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Wang, Zhiyuan

Publications and source records attributed to Wang, Zhiyuan.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Optimizing dietary rumen-degradable starch to rumen-degradable protein ratio improves lactation performance and nitrogen utilization efficiency in mid-lactating Holstein dairy cows

The dietary rumen-degradable starch (RDS) to rumen-degradable protein (RDP) ratio, denoted as the RDS-to-RDP ratio (SPR), has been proven to enhance in vitro rumen fermentation. However, the effects of dietary SPR in vivo remain largely unexplored. This study was conducted to investigate the effect of dietary SPR on lactation performance, nutrient digestibility, rumen fermentation patterns, blood indicators, and nitrogen (N) partitioning in mid-lactating Holstein cows. Seventy-two Holstein dairy cows were randomly assigned to three groups (24 head/group), balanced for (mean ± standard deviation) days in milk (116 ± 21.5), parity (2.1 ± 0.8), milk production (42 ± 2.1 kg/d), and body weight (705 ± 52.5 kg). The cows were fed diets with low (2.1, control), medium (2.3), or high (2.5) SPR, formulated to be isoenergetic, isonitrogenous, and iso-starch. The study consisted of a one-week adaptation phase followed by an eight-week experimental period. The results indicated that the high SPR group had a lower dry matter intake compared to the other groups ( p < 0.05). A quadratic increase in milk yield and feed efficiency was observed with increasing dietary SPR ( p < 0.05), peaking in the medium SPR group. The medium SPR group exhibited a lower milk somatic cell count and a higher blood total antioxidant capacity compared to other groups ( p < 0.05). With increasing dietary SPR, there was a quadratic improvement ( p < 0.05) in the total tract apparent digestibility of crude protein, ether extract, starch, neutral detergent fiber, and acid detergent fiber. Although no treatment effect was observed in rumen pH, the rumen total volatile fatty acids concentration and microbial crude protein synthesis increased quadratically ( p < 0.05) as dietary SPR increased. The molar proportion of propionate linearly increased ( p = 0.01), while branched-chain volatile fatty acids linearly decreased ( p = 0.01) with increasing dietary SPR. The low SPR group (control) exhibited higher concentration of milk urea N, rumen ammonia N, and blood urea N than other groups ( p < 0.05). Despite a linear decrease ( p < 0.05) in the proportion of urinary N to N intake, increasing dietary SPR led to a quadratic increase ( p = 0.01) in N utilization efficiency and a quadratic decrease ( p < 0.05) in the proportion of fecal N to N intake. In conclusion, optimizing dietary SPR has the potential to enhance lactation performance and N utilization efficiency. Based on our findings, a medium dietary SPR (with SPR = 2.3) is recommended for mid-lactating Holstein dairy cows. Nevertheless, further research on rumen microbial composition and metabolites is warranted to elucidate the underlying mechanisms of the observed effects.

Chen, Panliang↗
DOE OSTI2022

Optical Trapping of High-Aspect-Ratio NaYF Hexagonal Prisms for kHz-MHz Gravitational Wave Detectors

Here, we present experimental results on optical trapping of Yb-doped β-NaYF subwavelength-thickness high-aspect-ratio hexagonal prisms with a micron-scale radius. The prisms are trapped in vacuum using an optical standing wave, with the normal vector to their face oriented along the beam propagation direction, yielding much higher trapping frequencies than those typically achieved with microspheres of similar mass. This platelike geometry simultaneously enables trapping with low photon-recoil-heating, high mass, and high trap frequency, potentially leading to advances in high frequency gravitational wave searches in the Levitated Sensor Detector, currently under construction. The material used here has previously been shown to exhibit internal cooling via laser refrigeration when optically trapped and illuminated with light of suitable wavelength. Employing such laser refrigeration methods in the context of our work may enable higher trapping intensity and thus higher trap frequencies for gravitational wave searches approaching the several hundred kilohertz range.

47 OTHER INSTRUMENTATION↗
DOE OSTI2022

Boosting electrochemical reaction and suppressing phase transition with a high-entropy O3-type layered oxide for sodium-ion batteries

Complex phase transitions induced by interlayer slides in layered cathode materials lead to poor cycling stability and rate capability for sodium-ion batteries. Herein, we design and prepare a new six-component high-entropy oxide (HEO) layered cathode O3–Na(Fe 0.2 Co 0.2 Ni 0.2 Ti 0.2 Sn 0.1 Li 0.1 )O 2 to enable highly reversible electrochemical reaction and phase-transition behavior. The HEO cathode exhibits good cycling performance (capacity retention of ~81% after 100 cycles at 0.5C) and outstanding rate capability (capacity of ~81 mA h g –1 at 2.0C) due to the higher sodium diffusion coefficient (above 5.75 × 10 –11 cm 2 s –1 ) than most reported O3-type cathodes. Moreover, the high-entropy cathode has superior compatibility with the hard carbon anode and delivers a specific capacity of 90.4 mA h g –1 (energy density of ~267.5 W h kg –1 ). Ex situ X-ray diffraction proves that the high-entropy designing effectively suppresses the intermediate phase change to achieve reversible O3–P3 phase evolution, and in turn stabilizes the layered structure. X-ray absorption spectroscopy and Mössbauer spectrum of 57 Fe suggest that Ni 2+ /Ni 3.5+ , Co 3+ /Co 3.5+ , and part of Fe 3+ /Fe 3.5+ redox reaction contribute the charge compensation. Finally, the enhanced performance can be attributed to the disordered distribution of multi-component transition metals in HEO suppressing the ordering of electric charges and sodium vacancies, thereby inhibiting the interlayer slide and phase transition.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Dynamic Tuning of Moiré Excitons in a WSe 2 /WS 2 Heterostructure via Mechanical Deformation

Moiré superlattices in van der Waals (vdW) heterostructures form by stacking atomically thin layers on top of one another with a twist angle or lattice mismatch. The resulting moiré potential leads to a strong modification of the band structure, which can give rise to exotic quantum phenomena ranging from correlated insulators and superconductors to moiré excitons and Wigner crystals. Here, in this study, we demonstrate the dynamic tuning of moiré potential in a WSe 2 /WS 2 heterostructure at cryogenic temperature. We utilize the optical fiber tip of a cryogenic scanning near-field optical microscope (SNOM) to locally deform the heterostructure and measure its near-field optical response simultaneously. The deformation of the heterostructure increases the moiré potential, which leads to a red shift of the moiré exciton resonances. We observe the interlayer exciton resonance shifts up to 20 meV, while the intralayer exciton resonances shift up to 17 meV.

77 NANOSCIENCE AND NANOTECHNOLOGY↗