Assembling HTS tapes into cables is an effective solution to enhance the operating current of superconducting devices. With the advancement of cable research and its practical engineering applications, the demand for quality control of cables is rapidly increasing. In this paper, a fitting algorithm for cable defect detection is being proposed. This algorithm can effectively extract defect information within the cable and identify and correct for movements including position displacement and rotation of the cable. The method has been validated using both simulation and experimental data from HTS tapes and cables.

Due to the intrinsic brittleness of high-temperature superconducting materials, local defects are prone to occur during the winding of coils, which poses significant risks to the safe operation of magnets. This study proposes a coil defect detection method that utilizes a sensor matrix to measure the temperature distribution and propagation process on the coil under current-carrying conditions. The location of the defects can be traced through an inversion algorithm. This paper introduces the design, construction, and test results of the experimental setup. It has been verified that the method can effectively detect localized heat generation as low as 0.01 W, which corresponds to a local defect in coils with a 10% critical current reduction.

In order to accurately and efficiently study the transient process of quenching in non-insulated superconducting windings, the Partial Element Equivalent Circuit (PEEC) model is employed. This model regards the superconducting winding as being composed of multiple independent segments. To establish the model parameter matrix, it is necessary to calculate the resistance and inductance parameters for each independent segment. Among these, the inductance parameters can be derived from the relationship between the magnetic vector potential A and the current density J. However, during the derivation process, when calculating the self-inductance of each segment, a singularity problem may arise. This issue can be resolved through the method of partial integration. This paper will elaborate on the derivation process of the inductance matrix for circular windings, straight laminations, and D-shaped windings, with a focus on the solution to the self-inductance singularity problem.

By combining multiple high-temperature superconducting tapes into cables and then fabricating them into devices such as power cable and magnets, the system operating current can be effectively increased and manufacturing process difficulties can be reduced. To improve system reliability, it is necessary to conduct quality inspections on cables before assembly. In this paper, a non-contact cable measurement method utilizing the screen current effect is proposed. The distribution characteristics of screen current in conductor on round core (CORC) cables under dynamic excitation magnetic fields, as well as the magnetic field characteristics produced in space, were analyzed through simulation by J model. It was found that the cable can be effectively measured by combining two sets of excitation magnets and sensor arrays. Subsequently, a prototype was established, and CORC samples with artificially created defects were measured. The experiments confirmed the feasibility of this method.

Water encompasses vast quantities of energy in diverse forms, yet this energy is rarely exploited. Hydrovoltaic technology, as an emergent clean energy generation technology, has garnered extensive attention in recent years. Distinct from conventional hydroelectric power generation, hydrovoltaic technology ingeniously employs the interaction between functional materials and water, and achieves the direct conversion of water energy into electrical energy. This review initially delineates the mechanism of hydrovoltaic technology and deliberate on the various materials currently employed for hydroelectric power generation. Subsequently, experimental advancements in power generation from water droplets, water evaporation, and moisture are summarized to demonstrate the relevance of their fundamental mechanisms and their potential for harvesting energy from the water cycle. This work further expounds on the potential device applications of hydrovoltaic technology and proposes prospects for the development of emerging technologies.

Driven by the advantages of hydrogen energy, such as environmental protection and high energy density, the market has an urgent demand for hydrogen energy. Currently, the primary methods for hydrogen production mainly include hydrogen generation from fossil fuels, industrial by-products, and water electrolysis. Seawater electrolysis for hydrogen production, due to its advantages of cleanliness, environmental protection, and ease of integration with renewable energy sources, is considered the most promising method for hydrogen production. However, seawater electrolysis faces challenges such as the reduction of hydrogen production efficiency due to impurities in seawater, as well as high costs associated with system construction and operation. Therefore, it is particularly necessary to summarize optimization strategies for seawater electrolysis for hydrogen production to promote the development of this field. In this review, the current situation of hydrogen production by seawater electrolysis is first reviewed. Subsequently, the challenges faced by seawater electrolysis for hydrogen production are categorized and summarized, and solutions to these challenges are discussed in detail. Following this, an overview of an in situ large-scale direct electrolysis hydrogen production system at sea is presented. Last but not least, suggestions and prospects for the development of seawater electrolysis for hydrogen production are provided.

A comprehensive study of the angular distributions in the bottom-baryon decays Λ^0_b→Λ_c^+ h^-(h=π, K), followed by Λ_c^+→Λ h^+ with Λ→pπ^- or Λ_c^+→pK^0_S decays, is performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 9 fb^-1 collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 Te -0.1em V. The decay parameters and the associated charge-parity (CP) asymmetries are measured, with no significant CP violation observed. For the first time, the Λ^0_b →Λ_c^+ h^- decay parameters are measured. The most precise measurements of the decay parameters α, β and γ are obtained for Λ_c^+ decays and an independent measurement of the decay parameters for the strange-baryon Λ decay is provided. The results deepen our understanding of weak decay dynamics in baryon decays.

Abstract A measurement of CP-violating observables associated with the interference of B0→ D0K⋆(892)0 and $$ {B}^0\to {\overline{D}}^0{K}^{\star }{(892)}^0 $$ B 0 → D ¯ 0 K ⋆ 892 0 decay amplitudes is performed in the D0→ K∓π±(π+π−), D0→ π+π−(π+π−), and D0→ K+K− final states using data collected by the LHCb experiment corresponding to an integrated luminosity of 9 fb−1. CP-violating observables related to the interference of $$ {B}_s^0\to {D}^0{\overline{K}}^{\star }{(892)}^0 $$ B s 0 → D 0 K ¯ ⋆ 892 0 and $$ {B}_s^0\to {\overline{D}}^0{\overline{K}}^{\star }{(892)}^0 $$ B s 0 → D ¯ 0 K ¯ ⋆ 892 0 are also measured, but no evidence for interference is found. The B0 observables are used to constrain the parameter space of the CKM angle γ and the hadronic parameters $$ {r}_{B^0}^{DK\star } $$ r B 0 DK ⋆ and $$ {\delta}_{B^0}^{DK\star } $$ δ B 0 DK ⋆ with inputs from other measurements. In a combined analysis, these measurements allow for four solutions in the parameter space, only one of which is consistent with the world average.

The production cross-section of J/ψ pairs in proton-proton collisions at a centre-of-mass energy of √(s) = 13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb−1 collected by the LHCb experiment. The measurement is performed with both J/ψ mesons in the transverse momentum range 0 < pT < 14 GeV/c and rapidity range 2.0 < y < 4.5. The cross-section of this process is measured to be 16.36 ± 0.28 (stat) ± 0.88 (syst) nb. The contributions from single-parton scattering and double-parton scattering are separated based on the dependence of the cross-section on the absolute rapidity difference ∆y between the two J/ψ mesons. The effective cross-section of double-parton scattering is measured to be σeff = 13.1 ± 1.8 (stat) ± 2.3 (syst) mb. The distribution of the azimuthal angle ϕCS of one of the J/ψ mesons in the Collins-Soper frame and the pT-spectrum of the J/ψ pairs are also measured for the study of the gluon transverse-momentum dependent distributions inside protons. The extracted values of ⟨cos 2ϕCS⟩ and ⟨cos 4ϕCS⟩ are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed.

Abstract The decays of the B+ meson to the final state $$ {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ D ∗ − D s + π + are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb−1. The ratio of branching fractions of the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ B + → D ∗ − D s + π + and $$ {B}^0\to {D}^{\ast -}{D}_s^{+} $$ B 0 → D ∗ − D s + decays is measured to be 0.173 ± 0.006 ± 0.010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed $$ {D}_s^{\ast +}\to {D}_s^{+}\gamma $$ D s ∗ + → D s + γ and $$ {D}_s^{+}{\pi}^0 $$ D s + π 0 decays, the ratio of branching fractions between the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{\ast +}{\pi}^{+} $$ B + → D ∗ − D s ∗ + π + and $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ B + → D ∗ − D s + π + decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the $$ {B}^{+}\to {D}^{\ast -}{D}_s^{+}{\pi}^{+} $$ B + → D ∗ − D s + π + decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D*−π+ final state. No significant evidence of exotic contributions in the $$ {D}_s^{+}{\pi}^{+} $$ D s + π + or $$ {D}^{\ast -}{D}_s^{+} $$ D ∗ − D s + channels is found. The fit fraction of the scalar state $$ {T}_{c\overline{s}0}^{\ast }{(2900)}^{++} $$ T c s ¯ 0 ∗ 2900 + + observed in the $$ {B}^{+}\to {D}^{-}{D}_s^{+}{\pi}^{+} $$ B + → D − D s + π + decay is determined to be less than 2.3% at a 90% confidence level.

An amplitude analysis of the $B^{0}\to K^{*0}\mu^+\mu^-$ decay is presented using a dataset corresponding to an integrated luminosity of $4.7$ fb$^{-1}$ of $pp$ collision data collected with the LHCb experiment. For the first time, the coefficients associated to short-distance physics effects, sensitive to processes beyond the Standard Model, are extracted directly from the data through a $q^2$-unbinned amplitude analysis, where $q^2$ is the $\mu^+\mu^-$ invariant mass squared. Long-distance contributions, which originate from non-factorisable QCD processes, are systematically investigated and the most accurate assessment to date of their impact on the physical observables is obtained. The pattern of measured corrections to the short-distance couplings is found to be consistent with previous analyses of $b$- to $s$-quark transitions, with the largest discrepancy from the Standard Model predictions found to be at the level of 1.8 standard deviations. The global significance of the observed differences in the decay is 1.4 standard deviations.

Self-shielding high-temperature superconducting (HTS) DC cables made of REBCO tapes can almost eliminate the magnetic field within the cable layers, which can improve the uniformity of current distribution and magnetic field. In this paper, two self-shielding HTS DC cables made of REBCO tapes with different-direction currents under fault current are simulated based on H -formula and external circuit model. And the abilities of limiting fault current are also compared. Results show the design of “+–+” can limit DC fault currents better in restricting both the rising rate and the peak value of fault current. Self-shielding HTS cable can inhibit fault currents due to its magnetic shielding. And the “+–+” configuration performs better for limiting DC fault current than the “+-+-” configuration.

The decays Lambda(0)(b) -> Lambda(+)(c) (D) over bar (()*()0) K- and Lambda(0)(b) -> Lambda(+)(c) D-s*(-) are observed for the first time, in proton-proton collision data at root s = 13TeV, corresponding to an integrated luminosity of 5.4fb(-1) collected with the LHCb detector. Their ratios of branching fractions with respect to the Lambda(0)(b) -> Lambda(+)(c) D-s(-) mode are measured to be B(Lambda(0)(b) -> Lambda(+)(c) (D) over bar (0) K-)/B(Lambda(0)(b) -> Lambda(+)(c) D-s(-)) = 0.1908(-0.0034-0.0018)(+0.0036+0.0016) +/- 0.0038, B(Lambda(0)(b) -> Lambda(+)(c) (D) over bar*(0) K-)/B(Lambda(0)(b) -> Lambda(+)(c) D-s(-)) = 0.589(-0.017-0.018)(+0.018+0.017) +/- 0.012, B(Lambda(0)(b) -> Lambda(+)(c) D-s*(-))/B(Lambda(0)(b) -> Lambda(+)(c) D-s(-)) = 1.668 +/- 0.022(-0.055)(+0.061), where the first uncertainties are statistical, the second systematic, and the third, for the Lambda(0)(b) -> Lambda(+)(c) (D) over bar (()*()0) K- decays, are due to the uncertainties on the branching fractions of the D-s(-) -> K- K+ pi(-) and (D) over bar0 -> K+ pi(-) decay modes. The measured branching fractions probe factorization assumptions in effective theories and provide the normalization for future pentaquark searches in Lambda(0)(b) -> Lambda(+)(c) (D) over bar (()*()0) K- decay channels.

Floating solar materials and their devices, which can effectively solve the problems faced by powder solar materials, such as difficult recycling, poor stability, and difficult maintenance, have received widespread attention in recent years. However, it is still in the early stage of development and still faces many challenges in material design, device preparation, and systematic application. Therefore, it is particularly necessary to summarize the research progress of related aspects to promote the development of this field (To achieve large-scale applications, it is necessary to develop devices that can be applied on a large scale). In this review, the systematic construction methods of floating materials are reviewed from the aspects of lightweight carrier integration as well as functionalization and surface modification. Subsequently, the recent studies on floating solar materials and their devices are categorized and summarized. Their applications in the purification of polluted seawater, water splitting, CO2 reduction, and prevention of water bloom are reviewed in detail. Finally, the outlook for future development is critically discussed. In this review, the applications of floating solar materials and their devices in energy conversion and environmental remediation are summarized. The construction methods of floating systems are classified and summarized in detail. At the end of the review, there are some prospects for the future development of floating solar materials and their devices. image

A measurement of CP-violating observables associated with the interference of B^0→ D^0 K^*(892)^0 and B^0→D̅^0 K^*(892)^0 decay amplitudes is performed in the D^0 → K^∓π^±(π^+π^-), D^0 →π^+π^-(π^+π^-), and D^0→ K^+K^- final states using data collected by the LHCb experiment corresponding to an integrated luminosity of 9 fb^-1. CP-violating observables related to the interference of B^0_s→ D^0 K̅^*(892)^0 and B_s^0→D̅^0 K̅^*(892)^0 are also measured, but no evidence for interference is found. The B^0 observables are used to constrain the parameter space of the CKM angle γ and the hadronic parameters r_B^0^DK^* and δ_B^0^DK^* with inputs from other measurements. In a combined analysis, these measurements allow for four solutions in the parameter space, only one of which is consistent with the world average.

Abstract The cross-section of associated J/ψ-ψ(2S) production in proton-proton collisions at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb−1, collected by the LHCb experiment. The measurement is performed for both J/ψ and ψ(2S) mesons having transverse momentum pT< 14 GeV/c and rapidity 2.0 < y < 4.5, assuming negligible polarisation of the J/ψ and ψ(2S) mesons. The production cross-section is measured to be 4.5 ± 0.7 ± 0.3 nb, where the first uncertainty is statistical and the second systematic. The differential cross-sections are measured as functions of several kinematic variables of the J/ψ-ψ(2S) candidates. The results are combined with a measurement of J/ψ-J/ψ production, giving a cross-section ratio between J/ψ-ψ(2S) and J/ψ-J/ψ production of 0.274 ± 0.044 ± 0.008, where the first uncertainty is statistical and the second systematic.

AbstractThe $$\Xi _b^0 \rightarrow \Xi _c^+ D_s^-$$ Ξ b 0 → Ξ c + D s - and $$\Xi _b^- \rightarrow \Xi _c^0 D_s^-$$ Ξ b - → Ξ c 0 D s - decays are observed for the first time using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of $$\sqrt{s}=13\,\,\textrm{TeV}$$ s = 13 TeV , corresponding to an integrated luminosity of $$5.1\,\,\textrm{fb}^{-1}$$ 5.1 fb - 1 . The branching fractions times the production cross-sections of $$\Xi _b$$ Ξ b baryons relative to that of $$\Lambda _b^0$$ Λ b 0 baryon are measured to be $$\begin{aligned} \mathcal {R}\left( \frac{\Xi _b^0}{\Lambda _b^0}\right)&\equiv \frac{\sigma \left( \Xi _b^0\right) }{\sigma \left( \Lambda _b^0\right) } \times \frac{\mathcal {B}\left( \Xi _b^0 \rightarrow \Xi _c^+ D_s^-\right) }{\mathcal {B}\left( \Lambda _b^0 \rightarrow \Lambda _c^0 D_s^-\right) }\\&=(15.8\pm 1.1\pm 0.6\pm 7.7)\%,\\ \mathcal {R}\left( \frac{\Xi _b^-}{\Lambda _b^0}\right)&\equiv \frac{\sigma \left( \Xi _b^-\right) }{\sigma \left( \Lambda _b^0\right) } \times \frac{\mathcal {B}\left( \Xi _b^- \rightarrow \Xi _c^0 D_s^-\right) }{\mathcal {B}\left( \Lambda _b^0 \rightarrow \Lambda _c^0 D_s^-\right) } \\&=(16.9\pm 1.3\pm 0.9\pm 4.3)\%, \end{aligned}$$ R Ξ b 0 Λ b 0 ≡ σ Ξ b 0 σ Λ b 0 × B Ξ b 0 → Ξ c + D s - B Λ b 0 → Λ c 0 D s - = ( 15.8 ± 1.1 ± 0.6 ± 7.7 ) % , R Ξ b - Λ b 0 ≡ σ Ξ b - σ Λ b 0 × B Ξ b - → Ξ c 0 D s - B Λ b 0 → Λ c 0 D s - = ( 16.9 ± 1.3 ± 0.9 ± 4.3 ) % , where the first uncertainties are statistical, the second systematic, and the third due to the uncertainties on the decay branching fractions of relevant charmed baryons. The masses of $$\Xi _b^0$$ Ξ b 0 and $$\Xi _b^-$$ Ξ b - baryons are measured to be $$m_{\Xi _b^0}=5791.12\pm 0.60\pm 0.45\pm 0.24\,\,\textrm{MeV}/c^2$$ m Ξ b 0 = 5791.12 ± 0.60 ± 0.45 ± 0.24 MeV / c 2 and $$m_{\Xi _b^-}=5797.02\pm 0.63\pm 0.49\pm 0.29\,\,\textrm{MeV}/c^2$$ m Ξ b - = 5797.02 ± 0.63 ± 0.49 ± 0.29 MeV / c 2 , where the uncertainties are statistical, systematic, and those due to charmed-hadron masses, respectively.

The resonant structure of the radiative decay $\Lambda_b^0\to pK^-\gamma$ in the region of proton-kaon invariant-mass up to 2.5 GeV$/c^2$ is studied using proton-proton collision data recorded at centre-of-mass energies of 7, 8, and 13 TeV collected with the LHCb detector, corresponding to a total integrated luminosity of 9 fb$^{-1}$. Results are given in terms of fit and interference fractions between the different components contributing to this final state. Only $\Lambda$ resonances decaying to $pK^-$ are found to be relevant, where the largest contributions stem from the $\Lambda(1520)$, $\Lambda(1600)$, $\Lambda(1800)$, and $\Lambda(1890)$ states.

The first observation of the singly Cabibbo-suppressed Ω_{c}^{0}→Ω^{-}K^{+} and Ω_{c}^{0}→Ξ^{-}π^{+} decays is reported, using proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4  fb^{-1}, collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be B(Ω_{c}^{0}→Ω^{-}K^{+})/B(Ω_{c}^{0}→Ω^{-}π^{+})=[6.08±0.51(stat)±0.40(syst)]%,B(Ω_{c}^{0}→Ξ^{-}π^{+})/B(Ω_{c}^{0}→Ω^{-}π^{+})=[15.81±0.87(stat)±0.44(syst)±0.16(ext)]%. In addition, using the Ω_{c}^{0}→Ω^{-}π^{+} decay channel, the Ω_{c}^{0} baryon mass is measured to be M(Ω_{c}^{0})=2695.28±0.07(stat)±0.27(syst)±0.30(ext)  MeV, improving the precision of the previous world average by a factor of 4.

The ratio of production cross-sections of ψ(2S) over J/ψ mesons as a function of charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy √(s) = 13 TeV is measured with a data sample collected by the LHCb detector, corresponding to an integrated luminosity of 658 pb−1. The ratio is measured for both prompt and non-prompt ψ(2S) and J/ψ mesons. When there is an overlap between the rapidity ranges over which multiplicity and charmonia production are measured, a multiplicity-dependent modification of the ratio is observed for prompt mesons. No significant multiplicity dependence is found when the ranges do not overlap. For non-prompt production, the ψ(2S)-to-J/ψ production ratio is roughly independent of multiplicity, irrespective of the rapidity range over which the multiplicity is measured. The results are compared to predictions of the co-mover model and agree well except in the low multiplicity region. The ratio of production cross-sections of ψ(2S) over J/ψ mesons are cross-checked with other measurements in di-lepton channels and found to be compatible.