Exact Solution to Spin Squeezing of the Arbitrary-Range Spin Interaction and Transverse Field Model

We investigate spin squeezing effects of trapped ions in an off-resonance optical potential system using the arbitrary range spin spin interaction and transverse field model. The collective spin noises at any time are analyzed exactly. The general expression of spin squeezing factor is presented for arbitrary-range spin interaction. For the nearest-neighbor and next-nearest neighbor spin interaction model, the analytic solutions are reduced from the general expressions. It is shown that the maximum spin squeezing is enhanced for the general arbitrary-range spin interaction compared with the nearest-neighbor interaction model as the long-range interaction with arbitrary sites enforces stronger correlation.

Low Mantle Perovskite:Solid Solution, Spin State of Iron and Water Solubility

Silicate perovskites（（Mg, Fe）SiO 3 and CaS iO 3） are believed to be the major constituent minerals in the lower mantle. The phase relation, solid solution, spin state of iron and water solubility related to the lower mantle perovskite are of great effect on the geodynamics of the Earth＇s interior and on ore mineralization. Previous studies indicate that a large amount of iron coupled with aluminum can incorporate into magnesium perovskite, but this is discordant with the disproportionation of（Mg,Fe）SiO 3 perovskite into iron-free MgS i O3 perovskite and hexagonal phase（Mg0.6Fe0.4）SiO 3 in the Earth＇s lower mantle. MnS iO 3 is the first chemical component confirmed to form wide range solid solution with Ca SiO 3 perovskite and complete solid solution with MgS i O3 perovskite at the P-T conditions in the lower mantle, and addition of Mn Si O3 will strongly affects the mutual solubility between Mg Si O3 and CaS iO 3. The spin state of iron is deeply depends on the site occupation of the Fe3＋or Fe2＋, the synthesis and the annealing conditions of the sample. It seems that the spin state of Fe2＋ in the lower mantle perovskite can be settled as high spin, however, the existence of intermediate spin or low spin state of Fe2＋ in perovskite has not been clarified. Moreover, different results have also been reported for the spin state of Fe3＋ in perovskite. The water solubility of the lower mantle perovskite is related with its composition. In pure Mg SiO 3 perovskite, only less than 500 ppm water was reported. Al–Mg Si O3 perovskite or Al–Fe–MgS iO 3 perovskite in the lower mantle accommodates water of 1100 to 1800 ppm. Further experiments are necessary to clarify the detailed conditions for perovskite solid solution, to reliably analyze the valence and spin states of iron in the coexisting iron-bearing phases, and to compare the water solubility of different phases at different layers for deeply understanding the geodynamics of the Earth＇s interior and ore mineralization.

Double-stretching as an effective and generalizable strategy towards thinner nanofibers in solution blow spinning

Solution blow spinning(SBS)applies high-speed airflow to prepare fibers by generating a strong stretching force.It has the advantages of scalable production,tailorable morphologies,and wide applicability.Yet,the SBS strategy can hardly prepare fibers down to the sub-100 nanometers,which limits its performance in demanding applications.Herein,we overcome the limitation of SBS by introducing a second airflow.This novel strategy is termed double-stretching SBS(DS-SBS)because an extra stretching force is exerted on the fiber when it converges with the second airflow.Polyamide6 nanofibers with an average diameter of 80 nm are successfully prepared with the DS-SBS strategy,while the SBS strategy could only prepare submicron fibers with an average diameter of 120 nm.Further,the generality of the DS-SBS strategy to reduce fiber diameter is verified on numerous solute-solvent pairs.

Lignin-based carbon fibers: Formation, modification and potential applications

As an aromatic polymer in nature, lignin has recently attracted gross attention because of its advantages of high carbon content, low cost and bio-renewability. However, most lignin is directly burnt for power generation to satisfy the energy demand of the pulp mills. As a result, only a handful of isolated lignin is used as a raw material. Thus, increasing value addition on lignin to expand its scope of applications is currently a challenge demanding immediate attention. Many efforts have been made in the valorization of lignin, including the preparation of precursors for carbon fibers. However, its complex structure and diversity significantly restrict the spinnability of lignin. In this review, we provide elaborate knowledge on the preparation of lignin-based carbon fibers ranging from the relationships among chemical structures, formation conditions and properties of fibers, to their potential applications. Specifically, control procedures for different spinning methods of lignin, including melt spinning, solution spinning and electrospinning, together with stabilization and carbonization are deeply discussed to provide an overall understanding towards the formation of lignin-based carbon fibers. We also offer perspectives on the challenges and new directions for future development of lignin-based carbon fibers.

Polycaprolactone/polyvinyl pyrrolidone nanofibers developed by solution blow spinning for encapsulation of chlorogenic acid

Study on the application of nanofibers in food active packaging has been a research hotspot in recent years.In this work,solution blow spinning(SBS)was applied to rapidly fabricate the polycaprolactone(PCL),polyvinyl pyrrolidone(PVP),and PCL/PVP nanofibrous films to encapsulate chlorogenic acid(CGA).All films showed uniform and smooth nanofibers,and the Fourier transform infrared spectroscopy and X-ray diffraction proved the success of mixed spinning of PCL and PVP.With the increase of PVP content,the thermal stability of the PCL/PVP nanofibrous films improved.The PCL/PVP(weight ratio of 4:1)film possessed better mechanical properties than PCL and PVP films be-cause of the stronger fiber-fiber interactions.The addition of PCL endowed the hydrophobic surfaces to the PCL/PVP films,and the PCL/PVP films had better water vapor barrier ability.The PCL/PVP(4:1)film exhibited the best long-term continuous release of CGA during 72 h.The PVP nanofibrous film exhibited no inhibition against Staphylococcus aureus and Escherichia coli due to the low encapsulation efficiency,but the PCL and PCL/PVP films exhibited good antimicrobial activity.The above results suggested that the nanofibrous fims developed by SBS possess promising prospects in food packaging.

Synthesis of Snake-cage Resins and Study of Their Separation Ability

Several kinds of snake-cage resins containing both carboxylic and quaternary ammonium groups were synthesized from cage resin with 7 % crosslinking. The influence of the crosslinking degree on retardation capacity and separation ability has been studied. These resins were used to separate the water-soluble nonvolatile impurities (NVI) from the spinning SQlvent of polyacrylonitrile-sodium thiocyanate solution. Satisfactory results were achieved.

A non-surgical suturing strategy for rapid cardiac hemostasis

As the central organ of the human body,once the heart is damaged,it will cause devastating damage to the circulation system of the whole body,often leading to rapid death.Currently,the only treatment option to stop bleeding in penetrating cardiac injuries is surgical suturing,which is extremely complex and risky.In addition,it is difficult to implement this kind of treatment in battlefields with poor medical conditions.Therefore,there is an urgent need to develop an effective cardiac hemostasis strategy.In this work,we propose a two-step hemostasis strategy that can effectively stop bleeding for penetrating heart injuries.That is,cardiac hemostatic plug(CHP)is made from the nanocomposite(polylactic acid/gelatin/absorbable hemostatic particles,PLA/GEL/AHP)with high biosafety,excellent hemostatic performance,and degradability which is used to block cardiac bleeding,and then wound surface is sealed by in-situ electrospun medical glue fibers(N-octyl-2-cyanoacrylate,interfacial toughness:221±23 J·m−2),thus completing cardiac hemostasis(porcine heart with 1 cm diameter penetrating wound).The hemostasis process is simple and quick(<2 min).In addition,it is worth mentioning that we have also proposed a new composite method based on solution blow spinning that is suitable for doping various functional particles,and the PLA/GEL/AHP composite nanofiber membrane prepared by this method is also a promising hemostatic material.

Tunnel elasticity enhancement effect of 3D submicron ceramics(A_(l)2O_(3),TiO_(2),ZrO_(2)) fiber on polydimethylsiloxane (PDMS)

Some polymers are flexible,foldable,and wearable.Structural-functional composite is fabricated by adding inorganic fillers with functional properties.Up to date,compared with the polymer matrix,the composite prepared by polymer-inorganic fillers has lower flexibility,higher brittleness,and higher modulus of elasticity.In this paper,three-dimensional (3D) net-shaped submicron α-Al_(2)O_(3),orthorhombic ZrO_(2),and rutile TiO_(2) fiber were fabricated by solution blowing spinning on a large scale.On the contrary,the elastic modulus (E) of the composite prepared by this 3D ceramic fiber was greatly reduced,and the flexibility of the composite was higher than that of the polymer matrix.When the strain was 75%,the E of the 3D net-shaped Al_(2)O_(3) fiber-polydimethylsiloxane(PDMS) composite was 20% lower than that of PDMS.When the strain was 78%,the E of the 3D net-shaped TiO_(2) fiber-PDMS and 3D net-shaped ZrO_(2) fiber-PDMS composites decreased by 20% and 25%,respectively.This abnormal effect,namely the tunnel elastic enhancement effect,has great practical significance.In all-solid-state lithium-ion batteries,the composite inhibits lithium dendrite growth and the 3D inorganic network contributes to lithium ion transport.It is possible to promote the industrial production of low-cost and large-scale flexible solid-state lithium-ion batteries and it can enhance the energy storage density of energy storage materials.This novel idea also has bright prospects in flexible electronic materials.

Carbon dots embedded nanofiber films:Large-scale fabrication and enhanced mechanical properties

Valuable application prospects and large-scale production technologies are powerful driving forces for the development of materials science.Carbon dots(CDs)are a kind of promising carbon-based fluorescent nanomaterials,which possess wide application prospects based and even beyond the fluorescence properties.Herein,we report the fast and high-yield synthesis of CDs and the large-scale preparation of fluorescent nanofiber films with enhanced mechanical properties.CDs were prepared from magnetic hyperthermia treatment of citric acid and carbamide,with the output of 25.37 g in a single batch.The asprepared CDs exhibit a high absolute photoluminescence(PL)quantum yield(QY)of 67%and wonderful dispersibility in polar solvents.Then,solution blow spinning of CDs and polymer matrixes of alcohol soluble polyurethane(APU)and polyacrylonitrile(PAN)led to large-area fluorescent CDs-embedded nanofiber films,APU/CDs(size:120 cm×18 cm)and PAN/CDs(size:120 cm×22 cm),respectively.The resultant large-area APU/CDs and PAN/CDs nanofiber films have dramatically enhanced mechanical properties,to show integrated improvement of tensile strength and elongation.