113 research outputs found
ΠΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ ΠΎΡΠ³Π°Π½ΠΎΡ Π»ΠΎΡΡΠΈΠ»Π°Π½ΠΎΠ² ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ
The preparative gas chromatography method has been used for isolation and analysis of the organochlorsilanes isomers. The reaction of the organochlorsilanes with vapour of the water in the air has been studied. The method for isolation of the organochlorsilanes is proposed. It is based on using chromatographic column with efficiency up to 10000 theoretical plates. A high degree of purity (up to 99%) of the isolated compounds is achieved by an increase of separation selectivity, which is turned results from a temperature decrease. The effect of the parameters of chromatographic experiment (the column length, impregnation degree, the rate of gas-carrier) on the isolation of the compounds boiling up to 400o C was investigated.ΠΠ΅ΡΠΎΠ΄ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ, ΠΎΡΠ½ΠΎΠ²Π°Π½Π½ΡΠΉ Π½Π° ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠΈ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠ»ΠΎΠ½ΠΎΠΊ Ρ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡΡ Π΄ΠΎ 10000 ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ°ΡΠ΅Π»ΠΎΠΊ, ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ Π΄Π»Ρ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ ΠΈ Π°Π½Π°Π»ΠΈΠ·Π° Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
ΠΈΠ·ΠΎΠΌΠ΅ΡΠΎΠ² ΠΎΡΠ³Π°Π½ΠΎΡ
Π»ΠΎΡΡΠΈΠ»Π°Π½ΠΎΠ², ΠΊΠΎΡΠΎΡΡΠ΅ Π°ΠΊΡΠΈΠ²Π½ΠΎ ΡΠ΅Π°Π³ΠΈΡΡΡΡ Ρ Π²Π»Π°Π³ΠΎΠΉ Π²ΠΎΠ·Π΄ΡΡ
Π°. ΠΡΡΠΎΠΊΠ°Ρ ΡΠΈΡΡΠΎΡΠ° (Π΄ΠΎ 99%) Π²ΡΠ΄Π΅Π»Π΅Π½Π½ΡΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ Π΄ΠΎΡΡΠΈΠ³Π°Π΅ΡΡΡ Π·Π° ΡΡΠ΅Ρ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΡ ΡΠ΅Π»Π΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΠΏΡΡΠ΅ΠΌ ΠΏΠΎΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Ρ ΡΡΠ»ΠΎΠ²ΠΈΡ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
ΠΈΠ·ΠΎΠΌΠ΅ΡΠΎΠ² ΠΎΡΠ³Π°Π½ΠΎ- Ρ
Π»ΠΎΡΡΠΈΠ»Π°Π½ΠΎΠ² c ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ°ΠΌΠΈ ΠΊΠΈΠΏΠ΅Π½ΠΈΡ Π΄ΠΎ 400ΠΎ Π‘ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½Ρ ΠΏΡΡΠΈ ΠΏΡΠ΅ΠΎΠ΄ΠΎΠ»Π΅Π½ΠΈΡ ΠΌΠ΅ΡΠΎΠ΄ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΡΠ΄Π½ΠΎΡΡΠ΅ΠΉ, Π²ΠΎΠ·Π½ΠΈΠΊΠ°ΡΡΠΈΡ
ΠΏΡΠΈ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΠΈ Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ
ΠΈΠ·ΠΎΠΌΠ΅ΡΠΎΠ². ΠΡΠΈΠ²Π΅Π΄Π΅Π½Ρ Π΄Π°Π½Π½ΡΠ΅ ΠΏΠΎ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ ΠΈΠ·ΠΎΠΌΠ΅ΡΠΎΠ² Ρ
Π»ΠΎΡΡΠΈΠ»Π°Π½ΠΎΠ², ΡΠΎΠ΄Π΅ΡΠΆΠ°ΡΠΈΡ
ΡΠ°Π·Π»ΠΈΡΠ½ΡΠ΅ ΡΠ°Π΄ΠΈΠΊΠ°Π»Ρ (ΠΌΠ΅ΡΠΈΠ»-, Π²ΠΈΠ½ΠΈΠ»-, ΡΠ΅Π½ΠΈΠ»-, Π°Π΄Π°ΠΌΠ°Π½ΡΠΈΠ»-
ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΎΡΠ΅ΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΡ ΠΊΡΠ΅ΠΌΠ½ΠΈΠΉΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ ΠΆΠΈΠ΄ΠΊΠΎΡΡΠ΅ΠΉ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ ΡΠ°Π· Π² Π³Π°Π·ΠΎΠΆΠΈΠ΄ΠΊΠΎΡΡΠ½ΠΎΠΉ Ρ ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ
The thermal stability of organosilicon stationary phases for gas-liquid chromatography has been tested under conditions approximating the real operation of chromatographic column.ΠΡΠΎΠ²Π΅Π΄Π΅Π½Ρ ΠΈΡΠΏΡΡΠ°Π½ΠΈΡ ΡΠ΅ΡΠΌΠΎΡΡΠΎΠΉΠΊΠΎΡΡΠΈ ΠΎΡΠ΅ΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΡ
ΠΊΡΠ΅ΠΌΠ½ΠΈΠΉΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ
ΡΠ°Π· Π² ΡΡΠ»ΠΎΠ²ΠΈΡΡ
, ΠΏΡΠΈΠ±Π»ΠΈΠΆΠ΅Π½Π½ΡΡ
ΠΊ ΠΎΠ±ΡΡΠ½ΡΠΌ ΡΡΠ»ΠΎΠ²ΠΈΡΠΌ ΡΠ°Π±ΠΎΡΡ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΎΠ»ΠΎΠ½Π½. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Π·Π½Π°ΡΠ΅Π½ΠΈΡ Π²Π΅ΡΡ
Π½Π΅Π³ΠΎ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ΅Π΄Π΅Π»Π° Π±ΠΎΠ»ΡΡΠΈΠ½ΡΡΠ²Π° ΠΊΡΠ΅ΠΌΠ½ΠΈΠΉΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ
ΡΠ°Π· Π±ΡΠ»ΠΈ Π·Π°Π²ΡΡΠ΅Π½Ρ. ΠΠΏΡΠ΅Π΄Π΅Π»Π΅Π½Ρ Π·Π½Π°ΡΠ΅Π½ΠΈΡ Π²Π΅ΡΡ
Π½Π΅Π³ΠΎ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠ΅Π΄Π΅Π»Π° ΡΡΠΈΡ
Π½Π΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΡ
ΡΠ°Π·, ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΡΡΠΈΠ΅ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΡΠΌ ΡΡΠ΅Π±ΠΎΠ²Π°Π½ΠΈΡ
ΠΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ
Preparative gas chromatography is proposed to isolate some high-boiling organometallic compounds. Isolation of high-boiling substances should be conducted at a column temperature significantly below the boiling point, because most isolated compounds are thermally unstable at such temperatures. Stationary phases for preparative gas chromatography have a temperature limit of 350Β°C. The reduction of the column temperature is based on simultaneous changing the parameters of the chromatographic experiment (column length, impregnation degree, flow rate of the carrier gas). The influence of reducing the column temperature on the shape of the chromatographic peak is shown. The peak has an asymmetric shape, and its width increases. Therefore, the possibility of high-boiling substances preparative isolation depends on temperature decrease as the column separation efficiency is maintained.ΠΠ΅ΡΠΎΠ΄ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ Π΄Π»Ρ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ
Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ
ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ. ΠΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ
Π²Π΅ΡΠ΅ΡΡΠ² Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎ ΠΏΡΠΎΠ²ΠΎΠ΄ΠΈΡΡ ΠΏΡΠΈ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ΅, Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎ Π½ΠΈΠΆΠ΅ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΈΠΏΠ΅Π½ΠΈΡ, ΡΠ°ΠΊ ΠΊΠ°ΠΊ Π±ΠΎΠ»ΡΡΠΈΠ½ΡΡΠ²ΠΎ Π²ΡΠ΄Π΅Π»ΡΠ΅ΠΌΡΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΈ Π½Π΅ΡΡΡΠΎΠΉΡΠΈΠ²Ρ ΠΏΡΠΈ ΡΠ°ΠΊΠΈΡ
ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ°Ρ
. ΠΠ΅ΠΏΠΎΠ΄Π²ΠΈΠΆΠ½ΡΠ΅ ΡΠ°Π·Ρ Π΄Π»Ρ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ ΠΈΠΌΠ΅ΡΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΡΠΉ ΠΏΡΠ΅Π΄Π΅Π» 350ΒΊΠ‘. Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ
Π²Π΅ΡΠ΅ΡΡΠ² ΠΏΡΠΈ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠΈ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ ΠΎΡΠ½ΠΎΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΈΠΏΠ΅Π½ΠΈΡ Π²Π΅ΡΠ΅ΡΡΠ²Π°. ΠΠΎΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ Π΄ΠΎΡΡΠΈΠ³Π½ΡΡΠΎ ΠΏΡΡΠ΅ΠΌ ΠΎΠ΄Π½ΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ³ΠΎ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΠΏΡΡΠ° (Π΄Π»ΠΈΠ½Ρ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ, ΡΡΠ΅ΠΏΠ΅Π½ΠΈ ΠΏΡΠΎΠΏΠΈΡΠΊΠΈ, ΡΠΊΠΎΡΠΎΡΡΠΈ Π³Π°Π·Π°-Π½ΠΎΡΠΈΡΠ΅Π»Ρ). ΠΠ΄Π½Π°ΠΊΠΎ ΠΏΡΠΈ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠΈ ΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΈΠΏΠ΅Π½ΠΈΡ ΠΊ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ΅ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ Π½Π°Π±Π»ΡΠ΄Π°Π΅ΡΡΡ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΡΠΎΡΠΌΡ ΠΏΠΈΠΊΠ°, Π²ΠΎΠ·ΡΠ°ΡΡΠ°Π½ΠΈΠ΅ Π΅Π³ΠΎ ΡΠΈΡΠΈΠ½Ρ. ΠΠΎΡΡΠΎΠΌΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠ³ΠΎ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΡ Π²ΡΡΠΎΠΊΠΎΠΊΠΈΠΏΡΡΠΈΡ
Π²Π΅ΡΠ΅ΡΡΠ² Π·Π°Π²ΠΈΡΠΈΡ ΠΎΡ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΡ ΠΊΠΎΠ»ΠΎΠ½ΠΊΠΈ ΠΏΡΠΈ ΡΠΎΡ
ΡΠ°Π½Π΅Π½ΠΈΠΈ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠ°Π·Π΄Π΅Π»Π΅Π½ΠΈΡ
ΠΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ Π½Π΅ΠΊΠΎΡΠΎΡΡΡ ΠΊΡΠ΅ΠΌΠ½ΠΈΠΉΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ Π³Π΅ΡΠ΅ΡΠΎΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΈΡ ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ
The preparative gas chromatography method has been used for isolation of heterocyclic organosilicon compounds boiling up to 400o C. The ways are shown for solution of problems which arise in the course of isolation of such high boiling substances.ΠΡΠΎΠ²Π΅Π΄Π΅Π½ΠΎ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΠ΅ ΡΡΠ΄Π° ΠΊΡΠ΅ΠΌΠ½ΠΈΠΉΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
Π³Π΅ΡΠ΅ΡΠΎΡΠΈΠΊΠ»ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΎΠ΅Π΄ΠΈΠ½Π΅Π½ΠΈΠΉ c ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ°ΠΌΠΈ ΠΊΠΈΠΏΠ΅Π½ΠΈΡ Π΄ΠΎ 400 ΠΎ Π‘ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ. ΠΠΎΠΊΠ°Π·Π°Π½Ρ ΠΏΡΡΠΈ ΠΏΡΠ΅ΠΎΠ΄ΠΎΠ»Π΅Π½ΠΈΡ ΠΌΠ΅ΡΠΎΠ΄ΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΡΡΠ΄Π½ΠΎΡΡΠ΅ΠΉ, Π²ΠΎΠ·Π½ΠΈΠΊΠ°ΡΡΠΈΡ
ΠΏΡΠΈ Π²ΡΠ΄Π΅Π»Π΅Π½ΠΈΠΈ ΠΏΠΎΠ΄ΠΎΠ±Π½ΡΡ
Π²Π΅ΡΠ΅ΡΡΠ²
ΠΠ½Π°Π»ΠΈΠ· ΠΏΠΎΠ»ΠΈΠΌΠ΅ΡΠΈΠ»ΡΠ΅Π½ΠΈΠ»ΡΠΈΠ»ΠΎΠΊΡΠ°Π½ΠΎΠ²ΠΎΠΉ ΠΆΠΈΠ΄ΠΊΠΎΡΡΠΈ ΠΠ€ΠΠ‘-5 ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΠΠΠ₯
Polymethylphenylsiloxane liquid PFMS-5 is used as a high temperature heat transfer fluid and a working fluid in the high-vacuum pumps. It is one of the most high-temperature stationary phases in gas chromatography. However, some samples have an upper temperature limit of 280 to 350Β°Π‘. The composition of this fluid was studied by HPLC. For identification a set of compounds isolated by preparative gas chromatography was obtained. A previously synthesized product consisting of linear polymethylphenylsiloxanes with the number of silicon atoms from 3 to 120 was used. By using a diode array detector the UV-spectra of all the components in the obtained chromatogram were recorded. On the basis of these data it can be concluded that the liquid PFMS-5 consists of polymer homologues with the number of silicon atoms from 3 to 13. In addition to linear methylphenyloligosiloxanes methylphenylsiloxanes of other structure are present in the liquid. Linear methylphenyloligosiloxanes were identifiedΠΠΎΠ»ΠΈΠΌΠ΅ΡΠΈΠ»ΡΠ΅Π½ΠΈΠ»ΡΠΈΠ»ΠΎΠΊΡΠ°Π½ΠΎΠ²Π°Ρ ΠΆΠΈΠ΄ΠΊΠΎΡΡΡ ΠΠ€ΠΠ‘-5 ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΡΡΡ ΠΊΠ°ΠΊ Π²ΡΡΠΎΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΡΠΉ ΡΠ΅ΠΏΠ»ΠΎΠ½ΠΎΡΠΈΡΠ΅Π»Ρ, ΡΠ°Π±ΠΎΡΠ°Ρ ΠΆΠΈΠ΄ΠΊΠΎΡΡΡ Π² Π²ΡΡΠΎΠΊΠΎΠ²Π°ΠΊΡΡΠΌΠ½ΡΡ
Π½Π°ΡΠΎΡΠ°Ρ
ΠΈ ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΎΠ΄Π½ΠΎΠΉ ΠΈΠ· ΡΠ°ΠΌΡΡ
Π²ΡΡΠΎΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΡΡ
ΡΡΠ°ΡΠΈΠΎΠ½Π°ΡΠ½ΡΡ
ΡΠ°Π· Π² Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠΈ. ΠΠ΄Π½Π°ΠΊΠΎ Π½Π΅ΠΊΠΎΡΠΎΡΡΠ΅ ΠΎΠ±ΡΠ°Π·ΡΡ ΠΈΠΌΠ΅ΡΡ Π²Π΅ΡΡ
Π½ΠΈΠΉ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΡΠΉ ΠΏΡΠ΅Π΄Π΅Π» ΠΎΡ 280 Π΄ΠΎ 350Β°Π‘. Π‘ΠΎΡΡΠ°Π² ΡΡΠΎΠΉ ΠΆΠΈΠ΄ΠΊΠΎΡΡΠΈ Π±ΡΠ» ΠΈΠ·ΡΡΠ΅Π½ ΠΌΠ΅ΡΠΎΠ΄ΠΎΠΌ ΠΠΠΠ₯. ΠΠ»Ρ ΠΈΠ΄Π΅Π½ΡΠΈΡΠΈΠΊΠ°ΡΠΈΠΈ Π±ΡΠ» ΠΏΠΎΠ»ΡΡΠ΅Π½ Π½Π°Π±ΠΎΡ Π²Π΅ΡΠ΅ΡΡΠ², Π²ΡΠ΄Π΅Π»Π΅Π½Π½ΡΡ
ΠΏΡΠ΅ΠΏΠ°ΡΠ°ΡΠΈΠ²Π½ΠΎΠΉ Π³Π°Π·ΠΎΠ²ΠΎΠΉ Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΡΠΈΠ΅ΠΉ. ΠΡΠ» ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ ΡΠ°Π½Π΅Π΅ ΡΠΈΠ½ΡΠ΅Π·ΠΈΡΠΎΠ²Π°Π½Π½ΡΠΉ ΠΏΡΠΎΠ΄ΡΠΊΡ, ΡΠΎΡΡΠΎΡΡΠΈΠΉ ΠΈΠ· Π»ΠΈΠ½Π΅ΠΉΠ½ΡΡ
ΠΏΠΎΠ»ΠΈΠΌΠ΅ΡΠΈΠ»ΡΠ΅Π½ΠΈΠ»ΡΠΈΠ»ΠΎΠΊΡΠ°Π½ΠΎΠ² Ρ ΡΠΈΡΠ»ΠΎΠΌ Π°ΡΠΎΠΌΠΎΠ² ΠΊΡΠ΅ΠΌΠ½ΠΈΡ ΠΎΡ 3 Π΄ΠΎ 120. Π‘ ΠΏΠΎΠΌΠΎΡΡΡ Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠ° Ρ Π΄ΠΈΠΎΠ΄Π½ΠΎΠΉ ΠΌΠ°ΡΡΠΈΡΠ΅ΠΉ Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π£Ρ-ΡΠΏΠ΅ΠΊΡΡΡ Π²ΡΠ΅Ρ
ΠΊΠΎΠΌΠΏΠΎΠ½Π΅Π½ΡΠΎΠ², ΠΏΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Π½ΡΡ
Π½Π° Ρ
ΡΠΎΠΌΠ°ΡΠΎΠ³ΡΠ°ΠΌΠΌΠ΅. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
Π΄Π°Π½Π½ΡΡ
ΠΌΠΎΠΆΠ½ΠΎ Π·Π°ΠΊΠ»ΡΡΠΈΡΡ, ΡΡΠΎ ΠΆΠΈΠ΄ΠΊΠΎΡΡΡ ΡΠΎΡΡΠΎΠΈΡ ΠΈΠ· ΠΏΠΎΠ»ΠΈΠΌΠ΅ΡΠ³ΠΎΠΌΠΎΠ»ΠΎΠ³ΠΎΠ² Ρ ΡΠΈΡΠ»ΠΎΠΌ Π°ΡΠΎΠΌΠΎΠ² ΠΊΡΠ΅ΠΌΠ½ΠΈΡ ΠΎΡ 3 Π΄ΠΎ 13. ΠΠΎΠΌΠΈΠΌΠΎ Π»ΠΈΠ½Π΅ΠΉΠ½ΡΡ
ΠΎΠ»ΠΈΠ³ΠΎΡΠΈΠ»ΠΎΠΊΡΠ°Π½ΠΎΠ² Π² ΠΆΠΈΠ΄ΠΊΠΎΡΡΠΈ ΠΏΡΠΈΡΡΡΡΡΠ²ΡΡΡ ΠΌΠ΅ΡΠΈΠ»ΡΠ΅Π½ΠΈΠ»ΡΠΈΠ»ΠΎΠΊΡΠ°Π½Ρ Π΄ΡΡΠ³ΠΎΠ³ΠΎ ΡΡΡΠΎΠ΅Π½ΠΈΡ. ΠΠΈΠ½Π΅ΠΉΠ½ΡΠ΅ ΠΌΠ΅ΡΠΈΠ»ΡΠ΅Π½ΠΈΠ»ΠΎΠ»ΠΈΠ³ΠΎΡΠΈΠ»ΠΎΠΊΡΠ°Π½Ρ Π±ΡΠ»ΠΈ ΠΈΠ΄Π΅Π½ΡΠΈΡΠΈΡΠΈΡΠΎΠ²Π°Π½Ρ
Facilitating Memory for Novel Characters by Reducing Neural Repetition Suppression in the Left Fusiform Cortex
Gui Xue is with Beijing Normal University and University of Southern California, Leilei Mei is with Beijing Normal University and University of California Irvine, Chuansheng Chen is with University of California Irvine, Zhong-Lin Lu is with University of Southern California, Russell A. Poldrack is with UT Austin, Qi Dong is with Beijing Normal University.Background -- The left midfusiform and adjacent regions have been implicated in processing and memorizing familiar words, yet its role in memorizing novel characters has not been well understood. Methodology/Principal Findings -- Using functional MRI, the present study examined the hypothesis that the left midfusiform is also involved in memorizing novel characters and spaced learning could enhance the memory by enhancing the left midfusiform activity during learning. Nineteen native Chinese readers were scanned while memorizing the visual form of 120 Korean characters that were novel to the subjects. Each character was repeated four times during learning. Repetition suppression was manipulated by using two different repetition schedules: massed learning and spaced learning, pseudo-randomly mixed within the same scanning session. Under the massed learning condition, the four repetitions were consecutive (with a jittered inter-repetition interval to improve the design efficiency). Under the spaced learning condition, the four repetitions were interleaved with a minimal inter-repetition lag of 6 stimuli. Spaced learning significantly improved participants' performance during the recognition memory test administered one hour after the scan. Stronger left midfusiform and inferior temporal gyrus activities during learning (summed across four repetitions) were associated with better memory of the characters, based on both within- and cross-subjects analyses. Compared to massed learning, spaced learning significantly reduced neural repetition suppression and increased the overall activities in these regions, which were associated with better memory for novel characters. Conclusions/Significance -- These results demonstrated a strong link between cortical activity in the left midfusiform and memory for novel characters, and thus challenge the visual word form area (VWFA) hypothesis. Our results also shed light on the neural mechanisms of the spacing effect in memorizing novel characters.This study was supported by the Program for New Century Excellent Talents in University, the National Science Foundation (grant numbers BCS 0823624 and BCS 0823495), the National Institute of Health (grant number HD057884-01A2), and the 111 Project of China (B07008). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Psycholog
Challenges for Allergy Diagnosis in Regions with Complex Pollen Exposures
Over the past few decades, significant scientific progress has influenced clinical allergy practice. The biological standardization of extracts was followed by the massive identification and characterization of new allergens and their progressive use as diagnostic tools including allergen micro arrays that facilitate the simultaneous testing of more than 100 allergen components. Specific diagnosis is the basis of allergy practice and is always aiming to select the best therapeutic or avoidance intervention. As a consequence, redundant or irrelevant information might be adding unnecessary cost and complexity to daily clinical practice. A rational use of the different diagnostic alternatives would allow a significant improvement in the diagnosis and treatment of allergic patients, especially for those residing in complex pollen exposure areas
- β¦