Deuterium Experiments Research Articles

Degradation of fast-ion confinement depending on the neutral beam power in MHD quiescent LHD plasmas

We investigated the degradation of neutral beam (NB) fast-ion confinement depending on the NB power without magnetohydrodynamics instabilities in the Large Helical Device (LHD). In the LHD deuterium experiment, the neutron emission rate per NB power decreased by up to 20% with increasing injected NBs during a single discharge. Because there were no significant variations in the electron temperature and density, the NB shine-through rate, or the magnetic fluctuation due to the change in NB power, the reduction in the neutron emission rate indicates the degradation of the fast-ion confinement. In this paper, we formulated this degradation depending on the NB power and quantitatively estimated the degraded effective confinement time. In addition, we performed neutron emission rate simulations using the obtained effective confinement time. The simulation and experimental results were in good agreement, suggesting that the degraded effective confinement time is valid.

Mutualism in organic synthetic chemistry: Simultaneous heterodehydrocoupling of hydrostannane and reduction of quinoline

Here we report a one-pot strategy to simultaneously achieve both the heterodehydrocoupling of hydrostannane and reduction of quinoline by using B(C6F5)3 as catalyst under mild conditions. This method realizes the synthesis of heteroatom-tin complexes (NSn/OSn/PSn/SSn) by the same catalyst system. With the assistance of quinoline, the substrate scope was broadened and ESn yield was significantly enhanced. During the reaction, the generated heterodehydrocoupling intermediate [ESnH]+[HB(C6F5)3]− would accelerate the quinoline reduction by transforming 1,4-N-stannyl-dihydroquinoline intermediate into N-stannyl-tetrahydroquinoline whereas 1,4-N-stannyl-dihydroquinoline could serve as hydrogen acceptor to facilitate the conversion of [ESnH]+[HB(C6F5)3]− intermediate to produce ESn (E = N/O/P/S). The metathetical reaction of N-stannyl-tetrahydroquinoline and EH rapidly generates ESn and tetrahydroquinolines, thus mutually promoting the above process. The reaction mechanism is proposed on the basis of control experiments, capture and synthesis of key intermediates and deuterium experiments.

A dual-route optical emission spectroscopy diagnostic with wide spectral range and high wavelength resolution on HL-2A tokamak

A dual-route optical emission spectroscopy (D-OES) diagnostic is newly developed to monitor the optical emission from the X-point plasma region on the HL-2A tokamak. This diagnostic is composed of an imaging system, a beam-splitting system for dual-route measurements, fiber bundles, a spectrometer system, and a control and acquisition system. One route is used to obtain wide-spectral-range spectra, and the other route is used to acquire high-wavelength-resolution line shapes. The spectral resolution of the wide-range spectrometers is 0.8 nm with a coverage of 800 nm (@200–1000 nm). The spectral resolution of the high-resolution spectrometer is 0.01 nm with a coverage of 6 nm (@200–660 nm). The spatial resolution of each route of D-OES is about 4 cm with 11 channels. The temporal resolution is 16 ms at maximum in the single-channel mode. Wide-range spectra (containing Balmer series and a Fulcher band) and highly resolved line shapes are obtained by D-OES in the hydrogen glow discharge in the lab. D-OES measurements are carried out in the high-density deuterium experiments of HL-2A. The electron density and deuterium temperature in the X-point multifaceted asymmetric radiation from the edge (MARFE) region are derived simultaneously by fitting the measured shape. The density is observed to increase from ~ to ~ , and the temperature drops from ~14.4 eV to ~2.3 eV after the onset of MARFE in the discharge #38260.

Meta‐C−H Arylation of Aniline Derivatives via Palladium/ S,O‐Ligand/Norbornene Cooperative Catalysis

AbstractAromatic amines are ubiquitous moieties in organic molecules and their direct functionalization is of great interest in many research areas due to their prevalence in pharmaceuticals and organic electronics. While several synthetic tools exist for the ortho‐ and para‐functionalization of anilines, the functionalization of the less reactive meta‐position is not easy to achieve with current methods. To date, the meta‐C−H arylation of aniline derivatives has been restricted to either the use of directing groups & templates, or their transformation into anilides & quaternary anilinium salts. Herein, we report the first general and efficient meta‐C−H‐arylation of non‐directed aniline derivatives via cooperative catalysis with a palladium–S,O‐ligand–norbornene system. The reaction proceeds under mild conditions with a wide range of aniline derivatives and aryl iodides, while being operationally simple and scalable. Our preliminary mechanistic investigation–including the isolation of several palladium complexes and deuterium experiments–reveal useful insights into the substituent‐effects of both the aniline‐substrate and the norbornene‐mediator during the meta‐C−H activation step.

Fast-sampling fast-ion D-alpha measurement using multi-anode photomultiplier tube in large helical device.

A fast-sampling fast-ion D-alpha (F-FIDA) measurement has been developed in the large helical device in order to investigate fast ion dynamics associated with helically trapped fast-ion-driven Magnetohydrodynamic (MHD) bursts. F-FIDA consists of a multi-anode photomultiplier tube (PMT) and achieves a sampling rate of 10kHz. During the deuterium experiment campaign in 2022, F-FIDA measured the spectrum of perpendicular fast ions, using perpendicular lines of sight. We compared F-FIDA with conventional FIDA, using an electron multiplying charge coupled device, and confirmed that the time-averaged images were generally consistent between the two. The statistical properties of the temporal evolution associated with MHD bursts were analyzed using a conditional sampling technique. The results showed that the PMT signal varied in different spatial and wavelength channels. Although the signal-to-noise ratio was poor and there was room for improvement, it could provide useful information for studies on the phase-space dynamics of fast ions.

Ligand‐Dictated Regiodivergent Allylic Functionalizations via Palladium‐Catalyzed Remote Substitution

AbstractDifferent from classical allylic substitutions that require a vicinal leaving group, an olefin bearing a remote leaving group is scarcely viewed as a potential allylation substrate. Herein, we describe feasible protocols to achieve regiodivergent allylic C−H functionalizations via palladium‐catalyzed remote substitution, which provides a novel strategy for the seldomly studied migratory Tsuji–Trost reaction. Dictated by a suitable ligand, a process that involved 4,3‐hydrofunctionalization of the generated conjugated diene intermediate via metal walking is observed in generally >20 : 1 regioselectivity. Unexpectedly, a related 1,4‐hydrofunctionalization pathway is found to be a major route with a newly synthesized electron‐rich bisphosphine ligand, which challenges the conventional viewpoint on the potential regioselectivity of hydrofunctionalizations of linear internal conjugated dienes via η3‐substitution. A series of deuterium experiments and kinetic studies provide a preliminary insight into the potential catalytic cycle.

Ligand-Dictated Regiodivergent Allylic Functionalizations via Palladium-Catalyzed Remote Substitution.

Different from classical allylic substitutions requiring a vicinal leaving group, an olefin bearing a remote leaving group is scarcely viewed as a potential allylation substrate. Here we describe feasible protocols to achieve the regiodivergent allylic C-H functionalizations via palladium-catalyzed remote substitution, which provides a novel strategy for seldomly studied migratory Tsuji-Trost reaction. With the dictation of a suitable ligand, a processinvolved 4,3-hydrofunctionalization of the generated conjugated diene intermediate via metal walking is observed in generally >20:1 regioselectivity. Unexpectedly, related 1,4-hydrofunctionalization pathway is tuned to work as a major route with a newly synthesized electron-rich bisphosphine ligand, which breakouts the conventional viewpoint on the potential regioselectivity of hydrofunctionalizations of linear internal conjugated dienes via ƞ3-substitution. A series of deuterium experiments and kinetic studies provide preliminary insight into the potential catalytic cycle.

Constructing Four-Membered Heterocycles by Cycloisomerization

Four-membered heterocycles are highly sought after in modern drug discovery as they provide beneficial properties to the target molecules. Despite tremendous efforts by the synthetic research community, there is a need for a simple and new method to incorporate these motifs into the design molecules. Herein, we reveal a cycloisomerization strategy for the construction of oxetane and azetidine rings via metal hydride hydrogen atom transfer/radical polar crossover, which is challenging both enthalpically and entropically. This method is suitable for synthesizing polysubstituted four-membered heterocycles. This mild and functional-group tolerant reaction has a broad substrate scope, including the spiro structure, which is an important motif in drug discovery research. Various four-membered heterocyclic building blocks can be synthesized by product derivatization. We also discuss the reaction mechanism, focusing on the four-membered ring formation, by deuterium experiments and DFT studies.

Isotope effects under the influence of global radial electric fields in a helical configuration

Isotope effects under the influence of a radial electric field are examined in a helical magnetic field configuration. We perform global gyrokinetic simulations with additional poloidal rotations to estimate quasi-linear heat flux due to ion temperature gradient mode under the mixing length model. In single-ion-species plasmas, the mass number dependency of heat flux agrees with gyro-Bohm scaling in the absence of a radial electric field. Favorable mass number dependencies violating gyro-Bohm scaling are observed in the presence of a global radial electric field or a heavy hydrogen component in multi-ion-species plasmas. The radial electric field and the heavy hydrogen component affect the heat flux through an increase of wavelength as well as mode stabilization. Poloidal Mach number characterizes the transition from unfavorable to favorable mass number dependency under radial electric fields. While the heat flux is independent of mass number for a given poloidal Mach number, the heat flux decreases for higher mass numbers in a given radial electric field. The heat flux is also independent of average mass number in multi-ion-species plasmas because the heavy hydrogen component effectively enhances the light hydrogen heat flux. The present results are potentially relevant to the violation of gyro-Bohm scaling observed in the recent deuterium experiments in the Large Helical Device.

Iridium-Catalyzed Asymmetric Allylic Benzylation with Photogenerated Hydroxy-o-Quinodimethanes.

An iridium-catalyzed asymmetric allylic benzylation of aryl vinyl carbinols under light irradiation is described. 2-Methylbenzophenone derivatives are employed and activated to hydroxy-o-quinodimethanes by an ultraviolet (UV) light. This approach enables asymmetric allylic benzylation with high enantioselectivity (up to 99 % ee) from readily available 2-methylbenzophenones without the utilization of strong bases, and pre-activation or pre-functionalization of the substrates. Moreover, deuterium experiments reveal the generation of nucleophilic benzyl species from 2-methylbenzophenone under UV irradiation.

Iridium‐Catalyzed Asymmetric Allylic Benzylation with Photogenerated Hydroxy‐o‐Quinodimethanes

AbstractAn iridium‐catalyzed asymmetric allylic benzylation of aryl vinyl carbinols under light irradiation is described. 2‐Methylbenzophenone derivatives are employed and activated to hydroxy‐o‐quinodimethanes by an ultraviolet (UV) light. This approach enables asymmetric allylic benzylation with high enantioselectivity (up to 99 % ee) from readily available 2‐methylbenzophenones without the utilization of strong bases, and pre‐activation or pre‐functionalization of the substrates. Moreover, deuterium experiments reveal the generation of nucleophilic benzyl species from 2‐methylbenzophenone under UV irradiation.

Copper-Catalyzed Ligand-Controlled Selective Borocarbonylation of α-Substituted Styrenes Toward β-Boryl Aldehydes and Cyclopropyl Boronate Esters

Copper-Catalyzed Ligand-Controlled Selective Borocarbonylation of α-Substituted Styrenes Toward β-Boryl Aldehydes and Cyclopropyl Boronate Esters

The future is 2D: spectral-temporal fitting of dynamic MRS data provides exponential gains in precision over conventional approaches.

Many MRS paradigms produce 2D spectral-temporal datasets, including diffusion-weighted, functional, and hyperpolarized and enriched (carbon-13, deuterium) experiments. Conventionally, temporal parameters-such as T2 , T1 , or diffusion constants-are assessed by first fitting each spectrum independently and subsequently fitting a temporal model (1D fitting). We investigated whether simultaneously fitting the entire dataset using a single spectral-temporal model (2D fitting) would improve the precision of the relevant temporal parameter. We derived a Cramer Rao lower bound for the temporal parameters for both 1D and 2D approaches for 2 experiments: a multi-echo experiment designed to estimate metabolite T2 s, and a functional MRS experiment designed to estimate fractional change ( ) in metabolite concentrations. We investigated the dependence of the relative standard deviation (SD) of T2 in multi-echoand in functional MRS. When peaks were spectrally distant, 2D fitting improved precision by approximately 20% relative to 1D fitting, regardless of the experiment and other parameter values. These gains increased exponentially as peaks drew closer. Dependence on temporal model parameters was weak to negligible. Our results strongly support a 2D approach to MRS fitting where applicable, and particularly in nuclei such as hydrogen and deuterium, which exhibit substantial spectral overlap.

P‐139: Process Simulation Reflecting Hydrogen/Oxygen for Oxide Semiconductor Thin Film Transistor

To predict the effect of hydrogen and oxygen diffusion from the other adjacent layer to oxide semiconductor, we fabricated amorphous IGZO TFT (In‐Ga‐Zn‐O thin film transistor) with various gate insulator (SiOx) layer and various oxygen treatment above gate insulator. Then, simulation was performed to investigate the relationship among the hydrogen and oxygen content of the a‐IGZO and electrical properties of the TFTs. At this time, we obtained a certain diffusion coefficient for oxygen and hydrogen in each layer through deuterium and isotope experiments, and used these as input parameters for the simulation. And we found a high carrier concentration of IGZO was proportional to the increase in the amount of SiH4 gas ratio during the gate insulator deposition. And it was confirmed that the amount of oxygen in the active layer was different according to the oxygen treatment condition on top of the gate insulator. It is thought that oxygen in plasma state was injected into the silicon oxide (SiOx) layer before metal deposition occurred. The oxygen diffusion coefficient in metal is extremely small compared to SiOx, so it is impossible to inject oxygen into SiOx after metal deposition. As a result of applying the models of hydrogen and oxygen conditions, we were able to predict the Vth trend of the measurement results considerably

Cooperative Tertiary Phosphine/Palladium Catalyzed Nucleophilic Allylation between Morita‐Baylis‐Hillman Carbonates and Alkenes

AbstractIn this work, we report an unusual nucleophilic allylation reaction between isatin‐derived Morita–Baylis–Hillman carbonates and simple alkenes synergistically catalyzed by tertiary phosphines and palladium complexes, through chemoselective assemblies of in situ formed onium salts and η1‐allylpalladium species, respectively. A range of 3,3‐disubstituted oxindoles were easily constructed in moderate to good yields with exclusive linear regioselectivity. Moreover, a number of control and deuterium experiments have been conducted to elucidate the catalytic mechanism.

Numerical study of different electron density observed in Hydrogen and Deuterium ion source plasmas

Sequences of hydrogen (H) and deuterium (D) experiments have been done by NIFS research and development negative ion source (RNIS) for the deuterium NBI development. In the experiments, the co-extracted electron current with the negative ions and the electron density in the plasma generation region in the D experiment have been around three times higher than that in the H experiment. To explain the difference of the electron density in the RNIS driver region, a zero-dimensional numerical model is developed in the present study. The model only focuses on the isotope effect for vibrationally excited level of electronically grounded state molecules and its relevant cross-sections. The calculation results show that difference of the ionization channel numbers via molecular vibrationally excited states could be a reason to enhance ionization rate in D plasma.

Numerical analysis of isotope effect in NIFS negative ion source

Result of hydrogen (H) and deuterium (D) experiments done by NIFS research and development negative ion source (RNIS) demonstrated that the co-extracted electron current with the negative ions and the electron density in the driver region in the D experiment have been around three times higher than that in the H experiment. To investigate mechanism of this difference, electron transport simulation using 3D kinetic particle tracking model KEIO-MARC code has been modified and applied to analysis of the isotope effect in the NIFS negative ion source. Simulation result suggests that impacts of isotope effects of sheath potential drop, coulomb collisions, and some reactions of ground state molecules and ions on the electron density is not large to explain the experimental result of the increase in the electron density in the plasma.

Recent results from deuterium experiments on the large helical device and their contribution to fusion reactor development

In recent deuterium experiments on the large helical device (LHD), we succeeded in expanding the temperature domain to higher regions for both electron and ion temperatures. Suppression of the energetic particle driven resistive interchange mode (EIC) by a moderate electron temperature increase is a key technique to extend the high temperature domain of LHD plasmas. We found a clear isotope effect in the formation of the internal transport barrier in high temperature plasmas. A new technique to measure the hydrogen isotope fraction was developed in the LHD in order to investigate the behavior of the isotope mixing state. The technique revealed that the non-mixing and the mixing states of hydrogen isotopes can be realized in plasmas. In deuterium plasmas, we also succeeded in simultaneously realizing the formation of the edge transport barrier (ETB) and the divertor detachment. It is found that resonant magnetic perturbation plays an important role in the simultaneous formation of the ETB and the detachment. Contributions to fusion reactor development from the engineering point of view, i.e. negative-ion based neutral beam injector research and the mass balance study of tritium, are also discussed.

Water-involved tandem conversion of aryl ethers to alcohols over metal phosphide catalyst

Lignin-derived compounds provide a platform for the production of value-added chemicals. Herein, we reported metal phosphide (Pd-Ni-P) catalyzed the conversion of diphenyl ether (DPE) via a restricted pathway involving partial hydrogenation-hydrolysis-hydrogenation. Cyclohexanol, an important raw material for the polymer industry, was therefore obtained as the main product in 87% mole yield with a high production rate of 14.65 mol·g−1Pd·h−1. The results of X-ray diffraction, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy confirmed that Ni and P atoms were inserted into the face-centred cubic Pd lattices, leading to the expanded Ni-Ni lattices and Pd-P covalent bonds. The electronic deficient Pd contributes to the partial hydrogenation of DPE to cyclohexyl phenyl ether (CHPE), and the inserted Ni facilitates the hydrolysis of CHPE to monocycles. Various control experiments including deuterium experiment and reaction kinetic study revealed the strong hydrolysis ability of Pd-Ni-P catalyst accounting for the high production rate of cyclohexanol. Besides, several lignin-derived aryl ethers could undergo the same reaction pathway to produce alcohol chemicals with high yields ranging from 50% to 94%.

Hadronization model tuning in genie v3

The GENIE neutrino Monte Carlo describes neutrino-induced hadronization with an effective model, known as AGKY, which is interfaced with PYTHIA at high invariant mass. Only the low-mass AGKY model parameters were extracted from hadronic shower data from the FNAL 15 ft and BEBC experiments. In this paper, the first hadronization tune on averaged charged multiplicity data from deuterium and hydrogen bubble chamber experiments is presented, with a complete estimation of parameter uncertainties. A partial tune on deuterium data only highlights the tensions between hydrogen and deuterium datasets.