Mass Measurement of Single Intact Nanoparticles in a Cylindrical Ion Trap

Accurate nanoparticle mass characterization is a challenging task, especially at a single particle level. To solve this problem, a strategy for the mass measurement of single intact nanoparticle was proposed. A microscopy-based ion trap mass spectrometer was built up. To improve the detection sensitivity, a cylindrical ion trap with transparent conductive end-caps was used to increase the transmission of scattered light, and a vacuum ultraviolet lamp was used to increase the charge state of the isolated nanoparticle. By detecting the scattered light of the isolated nanoparticle, a series of secular frequencies were obtained, from which the corresponding mass-to-charge ratio of the nanoparticle was calculated. Finally, a Labview program was used to help deduce the charge state and absolute mass of the individual nanoparticle. Masses of gold nanoparticles with different sizes were accurately examined, which are (5.08 ± 0.44) × 10⁷ Da for 20 nm, (3.55 ± 0.34) × 10⁸ Da for 40 nm, and (1.22 ± 0.14) × 10⁹ Da for 60 nm, respectively. The mass of MOFs with irregular shapes was also determined, which is (6.48 ± 1.08) × 10⁹ Da. This method can provide the mass information on nanomaterials, thus opens up new possibility of characterizing nanoparticles at the single particle level

Memory Window Ratio Enhancement of p‑Type WSe₂ Memtransistors Using Dielectric GeSe₂ Nanosheets with Asymmetric Interfaces for Neuromorphic Computing

The emergence of 2D wide-bandgap semiconductor (WBGS) GeSe2 as charge-trapping dielectrics has helped realize superior devices by using an extremely simple device setup. However, the controllability of deep-gap-state defects in 2D GeSe2 poses a challenge due to the vulnerability and susceptibility of charge-trapping centers, resulting in various problems, i.e., small memory window and poor device durability during programming. Herein, we deliberately perform asymmetric interfacial oxidation to reinforce the memory performance based on the WSe2/Janus-GeSe2 van der Waals heterostructure, which exhibits a giant memory window ratio of 88.5% (70.8 V at ±40 V gate sweep range), high-room-temperature hole mobility of 15 cm2 V–1 s–1, and low nonlinearity factor close to 0 with regard to synaptic weight update characteristics. The information storage performance is excellent, owing to the interface rendered by asymmetric oxidation in the GeSe2 layer, providing an effective charge-trapping layer and atomically flat surface to enhance the mobility of the WSe2 channel. The controllable strategy helps to derive a simple design principle to realize high-performance 2D WBGS GeSe2-based memory and electrical synaptic devices with complex neural functions

Segregation ratio analysis of the four F₂ populations.

<p>Segregation ratio analysis of the four F₂ populations.</p

QTL locations, related maximum LOD values and their explanation of phenotypic variation for heading date detected in the four mapping populations.

<p>QTL locations, related maximum LOD values and their explanation of phenotypic variation for heading date detected in the four mapping populations.</p

Heading date variation and significance analyses of 28 CASLs and <i>Triticum aestivum</i> var. Chinese Spring (CS).

<p>Heading date variation and significance analyses of 28 CASLs and <i>Triticum aestivum</i> var. Chinese Spring (CS).</p

Distribution of heading dates in four wheat F₂ populations.

<p>M: Middle value; CS: Chinese Spring; 2BS: CASL2BS; 3AL: CASL3AL; E1:CASL2BS×CS (Planting time: 11/10/2012); E2: CASL2BS×CS (Plant time:1/26/2013); E3: CASL3AL×CASL 2BS (Planting time: 11/10/2012); E4:CASL3AL×CASL 2BS (Planting time: 1/26/2013).</p

General heading date statistics for the four F₂ populations and their two parents.

<p>General heading date statistics for the four F₂ populations and their two parents.</p

Identification of the <i>Ppd-B1</i> gene on chromosome arm 2BS by SSCP analysis of 28 CASLs (#1-#28) and their parents.

<p>C: CS; and T: TDIC140. The black arrow indicates the TDIC band in CASL2BS (#17).</p

TaqMan^® estimation of <i>Ppd-B1</i> copy number in Chinese Spring (CS), TDIC140 and CASL2BS.

<p>Solid circles are genotypes known to have a photoperiod sensitive (<i>Ppd-B1b</i>) allele and open circles are genotypes known to have a day neutral (<i>Ppd-B1a</i>) allele. Copy number was estimated based on the <i>Ppd-B1</i>/Internal Positive Control (IPC) signal ratio. Means and standard deviations of three measurements are shown. T-tests show the classes that differed significantly from one another (*<i>p</i><0.001).</p