Ion-selective and chemical-protective elastic block copolymer interphase for durable zinc metal anode

Aqueous rechargeable batteries based on zinc anodes are among the most promising systems to replace conventional lithium-ion batteries owing to their intrinsic safety, high ionic conductivity, and economic benefits. However, inferior reversibility of zinc anode resulting from zinc dendrites and surface side reactions limits the practical realization of zinc-ion batteries. Herein, we develop a thin but robust polymeric artificial interphase to enhance reversibility of zinc anode. The grafted maleic anhydride groups in the polymer structure restrain the detrimental reactions through selective zinc-ion penetration and homogenize ion distribution, leading to a smooth electrode surface after plating-stripping processes. Consequently, the coated zinc anode shows excellent stability with a long-term symmetric cell lifespan (>3,000 h at 3 mA??cm???2) and maintains capacity retention of 80% after 2,500 cycles, paired with a manganese oxide cathode. This study provides a facile fabrication process and accessible analysis methods to rationalize the development of high-performance zinc-ion batteries

A Case of Placenta Increta Presenting as Delayed Postabortal Intraperitoneal Bleeding in the First Trimester

Placenta increta is an uncommon and life-threatening complication of pregnancy characterized by complete or partial absence of the decidua basalis. Placenta increta usually presents with vaginal bleeding during difficult placental removal in the third-trimester. Although placenta increta may complicate first and early second-trimester pregnancy loss, the diagnosis can be very difficult during early pregnancy and thus the lesion is difficult to identify. We encountered with a woman who was diagnosed with placenta increta after receiving emergency hysterectomy due to intraperitoneal bleeding 2 months after an uncomplicated dilatation and curettage in the first trimester. Therefore, we report this case with a brief review of the literature

A study on the dephasing sources in superconducting transmon qubit in Ramsey experiments

We investigated decoherence sources in Ramsay measurement, which represents the depahsing time in superconducting transmon qubit in 3D cavity. The dephasing time is strongly influenced by the measurement environment in addition to the qubit itself. We studied the influence of the drive and readout pulses in time domain measurement. We will also discuss the trajectory measurement where the qubit state is represented on the bloch sphere. We expect the improvement of qubit operation including phase gate fidelity

Study on the Efficient Readout Scheme of a Single Superconducting Transmon Qubit in Dispersive Regime Circuit QED

We present analyses and measurements of the readout scheme in a dispersive circuit QED system by varying detuning between the qubit frequency and the cavity resonant frequency. With larger detuning, the ground state frequency and the bright state frequency get closer and the transition power between themincreases in the cavity transmission. This implies that the relatively strong microwave power is allowed for far-detuned qubit readout. Additional number splitting peaks are also observed in qubit spectroscopy. We will discuss the relation between the difference of the ground state and the bright state frequencies and the difference of the qubit and the cavity frequencies

Coupling strength between superconducting transmon qubit and mode of electromagnetic field in 3D microwave cavity

We investigate the coupling strength between a superconducting qubit and two different electromagnetic modes (TE101 and TE201) in the 3D cavity. Since the spontaneous decay of qubit depends on the coupling to the resonant mode of the cavity (the Purcell effect), the qubit relaxation depends not only on TE101(in case that the qubit is positioned in the middle of the cavity) but also on other adjacent higher order modes that couples to the qubit. In this study, we performed numerical simulations and measurements of the coupling strength of a qubit that is coupled to multiple modes. We also examined the dependence of the coupling strength on the position of the qubit in the cavity. This result is a crucial parameter in designing a circuit QED system for quantum information processing

Observation of Long Coherence Time in a Superconducting Transmon Qubit

The coherence time of superconducting qubit has been improved by many orders of magnitudes during last decades after its first demonstration in 1999.This improvement in the coherence was one of the key factors that have enabled implementation of a practical quantum information processing device, high fidelity gate operations, and possibility of fault-tolerant quantum computing. Here we report an observation of a coherence time over100 microseconds in our transmon qubit. The long coherence time was achieved by improvements in both device fabrication and measurement system configuration