Fast Injection Research Articles

A C-Band FMCW SAR Transmitter Based on Synthetic Bandwidth Technique

A $C$ -band frequency-modulated continuous wave (FMCW) transmitter based on synthetic bandwidth technique for synthetic aperture radar (SAR) imaging is presented. A 500-MHz narrowband chirp signal is up-converted to two adjacent carriers to obtain 1-GHz chirp at the $C$ -band. The adjacent carriers are obtained through fast switching subharmonic injection locking oscillator (SHILO) technique with 14-ns settling time. For narrowband chirp, a wideband fractional- $N$ phase locked loop (PLL) is used, covering 1.8–2.3 GHz and achieving low in-band phase noise of −115 to 120 dBc/Hz. The proposed technique achieves reconfigurable chirp period ranging from 0.3 to 6.3 ms. It can also be easily extended for wider chirp bandwidth by simply increasing the number of SHILO carriers. The chip consumes 84 mW, while occupying a total active area of 2.24 mm2.

Effect of linkers with different chemical structures on photovoltaic performance of CdSe quantum dot-sensitized solar cells

Introducing bifunctional linkers (COOH-R-SH) between TiO2 electrodes and quantum dots (QDs) was an effective apprIntroducing bifunctional linkers (COOH-R-SH) between TiO2 electrodes and quantum dots (QDs) was an effective approach in preparation of quantum dot-sensitized solar cells (QDSCs). Three types of linkers (4-mercaptobenzoic acid (MBA, R=phenyl), 3-thiophenecarboxylic acid (TPA, R=thiophene), and thioglycolic acid (TGA, R=alkyl)) were used to functionalize TiO2 electrodes and prepare TiO2/CdSe QDSCs with photoelectric conversion efficiency (PCE) of 5.50%, 4.59% and 4.85%, respectively. Various properties of modified and blank TiO2 electrodes, such as QDs loading, absorbance, work function, interfacial charge injection, recombination and their influence on PCE were investigated. In spite of low adsorption amounts of MBA on TiO2, the phenyl MBA-TiO2 electrodes obtained the highest Cd content due to regular arrangement and strong affinity to QDs. The FTIR spectra proved strong interactions between MBA and TiO2 electrodes, leading to fast electron injection from QDs to TiO2 electrodes. The electron injection rate in MBA-TiO2 electrodes was the same as blank-TiO2, larger than TGA- and TPA-ones. Work function of TiO2 electrodes modified by linkers could reduce several eV, in which the MBA-one decreased less, corresponding to the highest applied potential difference. The open-circuit voltage-decay measurement demonstrated that the MBA-TiO2 photoanodes had the least charge recombination. Enhanced light absorption capacity and fast electron injection rate were two key points for modified cell to improve short-circuit current, while low recombination and appropriate energy level positions increased open-circuit voltage. Those make MBA-TiO2 photoanodes obtain the best efficiency of 5.50%. We expected this work to guide the selection of linkers for design and optimization of photoanodes interface of QDSCs.oach in preparation of quantum dot-sensitized solar cells (QDSCs). Three types of linkers (4-mercaptobenzoic acid (MBA, R=phenyl), 3-thiophenecarboxylic acid (TPA, R=thiophene), and thioglycolic acid (TGA, R=alkyl)) were used to functionalize TiO2 electrodes and prepare TiO2/CdSe QDSCs with photoelectric conversion efficiency (PCE) of 5.50%, 4.59% and 4.85%, respectively. Various properties of modified and blank TiO2 electrodes, such as QDs loading, absorbance, work function, interfacial charge injection, recombination and their influence on PCE were investigated. In spite of low adsorption amounts of MBA on TiO2, the phenyl MBA-TiO2 electrodes obtained the highest Cd content due to regular arrangement and strong affinity to QDs. The FTIR spectra proved strong interactions between MBA and TiO2 electrodes, leading to fast electron injection from QDs to TiO2 electrodes. The electron injection rate in MBA-TiO2 electrodes was the same as blank-TiO2, larger than TGA- and TPA-ones. Work function of TiO2 electrodes modified by linkers could reduce several eV, in which the MBA-one decreased less, corresponding to the highest applied potential difference. The open-circuit voltage-decay measurement demonstrated that the MBA-TiO2 photoanodes had the least charge recombination. Enhanced light absorption capacity and fast electron injection rate were two key points for modified cell to improve short-circuit current, while low recombination and appropriate energy level positions increased open-circuit voltage. Those make MBA-TiO2 photoanodes obtain the best efficiency of 5.50%. We expected this work to guide the selection of linkers for design and optimization of photoanodes interface of QDSCs.

Plasmon-Driven Electrochemical Methanol Oxidation on Gold Nanohole Electrodes.

Direct methanol oxidation is expected to play a central role in low-polluting future power sources. However, the sluggish and complex electro-oxidation of methanol is one of the limiting factors for any practical application. To solve this issue, the use of plasmonic is considered as a promising way to accelerate the methanol oxidation reaction. In this study, we report on a novel approach for achieving enhanced methanol oxidation currents. Perforated gold thin film anodes were decorated with Pt/Ru via electrochemical deposition and investigated for their ability for plasmon-enhanced electrocatalytic methanol oxidation in alkaline media. The novel methanol oxidation anode (AuNHs/PtRu), combining the strong light absorption properties of a gold nanoholes array-based electrode (AuNHs) with surface-anchored bimetallic Pt/Ru nanostructures, known for their high activity toward methanol oxidation, proved to be highly efficient in converting methanol via the hot holes generated in the plasmonic electrode. Without light illumination, AuNHs/PtRu displayed a maximal current density of 13.7 mA/cm2 at -0.11 V vs Ag/AgCl. Enhancement to 17.2 mA/cm2 was achieved under 980 nm laser light illumination at a power density of 2 W/cm2. The thermal effect was negligible in this system, underlining a dominant plasmon process. Fast generation and injection of charge carriers were also evidenced by the abrupt change in the current density upon laser irradiation. The good stability of the interface over several cycles makes this system interesting for methanol electro-oxidation.

Embryo location in the uterus during embryo transfer: An in vitro simulation.

ObjectiveTo evaluate the location of transferred embryos under various parameters during embryo transfer in in vitro fertilization (IVF) by applying an in vitro experimental model for embryo transfer (ET).MethodsMock ET simulations were conducted with a laboratory model of the uterine cavity. The transfer catheter was loaded with a sequence of air and liquid volumes, including development-arrested embryos donated by patients. The transfer procedure was recorded using a digital video camera. An orthogonal design, including three independent variables (uterine orientation, distance of the catheter tip to the fundus, and injection speed) and one dependent variable (final embryo position), was applied.ResultsThe uterine cavity was divided into six regions. The distribution of the transferred matter within the uterine cavity varied according to the uterine orientation. Medium speed-injected embryos were mostly found in the static region while fast- and slow-speed injected embryos were mostly found in the fundal region and the cervical-left region, respectively. The possibility of embryo separation from the air bubble increased from 11.1% in slow injection cases to 29.6% and 48.1% in medium and fast injection cases, respectively.ConclusionThe experimental model provides a new method for investigating ET procedures. Fast injection of embryos into a retroverted uterus may be more likely to result in embryo separation from the air bubble.

Mass spectrometry-based measurements of cyclic adenosine monophosphate in cells, simplified using reversed phase liquid chromatography with a polar characterized stationary phase

3′, 5′ – Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that is involved in many cellular functions and biological processes. In several cell types, cholera toxin will increase the level of cAMP, which mediates toxic effects on cells. In this context, we have developed a fast and simple method based on extraction with 5% trichloroacetic acid (TCA) and quantitation with liquid chromatography-mass tandem spectrometry (LC-MS/MS) for measuring cAMP in cells. A main feature of the LC-MS method was employing a reversed phase C18 column (2.1 mm × 50 mm, 1.6 µm particles) compatible with a 100% aqueous mobile phase, providing retention of the highly polar analyte. Isocratic separations allowed for fast subsequent injections. Negative mode electrospray ionization detection was performed with a triple quadrupole (QqQ)MS. cAMP was extracted from cell samples (~106 cells per well) and spiked with a labelled internal standard, using 200 µL of 5% TCA. The extraction solvent was fully compatible for direct injection onto the reversed phase column. After 10 min incubation, the supernatant was removed, and 10 µL of the supernatant was directly analysed by LC-MS. The method was characterized by the simplicity of the extraction, and the speed (3 min retention time of cAMP), sensitivity (250 pg/mL detection limit), and selectivity (separation from interferences e.g. isomeric compounds) of the LC-MS method, and could be used for quantitation of cAMP in the range 1–500 ng/mL cell extract.

Aqueous Synthesis of DNA-Functionalized Near-Infrared AgInS2/ZnS Core/Shell Quantum Dots.

Biocompatibility, biofunctionality, and chemical stability are essential criteria to be fulfilled by quantum dot (QD) emitters for bio-imaging and -sensing applications. In addition to these criteria, achieving efficient near-infrared (NIR) emission with nontoxic QDs remains very challenging. In this perspective, we developed water-soluble NIR-emitting AgInS2/ZnS core/shell (AIS/ZnS) QDs functionalized with DNA. The newly established aqueous route relying on a two-step hot-injection synthesis led to highly luminescent chalcopyrite-type AIS/ZnS core/shell QDs with an unprecedented photoluminescence quantum yield (PLQY) of 55% at 700 nm and a long photoluminescence (PL) decay time of 900 ns. Fast and slow hot injection of the precursors were compared for the AIS core QD synthesis, yielding a completely different behavior in terms of size, size distribution, stoichiometry, and crystal structure. The PL peak positions of both types of core QDs were 710 (fast) and 760 nm (slow injection) with PLQYs of 36 and 8%, respectively. The slow and successive incorporation of the Zn and S precursors during the subsequent shell growth step on the stronger emitting cores promoted the formation of a three-monolayer thick ZnS shell, evidenced by the increase of the average QD size from 3.0 to 4.8 nm. Bioconjugation of the AIS/ZnS QDs with hexylthiol-modified DNA was achieved during the ZnS shell growth, resulting in a grafting level of 5-6 DNA single strands per QD. The successful chemical conjugation of DNA was attested by UV-vis spectroscopy and agarose gel electrophoresis. Importantly, surface plasmon resonance imaging experiments using complementary DNA strands further corroborated the successful coupling and the stability of the AIS/ZnS-DNA QD conjugates as well as the preservation of the biological activity of the anchored DNA. The strong NIR emission and biocompatibility of these AIS/ZnS-DNA QDs provide a high potential for their use in biomedical applications.

Comparison of Clinical Outcomes of Different Rates of Infusion in Caudal Epidural Steroid Injection: A Randomized Controlled Trial.

Study DesignProspective randomized controlled equivalence trial.PurposeTo compare the clinical outcomes between patients with lumbosacral radiculopathy that received caudal epidural steroid injection (CESI) at injection rates of 40 mL/min (fast rate) and 20 mL/min (slow rate) and to identify the complications associated with these different CESI rates.Overview of LiteratureCESI is widely used for chronic low back pain with lumbar radiculopathy. However, the influence of CESI rates on clinical outcomes has not been well studied.MethodsNinety patients were randomized into two CESI groups. Two patients did not complete the study. Eighty-eight were included in the final analysis: 44 patients were in the fast infusion group, and 44 patients were in the slow infusion group. Intragroup and intergroup comparisons were conducted with regard to the Visual Analog Scale (VAS), Roland 5-point pain scale, standing tolerance test, walking tolerance test, and patient satisfaction scale at pre-injection, 2 weeks, 6 weeks, and 12 weeks post-injection. Complications associated with the different rates were recorded.ResultsBoth groups demonstrated clinical improvement in all parameters, except for VAS, after injection. There were no statistically significant differences in any outcomes at each time point between the two groups. One patient in the fast rate group and no patients in the slow rate group experienced nausea and vomiting after injection (p=0.320). Eight patents in the fast rate group and two patients in the slow rate group experienced pain at the injection site (p=0.044).ConclusionsAlthough there were no significant differences between injection rates in the short-term clinical improvement outcomes, the fast injection rate group experienced more pain at the injection site, suggesting that the use of the slow injection rate may be considered.

Efficiency enhancement of perovskite solar cells based on graphene-CuInS2 quantum dots composite: The roles for fast electron injection and light harvests

A high performance perovskite solar cell based on graphene-CuInS2 QDs composite was fabricated. And an improved power conversion efficiency of 17.1% is achieved. The light harvests and electron injection in graphene-CuInS2 QDs composite based solar cell was quite enhanced and facilitated with the charge transfer time of only 9.3 ns. After the deep investigation, we proposed four possible charge transfer processes for the MAPbI3/graphene-CuInS2 QDs based solar cells for the explaining of high inner photocurrent conversion efficiency. Besides, the graphene-CuInS2 QDs based solar cells have rather high reproducibility and air stability. Our results demonstrates that the graphene-CuInS2 QDs composite is excellent photovoltaic materials for fabrication of high performance solar cells.

A Digital-Intensive Extended-Range Dual-Mode BLE5.0 and IEEE802.15.4 Transceiver SoC

The proposed fully integrated digital-intensive system on chip (SoC) allows dual-mode protocols of Bluetooth low energy (BLE) 5.0 and IEEE802.15.4 with extended-range wireless connectivity and ad hoc mesh networks for Internet-of-Things (IoT) systems in wireless sensor networks. The SoC fully integrates a dc–dc converter, LDOs, a digitally controlled crystal oscillator (DCXO), a PHY, a microcontroller (MCU), a security engine, an SRAM, and an eFlash memory. A triple-supply configuration and low-voltage circuit design enable the SoC to be applied for a wide range of battery-powered systems energy-efficiently and to extend battery lifetime. The TRX employs a low insertion-loss on-die TRX switch with impedance matching circuits, a pseudodifferential current-mode class-D PA with HD2 calibration, a low-IF RX architecture with fast AGC algorithm and complex CT- $\Delta \Sigma $ ADCs, and a low-power all-digital phase-locked loop (ADPLL) with fast settling injection LDOs and an LMS-based two-point direct frequency modulation structure. The TRX implemented in a 28-nm CMOS process achieves an output power of +10 dBm with a calibrated HD2 of −63 dBc while consuming 45 mW and sensitivities of −98 dBm in 2-Mb/s BLE and −102 dBm in 256-kb/s IEEE802.15.4 at ${10}^{-3}$ BER while consuming 6 mW.

Excited-State Properties of Metal-Free ((Z)-2-Cyano-3-(4-((E)-2-(6-(4-methoxyphenyl)-9-octyl-9H-carbazol-3-yl)vinyl)phenyl)acrylic Acid and (E)-2-Cyano-3-(4-((E)-4-(diphenylamino)styryl)phenyl)acrylic Acid) and Ru-Based (N719 and Z907) Dyes and Photoinduced Charge Transfer Processes in FTO/TiCl4/TiO2/Dye Photoanodes Fabricated by Conventional Staining and Potential-Assisted Adsorption.

Excited-state properties of two novel metal-free custom-made dyes D2d [(Z)-2-cyano-3-(4-((E)-2-(6-(4-methoxyphenyl)-9-octyl-9H-carbazol-3-yl)vinyl)phenyl)acrylic acid] and T-SB-C [(E)-2-cyano-3-(4-((E)-4-(diphenylamino)styryl)phenyl)acrylic acid] and two commercially available Ruthenium-based N719 and Z907 dyes were investigated with application of time-resolved absorption and emission. Singlet excited state lifetimes of D2d and T-SB-C were determined in acetonitrile and are 1.4 and 2.45 ns, respectively. The 3MLCT state lifetimes of N719 and Z907 dyes determined in methanol are 9.25 and 8.85 ns, respectively. Subsequently, photoexcited processes like electron injection and charge recombination were studied for those dyes adsorbed on the FTO/TiCl4/TiO2 photoanodes and fabricated via a conventional staining technique and innovative potential-assisted fast dye staining method. The dynamics of the spectro-temporal data was determined with application of single-wavelength and global fitting. All dye-TiO2 systems showed fast picosecond injection of excited electrons to the conduction band of the TiO2 layer and in complex multiphasic charge recombination processes. The dynamics of those processes is not altered by the dye adsorption method.

Room-Temperature Synthesis of Single Iron Site by Electrofiltration for Photoreduction of CO2 into Tunable Syngas

Developing a convenient and effective method to prepare single-atom catalysts at mild synthetic conditions remains a challenging task. Herein, a voltage-gauged electrofiltration method was demonstrated to synthesize single-atom site catalysts at room temperature. Under regulation of the graphene oxide membrane, a bulk Fe plate was directly converted into Fe single atoms, and the diffusion rate of Fe ions was greatly reduced, resulting in an ultralow concentration of Fe2+ around the working electrode, which successfully prevented the growing of nuclei and aggregating of metal atoms. Monatomic Fe atoms are homogeneously anchored on the as-prepared nitrogen-doped carbon. Owing to the fast photoelectron injection from photosensitizers to atomically dispersed Fe sites through the highly conductive supported N-C, the Fe-SAs/N-C exhibits an outstanding photocatalytic activity toward CO2 aqueous reduction into syngas with a tunable CO/H2 ratio under visible light irradiation. The gas evolution rates for CO and H2 are 4500 and 4950 μmol g-1 h-1, respectively, and the tunable CO/H2 ratio is from 0.3 to 8.8. This article presents an efficient strategy to develop the single-atom site catalysts and bridges the gap between heterogeneous and homogeneous catalysts toward photocatalytic CO2 aqueous reduction into syngas.

In vitro Implementation of Photopolymerizable Hydrogels as a Potential Treatment of Intracranial Aneurysms.

Intracranial aneurysms are increasingly being treated with endovascular therapy, namely coil embolization. Despite being minimally invasive, partial occlusion and recurrence are more frequent compared to open surgical clipping. Therefore, an alternative treatment is needed, ideally combining minimal invasiveness and long-term efficiency. Herein, we propose such an alternative treatment based on an injectable, radiopaque and photopolymerizable polyethylene glycol dimethacrylate hydrogel. The rheological measurements demonstrated a viscosity of 4.86 ± 1.70 mPa.s, which was significantly lower than contrast agent currently used in endovascular treatment (p = 0.42), allowing the hydrogel to be injected through 430 μm inner diameter microcatheters. Photorheology revealed fast hydrogel solidification in 8 min due to the use of a new visible photoinitiator. The addition of an iodinated contrast agent in the precursor contributed to the visibility of the precursor injection under fluoroscopy. Using a customized light-conducting microcatheter and illumination module, the hydrogel was implanted in an in vitro silicone aneurysm model. Specifically, in situ fast and controllable injection and photopolymerization of the developed hydrogel is shown to be feasible in this work. Finally, the precursor and the polymerized hydrogel exhibit no toxicity for the endothelial cells. Photopolymerizable hydrogels are expected to be promising candidates for future intracranial aneurysm treatments.

Laboratory Study on Fluid‐Induced Fault Slip Behavior: The Role of Fluid Pressurization Rate

AbstractUnderstanding the physical mechanisms governing fluid‐induced fault slip is important for improved mitigation of seismic risks associated with large‐scale fluid injection. We conducted fluid‐induced fault slip experiments in the laboratory on critically stressed saw‐cut sandstone samples with high permeability using different fluid pressurization rates. Our experimental results demonstrate that fault slip behavior is governed by fluid pressurization rate rather than injection pressure. Slow stick‐slip episodes (peak slip velocity < 4 μm/s) are induced by fast fluid injection rate, whereas fault creep with slip velocity < 0.4 μm/s mainly occurs in response to slow fluid injection rate. Fluid‐induced fault slip may remain mechanically stable for loading stiffness larger than fault stiffness. Independent of fault slip mode, we observed dynamic frictional weakening of the artificial fault at elevated pore pressure. Our observations highlight that varying fluid injection rates may assist in reducing potential seismic hazards of field‐scale fluid injection projects.

Photonic generation of tunable dual-chirp microwave waveforms using a dual-beam optically injected semiconductor laser.

An approach to generating dual-chirp microwave waveforms (DCMWs) is proposed and experimentally demonstrated. The proposed scheme consists of a typical semiconductor slave laser (SL), which is subject to a dual-beam optical injection from two master lasers with one being positively detuned (${\rm ML}_1$ML1) and the other negatively detuned (${\rm ML}_2$ML2) from the SL. Under proper injection conditions, the SL operates in the so-called Scenario B of dual-beam injection. After optical-to-electrical conversion, a dual-frequency microwave signal can be generated with one of its two frequencies increasing linearly and the other decreasing linearly as the ${\rm ML}_1$ML1 injection strength is increased. By incorporating a fast injection strength controller (formed by an intensity modulator and an electrical control signal), a DCMW with a large time-bandwidth product can be generated. In the experimental demonstration, a DCMW with a temporal period of 1 µs has been obtained. This simultaneously offers an up-chirp (13.4-20.2 GHz) and a down-chirp (27.3-20.5 GHz), and its frequency tunability has been achieved by simply adjusting the injection parameters. Furthermore, the auto-ambiguity function of the generated DCMW has also been investigated, which proves that the proposed scheme has the ability to improve the range-velocity resolution and, thus, could be promising for use in radar systems.

A130 RETROGRADE TRACING ANALYSIS OF THE SENSORY INNERVATION OF THE MOUSE COLON

Abstract Background Visceral pain is a primary symptom of many gastrointestinal diseases. One feature of visceral pain is its vague localization. We hypothesized that overlap in the receptive fields of spinal primary afferent neurons that innervate the gut may contribute to this vague localization. Many studies have confirmed that the proximal and distal colon are mainly innervated by spinal afferent neurons with cell bodies in thoraco-lumbar and lumbo-sacral dorsal root ganglia (DRG), respectively. However, no murine studies have examined whether individual DRG neurons simultaneously innervate both proximal and distal colon. Aims To determine the extent of overlap in receptive fields of colon-projecting DRG neurons. Methods C57BL/6 mice (n=8) were anesthetized, and two retrograde neuronal tracers with distinct fluorescence emission spectra (Fast blue and DiI) were injected separately into the smooth muscle layers of proximal and distal colon. Mice were left for 10–13 days for dye transport, before being euthanized. Thoraco, lumbar and lumbo-sacral DRGs (T8-13, L1-4, L5-S2) were dissected and fixed in 4% paraformaldehyde overnight. 12μm cryostat sections were obtained and analyzed using a fluorescent microscope equipped with filter cubes that detect Fast blue and DiI. Results When DiI was injected into the proximal colon, we observed labelling to be highest in T8-13 DRG with 12.6 +/- 4.5% of cell bodies labelled, followed by L1-4 was (8.2 +/- 1.4%) and in L5-S2 (6.5 +/- 0.8%). DiI injections into the distal colon resulted in labelling of similar numbers of neurons labelled in T8-13 and L1-4 ganglia, whereas half as many neurons were labelled in L5-S2 ganglia. This data shows that the majority of spinal afferent innervation of the colon originates in thoracolumbar DRG. Most importantly, 26.4% and 17.6% of thoracolumbar and lumbo-sacral DRG neurons labelled by Fast blue injection into the proximal colon were also double-labelled by DiI injected into the distal colon. Similarly, 16.6% and 13.8% of neurons in thoracolumbar and lumbosacral DRG labelled by Fast blue injection into the distal colon were double-labelled by DiI injected into the proximal colon. Conclusions These data reveal a surprisingly large number of DRG neurons that innervate the colon have receptive fields that cover both the proximal and distal colon, which may contribute to the poor spatial localization of pain emanating from the colon. Funding Agencies CCC, CIHR

A Novel Approach for Achieving High‐Efficiency Photoelectrochemical Water Oxidation in InGaN Nanorods Grown on Si System: MXene Nanosheets as Multifunctional Interfacial Modifier

AbstractMXene nanosheets with attractive electrical conductivity and tunable work function have been adopted as multifunctional interfacial modifier between InGaN nanorods and Si for photoelectrochemical water oxidation for the first time. Compared to bare InGaN/Si systems, MXene interfacial layers give rise to an ultralow onset potential of 75 mV versus reversible hydrogen electrode (RHE), which is the highest ever reported for InGaN‐ or Si‐based photoanodes by interfacial modification. Furthermore, the modified photoanode exhibits a significantly enhanced photocurrent density (7.27 mA cm−2) at 1.23 V versus RHE, which is about 10 times higher than that achieved with the InGaN/Si photoanode. The detailed mechanism demonstrates that the formed type‐II band alignment in InGaN/MXene heterojunction and an Ohmic junction at the MXene/Si interface make MXene an ideal electron‐migration channel to enhance charge separation and transfer process. This synergetic effect of MXene can significantly decrease the charge resistance at semiconductor/Si and semiconductor/electrolyte hetero‐interfaces, eventually resulting in the fast hole injection efficiency of 82% and superior stability against photocorrosion. This work not only provides valuable guidance for designing high‐efficiency photoelectrodes through the integration of multiscale and multifunctional materials, but also presents a novel strategy for achieving high‐performance artificial photosynthesis by introducing interfacial modifier.

Rational design of novel N-doped polyaromatic hydrocarbons as donors for the perylene based dye-sensitized solar cells

This paper reports designing a series of new D-π-A topology-based metal-free organic dye molecules using ullazine and perylene by DFT methods. This work emphasizes the combination of ullazine analogs as donors and perylene dicarboxylic anhydride as an acceptor along with acetylene linker as π-bridge for DSSC applications. The structural and optoelectronic properties of dyes before and after adsorption on to TiO2 semiconductor have been investigated. The screening of the designed dyes is carried out based on the energy gap (Eg), maximum absorption wavelength (λmax), light-harvesting efficiency (LHE), excited-state lifetime (τ), the free energy of electron injection (ΔGinj) and regeneration (ΔGreg). DFT results reveal that the presence of ullazine analogs as a donor reduces the energy gap (Eg) and leads to red-shift in absorption maximum. Further, two different binding modes of dye molecules with (TiO2)38 cluster have been investigated to unravel the binding associated changes in the electronic structure. The results show that the completely dissociated bidentate bridging (CBB2) mode is more favorable, which contains two carboxylic groups. Findings emphasize the remarkable charge transfer characteristics which favors the fast electron injection from excited dye to the conduction band of TiO2. For the first time, this study provides comprehensive structural and electronic information combined with the Dye-TiO2 interactions for the development of perylene based dyes for DSSC applications. This article demonstrates the rational design of novel N-doped Polyaromatic Hydrocarbons as Donors for the Perylene based Dye-Sensitized Solar Cells using state of the art computational methods. This study results in the relatively efficient new dye molecules for DSSC applications. Complete electronic and structural aspects of anatase-TiO2 interaction with designed dye molecules have been elucidated in detail.

Beyond selective spinal anesthesia: A flow pattern analysis of a hyperbaric dye solution injected in a lower-density fluid.

Introduction:Spinal anesthesia is a technique performed since more than a century and the introduction of hyperbaric anesthetics allowed the anesthesiologists to be more selective when using this technique. The aim of this study is to show the in vitro flow patterns of a hyperbaric dye solution through 27 G Quincke and Sprotte spinal needles, injected at different speeds, in a lower-density fluid.Methods:A simulator was made using a gummy-like sponge and a disposable plastic urine glass, filled with saline solution, which has a similar density to cerebrospinal fluid (CSF). A hyperbaric dye solution was composed by mixing 3 ml of plain methylene blue with 1 ml of glucose 33%. We used both 27 G Quincke and Sprotte spinal needles to perform a bevel up and a bevel down injection with both slow (15 s) and fast (4 s) injection speed of 0.5 mL hyperbaric dye solution. All the injections were performed using a preset syringe pump and recorded by a camera.Results:The least selectivity was observed after a bevel up-fast injection through the 27 G Sprotte needle, followed by both bevel up and down fast injections through the 27 G Quincke needle. On the contrary, the best selectivity was observed after a bevel down-slow injection through the 27 G Sprotte needle, followed by both bevel up and down slow injections through the 27 G Quincke needle.Conclusion:When a 27 G Sprotte needle is used to inject a hyperbaric solution in a lower-density fluid-like CSF, the spread depends on both the bevel direction and the injection speed.

FAPI Controller for Frequency Support in Low-Inertia Power Systems

This paper presents different forms of Fast Active Power Injection (FAPI) control schemes for the analysis and development of different mitigation measures to address the frequency stability problem due to the growth of the penetration level of the Power Electronic Interfaced Generation (PEIG) in sustainable interconnected energy systems. Among the studied FAPI control schemes, two different approaches in the form of a derivative-based control and a virtual synchronous power (VSP) based control for wind turbine applications are also proposed. All schemes are attached to the PEIG represented by a generic model of wind turbines type 4. The derivative-based FAPI control is applied as an extension of the droop based control scheme, which is dependent on the measurement of the network frequency. By contrast, the proposed VSP-based FAPI is fed by the measurement of the active power deviation. Additionally, unlike existing approaches for virtual synchronous machines, which are characterized by high-order transfer functions, the proposed VSP-based FAPI is defined by a second-order transfer function, which can contribute to fast mitigation of the system primary frequency deviations during containment period. The Great Britain (GB) test system, for the Gone-Green planning scenario for the year 2030 (GG2030), is used to evaluate the effects of the proposed FAPI controllers on the dynamics of the system frequency within the frequency containment period. Thanks to proposed FAPI controllers, it is possible to reach up to 70% for the share of wind power generation without violating the threshold limits for frequency stability. For verification purposes, a full-scale wind turbine facilitated with each FAPI controller is tested in EMT real-time simulation environment.

The band bending effect of LiI/NaI treated TiO2 photoanodes on the performance of dye-sensitized solar cells.

A new method has been developed for surface treatment of TiO2 photoanodes with LiI/NaI to enhance the photocurrent and, subsequently, the performance efficiency of the fabricated dye-sensitized solar cells (DSSCs). Three different concentrations (0.1, 0.25, and 0.5 mmol%) of LiI and NaI solutions were used to investigate the effect of this surface treatment on the device performance of DSSCs. A positive shift in the energy level of TiO2 has been experienced by surface treated devices, which is predominantly supported by the decrease in VOC. Furthermore, the introduction of LiI/NaI onto the TiO2 surface resulted in a reduction in the crystallite size, indicating an increase in the surface area which helps in more dye adsorption leading to higher JSC values of the devices. Besides, modification of the conduction band energy level, it also allows a fast electron injection process by shifting the density of states. Thus, this approach offers a simple but efficient route to enhance the photocurrent and efficiency of DSSCs.