels with the characteristics of high conductivity, stretchability and air-stability have potential applications for emerging wearable and bio-related electronic devices. In this study, we develop a rapid and green method for stretchable supercapcitors using safer chemicals to produce hygroscopic conductive polymer hydrogels, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/poly(vinyl alcohol)/poly(methacrylic acid) (PEDOT:PSS/PVA/PMAA). The as-fabricated conductive polymer hydrogels show a high stretchability as well as a high conductivity (3.1 S cm−1) after absorbing water moisture as the plasticizer, which are used as current collectors and electrode materials to assemble the supercapacitor. By modulating the PEDOT: PSS composition in the hydrogel, the fabricated supercapacitor exhibits fascinating mechanical properties and excellent electrochemical characteristics. The supercapacitor has a maximum specific capacitance of 7.38 mF cm−2 at 10 mV/s, and shows 82% capacitance retention over 2000 charge-discharge electrochemical cycling testing at a current density of 10 mA cm−2. More importantly, the device could be stretched up to 100% strain without affecting the electrochemical performance and is well conserved after stretching 1000 times under 30% tensile strain.

Advanced thermal insulation materials with low thermal conductivity and robustness derived from regenerative resources are badly needed for building energy conservation. Among them, nanofibrillated cellulose aerogels have huge application potential in the field of thermal insulation materials, but it is still a challenge to prepare cellulose aerogels of excellent comprehensive properties in a simple way. Herein, we demonstrate a unidirectional freeze-drying strategy to develop a novel "robust-soft" anisotropic nanofibrillated cellulose aerogel (NFC-Si-T) by integrating nanofibrillated cellulose (NFC) and Si-O-Si bonding networks under the catalytic dehydration of p-toluenesulfonic acid (TsOH). The anisotropic structure endows the NFC-Si-T with high flexibility that can be easily bent or even tied with a knot, and in addition, it possesses high Young's modulus (1-3.66 MPa) that can resist the compression weight of 10,000 times of its own weight without deformation. Furthermore, the NFC-Si-T aerogels exhibit anisotropic thermal insulation performances with a low average thermal conductivity (0.028-0.049 W m-1 K-1). More importantly, the limited oxygen index of the NFC-Si-T reaches up to 42.6-51%, showing excellent flame-retardant performance. Therefore, the "robust-soft" anisotropic NFC-Si-T aerogels can be used as an advanced thermal insulation material for building thermal insulation applications.

This paper investigates the energy-efficient communications and user capacity in the cognitive multiple input multiple output (MIMO) symmetric system of underlay mode. The advantage of the improved energy efficiency provided by the orthogonal slot allocation for time division multiple access (TDMA) has a side effect of restricting the number of users accessing the system. To tackle the above problem, this paper proposes a nonorthogonal time resource allocation method with sparse code multiple access (SCMA), which allows one to convert the orthogonal slot units of TDMA into non-orthogonal shared slot units for multiple secondary users (SUs). The method of adding virtual users is adopted, wherein each SU is treated as multiple SUs who occupy a shared unit, to facilitate the packet access. Finally, the greedy algorithm is applied to optimize the time slot allocation of unoccupied shared slot units. The simulation results show that SCMA-based nonorthogonal slot allocation can reduce not only the energy consumption by nearly 40%, but also the average power interference from SUs to primary users by nearly 2 dB if their number is relatively high. Moreover, in the case of satisfying the rate requirement of the users, the system user capacity increased by more than 50%.

Electrochemical conversion reaction based electrodes offer a high sodium storage capacity in rechargeable batteries by utilizing the variable valence states of transition metals. Thus, transition metal chalcogenides (TMCs) as such materials have been intensively investigated in recent years to explore the possibilities of practical application in rechargeable sodium-ion batteries; however, it is hindered by poor rate performance and a high-cost preparation method. In addition, some issues in regards to conversion reactions remain poorly understood, including incomplete reversible reaction processes, polarization, and hysteresis. Herein, a novel cagelike CoSe

Geothermal energy has received tremendous attention as a largely untapped renewable resource that does not produce significant CO2 emissions during electricity generation. Worldwide installed capacity of geothermal energy plants has reached 14.3 GWe in 2017. However, widespread adoption of geothermal technologies should consider its potential environmental impacts. In this study, we first review the current state-of-the-art enhanced geothermal systems around the world, especially the United States, Philippines, Indonesia, Turkey and New Zealand. Then, we address the challenges and barriers to its adoption from the institutional, regulatory, technological and financial aspects. We also propose several strategies to implement geothermal energy plans, including (1) establishment of clear national energy utilization policies, (2) consolidation of geothermal laws and regulations, (3) engagement in geothermal potential assessment and periodic maintenance services, and (4) provision of fiscal incentives, financial supports and guarantees. Finally, we illustrate the implementation plans and business model of enhanced geothermal system deployment to conduct a demonstration plan for geothermal energy utilization. A case study of geothermal utilization in Taiwan, i.e., the Chingshui geothermal field, was discussed.

Lithium-sulfur batteries have been considered as one of the most promising energy storage devices due to their high theoretical capacity and low cost. They go through complicated multistep electrochemical reactions from solid (sulfur)-liquid (soluble polysulfide) to liquid (soluble polysulfide)-solid (Li

Hierarchical arrays of ZnO/Si nanowires were prepared through very convenient two-step solution method on silicon substrates. The tree-like nanowire structures showed high crystal quality, where well aligned Si nanowires were grown vertical to the substrate surface, whereas uniform assembly of branched ZnO nanowires was grown normal to the Si nanowires (backbones). Raman analysis indicated that among all the specimens having identical chemical compositions and dimensions but different forms (thin films or nanowires), Ag-decorated hierarchical arrays of ZnO/Si nanowires possessed the highest intensity peak in surface enhanced Raman scattering spectra. Such arrays demonstrated exceptional ability of detecting Rhodamine 6 G, limiting to a value as low as 1×10−8 mol/L and an enhancement factor up to 1.5 × 104. Both, experimental designing and band structure analysis indicated that electromagnetic effect of the localized surface plasmon resonance of Ag nanoparticles caused eight times enhancement, whereas chemical effect of hierarchical arrays of ZnO/Si nanowires played a more critical role in the high Raman sensitivity. Our results would be helpful to better understand the enhancement mechanisms and meanwhile, could be extended for further potential applications of hierarchical semiconducting nanowires.

Bulk density is a critical parameter for predicting grain pressures in silos, determining the resistance to airflow, and estimating the grain mass in storage bins, so studying the bulk density distribution is critical for the storage security of wheat during storage. To investigate the bulk density distribution of the wheat bulk stored in an axisymmetric steel silo with flat bottom, the Modified Cam-Clay model was applied to calculate the bulk density of wheat at four different moisture levels at different depth and radius of the silo. The results showed that the bulk density of wheat at different depth was not uniform and it increased with increasing grain depth but decreased near the wall-bottom of silos. Moreover, it was found that the bulk density of the wheat decreased with increasing radius at the same depth and the same moisture content. Furthermore, the mean bulk density of a layer of wheat was negatively correlated with moisture content at the same grain depth and approached a plateau value when the wheat was close to the bottom of the silo at the same moisture content. The bulk density was adequately fitted as a function of the grain depth and moisture content in silos.

Plasmonic properties of the Ag nanocaps were analyzed by the finite-difference time-domain method, in addition to the fabrication and sensor application of the two-dimensional Ag nanocap arrays. The thickness limitation for the light penetration of the nanocaps was revealed. The evolution of the plasma modes with the shell thickness and structure of the nanocaps was illustrated. The hemisphere nanocap was found to own the strongest absorption intensity and field enhancement. The sensing ability of the fabricated Ag hemisphere nanocap arrays was evaluated by the Raman spectrum of the rhodamine 6G and methylene blue molecules. The ordered arrays displayed improved light absorption with intense plasmon coupling, resulting in the strong surface-enhanced Raman scattering with an enhanced factor 15 folds of the nanosphere arrays, which suggested that the metal nanocaps might be promising for biochemical sensor application.

Due to global climate change and resource shortages, significant attention has been focused on exploiting environmentally friendly materials, such as naturally derived materials (e.g., biomass), for electrochemical energy storage to achieve a circular economy. One current area of research focus is bionics, which is a promising strategy to make materials with three-dimensional ordered structures that offer multiple contributions to bulk electrochemical properties. To develop high-performance energy storage devices, this article first reviews advances in the design and synthesis of nanostructured materials from plant-based biomass. The challenges and limitations on achieving high-performance rechargeable batteries are also illustrated and discussed from the materials design point of view. Then, from the perspective of chemical engineering, the performance of porous carbon from plant-based biomass for various applications is elucidated. Comprehensive performance evaluations on the relationship between the structure and electrochemical properties of biomass-derived materials are performed and summarized. Finally, the environmental benefits and impacts of electrochemical energy storage devices using biomass are discussed. From the perspective of environmental engineering, the recycling and reuse of metal components from spent batteries through the concept of green chemistry are presented. This article should be considered a pioneering review providing a holistic overview of electrochemical energy storage devices using plant-based biomass from a cross-disciplinary perspective that encompasses on materials science, chemical engineering and environmental engineering.

Harnessing biomass to fabricate electronic devices has lately drawn significant research attention because it not only represents a promising strategy for making materials but is also beneficial for the sustainable development of technologies. Numerous recent studies have demonstrated that green materials are promising candidates for synthesizing high-performance materials, such as biopolymers and hierarchical porous carbons. To catch up with this emerging tide, we have here compiled a comprehensive overview of state-of-the-art green materials, with a specific emphasis on recent progress in biodegradable polymeric materials and biomass-based carbon materials, together with their electronics and energy storage applications. Besides, we also assess the performance of end-of-life electronics recycling to highlight the merits of integrating green design with resource recovery.

To determine the parameters of Modified Cam-Clay model for paddy grain, a constitutive stress-strain equation, was used to study the stress-strain behavior of paddy grain. Triaxial tests were carried out four different moisture contents of paddy. This elastoplastic model contains five parameters: the critical state ratio M, the logarithmic hardening modulus λ, the isotropic swelling index κ, the elastic modulus E and the Poisson’s ratio ν, which can be evaluated in axial compression test and the isotropic compression test. The experimental results reveal that the M of paddy grain (Xiandao 118) with four different moisture contents (11.75%, 13.34%, 14.93% and 16.43%w.b.) were 2.1195, 2.1093, 2.0931 and 2.0110, the λ were 0.1408, 0.1390, 0.1355 and 0.1304, the κ were 0.1018, 0.0935, 0.0986 and 0.0948, and the ν were 0.145, 0.152, 0.155 and 0.166, respectively. The relation equations between the elastic modulus E with generalized shearing force q and mean principal stress p were obtained from the analysis of the experimental results. The comparisons between the Modified Cam-Clay model calculated values and measured values showed that the calculated parameters of the Modified Cam-Clay model are reasonable and the model can adequately describe the stress-strain behavior of paddy grain for the conditions tested.

Multi-walled carbon nanotubes (MWCNTs) respond as brittle materials at room temperature (RT) and fail upon any imposed strain for elongation. By following up our previous study on electron-beam (e-beam)-induced non-uniform elongation of MWCNTs (Khan et al. in J Phys Condens Matter 30:385302, 2018), here, it is illustrated that through moderate irradiation to a high enough intensity e-beam, dramatic uniform elongations can be attained for thin enough MWCNTs at RT, where homogeneous plastic flow of carbon atoms along the tube shells in the tube axis direction takes place with uniform inward diffusion of tube shells. The study also reports well-fitting results for quantitative kinetic relationship of the shrinkage time consequences under nanoscaled curvature, revealing predominant effect of much greater surface energy. These findings are purposeful for processing CNTs and other conventional nanotubes for their utilization in nanodevices and nanotechnology.

Blue energy conversion, where the chemical energy stored in salinity gradients can be converted into electricity with ion-selective nanochannel membranes, has considered to be one of the most promising renewable energies. Conventional understanding on this energy suggests that as to largely reduce the resistance, ultrashort channel membranes are required to gain high-energy output. To understand the channel-length-dependent blue energy conversion in detail, we engineered a series of highly ordered and uniform ~23.0 nm in diameter alumina nanochannel membranes with various lengths. Most anomalously, our experiments however show that for sufficiently short nanochannels, the shorter the channel length, regardless of surface charge nature, the smaller the generated power, violating the past understanding. The anomalous channel-length-dependent blue energy conversion is well supported by our rigorous model. The modeling reveals that ultrashort nanochannels will induce the significant ion concentration polarization effect, which appreciably undermines effective salinity ratio and ion selectivity in the nanochannel. If this effect dominates, the nanofluidic osmotic power turns into a decrease with decreasing channel length. Both the experimental and theoretical results reported consistently highlight the importance of osmotic ion transport especially in ultrashort nanochannels, and this finding shed light on the design of high-efficiency blue energy harvesters.

Green infrastructure practices could provide innovative solutions for on-site stormwater management and runoff pollution control, which could relieve the stress of nonpoint pollution resulting from heavy rainfall events. In this study, the performance and cost-effectiveness of six green infrastructure practices, namely, green roofs, rain gardens, pervious surfaces, swales, detention basins, and constructed wetlands, were investigated. The comprehensive performance evaluation in terms of the engineering performance, environmental impact, and economic cost was determined in the proposed engineering–environmental–economic (3E) triangle model. The results revealed that these green infrastructure practices were effective for stormwater management in terms of runoff attenuation, peak flow reduction and delay, and pollutant attenuation. It was suggested that for pollution control, detention basins can efficiently reduce the total suspended solids, total nitrogen, total phosphorus, and lead. The implementation of detention basins is highly recommended due to their higher engineering performance and lower environmental impact and economic cost. A case study of a preliminary cost–benefit analysis of green infrastructure practice exemplified by the Pearl River Delta in China was addressed. It suggested that green infrastructure was cost-effective in stormwater management in this area, which would be helpful for sustaining healthy urban watersheds.

Carbohydrate-based block copolymers, such as maltoheptaose-block-polyisoprene (MHPI), were successfully employed as polyelectrolytes in a light-emitting electrochemical cell (LEC) to realize organic multi-state electrical memory. The observation of distinctive multi-state memristive behavior could be attributed to the controlled ion motion in MHPI and the electron capture capabilities introduced by its constituent hydroxyl groups. The newly developed sandwich-structured memory device is based on a LEC platform as the light-emitting electrochemical cell memory (LECM). Furthermore, the fabricated LECM exhibited excellent ternary-state memory behavior with high ON2/ON1/OFF current ratios of 106/105/1 as well as excellent stabilities for each respective state. The study not only illustrates the use of carbohydrate-based materials as promising electrolytes for LECM applications, but also provides a new horizon in the development of organic multi-state electrical memory devices.

A high performance lithium–sulfur (Li–S) battery comprising a symmetric fluorinated diethoxyethane electrolyte coupled with a fish-scale porous carbon/S composite electrode was demonstrated. 1,2-Bis(1,1,2,2-tetrafluoroethoxy)ethane (TFEE) was first studied as a new electrolyte solvent for Li–S chemistry. When co-mixed with 1,3-dioxolane (DOL), the DOL/TFEE electrolyte suppressed the polysulfide dissolution and shuttling reaction. When coupled with a fish-scale porous carbon/S composite electrode, the Li–S cell exhibited a significantly high capacity retention of 99.5% per cycle for 100 cycles, which is far superior to the reported numerous systems.

Numerous studies on osmotic power generators with nanoscale pores are conducted. However, their performance output is limited because of the finite osmotic current and conductance from such tiny pores. Here, a proof-of-concept study demonstrating that the rectified mesopore (sub-micrometer-scale pore) with high surface charges can be applied in osmotic energy conversion is reported. A single conical mesopore of ≈405 nm in tip diameter, which can reach an osmotic conductance as high as 0.284 μS (corresponding to a current of 27.5 nA and voltage of 97 mV), enables a record-high power of 667 pW under a 1000-fold salinity gradient, more than doubling all of the state-of-the-art single-pore osmotic power generators reported. This work extends the knowledge of osmotic energy with solid-state pores from nanoscale to mesoscale and opens up a promising avenue toward ultrahigh performance osmotic power.

Hierarchical heterogeneous ZnO/Si nanowire arrays grown from metal-induced wet etching process on p-type silicon wafer were obtained and have been strategically sensitized by narrow bandgap semiconductors of In2S3 nanosheets and Ag2S quantum dots via successive ionic layer adsorption and reaction technique. The photodegradation of methylene blue as catalyzed by the arrays was conducted under visible light and ultraviolet light. By introducing the coating layers, the specimens were found to achieve absorptivity higher than 94% and yield a quarter of the resistance and 31-fold of the photo-current as compared to the primary nanowire arrays. The photodegradation efficiency was improved from 48.9% to 62.0%, and 43.0% to 55.0%, respectively in visible light and ultraviolet light with an enhanced recyclability. Band structure analysis indicated that the coating brought different Z-scheme heterojunctions for efficient photocatalytic performance, while the function could only work in a given spectral range. These results would be helpful to better realize the photocatalytic mechanisms and meanwhile, could be extended to design heterogeneous semiconductor nanomaterials for their potential applications.

Ag2S quantum dots-sensitized ZnO/SnO2 core-shell nanowire arrays were successfully synthesized layer by layer through hydrothermal growth, atomic layer deposition, and successive ionic layer adsorption and reaction process. By introducing the two-layer semiconductors, the bandgap of ZnO component in the arrays was slightly modulated, while the light absorption was obviously improved with an absorptivity higher than 95% in visible and ultraviolet range. In contrast to the ZnO NW arrays, the photocurrent response of the ZnO/SnO2/Ag2S NW arrays for the visible light was improved from 0.42 μA to 22.5 μA, and the photodegradation efficiency of methylene blue was increased from 45.24% to 71.61%, and 42.61% to 57.58%, respectively in visible light and ultraviolet light. Band structure analysis indicated that the coating layer brought different staggered gaps and suitable band alignment for efficient photocatalytic performance, which could be extended to design heterogeneous semiconductor nanomaterials for their potential applications.

Polar coding and sparse code multiple access (SCMA) technique are excellent candidates for 5G, and have a promising prospect in optical communication, the joint design of polar coded sparse code multiple access (PC-SCMA) system is important to enhance the overall system performance. In this paper, a serial joint iterative detection and decoding scheme is proposed by passing message between serial max-log message passing algorithm and soft cancellation (SCAN) algorithm, the strategy can accelerate the algorithm convergence speed by reducing the number of required iterations, decrease the computational complexity and achieve ideal bit error rate (BER) performance. In order to further improve the BER performance, a cyclic redundancy check (CRC) is added in the joint iterative process as an early stopping criterion to avoid decoding divergence caused by a low signal to noise ratio (SNR). Simulation results demonstrate that the addition of a termination mechanism can obtain an excellent performance gain compares with the conventional JIDD algorithm.