Stack Of Units Research Articles

Numerical and Experimental Study on a High-Power Cold Achieving Process of a Coil-Plate Ice-Storage System

Heat dissipation of high-power lasers needs a cold storage and supply system to provide sufficient cooling power. A compact coil-plate heat exchange device has been proposed and applied in the phase-change cold storage system with ice as the cold-storage medium and glycol aqueous solution as the coolant. The heat exchanger consists of several stacked coil-plate units and each unit is constructed with a flat plate and serpentine coils welded on the plate. A simulation model on the cold achieving process of a coil-plate unit was built and verified by the corresponding experiment. The influences of the structural parameters (tube diameter, tube pitch, and plate spacing) of the unit and the inlet temperature and volume flow rate of the coolant on the heat exchange power density were analyzed to obtain the maximal cooling effect in a limited time period. It was found that the heat exchange power density is limited when the tube pitch and plate spacing are large, otherwise, the effective cooling time period is limited. A small plate spacing can make the power density decrease rapidly in the later stage. The inlet coolant temperature can significantly affect the heat exchange power density while the coolant volume flow rate in tube has a small effect on the power density when the coolant is in turbulent state. In a time period of 900 s, for a coil-plate heat exchanger with a plate size of 940 mm ×770 mm and a tube pitch of 78 mm, when the plate spacing is 20 mm, the average heat exchange power density is 5.1 kW/m2 when the inlet temperature and volume flow rate of the coolant are 20 °C and 0.5 m3/h, respectively. The total cooling power of several stacked coil-plate units in the limited time period can match the high requirement of laser heat dissipation.

Reliable sealing design of metal-based solid oxide fuel cell stacks for transportation applications

Recently, metal-based solid oxide fuel cells (SOFCs) receive much attention as new power converting systems, and reliable sealing is an essential requirement for the metal-based SOFC stacks. In this study, metal-based SOFC stacks with a reliable sealing method are developed for transportation applications. For successful development, bolt-spring and hydraulic compression methods for stack tightening are discussed in terms of their applicability to vehicles. Then, detailed stack designs are developed to obtain sufficient compressive stress on the surfaces of the sealing gaskets based on the finite element method (FEM). To maintain the compression and heat insulation of the stack, a hot box is designed based on the thermogravimetric properties, shrinkage behaviors, and mechanical properties of sealing gaskets of mica and Thermiculite 866LS, and ceramic fiber insulating board. As a result, a 1-cell stack unit is successfully fabricated and tested based on the designs, and a sealing rate of 100 ± 0.78% is achieved at an operating temperature of 800 °C. This study investigates comprehensive stack and sealing design processes, and it has broad implications for reliable stack development.

Coherent Charge Transfer Exciton Formation in Regioregular P3HT: A Quantum Dynamical Study.

The ultrafast formation of charge transfer excitons (CTXs) in regioregular poly(3-hexyl thiophene) (rrP3HT) domains is elucidated by electronic structure and quantum dynamical studies of an aggregate model system comprising five stacked quaterthiophene units. Using a multistate vibronic coupling Hamiltonian parametrized by TDDFT calculations for 13 electronic states of Frenkel and CTX type, along with 78 vibrational modes, quantum dynamical simulations are carried out using the Multi-Layer Multi-Configuration Time-Dependent Hartree (ML-MCTDH) method. In line with time-resolved spectroscopic results [ De Sio , A. ; et al. Nat. Commun. 2016 , 7 , 13742 ], it is found that CTX formation occurs immediately upon photoexcitation, accompanied by sustained regular oscillations with a ∼22 fs periodicity. These coherent features, whose presence may seem surprising in a high-dimensional aggregate or thin film material, can be traced back to a dominant vibronic signature of CC stretch-type high-frequency modes. These vibrational signatures are found to be enhanced due to a collective vibronic response that is prompted by the initial generation of a delocalized bright exciton and its subsequent relaxation, by internal conversion, to a polaronic local exciton ground state.

Structure Elucidation of a Melam-Melem Adduct by a Combined Approach of Synchrotron X-ray Diffraction and DFT Calculations.

Melam-melem (1:1), an adduct compound that can be obtained from dicyandiamide in autoclave reactions at 450 °C and elevated ammonia pressure, had previously been described based on mass spectrometry and NMR spectroscopy, but only incompletely characterized. The crystal structure of this compound has now been elucidated by means of synchrotron microfocus diffraction and subsequent quantum-chemical structure optimization applying DFT methods. The structure was refined in triclinic space group P based on X-ray data. Cell parameters of a=4.56(2), b=19.34(8), c=21.58(11) Å, α=73.34(11)°, β=89.1(2)°, and γ=88.4(2)° were experimentally obtained. The resulting cell volumes agree with the DFT optimized value to within 7 %. Molecular units in the structure form stacks that are interconnected by a vast array of hydrogen bridge interactions. Remarkably large melam dihedral angles of 48.4° were found that allow melam to interact with melem molecules from different stack layers, thus forming a 3D network. π-stacking interactions appear to play no major role in this structure.

The Exhumation of Continental Crust in Collisional Belts: Insights from the Deep Structure of Alpine Corsica in the Cima Pedani Area

In northern Corsica, the Cima Pedani area is characterized by a stack of continental and oceanic units belonging to Alpine Corsica. The base of the unit stack consists of three metamorphic continental units (Canavaggia, Pedani, and Scoltola) that are overthrust by the Schistes Lustrés Complex, represented by oceanic units. The continental units are metamorphic fragments of the European continental margin. They include a Paleozoic basement intruded by Permo-Carboniferous metagranitoids covered by Permian metavolcanites and a Triassic-Jurassic metacarbonatic sequence, unconformably covered by metabreccias and metasandstones of Eocene age. These units are affected by a polyphased tectonometamorphic history acquired in a time frame from the Priabonian to the Aquitanian. The reconstructed pressure-temperature (P-T) paths and the related deformations describe a retrograde history acquired during their progressive exhumation, whereas no trace of the older prograde history has been preserved. In all the reconstructed P-T paths, the P peak (1.04–1.35 GPa) corresponds to the maximum depth reached by these units, whereas the subsequent history includes a progressive P decrease associated with a coeval T increase. The deformation history related to exhumation includes three deformation phases. In particular, the D2 phase is characterized by noncoaxial ductile structures parallel to the boundaries of the units observed in the Cima Pedani tectonic window. The sense of shear of these shear zones is generally top-to-the-W (i.e., toward the Alpine foreland). The collected data provide evidence that the continental units were deformed and metamorphosed during the exhumation following their ascent path along the plate boundary interface. The geodynamic mechanism we propose for the exhumation of the Cima Pedani units is the subduction channel, in which high-pressure units arise between the down-going plate and the former accretionary wedge built up during the oceanic subduction, represented by the Schistes Lustrés Complex.

Tunable Anisotropic Absorption in Hyperbolic Metamaterials Based on Black Phosphorous/Dielectric Multilayer Structures

Black phosphorus (BP) as a promising two-dimensional material with extraordinary optical properties constitutes an excellent building block in multilayer hyperbolic metamaterials. In this work, we design a multilayer structure composed of BP/dielectric layer stacking unit cells patterned on a gold mirror and theoretically demonstrate the tunable anisotropic absorption in the infrared regime. The electric dipole resonance between the adjacent unit cells drives the structure in the critical coupling state, and impedance of the structure matches to that of free space, showing the perfect absorption for one polarization direction, while the impedance mismatch for the other polarization direction leads to only 8.2$\%$ absorption at the same wavelength. The anisotropic absorption response of the proposed structure can be attributed to the intrinsic anisotropy of BP, which exhibits few dependence on the incident angle. Furthermore, we investigate the tunable optical absorption of the proposed structure with the electron doping of BP and the geometric parameters. These results demonstrate great potentials of BP in constituting multilayer hyperbolic metamaterials, and open up avenues in designing anisotropic metadevices with tunable spectral and polarization selectivity in the infrared regime.

Does Integrative Medicine Reduce Prescribed Opioid Use/Dose for Chronic Pain? A Systematic Literature Review

Hydrogen as a clean fuel and a new energy source can be produced by various methods. One of these common and economical methods of hydrogen production is hydrocarbon vapor modification. This research studies hydrogen production using a propane steam reforming process inside a high temperature heat exchanger. The application of this high temperature heat exchanger in the path of the power supply line is a fuel cell stack unit to supply the required hydrogen of the device. The heat exchanger consists of a set of cylindrical tubes housed inside a packed-bed called a reformer. The energy required to perform the reaction is supplied through these tubes in which high temperature gas is injected and the heat exchanger is insulated to prevent energy loss. The results show that at maximum temperature and velocity of hot gases, (900 K and 1.5 m s−1), complete consumption of propane can be observed before the outlet of the reformer. Also, in the mentioned conditions, the maximum hydrogen production (above 92%) is obtained. The best permeability under which the system can perform best is 1×10−9 m2.

Single-objective Optimization for Stack Unit of Standing Wave Thermoacoustic Refrigerator through Particle Swarm Optimization Method

Thermoacoustic refrigeration is being regarded as a promising alternative technology with the absence of harmful refrigerants including no or few moving parts, providing the ability to use low grade energy sources for energy conservation. However, the performances of thermoacoustic refrigerators are still low compared to their counterparts, the conventional vapor-compression ones due to involving multi-scale, even multi-field thermo-physical matters with electromagnetic or piezoelectric actuators. Therefore, design optimization of such systems has become quite necessary and significant for achieving competitive performances. In the present study, particle swarm optimization (PSO) is introduced as an intelligent method for such optimization. The stack unit as the key element responsible for thermoacoustic cooling effect, is focused in our first attempt. Coefficient of performance (COP) of the stack unit would be considered as the single-objective function to be maximized under some constraints including stack length, stack center position, blockage ratio and drive ratio. The present study had shown the capability and significant advantages of PSO through showing better optimal result compared to published literature ones. In addition, some considerations for optimization criteria were discussed. Based on this study, PSO could be possibly a favorable intelligent method suitable to the design optimization of thermoacoustic refrigerators or heat engines and their key components effectively.

Superconductivity enhancement in Ta1+xSe2 with a randomly stacked structure

A series of Ta1+xSe2 (0.00 ≤ x ≤ 0.12) samples was prepared and characterized by x-ray powder diffraction, resistance, magnetization and specific heat measurements. Based on the fitting of the diffraction patterns, we found that Ta1+xSe2 has two randomly stacked structures with distinct stacking units: 2Hb and 3R slabs when x ≤ 0.06 and single TaSe2 layers with Ta atoms in trigonal prismatic coordination with Se when x > 0.06. The superconducting critical temperatures (Tc) of the Ta1+xSe2 samples can be significantly enhanced from 0.14 K for pure TaSe2 to above 2 K in the Ta-rich samples with both structures. The maximum Tc of 3.2 K was obtained in Ta1.06Se2. The remarkable enhancement of Tc in Ta1+xSe2 originates from the enhancement of N(EF) and λ.

Coal microcrystalline structural changes related to methane adsorption/desorption

Methane adsorption/desorption not only causes coal matrix shrinkage and swelling, but also has an important influence on the microcrystalline structure of coal. In this study, high-pressure isothermal adsorption/desorption experiments were carried out for 8 coal samples with different degrees of metamorphosis. The microcrystalline structure of the samples before and after methane adsorption/desorption were quantitatively examined using X-ray diffraction, high-resolution transmission electron microscopy, and laser Raman spectroscopy. The results showed that after methane adsorption/desorption, the interplanar spacing (d002) of the coal samples increased, and the unit stacking height (Lc) and unit lateral size (La) of coal crystallites decreased as compared with the raw samples. The changes in Lc were greater than those in La for the same sample. In other words, deformation from high-pressure adsorption/desorption has an especially significant impact on Lc. Furthermore, the fringe spacing of the samples increased, and the proportion sized 0.36–0.40 nm increased in the frequency histogram. While the fringe length showed a decreasing trend, the proportion in the range of 0.30–1.00 nm was significantly increased in the frequency histogram. In addition, the D peak positions of the samples increased while those of the G peak decreased, and their difference decreased. Moreover, the full widths at half maximum of G and D peaks, and the area ratio between D and G all increased. These results are of great significance for further understanding the source of excess coalbed methane (CBM) and its state.

Single-objective optimization for stack unit of standing wave thermoacoustic refrigerator through fruit fly optimization algorithm

Thermoacoustic refrigeration is considered as a potential alternative refrigeration technology with environmentally-friendly working substance, no or few moving parts, high reliability as well as utilization of low grade energy. Optimization for thermoacoustic systems or their key components has become a crucial task to make their performances competitive over conventional vapor-compression ones. In this study, fruit fly optimization algorithm (FOA) as an intelligent method is introduced to separately maximize coefficient of performance of stack unit and cooling power produced for one standing wave thermoacoustic refrigerator, as single objective functions under optimized stack length, stack center position, blockage ratio and drive ratio. FOA had shown better optimal results, compared to published literature results. Compared to results of genetic algorithm, COP had been enhanced by 15.8%. Moreover, cooling power was first discussed as another important objective to optimize. Studied results demonstrated that FOA is an effective approach for design optimization of thermoacoustic refrigerators.

The distinctive tectonic and metamorphic history of the Barru Block, South Sulawesi, Indonesia: Petrological, geochemical and geochronological evidence

This study describes the field relationships, petrography and geochemistry of various metamorphic and magmatic rocks from the Barru Block, South Sulawesi, Indonesia, and reports Rb-Sr isochron ages for clastic metasedimentary rocks. The Barru Block is composed of a tectonic stack of various lithological units, including cherts, radiolarian mudstone, breccias, shales, phyllites, mica schist, gneisses, amphibolite and ultramafic rocks. Dacitic rocks intrude the metamorphic and ultramafic sequences. Greenschist- to amphibolite-facies metasedimentary rocks represent detritus from nearby continental blocks that have been redistributed by turbidity currents. Quartzofeldspathic gneisses are derived from andesitic and dacitic protoliths, whereas amphibolites have basaltic precursors. The clastic metasedimentary rocks show enrichment in LILE and HFSE, particularly Nb, but depletion in Sr. The amphibolites display trace element patterns typical of N-MORB rocks, whereas compositional characteristics of gneisses and dacites suggest that they originated in an arc-related environment.Geothermobarometric calculations and mineral assemblages of greenschist facies-rocks suggest metamorphic equilibration at 250–300 °C and a maximum pressure of 5 kbar. Temperature estimates for amphibolites are 640 ± 20 °C at a pressure of 1.3–3 kbar, whereas the temperature estimates for quartzofeldspathic gneisses range from ca. 630–660 °C for peak conditions to 430–520 °C for the retrograde stage. Internal Rb-Sr mineral isochrons for three medium-pressure mica schists indicate metamorphic ages of ca. 70.7 ± 2.4 Ma, 107.3 ± 0.7 Ma and 110 ± 2.4 Ma, respectively. This age range confirms the importance of Early Cretaceous (Albian) metamorphism within the region, but also indicates a previously unknown Late Cretaceous (Maastrichtian) metamorphic or deformational event at ca. 70 Ma.The Barru rocks show a range of tectonic environments as diverse as that of the adjacent Bantimala Block, but overall, the Barru rock association is more felsic in composition. Although the two blocks accreted approximately at the same time (Early Cretaceous), differences in protoliths, geochemistry and metamorphic P–T conditions imply that they were not geographically close together at that time, but were subsequently juxtaposed tectonically.

Cluster-Based Metal-Organic Frameworks: Modulated Singlet-Triplet Excited States and Temperature-Responsive Phosphorescent Switch.

Luminescent metal-organic frameworks (MOFs) have received much attention due to their applications in color displays, sensors, and smart materials. However, how to balance the energy distribution between singlet and triplet excited states for a new generation of persistent luminescent MOFs is still a challenging goal. In this work, we report that the construction of cluster-based MOFs can supply an effective way to modulate the fluorescence and room-temperature phosphorescence (RTP) emission based on adjustable π-π stacking, halogen-bonding interaction, and metal-cluster units. Compared to the pristine ligand (5-bromoisophthalic acid) with obvious spin-orbit coupling, Zn5 and Zn3 cluster-based MOFs exhibit tunable photoluminescence (such as fluorescence and RTP wavelength, lifetime, and quantum yield). The ultralong-lived RTP visualization and temperature-dependent luminescence also provide the Zn5 cluster-based MOF as a new type of anticounterfeiting and temperature-responsive phosphorescent switch material. Therefore, this work highlights the first example of cluster-based MOFs as ultralong-lived persistent luminescent materials for tuning singlet and triplet excited states, which may be extended to other similar systems for developing ultralong RTP and delayed fluorescence materials.

Reexamination of Solvothermal Synthesis of Layered Carbon Nitride

“Graphitic carbon nitride” synthesized by the solvothermal reaction between cyanuric chloride (C3N3Cl3) and sodium amide (NaNH2), which was one of the most common methods reported so far, was carefully examined by several analytical techniques for its chemical and structural characteristics. The chemical quantification by the electron microprobe and combustion methods showed that the product synthesized has a significant amount of hydrogen with a composition C3N5H3. Moreover, we found by FT-IR and IR-Raman measurements that the product consists mainly of stacked s-triazine units on the basis of the structural framework of cyanuric chloride, suggesting that s-triazine-based carbon nitride is more stable than heptazine-based one under a mild temperature condition (~200°C). The present study clearly demonstrates that hydrogen-free, pure graphitic C3N4 cannot be produced by the present solvothermal reaction proposed by the earlier study.

Gas Diffusion Media and NaCl Contamination of Polymer Electrolyte Fuel Cells for Marine Applications

Polymer electrolyte fuel cells (PEFCs) are able to operate with high efficiency, reduce greenhouse gas emissions and meet exhaust gas (SOx, NOx and PM) regulations. Therefore, the application of PEFCs for marine vessels will be an effective means of reducing environmental impact and solving energy crisis problems. Some projects related to the commercialization of PEFC vessels are being performed in Japan as a prelude to the Tokyo Olympic and Paralympic Games in 2020. Marine PEFCs require special output power characteristics that allow long-term operation under high load conditions and responsiveness to rapid load fluctuations. The enhancements of durability, reliability, and tolerance for the harsh conditions commonly faced in marine environments (such as ship vibrations and sea salt exposure) are essential to the commercialization of marine PEFCs. A PEFC system consists of a cell stack and ancillary units, such as cooling, hydrogen and air feeds and humidification systems. A number of single cells are normally connected in series to produce high output power, and the abnormal operation of even a single cell can result in malfunction of the entire cell stack. Therefore, detecting the abnormal operational conditions is essential to enhance the durability and reliability of marine PEFCs and to ensure long-term safe and stable operation. Electrochemical impedance spectroscopy (EIS) is a technique suitable for the real-time diagnosis of operating PEFCs. The present work investigated the effects of abnormal variations in the cell temperature and the flow rate and relative humidity of supplied gases (caused by malfunctions of ancillary units) on the cell resistance and capacitance values in an equivalent circuit model using EIS analysis. Both increasing the cell temperature and decreasing the supplied gas humidity degrade the proton conductivity, thereby raising the ohmic resistance. It is therefore essential to maintain the hydration of the membrane so as to obtain sufficient proton conductivity. However, overly high gas humidity will allow liquid water to accumulate in the electrode, the gas diffusion layer and the separator flow channels. This reduces the supply of oxygen to the electrode, thereby increasing the mass transport resistance. The gas diffusion layer coated with a microporous layer containing hydrophilic carbon nanotubes (CNTs) was effective at preventing both membrane dehydration and flooding regardless of the humidity conditions. The effect of injecting a sodium chloride (NaCl) solution into the cathode inlet air on the PEFC performance was also evaluated. The cell voltage at a constant current density of 0.5 Acm-2 decreased from 0.71V to 0.62V after injecting a NaCl solution for a span of 2 h. The reduced cell voltage could be attributable to lowered proton conductivity due to the displacement of protons in the membrane by sodium ions. The presence of chloride ions would block active Pt sites and accelerate the dissolution of Pt. These effects reduced the total active area at the catalyst layer during operation. The presence of NaCl in the cathode air stream increased all the resistances, thus degrading the cell performance. However, the increase in the charge transfer resistance was the most significant. The effect of injecting distilled water instead of a NaCl solution after detecting performance degradation due to NaCl contamination was evaluated. The extent of chlorine ions adsorption on Pt in the catalyst layer was relatively low during the initial stage of performance degradation. The cell voltage increased gradually for 6 h after initiating the injection of distilled water, and reached to a constant value of 0.69V, which represented a recovery value of 97% compared with that obtained under normal conditions without NaCl contamination. Injecting distilled water after the initial detection of abnormal operational conditions was evidently effective at recovering the cell performance at this early stage.

Organo-vermiculites with biphenyl and dipyridyl gemini surfactants for adsorption of bisphenol A: Structure, mechanism and regeneration

Two novel biphenyl and dipyridyl gemini surfactants, bis-N, N, N,-hexadecyldimethyl-p-biphenylenediammonium dichloride (BHBP) and 1,1′-dihexadecyl-4,4′-bispyridinium bromide (DHBP) were designed and used to functionalize the high layer charged vermiculite (Vt) for the first time. Key organo-Vt characteristics, such as the modifier loading, arrangement and the stacking unit of platelets were specified by FT-IR, XRD, TG, SEM and Elemental Analysis. The saturated surfactant dosage in the modification process, in reverse relationship with the availability of the modifier, was defined as low as 0.4 CEC of Vt. The adsorption performance of organo-Vts were tested by bisphenol A (BPA), which showed great potential as organic adsorbents (143.5 mg g−1 and 139.7 mg g−1 for BHBP-Vt and DHBP-Vt, respectively). Insights into the adsorption mechanism were discussed through kinetics, isotherms and thermodynamics, as well as characterization of the spent samples. BPA onto orgno-Vts matched well with pseudo-second-order, Freundlich models and an exothermic process in nature. Interestingly, π-π interactions between aromatic rings were stronger than that between heteroaromatic ring and aromatic ring, and π-π stacking between the BPA adsorbed and dissociated in solution turned out to promote the adsorption process. The organo-Vts were sustainable and could reuse by ethanol at least for three cycles. Organo-Vts could not only guide focuses on the high layer charged precursors, but open up a new area for the fabrication of novel materials to serve as tunable and cost-effective adsorbents.

Serviceability of Phase-1 RBMK-1000 FA After Service-Life Characteristics Restoration

The serviceability of fuel assemblies during operation in the reactor core after restoration of the service-life characteristics of the graphite stack of phase-1 power-generation units with RBMK-1000 is evaluated. The results of FA loading and unloading operations in bent fuel channels and evaluations of the interrelation of the degree and profile of the bending of the fuel channels with a gap between the fuel elements of the outer row and inner surface of the channel tube and the conditions of FA operation in the fuel channels of the modified as well as restored geometry of the actual state of the FA recorded during inspections are presented. It is concluded that the RBMK-1000 FA are serviceable during operation before restoration of the service-life characteristics of the graphite stack as well as after restorative repairs.

Economic Aspects of RBMK Service Life Characteristics Restoration

The economic aspects of the R&D complex to support RBMK operation under conditions of graphite distortion, development and adoption of the restoration technology for the service characteristics of the graphite stack are examined. The results of a technical-economic analysis of the restoration of the graphite stack of RBMK power-generating units, performed on the basis of a modeling scenario, are presented. Comparative economic indices of electricity production, proceeds, and investment resources are presented for the studied scenarios. It is shown that the restoration of the graphite stack in NPP with RBMK is economically efficient.

Late Cretaceous eclogite in the Eastern Rhodopes (Bulgaria): evidence for subduction under the Sredna Gora magmatic arc

The Rhodopes in Bulgaria and Greece represent a nappe stack of high-grade units with polymetamorphic history. Constraining the time of metamorphism in individual subunits is essential for unraveling the controversial framework of subduction, exhumation and nappe stacking. Here we present new evidence for Late Cretaceous high-pressure metamorphism in the Eastern Rhodopes. In eclogite from the Byala Reka–Kechros Dome (Kazak eclogite), garnet growth is dated at 81.6 ± 3.5 Ma by Lu–Hf chronometry, indicating that prograde eclogite-facies metamorphism occurred during the Late Cretaceous. Petrological data and modeling suggest peak-pressure conditions of 1.2–1.6 GPa, 570–620 °C. We propose that metamorphism took place in a subduction zone dipping towards north under the Sredna Gora section of the Apuseni–Banat–Timok–Sredna Gora continental magmatic arc. Eclogite-facies metamorphism coincides with the main phase of granitoid intrusions in the Sredna Gora Zone. The site of magmatic activity in this area shifted southward during the Late Cretaceous and arrived in the Eastern Rhodopes at ~ 69 Ma, as shown by granite intrusions of that age only 4 km north of the locality of the dated eclogite sample. This proximity may be explained by south-directed rollback of the subduction zone, although also post-69 Ma tectonic displacement has to be considered. Together with published age data from other parts of the Rhodopes, the new data confirm that multiple subduction events took place between ~ 200 and ~ 40 Ma along this section of the southern European plate boundary.

A new strategy for hydrophobic drug delivery using a hydrophilic polymer equipped with stacking units.

A highly hydrophilic polymer equipped with guanidinium groups was used to load aromatic ring-containing hydrophobic agent doxorubicin (DOX) via π-π interaction. The results have shown that the delivery system exhibited enhanced cellular uptake and antitumor efficiency compared with free drugs. This study opens new avenues for the application of hydrophilic polymers in drug delivery.