Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: mechanizmy retencji

Sortuj według:

Ogranicz wyniki do:

Retention efficiency of vegetative filter strips for nitrogen in Danjiangkou Reservoir area, Central China

Lei Junshan, Chen Jiazhou, Yin Wei

Ecological Chemistry and Engineering. S

2019

Vol. 26, nr 2

279--297

To investigate the retention efficiency and mechanism of nitrogen of Vegetative filter strips (VFSs) in the Danjiangkou Reservoir area, simulated runoff discharging experiments were carried out in a new-established Bermuda VFS. The results showed that the Bermuda VFS reduced 73.1-86.1 % of surface runoff through infiltration. The outflow rate of runoff increased first and then became stable with time. The concentration reduction rates (CRRs) and load reduction rates (LRRs) of NH3-N increased initially and then decreased with the increase of inflow concentration. The average CRRs and LRRs of NH3-N in three treatments ranged 66.1-90.3 % and 90.0-96.7 %, respectively. The concentration reduction of NH3-N was primarily achieved by soil adsorption. The optimal inflow concentration of NH3-N for the optimum CRR was between 0.65 and 3.52 mg/dm3. The CRRs and LRRs of NO3-N fluctuated between 6.8-14.0 % and 72.0-77.9 % in three treatments. The concentration reduction of NO3-N was primarily achieved by plant uptake and soil microbe assimilation. The optimal inflow concentration of NO3-N for optimum CRR exceeded 6.78 mg/dm3. The CRRs and LRRs of TN increased with the increase of inflow concentrations. The average CRRs in the low, moderate and high treatments reached 9.7, 14.8 and 27.4 %, respectively, and the average LRRs reached 72.1, 74.3 and 81.2 %, respectively. The optimal inflow concentration of TN for optimum CRR exceeded 10.21 mg/dm3. The study showed that Bermuda grass can retain nitrogen in runoff efficiently and should be promoted around the Danjiangkou reservoir.

Progress in the liquid chromatography of synthetic non-charged lipophilic macromolecules

Berek D.

Polimery

2001

T. 46, nr 11-12

777-784

A review with 30 refs. covering high-performance liquid chromatography (HPLC) as a tool to determine molecular properties (mainly M and MWD) of synthetic polymers, with particular reference to retention mechanisms (entropy-based size exclusion, and enthalpy-based adsorption, partition and phase separation). Further size-exclusion chromatography (SEC) for lipophiles (gel permeation chromatography) and biopolymers (gel filtration chromatography), coupled LC procedures (e.g., isocratic compensation approach), HPLC under "critical" (weak enthalpic interactions) conditions (LCCC), (continuous) eluent gradient polymer LC (EGPLC), LC-like approaches including the full adsorption-desorption technique, and multidimensional HPLC of complex polymers are discussed. Instrumentation (e.g., detectors), pumps, materials, and applications of analytical HPLC for polymers (evaluation of long chain branching, radius of gyration, limiting viscosity number, etc.) are also briefly reviewed.

Dokonano przeglądu podstaw i rozwoju wysoce sprawnej chromatografii cieczowej (HPLC). Omówiono w związku z tym mechanizmy retencji zdominowane przez oddziaływania entropowe oraz entalpowe (i związane z tym typy HPLC), chromatografię rozdziału na podstawie wymiarów cząsteczek (SEC) w odniesieniu do polimerów lrpolilowyćh i MOpOlilflG1-rów, techniki sprzężone (np. z zastosowaniem kompensacji izokratycznej), HPLC w warunkach słabych oddziaływań entalpowych ("krytycznych") i ciągłego gradientu eluenta, wielowymiarową HPLC w zastosowaniu do polimerów kompleksowych i inn. Naszkicowano zagadnienia dotyczące oprzyrządowania (pompy, detektory, materiały) oraz wymieniono właściwości, które określa się metodą chromatografii cieczowej, np. ciężar cząsteczkowy i jego rozkład, rozgałęzienia długołańcuchowe, promień bezwładności (radius of gyra-tion) lub graniczna liczba lepkościowa.