Metallic single-electron transistor without traditional tunnel barriers

We report on a new type of single-electron transistor (SET) comprising two highly resistive Cr thin-film strips (~ 1um long) connecting a 1 um-long Al island to two Al outer electrodes. These resistors replace small-area oxide tunnel junctions of traditional SETs. Our transistor with a total asymptotic resistance of 110 kOhm showed a very sharp Coulomb blockade and reproducible, deep and strictly e-periodic gate modulation in wide ranges of bias currents I and gate voltages V_g. In the Coulomb blockade region (|V| < 0.5 mV), we observed a strong suppression of the cotunneling current allowing appreciable modulation curves V-V_g to be measured at currents I as low as 100 fA. The noise figure of our SET was found to be similar to that of typical Al/AlOx/Al single-electron transistors.Comment: 5 pages incl. 4 fig

Noise in Al single electron transistors of stacked design

We have fabricated and examined several Al single electron transistors whose small islands were positioned on top of a counter electrode and hence did not come into contact with a dielectric substrate. The equivalent charge noise figure of all transistors turned out to be surprisingly low, (2.5 - 7)*10E-5 e/sqrt(Hz) at f = 10 Hz. Although the lowest detected noise originates mostly from fluctuations of background charge, the noise contribution of the tunnel junction conductances was, on occasion, found to be dominant.Comment: 4 pages of text with 1 table and 5 figure

Разработка методов синтеза малатиона-D6, хлорофоса-D6 и дихлофоса-D6 для использования в качестве внутренних стандартов при анализе лекарственного растительного сырья и фитопрепаратов

Scientific relevance. Deuterated analogues of test substances, when used as internal standards, enable analysts to determine traces of residual pesticides in a medicinal plant raw material by gas or liquid chromatography coupled with mass spectrometry. This prompts the search for an undemanding method for the synthesis of deuterated reference standards, with the ultimate goal of expanding the range of reference standards produced in Russia.Aim. The study aimed to synthesise deuterated reference standards (malathion-D6, chlorophos-D6, dichlorophos-D6, and their precursors) and determine their spectral characteristics using 1Н, 2Н, 13С and 31Р nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry.Materials and methods. The study involved methanol-D4, phosphorus pentasulfide, phosphorus trichloride, maleic acid diethyl ether, triethylamine, hydroquinone, and chloral hydrate. The authors recorded 1H, 2H, 13C, and 31P NMR spectra using a QONE AS400 NMR spectrometer operating at a temperature of 298 °K and respective frequencies of 399.83, 61.38, 100.55, and 161.85  MHz. Mass spectra were obtained using an analytical system comprising an Agilent Infinity 1260 liquid chromatograph equipped with an automatic sample injector and coupled with a Thermo Scientific Orbitrap Fusion Lumos high-resolution mass-selective tandem spectrometer operating in electrospray ionisation mode.Results. The authors used existing methods for the synthesis of organophosphate pesticides as a basis and developed synthesis routes to produce the deuterated analogues malathion-D6, chlorophos-D6, and dichlorophos-D6. The synthesised compounds were identified by NMR spectroscopy and high-resolution mass spectrometry.Conclusions. The synthesised compounds are highly pure and suitable for use as internal standards in the determination of organophosphate pesticides in medicinal plant raw materials. The synthesis methods developed by the authors can be used to produce reference standards in Russia.Актуальность. Использование дейтерированных аналогов исследуемых веществ в качестве внутренних стандартов позволяет определять остаточные пестициды в лекарственном растительном сырье в следовых количествах методами газовой и жидкостной хроматомасс-спектрометрии. Таким образом, становится актуален вопрос доступного синтеза дейтерированных стандартов для расширения готового банка стандартов отечественного производства.Цель. Синтез дейтерированных внутренних стандартов  — малатиона-D6, хлорофоса-D6 и дихлофоса-D6. Определение спектральных характеристик полученных соединений с помощью 1Н, 2Н, 13С и 31Р ЯМР-спектроскопии и масс-спектрометрии высокого разрешения.Материалы и методы. Использовали метанол-D4, фосфора пентасульфид, треххлористый фосфор, диэтиловый эфир малеиновой кислоты, триэтиламин, гидрохинон, хлоральгидрат. Спектры ЯМР 1Н, 2Н, 13С и 31Р записаны на ЯМР-спектрометре QONE AS400 при температуре 298 °К на частотах 399,83; 61,38; 100,55 и 161,85 МГц соответственно. Регистрация масс-спектров проведена на аналитической станции, состоящей из жидкостного хроматографа Agilent Infinity 1260, оборудованного системой автоматического ввода пробы, с масс-селективным тандемным анализатором высокого разрешения Thermo Scientific Orbitrap Fusion Lumos, в режиме электрораспылительной ионизации.Результаты. На основе разработанных ранее методик синтеза фосфорорганических пестицидов определены пути синтеза их дейтерированных аналогов малатиона-D6, хлорофоса-D6, дихлофоса-D6. Подлинность синтезированных соединений подтверждена методами ЯМР-спектроскопии и масс-спектрометрии высокого разрешения.Выводы. Полученные соединения характеризуются высокой чистотой и пригодны для использования в качестве внутренних стандартов при определении фосфорорганических пестицидов в лекарственном растительном сырье. Разработанные методики синтеза могут использоваться для получения отечественных стандартных образцов

The Egalitarian sharing rule in provision of public goods

In this note we consider a society that partitions itself into disjoint jurisdictions, each choosing a location of its public project and a taxation scheme to finance it. The set of public project is multi-dimensional, and their costs could vary from jurisdiction to jurisdiction. We impose two principles, egalitarianism, that requires the equalization of the total cost for all agents in the same jurisdiction, and efficiency, that implies the minimization of the aggregate total cost within jurisdiction. We show that these two principles always yield a core-stable partition but a Nash stable partition may fail to exist. We demonstrate moreover that stable partitions are not necessarily consecutive

Development of Methods for the Synthesis of Malathion-D₆, Chlorophos-D₆, and Dichlorophos-D₆ for Use as Internal Standards in the Analysis of Medicinal Plant Raw Materials and Herbal Medicinal Products

Scientific relevance. Deuterated analogues of test substances, when used as internal standards, enable analysts to determine traces of residual pesticides in a medicinal plant raw material by gas or liquid chromatography coupled with mass spectrometry. This prompts the search for an undemanding method for the synthesis of deuterated reference standards, with the ultimate goal of expanding the range of reference standards produced in Russia.Aim. The study aimed to synthesise deuterated reference standards (malathion-D6, chlorophos-D6, dichlorophos-D6, and their precursors) and determine their spectral characteristics using 1Н, 2Н, 13С and 31Р nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry.Materials and methods. The study involved methanol-D4, phosphorus pentasulfide, phosphorus trichloride, maleic acid diethyl ether, triethylamine, hydroquinone, and chloral hydrate. The authors recorded 1H, 2H, 13C, and 31P NMR spectra using a QONE AS400 NMR spectrometer operating at a temperature of 298 °K and respective frequencies of 399.83, 61.38, 100.55, and 161.85  MHz. Mass spectra were obtained using an analytical system comprising an Agilent Infinity 1260 liquid chromatograph equipped with an automatic sample injector and coupled with a Thermo Scientific Orbitrap Fusion Lumos high-resolution mass-selective tandem spectrometer operating in electrospray ionisation mode.Results. The authors used existing methods for the synthesis of organophosphate pesticides as a basis and developed synthesis routes to produce the deuterated analogues malathion-D6, chlorophos-D6, and dichlorophos-D6. The synthesised compounds were identified by NMR spectroscopy and high-resolution mass spectrometry.Conclusions. The synthesised compounds are highly pure and suitable for use as internal standards in the determination of organophosphate pesticides in medicinal plant raw materials. The synthesis methods developed by the authors can be used to produce reference standards in Russia