Internal Electron Research Articles

Fe-Doped CoP Flower-Like Microstructure on Carbon Membrane as Integrated Electrode with Enhanced Sodium Ion Storage.

Poor cyclability and rate performance always impede the development of transition metal phosphide-based anode materials. Many strategies have been used to address the above problems, such as the designing of hierarchical structures, combination with carbon materials, and doping with other metal elements. Considering those strategies, a flower-like Fe-doped CoP material is designed. The synthesis consists of microsheets grown on a carbon membrane (CM, leaves as precursor) through a hydrothermal method and in situ phosphorization. The Fe doping and carbon membrane synergistically induce the formation of a flower-like hierarchical microstructure during the crystal-growing process. The unique hierarchical microstructure increases the contact area between electrode and electrolyte, and accommodates the volume expansion during cycling. The hierarchical Fe-doped CoP grown directly on the carbon membrane increases the active sites for intercalation of sodium species and further promotes the internal electron conduction in the Fe-doped CoP/CM electrode. Thereby, the Fe-doped CoP/CM as the anode electrode for sodium ion batteries exhibits a high specific capacity of 515 mA h g-1 at 100 mA g-1 after 100 cycles. Even if the current density rises to 500 mA g-1 , the specific capacity is still maintained at 324 mA h g-1 after 500 cycles, showing superior rate performances and cyclability.

Quantifying internal charge transfer and mixed ion-electron transfer in conjugated radical polymers.

Macromolecular radicals are receiving growing interest as functional materials in energy storage devices and in electronics. With the need for enhanced conductivity, researchers have turned to macromolecular radicals bearing conjugated backbones, but results thus far have yielded conjugated radical polymers that are inferior in comparison to their non-conjugated partners. The emerging explanation is that the radical unit and the conjugated backbone (both being redox active) transfer electrons between each other, essentially “quenching” conductivity or capacity. Here, the internal charge transfer process is quantified using a polythiophene loaded with 0, 25, or 100% nitroxide radicals (2,2,6,6-tetramethyl-1-piperidinyloxy [TEMPO]). Importantly, deconvolution of the cyclic voltammograms shows mixed faradaic and non-faradaic contributions that contribute to the internal charge transfer process. Further, mixed ion-electron transfer is determined for the 100% TEMPO-loaded conjugated radical polymer, from which it is estimated that one triflate anion and one propylene carbone molecule are exchanged for every electron. Although these findings indicate the reason behind their poor conductivity and capacity, they point to how these materials might be used as voltage regulators in the future.

Activation of Alternative Respiration with Internal Electron Acceptor during Anaerobic Glucose Utilization in Escherichia coli Strains with Impaired Fermentation Ability

The activation of alternative respiration with an internal electron acceptor during anaerobic glucose utilization in E. coli strains with impaired fermentation ability has been studied. It was found out that respiration processes utilizing pyruvic acid as an endogenous electron acceptor can markedly contribute to the maintenance of the anaerobic redox balance in E. coli strains deficient in mixed acid fermentation pathways. The sequential inactivation of the pathways of anaerobic dissimilation of pyruvate and impairment of the functionality of the reductive branch of the tricarboxylic acid cycle led to an increase in the contribution (from 11 to 54%) of the respiratory formation of lactic acid and alanine to the biosynthesis of the reduced products of anaerobic glucose utilization by the strains. Analysis of the enantiomeric composition of the lactic acid and alanine secreted by the strains demonstrated that D-lactate dehydrogenase (Dld), L-lactate dehydrogenase (LctD), and D-alanine dehydrogenase (DadA) participated in the biosynthesis of the respective compounds.

Variability in Loss of Multiple Enzyme Activities Due to the Human Genetic Variation P284T Located in the Flexible Hinge Region of NADPH Cytochrome P450 Oxidoreductase.

Cytochromes P450 located in the endoplasmic reticulum require NADPH cytochrome P450 oxidoreductase (POR) for their catalytic activities. Mutations in POR cause multiple disorders in humans related to the biosynthesis of steroid hormones and also affect drug-metabolizing cytochrome P450 activities. Electron transfer in POR occurs from NADH to FAD to FMN, and the flexible hinge region in POR is essential for domain movements to bring the FAD and FMN close together for electron transfer. We tested the effect of variations in the hinge region of POR to check if the effects would be similar across all redox partners or there will be differences in activities. Here we are reporting the effects of a POR genetic variant P284T located in the hinge region of POR that is necessary for the domain movements and internal electron transfer between co-factors. Human wild-type and P284T mutant of POR and cytochrome P450 proteins were expressed in bacteria, purified, and reconstituted for enzyme assays. We found that for the P284T variant of POR, the cytochrome c reduction activity was reduced to 47% of the WT and MTT reduction was reduced to only 15% of the WT. No impact on ferricyanide reduction activity was observed, indicating intact direct electron transfer from FAD to ferricyanide, but a severe loss of CYP19A1 (aromatase) activity was observed (9% of WT). In the assays of drug-metabolizing cytochrome P450 enzymes, the P284T variant of POR showed 26% activity for CYP2C9, 44% activity for CYP2C19, 23% activity for CYP3A4, and 44% activity in CYP3A5 assays compared to the WT POR. These results indicate a severe effect on several cytochrome P450 activities due to the P284T variation in POR, which suggests a negative impact on both the steroid as well as drug metabolism in the individuals carrying this variation. The negative impact of P284T mutation in the hinge region of POR seems to be due to disruption of FAD to FMN electron transfer. These results further emphasize the importance of hinge region in POR for protein flexibility and electron transfer within POR as well as the interaction of POR with different redox partners.

Study of secondary electron emission from semiconductors induced by electrons from 20 eV to 800 eV and surface state of semiconductors

Based on processes and characteristics of secondary electron emission (SEE), experimental data and the relations among parameters of secondary electron yield from semiconductors δ, the formula for δ in the range of 20 eV ≤ Epo ≤ 800 eV of semiconductors with Epom ≤ 800 eV as a function of Epo, Epom, atomic number Z and maximum δ (δm) was deduced and proved experimentally, where Epo and Epom are incident energy of primary electron and the Epo of δm, respectively. From the existing formula and the relation among Z, mean escape depth of secondary electrons emitted from semiconductors and primary range R at Epom deduced in this study, the formula for R in the range of 150 eV ≤ Epo ≤ 800 eV in monocrystalline semiconductors with Epom ≤ 800 eV, χ ≥ 0.6 eV and Eg ≥ 0.6 eV was successfully deduced, where χ is original electron affinity, Eg is the width of forbidden band. The method of calculating B(χreal, Eg) of semiconductor with Epom ≤ 800 eV, χreal ≥ 0.5 eV and Eg ≥ 0.6 eV and that of calculating B of semiconductor with Epom ≤ 800 eV were presented, respectively; Where B is the probability that an internal secondary electron escapes into vacuum upon reaching the surface of semiconductor, and the B(χreal, Eg) is the B relative to semiconductor with Eg and real electron affinity χreal. It can be concluded that the two methods are correct. From the analysis of calculated B, experimental Epom and relations among parameters of SEE, it can be concluded that this paper can research the surface state of semiconductor with Epom ≤ 800 eV by SEE.

A multi-channel beta–gamma coincidence counting system using well-HPGe and plastic scintillation detectors for radioactive Xenon measurements

Abstract A new type of multi-channel beta–gammacoincidence counting system was developed for the analysis of radioactive Xenon samples with low-level radioactivity . The proposed system consists of a state-of-the-art well-HPGe detector with a large well volume ( ∅ 28 mm × 40 mm) and a cylindrical plastic scintillation detector with an interior volume of 8.8 cm3. A two-dimensional beta–gamma coincidence histogram was obtained, and the beta–gamma coincidence counting efficiency was estimated using gaseous radioxenons and Monte Carlo simulation with the MCNP code. The energy resolution of the plastic scintillation detector for the 129.4 keV internal conversion electron was 29%, and the minimum detectable concentration for 131m Xe, 133Xe, 133m Xe, and 135Xe was calculated as 0.27 mBq/m3, 0.23 mBq/m3, 0.16 mBq/m3 and 0.24 mBq/m3 under the assumed conditions of a 20000 s measurement and a 10 m3 air sample with the beta–gamma​ coincidence mode, respectively.

Assessment of self- and cross-absorbed SAF values for HDRK-man using Geant4 code: internal photon and electron emitters

The ultimate need to account for the partial amount of energy deposited in target tissue/organ resulting from internal inhalation, ingestion, and injection intakes of radionuclides, defined by the Medical Internal Radiation Dosimetry committee as the specific absorbed fraction (SAF), has become obvious. In this study, we assessed the SAF values for self- and cross-absorption, which were calculated for a uniform distribution of monoenergetic photon and electron emitters with energies ranging from 15 keV to 3 MeV. The voxelized human phantom “High-Definition Reference Korean-man” (HDRK-man), which was implemented using the Monte Carlo simulation code Geant4 (version 10.1), was used for several combinations of target–source organs. The results were compared to those of the International Commission on Radiological Protection Reference (ICRP133) and Zubal phantoms. It was found that the SAF values of the three models have a similar trend. However, the SAF values for the HDRK-man phantom were higher than those of the other two models, with a relatively good agreement with those for the ICRP133 phantom (differences of 13.9 ± 2.8 and 12.1 ± 3.2 for photon and electron emitters, respectively). To analyze the differences in SAF values, we calculated the chord length distributions (CLDs) for selected target–source combinations. The parameters of organ mass (or volume) and CLDs, in addition to the adopted computational procedures, mainly cause such discrepancies. For realistic radionuclide emission spectra, an overall overestimation was observed when computing the S values for three radiopharmaceuticals studied (I-131, In-111, and Lu-177) and for liver–spleen intra- and inter-organ absorption when compared with published data. The new arrangement of S and SAF values is expected to add value for multidisciplinary research and clinical communities.

Role of a Multidentate Carbonate Donor in MgCl2-Supported Ziegler–Natta Olefin Polymerization Catalysis: An Experimental and Computational Approach

A new multidentate carbonate (3,3,3′,3′-tetramethyl-2,2′,3,3′-tetrahydro-1,1′-spirobiindane-5,5′,6,6′-tetracarbonate) is studied as a potential internal electron donor for Ziegler–Natta (Z–N) catal...

(Invited) Electron Beam Induced Current Microscopy of Interfacial Barrier Effects in Al2O3/TiOx Resistive Switches

Resistive switching devices (ReRAM) represent a broad class of two-terminal continuously tunable resistors including memristors, phase change memory (PCM), valence change memory (VCM), and electrochemical metallization cells (ECM). Though these devices, especially PCM, are increasingly being commercialized by industry for use in next generation memories, they are also all actively studied for use as synaptic weights in next generation hardware-accelerated neuromorphic networks. We have previously investigated Electron Beam Induced Current Microscopy as a means of reliably characterizing resistive switches. In that investigation, we observed surprising electronic effects, such as internal secondary electron emission, in addition to more traditional electron-hole pair separation, and we broke those up into constituent currents based on their origin through Monte-Carlo modeling of the electron beam-matter interaction. Now, armed with a new understanding of the physics of EBIC imaging, we study the impact of manufacturing variations on resistive switches by continuously tuning the thickness of an Al2O3 interfacial barrier. Shifts in the apparent ratios of internal secondary electron emission from the top electrode to the bottom electrode and vice versa appear to indicate a continuous tuning of the apparent filament diameter as both a function of the injected current and the interfacial barrier thickness. This yields an apparent reduction in the current density, the primary effect of which is a reduction in the device damage from forming and a suppression of parasitic leakage currents imaged in devices without interfacial barriers. Figure 1

Deactivation Effect Caused by Catalyst-Cocatalyst Pre-contact in Propylene Polymerization with MgCl2-supported Ziegler-Natta Catalyst

Propylene slurry polymerization with a MgCl2-supported Ziegler-Natta catalyst containing internal electron donor was conducted after different durations of pre-contact of the catalyst with triethylaluminum cocatalyst. The number of active centers ([C*]/[Ti]) was determined by quenching the polymerization with 2-thiophenecarbonyl chloride and measuring sulfur content in the polymer. The pre-contact treatment caused selective deactivation of a part of active centers with low stereoselectivity and much lower activity in the initial stage of polymerization as compared with the polymerization run without the pre-contact stage. The active center concentration and polymerization activity decreased with prolonging of the pre-contact stage. The proportion of stereoselective active centers was increased by prolonging the pre-contact stage, so the isotacticity of produced polypropylene was enhanced. Release of active centers through catalyst particle fragmentation was significantly retarded, and the polymerization rate curve changed from decay type to induction type by the precontact treatment. In the induction period both non-stereoselective and stereoselective active centers were released and activated, resulting in gradual reduction of the polymer’s isotacticity in the first 5–10 min of polymerization. Selective deactivation of non-stereoselective active centers also took place in propylene polymerization using the catalyst without pre-contacting with the cocatalyst. In this case, the polymerization rate decayed with time after a short induction period of 2–5 min. Over reduction of the active center precursors with low stereoselectivity by triethylaluminum was considered as the reason for their deactivation during the pre-contact or the polymerization processes.

Conversion electron spectroscopy of the 59.54 keV transition in 241Am alpha decay

A windowless Peltier-cooled silicon drift detector (SDD) was used to measure internal conversion electron (ICE) spectra of thin 241Am sources. The ICE peaks associated with the 59.54 keV gamma transition in 237Np were deconvoluted and relative ICE intensities were derived from the fitted peak areas. Corrections were made for energy dependence of the full-energy-peak counting efficiency, based on Monte Carlo simulations. As expected for this anomalous E1 transition, a significant discrepancy was found with the theoretical internal conversion coefficient (ICC) values calculated from the BrIcc database. Penetration effects are known to cause such anomalies in highly retarded transitions. The measured ICE intensities are in good agreement with a specific combination of literature data obtained with magnetic spectrometers.

An experimental investigation of the 15.1 keV M1 + E2 nuclear transition in 227Th from the $\beta^{-}$ decay of 227Ac

Using the internal conversion electron spectroscopy, the energy of the 15.1 keV $ M1+E2$ nuclear transition in 227Th populated in the $ \beta^{-}$ decay of 227Ac was determined to be $ 15098.6 \pm 1.0$ eV. This value is more accurate than the present accepted one by a factor of 200. The present uncertainty in the transition multipolarity was removed and it was found to be $ M1+E2$ with the admixture $ \vert\delta (E2/M1)\vert = 0.035 \pm 0.006$.

Template-free synthesis of porous Mo3P/MoP nanobelts as efficient catalysts for hydrogen generation

Hydrogen has attracted extensive attention as a potential alternative energy and many achievements have been made in the research of transition metal phosphide catalysts, but further improvements are still strongly demanded. In this report, we propose a novel strategy for the template-free synthesis of Mo3P/MoP porous nanobelts as efficient catalysts for hydrogen generation. The porous structures can give more active sites, and the presence of Mo3P can further improve the internal electron transfer ability through the strong bond. Thus, the porous Mo3P/MoP hybrid catalyst exhibits an outstanding hydrogen evolution activity and a good stability. This study may provide a facile and effective strategy for the improvement of transition metal phosphide catalysts by controlling the structures and compositions.

Direct Search for keV-Sterile Neutrino in Nuclear Decay. Troitsk Nu-Mass (Scientific Summary)

We present a brief review of experimental status in searching for hypothetical sterile neutrino in nuclear decay in laboratory testing. The main idea is based on search for an additional small component in the β-spectrum or a shift in the internal electron conversion energy. For example, in a three-body β-decay it looks like a kink in the continuous spectrum shifted by the value of sterile neutrino mass from the spectrum endpoint. After a short general motivation for such a search we discuss the way how to find sterile neutrino in the nuclear β-decay and present the current status of upper limits on sterile neutrino mixing with electron antineutrino. The advantages and problems arising in the precise measurements of β-spectrum are demonstrated on the basis of the “Troitsk nu-mass” experiment by presenting the all measurement and analysis procedures in details. At the end we discuss the nearest future of such experiments.

(Invited) Fructose Biosensors Based on Direct Electron Transfer between Fructose Dehydrogenase and Electrodes

Fructose dehydrogenase (FDH, EC 1.1.99.11) is a bacterial membrane bound flavocytochrome oxidoreductase, which has been widely employed to develop direct electron transfer (DET) and mediated electron transfer (MET) based electrode platforms [1]. Most commonly FDH from Gluconobacter japonicus has been studied. FDH is a heterotrimer consisting of a catalytic dehydrogenase domain, DHFDH (subunit I), where D-(−)-fructose oxidation occurs at the covalently flavin cofactor (FAD), followed by an internal electron transfer (IET) to the cytochrome domain (CYTFDH, subunit II), which contains three heme c moieties coordinated by the enzyme scaffold, and a subunit III, which is not involved in the ET process. We have recently investigated [2-4] how to optimize orientation and the DET reaction between FDH and electrodes. In [2] we report on the influence of pH and monovalent/divalent cations on the catalytic current response, the IET, and the structure of FDH by using amperometry, spectrophotometry, and circular dichroism. Amperometric measurements were performed on graphite electrodes, onto which FDH was adsorbed and the effect on the response current to fructose was investigated when varying the pH and the concentrations of divalent/monovalent cations. In the presence of 10 mM CaCl2, a current increase of up to ≈ 240% was observed, probably due to an intra-complexation reaction between Ca2+ and the aspartate/glutamate residues found at the interface between the DHFDH and CYTFDH. In [3] we present a new method to electrodeposit highly mesoporous gold onto a polycrystalline solid gold electrode without any template. The electrodeposition is carried out by first cycling the electrode potential between +0.8 and 0 V in 10 mM HAuCl4 with 2.5 M NH4Cl and then applying a negative potential for the production of H2 bubbles at the electrode surface. This mesoporous gold electrode was modified with 4-mercaptophenol onto which FDH was orientated to optimize the DET reaction. In [4] an efficient DET reaction was also achieved between FDH and anthracene-modified single-walled carbon nanotubes (SWCNT) deposited onto a glassy-carbon electrode. The SWCNTs were activated in situ with a diazonium salt synthesized through the reaction of 2-aminoanthracene with NaNO2 in 0.5 M HCl for 5 min at 0° C. After the in situ reaction, the 2-aminoanthracene diazonium salt was electrodeposited by running cyclic voltammograms from +1000 to −1000 mV. The anthracene-SWCNT-modified GCE was further incubated in an FDH solution to allow FDH to adsorb. Cyclic voltammograms of the FDH-modified electrode revealed two couples of redox waves ascribed to the heme c 1 and heme c 3 of the CYTFDH. In the presence of 10 mM fructose two catalytic waves could clearly be seen and were correlated with two heme c:s, with a maximum current density of 485±21 μA cm − 2 at 0.4 V at a sweep rate of 10 mV s − 1.

Reversible electron transfer in organolanthanide chemistry.

This article relates the synthesis and characterization of novel heterobimetallic complexes containing a low-valent lanthanide, a tetradentate redox non-innocent ligand, viz. the 4,5,9,10-tetraazaphenanthrene, taphen ligand and transition metal fragments of PdMe2 and PtMe2. The experimental results are supported by a theoretical study. Investigation of their reduction properties allowed the formation of isostructural original heterotrimetallic complexes containing two Cp*2Yb fragments and the (taphen)MMe2 (M = Pd and Pt) motifs. These complexes are stable in non-coordinating solvent such as toluene but decompose in coordinating solvents such as thf. Investigation of the internal electron transfer shows that the taphen ligand behaves as a two-electrons reservoir but is capable of transferring back only one electron in thf. This reversible electron(s) transfer is rare in organolanthanide chemistry and show the potential interest of these complexes in reductive chemistry. Additionally, the trinuclear complexes feature odd X-ray crystal structures in which a deviation of symmetry is observed. The latter observation was studied in depth using quantum chemistry calculations highlighting the role of non-covalent weak interactions.

Tracking Internal Electron Shuttle Using X-ray Spectroscopies in La/Zr Hydroxide for Reconciliation of Charge-Transfer Interaction and Coordination toward Phosphate.

Metallic hydroxides have been applied as the adsorbents of oxyanion contaminants, with the oxygen-bonded metal (M-O) considered as the core site for adsorption. For enhanced adsorption toward oxyanions, multimetallic modification of M-O is a promising approach for high removal performance. Here, bimetallic La/Zr hydroxides were prepared via a solvothermal route with varying La/Zr dosages. Bimetallic La/Zr hydroxides exhibited higher oxyanion adsorption capacity than La or Zr hydroxide. A maximum phosphate adsorption capacity of ∼160 mg g-1 was achieved under the La/Zr atomic ratio of 1:1, representing a new record among comparable adsorbents. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure (XANES) spectroscopy showed that the incorporation of [LaO6] and [ZrO6] can induce an internal charge shuttle owing to the electronegativity difference of La and Zr. The charge transfers from La to Zr through the surrounding O 2p ligand, where the electrons in the highest occupied molecular orbitals of the [LaO6] octahedron filled unoccupied π orbitals of [ZrO6]. The as-induced internal electron shuttle in the bimetallic hydroxides primarily strengthened the formation of [MO6]···PO4 species (backdonation interaction). Further, the σP-O donation interaction between [LaO6] and [PO4] was clearly increased via intensification of the covalent coordination with O, as confirmed by the P K-edge XANES spectra for the as-used samples.

Functional Metallofullerene Materials and Their Applications in Nanomedicine, Magnetics, and Electronics

Endohedral metallofullerenes exhibit combined properties from carbon cages as well as internal metal moieties and have great potential in a wide range of applications as molecule materials. Along with the breakthrough of mass production of metallofullerenes, their applied research has been greatly developed with more and more new functions and practical applications. For gadolinium metallofullerenes, their water-soluble derivatives have been demonstrated with antitumor activity and unprecedented tumor vascular-targeting therapy. Metallofullerene water-soluble derivatives also can be applied to treat reactive oxygen species (ROS)-induced diseases due to their high antioxidative activity. For magnetic metallofullerenes, the internal electron spin and metal species bring about spin sensitivity, molecular magnets, and spin quantum qubits, which have many promising applications. Metallofullerenes are significant candidates for fabricating useful electronic devices because of their various electronic structures. This Review provides a summary of the metallofullerene studies reported recently, in the fields of tumor inhibition, tumor vascular-targeting therapies, antioxidative activity, spin probes, single-molecule magnets, spin qubits, and electronic devices. This is not an exhaustive summary and there are many other important study results regarding metallofullerenes. All of this research has revealed the irreplaceable role of metallofullerene materials.

Di-manganese(0) carbonyl mediated azo bond cleavage and recombination reaction in azo-aromatic ligand: An effect of extended phenolate donor

Three manganese complexes of the anionic azo-phenolate ligand [L1]−, obtained from the reaction between HL1 and Mn(OAc)2.4H2O (OAc = acetate) or Mn2(CO)10, are reported. The chosen manganese precursors are of different characters: the hydrated Mn(OAc)2 is a common source of Mn(II), while the carbonyl complex is known for its strong reducing character. The reaction between the Mn(II)-salt and HL1 (HL1 = 2,4-di-tert-butyl-6-(pyridin-2-ylazo)-phenol) produced a low-spin Mn(III) complex, ls-[MnIII(L1)−(L1)2−]; 1 via substitution and internal electron transfer (Mn(II) → [L1]−). The chemical oxidation of this molecular complex with I2 provided access to the cationic complex, ls-[MnIII(L1)−2]I3; [1]+[I3]− in quantitative yield. On the other hand, the reaction between Mn2(CO)10 and 4 equivalent of HL1 is complex. The reaction produced a heteroleptic high-spin Mn(III)-complex, hs-[MnIII(L1)−(L2)2−]; 2 in moderate yield. The ligand H2L2 (H2L2 = 2,2′-dihydroxo-3,5,3′,5′-tetra-tert-butylazobenzene) produced in situ via simultaneous azo-cleavage of [L1]− and recombination of two amido-phenolate fragments. The electronic structures of all three complexes coordinated by the two redox noninnocent ligands [L1/2]−/2− have been elucidated by using a host of physical methods: X-ray crystallography, magnetic susceptibility measurements, cyclic voltammetry, absorption spectroscopy and density functional theory (DFT). Their experimental structures are well reproduced by DFT calculations and support the overall electronic structures of the above compounds. The complexes 1, [1]+[I3]− and 2 have one, two and four unpaired electrons respectively, as evidenced by room temperature magnetic susceptibility measurements. The redox process between [1]+/1 is ligand centred which does not affect the trivalent oxidation state of the metal ion. The chemical conversion [L1]− → [L2]2− occurs only in aerobic condition and a rationale for the reaction is discussed.

THEORETICAL RESEARCH OF SECONDARY ELECTRON EMISSION FROM NEGATIVE ELECTRON AFFINITY SEMICONDUCTORS

Based on primary range [Formula: see text], relationships among parameters of secondary electron yield [Formula: see text] and the processes and characteristics of secondary electron emission (SEE) from negative electron affinity (NEA) semiconductors, the universal formulas for [Formula: see text] at [Formula: see text] and at [Formula: see text] for NEA semiconductors were deduced, respectively; where [Formula: see text] is incident energy of primary electron. According to the characteristics of SEE from NEA semiconductors with [Formula: see text], [Formula: see text], deduced universal formulas for [Formula: see text] at [Formula: see text] and at [Formula: see text] for NEA semiconductors and experimental data, special formulas for [Formula: see text] at 0.5[Formula: see text] of several NEA semiconductors with [Formula: see text] were deduced and proved to be true experimentally, respectively; where [Formula: see text] is the [Formula: see text] at which [Formula: see text] reaches maximum secondary electron yield. It can be concluded that the formula for [Formula: see text] of NEA semiconductors with [Formula: see text] was deduced and could be used to calculate [Formula: see text], and that the method of calculating the 1/[Formula: see text] of NEA semiconductors with [Formula: see text] is plausible; where [Formula: see text] is the probability that an internal secondary electron escapes into vacuum upon reaching the surface of emitter, and 1/[Formula: see text] is mean escape depth of secondary electron.