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Owing to the dramatically enhanced charge-mass transport and abundant electrochemically active sites, transition metal compound electrodes are increasingly attractive for achieving high-performance supercapacitors (SCs). Here, we report the fabrication of nickel foam supported three-dimensional (3D) branched nickel–cobalt phosphides@tri-metal cobalt–nickel-molybdenum phosphides core/shell nanowire heterostructures (denoted as NiCo-P@CoNiMo-P) as high-performance electrode materials for hybrid supercapacitors. The presence of multiple valences of the cations in such NiCo-P@CoNiMo-P enables rich redox reactions and promoted synergy effects. Benefiting from their collective effects, the resulting electrode demonstrates high specific capacity of 1366 C g−1 at 2 A g−1 (2.03 C cm−2 at 2 mA cm−2) and 922 C g−1 at 10 A g−1, as well as good cycling stability (retaining ~ 94% of the initial capacity after 6000 cycles at 15 A g−1). A hybrid SC using the NiCo-P@CoNiMo-P as the positive electrode and N-doped rGOs as the negative electrode exhibits a high energy density of 81.4 Wh kg−1 at a power density of 1213 W kg−1 and a capacity retention of 132% even after 6000 cycles at 10 A g−1. Our findings can facilitate the material design for boosting the performance of transition metal compounds based materials for fast energy storage.

Tyrosine hydroxylase (TH) is the initial enzyme responsible for cuticle sclerotization and pigmentation in many insect species, but to date, no direct functional studies have focused on TH in Zeugodacus tau. Here, the 3336-bp full-length cDNA of TH was isolated from Z. tau, a notorious horticultural pest infesting fruits and vegetables. qRT-polymerase chain reaction revealed that ZtTH transcripts were highly abundant at the time of pupal tanning and during adult emergence and were expressed in the midgut, integument and head of molting larvae. The pupation and eclosion rates gradually decreased when the 1st-instar larvae were fed diets containing higher concentrations of the TH inhibitor 3-iodo-tyrosine (3-IT). Moreover, pupal weights were significantly decreased, and abnormal uncolored phenotypes were observed after 20 mg/g 3-IT was incorporated into the diet. In addition, the suppression of TH function (mediated by RNA interference) led to a decrease in TH mRNAs and eclosion rates, accompanied by less-pigmented phenotypes. There was a severe impairment of larval-pupal cuticle tanning, leading to pupae with less yellowish pigment or that were completely white and transparent, when we injected 2 μL of 24.4 mM or 73.27 mM 3-IT into 3rd-instar larvae or prepupae. These results suggest that TH is an important enzyme for the normal growth and pupal pigmentation of Z. tau and that TH is a potential gene target for use in the control of Z. tau.

For Ni-Mn-Z based (Z = Sn, In, Sb) alloys, the martensite transformation (MT) and magnetic transition in austenite state create opposite magnetic cooling effect, which offsets each other when the first-order MT (FOMT) coincides with the second-order magnetic transition (SOMT). In the present study, two successive magnetization peaks are introduced in a Ni48.4Fe1.1Mn38.5Sn12.0 alloy by creation of a partial overlap between reverse MT and magnetic transition in the austenite phase with 1.1 at.% Fe-doping. In addition, significant enhancement of the magnetization difference (ΔM) between martensite/austenite phases is achieved. Consequently, an inverse magnetocaloric effect (IMCE) associated with a positive isothermal magnetic entropy change (ΔSM) of 9.6 J/kg∙K and a working temperature interval (ΔTFWHM) of 306–314 K is found under an external magnetic field of 5.0 T in the reverse MT and TCA temperature range. This IMCE is followed by a conventional magnetocaloric effect (CMCE) with a negative ΔSM of −2.7 J/kg∙K and ΔTFWHM of 316–339 K under 5.0 T. By taking advantage of these two successive MCEs using a special designed device, large caloric cooling effect with enhanced working temperature interval may be of interesting for practical room-temperature refrigeration applications.

With the development of lead-free electronic devices, the failure caused by the growth of tin whiskers poses a potential threat to the reliability of electronic products. In this study, the modified embedded atomic potential proposed by Baskes was used to simulate the interfacial evolution and the whisker growth of copper and tin coatings under electrothermal coupling by using molecular dynamics. Numerical results show that the increase in electric field intensity and temperature can promote the diffusion of Cu atom to Sn atom, and the intermetallic compounds Cu6Sn5 and Cu3Sn are formed successively at the interface of the coating. Compression stress is formed in the coating, and the whisker is shaped at the weak part of the oxide film on the tin layer surface. The increase in electric field intensity and temperature can accelerate the growth of the whisker. This condition is because the increase in electric field intensity or temperature promotes the formation of intermetallic compounds, providing a greater driving force for the growth of tin whiskers. The results can provide a theoretical basis for the growth mechanism of tin whiskers.

Fopius arisanus (Sonan) and Psyttalia incisi (Silvestri) are two important solitary endoparasitoids of Bactrocera dorsalis (Hendel). This study investigated the interspecific competition between these two parasitoids in the oriental fruit fly and the parasitic effect of P. incisi on hosts that have previously been parasitized by F. arisanus. The results showed that P. incisi did not discriminate against hosts that had been parasitized by F. arisanus at the egg stage. The parasitism percentage by P. incisi was lower on hosts previously parasitized by F. arisanus (75.3%) than on non-parasitized hosts (83.3%). Successive parasitization by F. arisanus and P. incisi resulted in the mass mortality of host larvae and pupae, with the death of 50.8% of the host pupae. The dissection of multiparasitized hosts showed that F. arisanus was the dominant parasitoid of host larvae; the higher mortality in the supernumerary P. incisi was due to physiological inhibition by the pioneer. The results further indicated that F. arisanus won almost all competitions against P. incisi, as demonstrated by the finding that F. arisanus emerged more often than P. incisi from multiparasitized hosts. The total emergence of parasitoids (76.5%) from the treatment in which the hosts were successively exposed to the two parasitoids was slightly higher than the emergence from the treatments in which the hosts were exposed to only one species (F. arisanus: 62.9%, P. incisi: 71.8%), which suggests that the combined application of these two parasitoids is a promising approach for biological control.

Effect of annealing on martensite transformation (MT) and magnetocaloric effect (MCE) in a Ni41.3Co6.3Mn42.4Sn10.0 microwire was investigated. After annealing at temperatures 723–1173 K, the MT temperatures and Curie points shifted to higher range; meanwhile, the thermal hysteresis (ΔThys) decreased. However, partial transition arrest appeared when annealed at temperatures > 1073 K, leading to decreased magnetization difference (ΔM) between martensite and austenite phases. The maxima ΔM and minima ΔThys were produced at an annealing temperature 1023 K. Consequently, a large magnetic entropy change ( Δ S M max ) 20.1 J/kg·K, wide working temperature span (ΔTFWHM) 20 K and thus high effective refrigeration capacity (RCeff) 197 J/kg were obtained under a magnetic field 5.0 T after annealing at 1023 K for 1 h. These facts make Ni-Co-Mn-Sn microwires promising for miniature refrigeration devices due to their high specific surface area, low thermal hysteresis and markedly reduced annealing temperature and time.

Electrochemical nitrate reduction to ammonia (NRA) catalyzed by Cu-based electrodes can realize green synthesis of NH3 while removing nitrate contaminant. However, there still lacks exploration for the effect of supporting matrixes on NRA performance of Cu-based catalysts. We present here the design of three kinds of supporting matrixes including Ni foams (NF), Cu foams (CF) and carbon clothes (CC) to electrochemically grow Cu catalysts and the investigations of their NRA performance. Results show that NF-supported Cu catalyst (Cu@NF) exhibits the best performance in terms of NH3 yield rate, selectivity and Faradaic efficiency. Remarkably, at −0.23 V vs. RHE, Cu@NF delivers a NH3 yield rate up to 0.252 mmol h−1 cm−2, outperforming Cu@CF (0.148 mmol h−1 cm−2) and Cu@CC (0.076 mmol h−1 cm−2). Moreover, Cu@NF well retains NH3 yield rate and selectivity after consecutive five cycles, demonstrating an excellent stability. It is found that NF as supporting matrix can induce Ni doping to Cu catalyst for Cu@NF, which is proposed to favor atomic hydrogen reduction pathway. This work not only explores the effect of supporting matrixes on NRA performance of Cu-based catalysts but also can be extended to design rational supporting matrixes for other electrocatalytic and electro-synthetic systems.

Inferior electronic conductivity and sluggish sodium ion diffusion are still two big challenges for TiO2 anode material for Na ion batteries (SIBs). Herein, we synthesize TiO2/C composites by the pyrolysis of MIL-125(Ti) precursor and successfully introduce defects to TiO2/C composite by a simple magnesium reduction. The as-prepared defect-rich TiO2-δ/C composite shows mooncake-shaped morphology consisting of TiO2-δ nanocrystals with an average particle size of 5 nm well dispersed in the carbon matrix. When used as a SIBs anode, the defect-rich TiO2-δ/C composite exhibits a high reversible capacity of 330.2 mAh g−1 at 50 mA g−1 at the voltage range of 0.001–3.0 V and long-term cycling stability with negligible decay after 5000 cycles. Compared with other four TiO2/C samples, the electrochemical performance of defect-rich TiO2-δ/C is highly improved, which may benefit from the enhanced electronic/ionic conductivities owing to the defect-rich features, high surface area rendering shortened electronic and ionic diffusion path, and the suppress of the TiO2 crystal aggregation during sodiation and desodiation process by the carbon matrix.

Fopius arisanus (Sonan) is a dominant egg-pupal parasitoid of many fruit fly pests. Bactrocera dorsalis (Hendel) is one of F. arisanus ’ hosts and is the usual host used for mass rearing F. arisanus. To obtain parasitoids without hosts suitable for the release of F. arisanus in the field—skipping the need to separate parasitoids and unparasitized hosts—radiation (15, 20, 25 and 30 Gy) was applied to B. dorsalis eggs of five different ages (24, 27, 30, 33, and 36 h). Hatch rates, pupation rates, pupae weights, emergence rates, sex ratios, flight abilities, mortality rates and fertilities were analyzed during parasitoid development from irradiated eggs to adults. Irradiation of eggs aged 30–36 h at 20 Gy might be the optimal age and dosage when using B. dorsalis as hosts for mass rearing of F. arisanus . Furthermore, we investigated the viability of the parents and offspring of F. arisanus when the parents were raised from irradiated eggs under both laboratory and field cage conditions. The parasitism percentage, emergence rate, sex ratio (female: male) and longevity of parasitoids reared with irradiated hosts were similar to those of parasitoids obtained from non-irradiated host eggs. Significantly, the results revealed that unparasitized B. dorsalis previously irradiated with an appropriate dose at appropriate ages do not emerge: a finding that solves the problem of separating unparasitized emerging flies during mass rearing. This experiment also demonstrates that F. arisanus reared on irradiated hosts can find, identify, and parasitize hosts normally—both indoors and outdoors—and that the resulting parasitoids can be directly applied to control pest populations in the field.

Small-sized materials with large surface to volume ratio favor heat transfer during magnetic refrigeration cycling and thus may help enhancing the refrigeration efficiency. Here, high Fe content Ni44.9Fe4.3Mn38.3Sn12.5 polycrystalline microwires were prepared by a melt-extraction technique. The as-extracted microwires were annealed at 1173 K for 60 min, leading to significant grain growth and formation of a secondary Fe-rich γ phase. The annealed microwire exhibits larger magnetization difference (ΔM) between the austenite and martensite phases and smaller thermal hysteresis compared to the as-extracted microwire. The annealed microwire possesses a magnetic transition to austenite at 299 K, followed by a martensitic transformation (MT) from a ferromagnetic austenite to a weak-magnetic martensite at 208 K upon cooling. Under a magnetic field of 50 kOe, the annealed microwires show a maximum magnetic entropy change ΔSm of 6.9 J/kg·K and an effective refrigeration capacity RCeff of 78.0 J/kg over a broad working temperature span ΔTFWHM of 20 K around the MT. In addition, magnetic transition of the austenite gives rise to ΔSm −3.7 J/kg·K and RCmag 232.5 J/kg with ΔTFWHM of 85 K under 50 kOe. Keywords: Ferromagnetic shape memory alloys, Microwires, Martensitic transformation, Magnetocaloric effect, Ni-Fe-Mn-Sn

Ni-Mn-Sn alloys exhibit high magnetocaloric effect (MCE) during the magnetic-field-induced martensite to austenite phase transformation. However, the low magnetization of the austenite, narrow working temperature interval and high magnetic hysteresis reduced their magnetic refrigeration capacity. Here, the effects of Fe doping on the structural and magnetic transitions of Ni 50-x Fe x Mn 38 Sn 12 alloys were investigated. The doping of Fe higher than 2.9% induced the occurrence of a secondary γ phase, creating a dual phase alloy. The martensite transformation temperature significantly decreased with the occurrence of the secondary phase. However, the Curie temperatures of both austenite and martensite changed slightly with the formation of the secondary phase. As a result, the magnetostructural coupling, i.e. overlap of the structural and magnetic transitions between the ferromagnetic austenite and the paramagnetic martensite, occurred in the alloys with x = 0.5 - ∼4.2. Furthermore, the magnetization of the austenite and martensite both increased with increasing Fe content from x = 0 to x = 5.5, with the magnetization difference between the austenite and martensite saturating at x = 4.2. The dual phase Ni 45.8 Fe 4.2 Mn 38 Sn 12 alloy, exhibiting a magnetic field dependence of martensite transformation temperature ΔT M / μΔH - 0.28 K/kOe, showed a wider working temperature interval than that of the un-doped Ni 50 Mn 38 Sn 12 alloy. This demonstrated that the Ni 45.8 Fe 4.2 Mn 38 Sn 12 alloy might exhibit a high magnetic entropy change, wide working temperature interval and low magnetic hysteresis, and thus may be a promising magnetic refrigeration material.

The impacts of SiC on the wettability, mechanical properties and growth of intermetallic compound (IMC) of the low silver Sn-0.3Ag-0.7Cu (SAC0307) –xSiC composite solders paste prepared by mechanical mixing were investigated. It is found that there is an improvement in the wettability and a large reduction in the thickness of IMC with increasing SiC content, such as the contact angle shrinks by 11.48% and the thickness of IMC at the interface decreases by 63% with 0.10 wt% SiC addition. Meanwhile, according to the fracture morphology analysis, the IMC grains are refined repeatedly with increasing SiC content before less than 0.06 wt%, then agglomerated SiC and brittle phase Ag3Sn appear with further increase in SiC content. As a result, the tensile strength of solders joint increased continuously up to the maximum value of 30.49 MPa with 0.06 wt% SiC addition.

Enhanced magnetic refrigeration performance via introducing pores in a ferromagnetic shape memory Ni-Mn-Sn-Co alloy was demonstrated. The Ni40.7Mn42.9Sn10.4Co6.0 foam, with a porosity of 56% created by replication casting technique, exhibited reduced thermal hysteresis because of the high specific surface area. A maximum magnetic entropy change (ΔSM) 4.7 J/kg·K with a very wide working temperature span (ΔTFWHM) 40 K under 5.0 T were found in the annealed foam. Furthermore, the foam showed a small hysteresis loss (AHL) 17.4 J/kg under 5.0 T. As a result, refrigeration capacity (RC) 155 J/kg and relative cooling power (RCP) 188 J/kg were produced.

La 2 NiO 4 compounds were prepared by a modified sol–gel auto-combustion method, which is a low-temperature combustion synthesis procedure using microwave-assisted sol–gel as precursors. The high-temperature transport properties of the samples were investigated. The band structure, total density of states (DOS), and partial density of states (PDOS) of low-temperature orthorhombic (Bmab) phase and high-temperature tetragonal (I4 / mmm) phase for La 2 NiO 4 were calculated in order to study the transport properties of the as-obtained samples.

SrO(SrTiO 3 ) n ( n = 1, 2, …, ∞) powders were prepared by a modified sol–gel self-propagating combustion method and characterized by ultraviolet–visible (UV–vis) absorption spectroscopy and infrared spectra. UV–vis spectra indicate that the absorption edge of SrO(SrTiO 3 ) n ( n = 1, 2) shift to the violet with the decrease of n value, and the band gap values obtained from the UV–vis spectroscopy measurements are 3.41 and 3.26 eV, respectively. The infrared spectra show that the width of absorption band of TiO 6 octahedron stretching vibration decreases with the increasing of n value. The optical absorption of the compounds SrO(SrTiO 3 ) n ( n = 1, 2, …, ∞) were investigated by theoretical caculation using density functional theory (DFT). The interband transitions were assigned according to the partial density of states (PDOS). The calculated results are close to the experimental results.