The purpose of this experiment was to evaluate the contribution of epiphytic microbiota on alfalfa (AL), oat (OT), and red clover (RC) to ensiling characteristics and bacterial community diversity of oat. With the irradiation of γ-ray, sterile OT (~233 g/kg dry matter (DM)) was inoculated by sterile water (STOT), epiphytic microbiota from OT (OTOT), AL (OTAL) and RC (OTRC), respectively. Triplicate silage-bags for each treatment were sampled after different days (1, 3, 7, 15, 30 and 60) of fermentation, respectively. Similar chemical compositions were found between fresh oat and STOT. Lower (P < 0.05) contents of ammonia nitrogen (NH3-N) and higher (P < 0.05) accumulation of lactic acid were found in OTAL compared with OTRC and OTOT on day 3. The greatest (P < 0.05) NH3-N, acetic acid concentrations and pH and the lowest (P < 0.05) concentration of lactic acid were found in OTRC on day 60. After 3 days of ensiling, Lactobacillus accounted for a big proportion in OTAL and OTOT, and Hafnia-Obesumbacterium was predominant in OTRC. The bacterial communities in OTAL and OTOT had lower (P < 0.05) abundances of ‘Genetic Information Processing’ than OTRC after 3 days. Overall, the composition, diversity, and activity of epiphytic microbiota can notably influence the ensiling characteristics of forage oat. The lactic acid bacteria (hetero-fermentative type) and Enterobacteriaceae species played an important role in producing ethanol contents during the ensiling of forage oat.

This study examined the fermentation dynamics, bacterial community composition and bacterial β-carotene synthesis in alfalfa that was ensiled for 3, 15, 45 and 90 days without additives (CON), or with a chemical agent (propionic acid, PA); or a combination of PA and squalene, SQPA). The results showed that silage treated with PA had a lower (P < 0.01) pH value than the CON silage in the early ensiling phase (3–15 days). Meanwhile, silage treated with PA had the highest contents of lactic acid, acetic acid and PA after 90 days of ensiling (P < 0.01). The β-carotene in alfalfa was lost seriously in the initial ensiling phase (3 days) and epiphytic Pantoea agglomerans with the ability to produce β-carotene became extinct. With the extension of ensiling time, the loss of β-carotene was alleviated in all silages. PA and SQPA not only lowered bacterial diversity and simplified bacterial networks but also facilitated the emergence of new β-carotene-producing bacteria. The metabolic function prediction indicated that β-carotene synthesis tended to decrease initially and subsequently increase during ensiling. Furthermore, the variance of enzymes involved in the bacterial synthesis of β-carotene in silages was influenced by PA, SQPA and ensiling time. In summary, the impact of solely adding PA demonstrated superior effects on the fermentation quality of alfalfa silage compared to the effects observed with SQPA. Throughout the ensiling of alfalfa, the succession of different β-carotene-producing bacteria resulted in fluctuations in the levels of β-carotene.

The work aimed to evaluate the effect of lactic acid bacteria, natamycin and hexanoic acid on the fermentation quality, aerobic stability and in vitro digestibility of total mixed ration (TMR) silages containing water bamboo sheath leaves. The treatments were as follows: (1) no additives (control, C), (2) lactic acid bacteria (L), (3) natamycin (N), (4) hexanoic acid (H), (5) lactic acid bacteria + natamycin (LN), (6) lactic acid bacteria + hexanoic acid (LH). Silos were opened and silages were evaluated to assess fermentation quality, aerobic stability and in vitro digestibility. All TMR silages were well-preserved as indicated by dominant lactic acid content, low ammonia nitrogen/total nitrogen, trace propionic acid and negligible butyric acid contents. All additives improved the fermentation quality and in vitro digestibility, evidenced by higher lactic acid/acetic acid ratio, lactic acid, acetic acid, water-soluble carbohydrate contents and lactic acid bacteria count, and lower pH, aerobic bacteria and yeast counts. The LN had the highest lactic acid, acetic acid, lactic acid/acetic acid ratio, in vitro gas production and in vitro digestibility. During aerobic exposure, the LN silage had the highest lactic acid and acetic acid contents, and the lowest pH among all TMR silages. The LN and LH prolonged aerobic stability, reaching 85.5 and 81.5 h, respectively. The LN is recommended to improve the fermentation quality, aerobic stability and in vitro digestibility of TMR prepared with water bamboo sheath leaves.

We study higher uniformity properties of the Möbius function $\mu $, the von Mangoldt function $\Lambda $, and the divisor functions $d_k$ on short intervals $(X,X+H]$ with $X^{\theta +\varepsilon } \leq H \leq X^{1-\varepsilon }$ for a fixed constant $0 \leq \theta < 1$ and any $\varepsilon>0$.

More precisely, letting $\Lambda ^\sharp $ and $d_k^\sharp $ be suitable approximants of $\Lambda $ and $d_k$ and $\mu ^\sharp = 0$, we show for instance that, for any nilsequence $F(g(n)\Gamma )$, we have

$$\begin{align*}\sum_{X < n \leq X+H} (f(n)-f^\sharp(n)) F(g(n) \Gamma) \ll H \log^{-A} X \end{align*}$$

when $\theta = 5/8$ and $f \in \{\Lambda , \mu , d_k\}$ or $\theta = 1/3$ and $f = d_2$.

As a consequence, we show that the short interval Gowers norms $\|f-f^\sharp \|_{U^s(X,X+H]}$ are also asymptotically small for any fixed s for these choices of $f,\theta $. As applications, we prove an asymptotic formula for the number of solutions to linear equations in primes in short intervals and show that multiple ergodic averages along primes in short intervals converge in $L^2$.

Our innovations include the use of multiparameter nilsequence equidistribution theorems to control type $II$ sums and an elementary decomposition of the neighborhood of a hyperbola into arithmetic progressions to control type $I_2$ sums.

The bacterial community is important for shaping the fermentation characteristics of silage. This study aimed to investigate the fermentation characteristics, bacterial community and predicted functional characteristics of red clover (Trifolium pratense L.) silage. First-cutting red clover was collected at the early bloom stage, wilted for 5 h and then ensiled in 10 litre-capacity silos. Triplicate silos were sampled after 1, 3, 7, 15, 30 and 60 days of ensiling, respectively. The bacterial communities on days 3 and 60 were assessed through high-throughput sequencing technology, and 16S rRNA-gene predicted functional characteristics were analysed based on the KEGG using Tax4Fun. After 60 days of ensiling, red clover silage was fermented well, as indicated by high lactic acid (~77.3 g/kg DM), and low concentrations of butyric acid (~3.73 g/kg DM) and ammonia nitrogen (~55.0 g/kg TN). During the initial stage of ensiling, fructose and glucose were more preferred than sucrose for microbes. The predominant genus Lactococcus (0.542) on day 3 was replaced by Lactobacillus (0.553) on day 60. The metabolism of amino acids, energy, cofactors and vitamins was inhibited, while the metabolism of nucleotides and carbohydrates was enhanced after ensiling. High-throughput sequencing technology combined with 16S rRNA gene-predicted functional analyses revealed the differences during the early and late stages of red clover silage not only for distinct bacterial compositions but also for specific functional traits. Our results could provide a comprehensive insight into bacterial community and their functional profiles to further improve the silage quality.

This experiment was conducted to evaluate the impact of substituting rice straw with citrus pulp (CRP), sweet potato peels (SPP) and vines (SPV) on fermentation quality and in vitro digestibility when ensiled with or without wet brewers' grains (WBG). Seven treatments were set as follows: (i) rice straw only (control); (ii) 800 g rice straw/kg + 200 g CRP/kg (RC); (iii) 720 g rice straw/kg + 180 g CRP/kg + 100 g WBG/kg (RC+); (iv) 800 g rice straw/kg + 200 g SPP/kg (RP); (v) 720 g rice straw + 180 g SPP/kg + 100 g WBG/kg (RP+); (vi) 800 g rice straw/kg + 200 g SPV/kg (RV); (vii) 720 g rice straw/kg + 180 g SPV/kg + 100 g WBG/kg (RV+). After ensiling for 3, 7, 14, 30 and 60 days, silos were opened for fermentation profile, aerobic stability and in vitro parameter analyses. All substitution types improved fermentation quality, characterized by significantly lower pH and NH3-N content, higher lactic acid content and V-scores. WBG application promoted hetero-fermentation and significantly increased DM losses, acetic acid and ethanol contents. After 60 days of ensiling, the NDF, ADF and cellulose contents in mixed silages significantly decreased compared to control. During aerobic exposure, WBG application significantly prolonged aerobic stability. SPV substitution significantly improved in vitro digestibility of dry matter, NDF and ADF. In conclusion, the SPP substitution combined with WBG application was recommended as a result of the optimal balance of fermentation quality, aerobic stability and in vitro digestibility.

Tempering cooling rate plays a significant role in the impact toughness of 2CrMoV weld metal. Three different tempering cooling rate experiments were carried out; it is found that the impact toughness of weld metal improved from 44.61 to 117.49 J as the cooling rate increased from 5 to 40 °C/h. Microstructure characterization revealed that the large blocky M–A constituents and cluster precipitation were considered to act as stress concentration sources and cleavage fracture initiators at a cooling rate of 5 °C/h. Under the cooling rate of 20 °C/h, the decrease of blocky M–A constituents as well as homogeneous distribution of precipitation induced the transition from cleavage to interfacial decohesion. The chance of crack propagation in intragranular ferrite matrix was increased, which needed to absorb more energy and improve impact toughness. When the tempering cooling rate reached at 40 °C/h, the cracks mainly propagated in the ferrite matrix; meanwhile, fine and homogeneous distribution of precipitation greatly inhibited crack propagation and led to higher impact toughness.

Measurement of runaway electron beam (REB) is essential to investigate behavior of runaway electrons produced in nanosecond-pulse gas discharge. A Faraday cup is designed to measure the REB current in nanosecond-pulse discharge when the applied dV/dt is 75 kV/ns. The Faraday cup considers the impendence match with the oscilloscope and the design of the receiving part. The experimental results show that the measured REB current has a rise time of 348 ps and a full width at half maximum of 510 ps. The comparison of the measurement results by the Faraday cup and a REB collector confirm that the Faraday cup is able to measure REB current in nanosecond-pulse discharge. Furthermore, consecutive waveforms of the REB currents show stable results by using the designed Faraday cup. In addition, effects of the interelectrode gap, gas pressure, and cathode material on the REB current are investigated by the designed Faraday cup, and the measurement results provide characteristics of REB current under different conditions. The REB current decreases when the gap spacing or gas pressure increases. REB current increases with the cathode diameter. It indicates that the high-energy electrons are generated not only at the edge of the cathode but also on the side surface of the cathode.

The parameters of X-ray radiation and runaway electron beams (RAEBs) generated at long-pulse discharges in atmospheric-pressure air were investigated. In the experiments, high-voltage pulses with the rise times of 500 and 50 ns were applied to an interelectrode gap. The gap geometry provided non-uniform distribution of the electric field strength. It was founded that at the voltage pulse rise time of 500 ns and the maximum breakdown voltage Um for 1 cm-length gap, a duration [full width at half maximum (FWHM)] of a RAEB current pulse shrinks to 0.1 ns. A decrease in the breakdown voltage under conditions of a diffuse discharge leads to an increase in the FWHM duration of the electron beam current pulse up to several nanoseconds. It was shown that when the rise time of the voltage pulse is of 500 ns and the diffuse discharge occurs in the gap, the FWHM duration of the X-ray radiation pulse can reach ≈100 ns. It was established that at a pulse-periodic diffuse discharge fed by high-voltage pulses with the rise time of 50 ns, an energy of X-ray quanta and their number increase with increasing breakdown voltage. Wherein the parameter Um/pd is saved.

The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.

In this paper, a novel microstrip bandpass filter is proposed to enhance sideband selectivity, suppress harmonic frequency up to three-order as well as to keep a miniaturized size for frequency synthesizer application. The filter is constructed by four λ/4 folded stepped-impedance resonators (FSIRs) and two λ/2 stepped-impedance resonators at input/output ports to create three pairs of coupling paths and then to produce three cross-coupling transmission zeros (TZs) as well as to achieve a size miniaturization with 96% reduction compared with the conventional filter. By adding a common grounded metallized via hole among four λ/4 FSIRs of the filter, additional four mixed electric and magnetic coupling paths are set to generate extra four TZs. With these seven TZs, the proposed filter achieves a good sideband selectivity and harmonic suppression. Finally, the filter is designed, fabricated, and measured, its measured results are in well agreement with its simulated results.

In this paper, field effect transistors (FET) based on different kinds of non-graphene materials are introduced, which are MoS2, WSe2 and black phosphorus (BP). Those devices have their unique features in fabrication process compared with conventional FETs. Among them, MoS2 FET shows better electrical characteristics by applying a SiO2 protective layer; WSe2 FET is fabricated based on a new low pressure chemical vapor deposition (LPCVD) method; BP FET acquires high on/off ratio and high hole mobility by using a simple dry transfer method. Those novel non-graphene materials inspire new design and fabrication process of basic logic device.

Runaway electrons preionized diffuse discharge (REP DD) could generate volume non-thermal plasmas at atmospheric pressure, thus is widely used for surface modification. In this paper, two pulsed generators are used to produce REP DD for modifying copper (Cu) foil in atmospheric air. One generator produces repetitive pulses with a peak voltage of 40 kV and a rise time of 150 ns. The other generator produces single pulse with a peak voltage of 280 kV and a rise time of 0.5 ns. After the treatment, the modification results for including the macro topography, chemical composition and microhardness in different depths of the Cu surface are analyzed. In order to estimate the modification results in different areas of the Cu foil, several points from the center to the edge of the Cu sample are selected. It could be observed that the maximal modification effect usually appears in the area where the density of the diffuse discharge plasma is highest. The experimental results show REP DD treatment could significantly decrease the water contact angle and increase surface energy of the Cu foil. Meanwhile, it could decrease the carbon concentration and increase oxygen concentration in the near-surface layer of the Cu sample, and enhance the microhardness in different depths of the Cu foil.

Nanosecond pulse discharges can provide high reduced electric field for exciting high-energy electrons, and the ultrafast rising time of the applied pulse can effectively suppress the generation of spark streamer and produce homogeneous discharges preionized by runaway electrons in atmospheric-pressure air. In this paper, the electrostatic field in a tube-plate electrodes gap is calculated using a calculation software. Furthermore, a simple physical model of nanosecond pulse discharges is established to investigate the behavior of the runaway electrons during the nanosecond pulse discharges with a rise time of 1.6 ns and a full-width at half-maximum of 3–5 ns in air. The physical model is coded by a numerical software, and then the runaway electrons and electron avalanche are investigated under different conditions. The simulated results show that the applied voltage, voltage polarity, and gas pressure can significantly affect the formation of the avalanche and the behavior of the runaway electrons. The inception time of runaway breakdown decreases when the applied voltage increases. In addition, the threshold voltage of runaway breakdown has a minimum value (10 kPa) with the variation of gas pressure.

PACS: 52.80.-s