Shoot multiplication of Syringa reticulata var.mandshurica from in vitro cultured seedlings

We developed a shoot multiplication protocol for Syringa reticulata Blume vat. mandshurica Hara from in vitro cultured seedlings that derived from in vitro germinated seeds. The shoots could be induced on Murashige and Skoog （MS） medium with proper plant growth regulator combinations of 6-benzylaminopurine （BA） and indole-3-butyric acid （IBA）. The better medium for shoot multiplication and growth was MS ＋ 5 mg L-1 BA ＋ 0.5 mg L-1 IBA ＋ 20 g L-1 sucrose ＋ 7 g L-1 agar, and the corresponding shoot induction rate was 75 %. The plantlets grew well after rooting on I/2MS medium （macro-elements of MS medium are at half-strength） sup- plemented with 1 mg L-1 IBA, and the survival percentage was 〉80 % at 16 weeks after transplanting.

Deterministic N-photon state generation using lithium niobate on insulator device

The large-photon-number quantum state is a fundamental but nonresolved request for practical quantum information applications.We propose an N-photon state generation scheme that is feasible and scalable,using lithium niobate on insulator circuits.Such a scheme is based on the integration of a common building block called photon-number doubling unit(PDU)for deterministic single-photon parametric downconversion and upconversion.The PDU relies on a 107-optical-quality-factor resonator and mW-level on-chip power,which is within the current fabrication and experimental limits.N-photon state generation schemes,with cluster and Greenberger–Horne–Zeilinger state as examples,are shown for different quantum tasks.

High-speed free-space optical communication using standard fiber communication components without optical amplification

Free-space optical communication(FSO)can achieve fast,secure,and license-free communication without physical cables,providing a cost-effective,energy-efficient,and flexible solution when fiber connection is unavailable.To achieve FSO on demand,portable FSO devices are essential for flexible and fast deployment,where the key is achieving compact structure and plug-and-play operation.Here,we develop a miniaturized FSO system and realize 9.16 Gbps FSO in a 1 km link,using commercial single-mode-fibercoupled optical transceiver modules without optical amplification.Fully automatic four-stage acquisition,pointing,and tracking systems are developed,which control the tracking error within 3μrad,resulting in an average link loss of 13.7 dB.It is the key for removing optical amplification;hence FSO is achieved with direct use of commercial transceiver modules in a bidirectional way.Each FSO device is within an overall size of 45 cm×40 cm×35 cm,and 9.5 kg weight,with power consumption of∼10 W.The optical link up to 4 km is tested with average loss of 18 dB,limited by the foggy test environment.With better weather conditions and optical amplification,longer FSO can be expected.Such a portable and automatic FSO system will produce massive applications of field-deployable high-speed wireless communication in the future.

Effect of Aging on Hardening Behavior of 15-5 PH Stainless Steel

Microstructure transformation and aging hardening behavior of 15-5 PH stainless steel were studied by optical microscopy （OM）, X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The results showed that the 15-5 PH stainless steel consists of NbC precipitates and lath matensite with a high dislocation density after solution treatment. With increasing aging temperature and aging time, the martensitic laths were resolved gradually. Meanwhile, the nanometric-sized Cu precipitates gradually coarsened and lost their coherency with＇the martensite matrix, which exhibited an elliptical shape finally. Fine Cu precipitates can lead to significant dispersion hardening effect, while the coarsened Cu precipitates have no contribution to strengthening. The reversed austenite was observed in the speci- mens aged at 550 ℃ and above; moreover, the amount of reversed austenite increased as aging temperature in- creased. The precipitation hardening behavior of 15-5 PH stainless steel may depend on the balance between the softening caused by the formation of reversed austenite and the hardening caused by the precipitation of copper.