The effects of emission trading system on corporate innovation and productivity-empirical evidence from China's SO2 emission trading system.

Emission trading system is a significant market-based environmental regulation tool worldwide. This study fills existing knowledge gap on whether ETSs have "weak" and "strong" version of Porter hypothesis effects in China, by examining the effects of the Chinese SO2 emission trading on corporate innovation and productivity. Using the micro-data of domestic-listed manufacturing companies from 2004 to 2015, this study regarded China's SO2 emission trading system as a quasi-natural experiment by applying a difference-in-difference framework to eliminate endogenous problems. It was found that the SO2 emission trading system significantly promoted corporate innovation but did not have a significant effect on corporate productivity. The cause analysis showed that suboptimal institutional context and lack of corporate dynamic response led to the failure of strong Porter hypothesis effect. In addition, small- and medium-sized enterprises and non-state-owned enterprises gained greater innovation compensation effects of the emission trading system. This research believed that, the design, institutional context, and market incentives of emission trading systems need to be improved from the top down, to achieve the dual goal of environmental sustainability and economic growth.

Sample-Sample Correlation Asynchronous Spectroscopic Method Coupled with Multivariate Curve Resolution-Alternating Least Squares To Analyze Challenging Bilinear Data.

An approach to construct a secondary asynchronous spectrum via sample-sample correlation (SASS) is proposed to analyze bilinear data from hyphenated spectroscopic experiments. In SASS, bilinear data is used to construct a series of two-dimensional (2D) sample-sample correlation spectra. Then a vertical slice is extracted from each 2D sample-sample correlation spectrum so that a secondary 2D asynchronous spectrum is constructed via these slices. The advantage of SASS is demonstrated by a model system with the following challenging situations: (1) Temporal profiles of different components severely overlap, making spectra of pure components difficult to directly obtain from either original bilinear data or multivariate curve resolution-alternating least squares (MCR-ALS) with non-negativity and unimodality constraints. (2) Every peak in the spectra of the eluted samples contains contributions from at least two components. Hence, two-dimensional correlation spectroscopy (2D-COS) and n-dimensional (nD) asynchronous spectroscopic method developed in our previous work, which previously worked so well, are now invalid. SASS managed to reveal different groups of systematic absences of cross peaks (SACPs) that reflect the lack of spectral contributions of different components at different regions in the second asynchronous spectrum. Spectra of different components can still be faithfully retrieved via MCR-ALS calculation using constraints revealed by different groups of SACPs. The results demonstrate that implicit but intrinsic information revealed by SASS is indispensable in solving challenging bilinear data as the model system. We applied SASS on two real-world examples from thermogravimetry-Fourier transform infrared spectroscopy (TG-FT-IR) experiments of mixtures (H2O/HOD/D2O and H2O/isopropanol/pyridine). FT-IR spectra of different components were successfully recovered. Moreover, FT-IR spectrum of HOD, which is difficult to obtain, was successfully extracted. SASS can be applied in the analysis of gaseous mixtures from TG-FT-IR experiment and a combination of quantum cascade lasers with substrate-integrated hollow waveguides in environmental monitoring and biomedical diagnosis. Furthermore, SASS is also useful in various advanced hyphenated spectroscopic experiments.

A novel systematic absence of cross peaks-based 2D-COS approach for bilinear data.

A novel approach to use two-dimensional correlation spectroscopy (2D-COS) to analyze bilinear data is proposed. A phenomenon called Systematic Absence of Cross Peaks (SACPs) is observed in a 2D asynchronous spectrum. Two theorems relevant to SACPs have been derived. The SACP-based 2D-COS method has been successfully applied on analyzing bilinear data from mixed samples (including one model system and two real systems). Implicit isolated peaks can be identified and assigned to different components based on characteristic pattern of SACPs even if the time-related profiles of different components are severely overlapped. Based on the results of SACPs, spectra of pure components can be retrieved. Identification of SACPs can still be achieved in the presence of artifacts. Thus, neither noise nor baseline drift can produce significant influence on the results obtained from the approach described in this paper. We have used several well-established chemometric methods, including N-Findr, VCA, and MCR with various initial settings, on two systems that can be successfully solved using the 2D-COS method. The chemometric methods mentioned above cannot provide correct spectra of pure components because of severe problem of rotational ambiguity derived from severe overlapping of the time-related profiles. Only when the information from SACPs in 2D-COS is used as additional constraints in MCR calculation, correct spectra can be obtained. That is to say, the SACP-based 2D-COS method provides intrinsic information which is crucial in the analysis of chromatographic-spectroscopic and analogous data even if the time-related profiles of different components overlap severely.

Two-dimensional correlation spectroscopic studies on coordination between organic ligands and Ni2+ ions.

3A2g→3T1g(P) transition band of Ni2+ is used to probe the coordination of Ni2+. Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design (DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g→3T1g(P) transition band of Ni2+ are utilized to probe coordination between Ni2+ and various ligands. We studied the spectral behavior of the 3A2g→3T1g(P) transition band when Ni2+ is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2+ and galactitol is also investigated. Although no clearly observable change is found on the 3A2g→3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2+ and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g→3T1g(P) transition band of Ni(galactitol)x2+ is considerably different from those of Ni(H2O)62+. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.

[On the Tributylphosphate-Based Super-Concentrated HCl System].

We reported a new super-concentrated hydrochloric acid system prepared by using tri-n-butyl phosphate (TBP)-constructed reversed micelles at ambient temperature and pressure. According to the titration result, the molar ratio of H+ to H2O (denoted as nH+/nH2O) in the super-concentrated HCl range from 0.50 to 1.50 which are higher than that in saturated aqueous HCl bulk solution (0.28). Significant a moment of hydrochloric acid is confined in W/O reversed micelles. Therefore, the behavior and status of HCl are different from those of conventional bluk solution. FTIR spectroscopic results demonstrate that a significant amount of HCl remains in the molecular form rather than being ionized into H+ and Cl-. Thus, super-concentrated HCl provides an extraordinary chemical environment which may have significant influence on certain substances. We found that the color of the solution is reddish brown when copper ion is dissolved in super-concentrated HCl, while the color of the saturated HCl aqueous solution (37 Wt%) containing copper ion is green. That is to say, the copper ions exist in a special state under the unique chemical environment of super-concentrated HCl. UV-Vis-NIR spectra indicate that both d-d transition band and charge transfer transition band of copper ions in super-concentrated HCl solution underwent significant variations. In addition, copper ions also have obvious influence on the hydrogen bond network among HCl in the super-concentrated HCl solution. Remarkable variation is introduced in the H-Cl stretching band in FTIR spectra.

[Influence of Concentration Sequence on the Signal-to-Noise Ratio of Cross Peaks of 2D Asynchronous Spectra Generated by Using the DAOSD Approach].

In the present work, computer simulation was performed on a model chemical system where two solutes (denoted as P and Q, respectively) are dissolved in the same solution. Under intermolecular interaction between P and Q, part of P undergoes subtle structural variation and converts into U while part of Q converts into V. The strength of intermolecular interaction can be characterized by the corresponding equilibrium constant K. Our preliminary studies indicate that the S/N ratio of cross peak increases considerably as n increases. Moreover, the S/N ratio of the cross peak from the asynchronous spectra can be improved significantly when the suitable concentrations of P and Q are adopted. This work is helpful for a selection of suitable concentration sequence to maximize S/N ratio of cross peaks in the 2D asynchronous spectra generated by using the DAOSD approach proposed in our previous study so that weak intermolecular interaction can be probed.

[Studies on carbonization of saccharides by using aqueous solution of various acids].

The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol · L(-1) acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease compared with pure 2-deoxy-ribose and fructose. In the XPS spectra, the is peaks of 2-deoxy-ribose, strong sub peak at 286. 05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C is peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1 600 cm(-1), indicating that C==C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency.

Dipole-dipole interactions in solution mixtures probed by two-dimensional synchronous spectroscopy based on orthogonal sample design scheme.

Two-dimensional (2D) synchronous spectroscopy together with a new approach called "Orthogonal Sample Design Scheme" was used to study the dipole-dipole interactions in two representative ternary chemical systems (N,N-dimethyllformamide (DMF)/CH3COOC2H5/CCl4 and C60/CH3COOC2H5/CCl4). For the first system, dipole-dipole interactions among carbonyl groups from DMF and CH3COOC2H5 are characterized by using the cross peak in 2D Fourier Transform Infrared Radiation (FT-IR) spectroscopy. For the second system, intermolecular interaction among π-π transition from C60 and vibration transition from the carbonyl band of ethyl acetate is probed by using 2D spectra. The experimental results demonstrate that "Orthogonal Sample Design Scheme" can effectively remove interfering part that is not relevant to intermolecular interaction. Additional procedures are carried out to preclude the possibilities of producing interfering cross peaks by other reasons, such as experimental errors. Dipole-dipole interactions that manifest in the form of deviation from the Beer-Lambert law generate distinct cross peaks visualized in the resultant 2D synchronous spectra of the two chemical systems. This work demonstrates that 2D synchronous spectra coupled with orthogonal sample design scheme provide us an applicable experimental approach to probing and characterizing dipole-dipole interactions in complex molecular systems.

Detection of gastric cancer with Fourier transform infrared spectroscopy and support vector machine classification.

Early diagnosis and early medical treatments are the keys to save the patients' lives and improve the living quality. Fourier transform infrared (FT-IR) spectroscopy can distinguish malignant from normal tissues at the molecular level. In this paper, programs were made with pattern recognition method to classify unknown samples. Spectral data were pretreated by using smoothing and standard normal variate (SNV) methods. Leave-one-out cross validation was used to evaluate the discrimination result of support vector machine (SVM) method. A total of 54 gastric tissue samples were employed in this study, including 24 cases of normal tissue samples and 30 cases of cancerous tissue samples. The discrimination results of SVM method showed the sensitivity with 100%, specificity with 83.3%, and total discrimination accuracy with 92.2%.

(Butane-1,2,3,4-tetraol-κ(3) O (1),O (2),O (3))(ethanol-κO)tris-(nitrato-κ(2) O,O')erbium(III).

In the title Er(III)-erythritol complex, [Er(NO3)3(C2H5OH)(C4H10O4)], the Er(III) cation is chelated by one erythritol mol-ecule, three nitrate anions and an ethanol mol-ecule, completing an irregular ErO10 coordination geometry. The Er-O bond lengths are in the range 2.348 (3)-2.583 (3) Å. In the crystal, extensive O-H⋯O hydrogen bonding links the mol-ecules into a three-dimensional supra-molecular structure.

[(2R,3S)-Butane-1,2,3,4-tetraol-κ(3) O (1),O (2),O (3)](ethanol-κO)tris-(nitrato-κ(2) O,O')samarium(III).

The title Sm(III)-erythritol complex, [Sm(NO3)3(C2H6O)(C4H10O4)], is isotypic with its Nd, Eu, Y, Gd, Tb and Ho analogues. The Sm(III) cation exhibits a coordination number of ten and is chelated by a tridentate erythritol ligand and three bidentate nitrate anions. It is additionally coordinated by an O atom of an ethanol mol-ecule, completing an irregular coordination sphere. The Sm-O bond lengths range from 2.416 (2) to 2.611 (2) Å. In the crystal, extensive O-H⋯O hydrogen bonding involving all hy-droxy groups and some of the nitrate O atoms links the mol-ecules into a three-dimensional network.

[Investigation of nascent polypropylene in-reactor alloy particles].

Heterogeneous nascent particles were observed in a pilot product of polypropylene in-reactor alloy, which was polymerized by Ziegler-Natta/Metallocene hybrid catalyst using Spheripol technology. Most of the particles in the product are translucent, and opaque particles were observed as well. The differences in morphology, composition, chain structure, thermal properties and mechanical properties between these two kinds of particles were investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), polarized optical microscopy (POM), and differential scanning calorimetry (DSC) techniques. The results of FTIR, NMR and SEM indicate that different morphology of these two different particles is caused by different content of ethylene-propylene copolymers. The results of DSC and POM showed that the translucent particles has higher crystallization rate than opaque particles due to the presence of ethylene-propylene copolymers. The mechanical properties results showed that the impact resistance property of opaque particles is obviously lower than that of translucent particles, while its tensile strength and bending modulus are much higher than that of translucent particles. Based on the process of Spheripol technology, a preliminary explanation for the formation of different nascent PP in-reactor alloy particles is proposed.

(Butane-1,2,3,4-tetraol-κ(3) O (1),O (2),O (3))(ethanol-κO)tris-(nitrato-κ(2) O,O')holmium(III).

In the title Ho(III)-erythritol complex, [Ho(NO3)3(C4H10O4)(C2H5OH)], the Ho(III) cation is chelated by a tridentate erythritol ligand and three bidentate nitrate anions. An ethanol mol-ecule further coordinates the Ho(III) cation, completing the irregular O10 coordination geometry. In the crystal, an extensive O-H⋯O hydrogen-bond network links the mol-ecules into a three-dimensional supra-molecular structure.

[Application of FTIR spectrometry to monitoring chemosensitivity of breast cancer cell line using 5-FU].

The purpose of the present study was to compare the changes of infrared spectrum of breast cancer cell line MCF-7 treated by 5-fluorouracil with various concentrations and treating time. The results indicate that the relative intensity ratios of I2 920/I1 460 increased in the FTIR spectra of cell line MCF-7 while I1 400/I1 460, I1 080 /I1 550 and I1 240/I1 550 decreased significantly within forty-eight hours, however, no regular change was observed during 48-72 hours. The relative intensity ratio of I1 640/ I1 550 decreases along with the increase in the concentration of 5-fluorouracil. The changes of infrared spectra are consistent with the biochemical changes in breast cancer cell, and it can be the reference designators when assessing curative effect of breast cancer cell by FTIR spectrometry.

[Label-free monitoring 5-FU induced SW 620 cells apoptosis using FTIR microspectroscopy].

The aim of the present study was to evaluate Fourier transform infrared spectroscopy (FTIR) monitoring of biochemical changes in apoptosis cells. Different concentrations of 5-fluorouracil (5-FU) treated colon cancer cell lines SW620 were used to determine the optimum concentration of 5-FU IC50 by means of MTT assay. Cell starvation and 5-Fu synergistic cell cycle arrest was in G1 and S phase. FTIR combined with flow cytometry was applied to analysis of SW 620 cells and SW620 cells treated with 5-FU for 12h, 24h (early apoptosis) and 48 h (late apoptosis) respectively. The peak position and the intensity of all bands were measured and comparison was made between the SW620 and apoptotic SW620 cells. Apoptosis cells have following characteristics compared with SW620 cells (1) The band at 1 740 cm-1 is an C=O stretching vibration. Changes in these bands can reflect lipid changes, and relative peak intensity ratio 11740/11460 significantly increased (p<0. 05), indicating that the relative contents of lipid in apoptosis cells increased. (2) The band at the 1 410 cm-1 peak represents that C-H stretching related was increased to amino acid residues and shifted to higher wave numbers compared to other groups. I1410o/I 460 at early and late death phase was significantly increased, which suggests that the relative contents of amino acid residues in apoptosis cells increased (p <0. 05). New vibrational bands at 1 120 cm-1 appeared at 24 h and increased at 48 h compared with other groups. The 1 120 cm-1 absorption band is mainly due to ser, serine and threonine C-O(H) stretching vibration, and I1120/I 1460 significantly increased (p<0. 05), indicating that the relative quantity of amino acid residues in apoptosis cells increased due to that DNA unwinds the double helix. (3) 1 240 cm-1 is mainly due to the asymmetric stretching modes of phosphodiester groups shifting to higher wave number, illustrating that nucleic acid conformation was changed in apoptosis cells. (4) The band 1 040 cm-1 associated with polysaccharide appeared at 24 and 48 h, meanwhile shifted to higher wave number, suggesting that polysaccharide decreased in late apoptotic cells, and I 1040/I1400 increased at late stage apoptosis, indicating that the relative content of polysaccharide in apoptosis cells increased. The authors' results suggest that FTIR applied to monitoring SW620 cells apoptosis may be as a potential diagnostic tool for cancer chemotherapy monitoring.

[Synthesis and characterization of chromium doped Y3Al5O12 compound pigment].

The authors synthesized a new kind of green pigment via co-precipitation method by doping Y3Al5O12 with Cr+. The size of the pigment particles is around 200 nm as observed under scanning electron microscope. XRD results demonstrate that the pigment crystalline form of the pigment is yttrium alluminium garnet. UV-Vis spectra were used to investigate the coordination states and transition behavior of the doping ions. In addition, the colour feature was measured by CIE L* a* b* chroma value. The pigment was blended with polypropylene and then polypropylene fiber was produced using the polypropelene-pigment composite via molten spinning process. The distribution of the pigment particles in the polypropylene fibers was characterized by Xray computed tomography (CT) technique on the Beijing synchrotron radiation facility. The result states that the composite oxide pigment particles are homogeneously dispersed in the polypropylene fibers. The pigments are stable, non-toxic to the environment, and may be applied in non-aqueous dyeing to reduce waste water emitted by textile dyeing and printing industry.

[The analysis for silver iodide fine particles of TLC/FTIR matrix].

In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use AgI fine particles as stationary phase of TLC plate. The reasons are as follows: Silver iodide fine particles have no absorbance in an IR region between 4 000 and 800 cm(-1), therefore, the interference caused by IR absorption of stationary phase can be removed. Moreover, silver iodide is stable and insolvable in water and organic solvents and thus it will not be destroyed by mobile phase or react with samples during the TLC separation. To improve TLC separation efficiency and quality of FTIR spectra during the TLC/FTIR analysis, the size of AgI particles should be below 500 nm. We used orthogonal design approach to optimize the experimental condition to AgI particles so that the average size of AgI particles is around 100 nm. No absorption of impurity or adsorbed water were observed in FTIR spectrum of the AgI particles the authors used "settlement volatilization method" to prepare TLC plate without using polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using AgI fine particles as stationary phase can separate mixtures of rhodamine B and bromophenol blue successfully. Applications of silver iodide fine particles as stationary phase have bright perspective in the development of in-situ TLC/FTIR analysis techniques.

[Synthesis and characterization of mixed metal oxide pigments].

In the present work, aluminum chloride and various soluble salts of doping ions were dissolved in water. In addition, urea and polyvinyl pyrrolidone (PVP) were also dissolved in the above aqueous solution under supersonic treatments. Then the solutions were heated to induce the hydrolysis of urea so that soluble aluminum and doping ions convert into insoluble hydroxide or carbonate gels. After calcinations, the obtained gels change to mixed metal oxide pigments whose color is related to type and concentrations of the doping ions. XRD characterization demonstrates that the diffraction patterns of the products are the same as that of alpha-alumina. Diffuse reflectance spectra of samples of the samples in UV-Vis regions show that the absorption bands for d-d transitions of the doping ions undergo considerable change as the coordinate environments change. In addition, L*, a* and b* values of the pigments were measured by using UV-Vis densitometer. SEM results indicate that the size of the pigment powders is in the range 200-300 nm. The pigments are quite stable since no evidence of dissolution was observed after the synthesized pigment is soaked for 24 hours. ICP test shows that very little amount of doped metal occurs in the corresponding filtrate. The above results suggest that these new kinds of mixed metal oxide pigments are stable, non-toxic, environmental friendly and they may be applicable in molten spinning process and provide a new chance for non-aqueous printing and dyeing industry.

Identification of colitis and cancer in colon biopsies by Fourier Transform Infrared spectroscopy and chemometrics.

Cancer is a disease that does great harms to the health of human beings. FT-IR spectroscopy could identify variability at the molecular level in biological specimens. It is a rapid and noninvasive method, which could be used intraoperatively to modify surgical procedures. The aim of this paper is to identify and separate cancer from colitis in endoscopic colon biopsies through the use of FT-IR spectroscopy. A total of 88 endoscopic colon samples, including 41 cases of colitis and 47 cases of colon cancer, were obtained. Specimens were placed on an ATR accessory linked to FT-IR spectrometer with a MCT detector for greater stability and sensitivity. Later, specimens were sent for the histological examination as the reference in the spectral analysis. 41 colitis and 47 cancer specimens were compared. Spectra preprocessed with smoothing and normalization were used for discrimination analysis. PCA was processed to simplify the spectrum data set. Naive Bayes classifier model was constructed for diagnostic classification. Leave-one-out cross-validation method was utilized to assess the discrimination results. The sensitivity of FT-IR detection for cancer achieves 97.6%. The results showed that colon cancer could be distinguished from colitis with high accuracy using FT-IR spectroscopy and chemometrics.

[Investigation of thermal behaviors of γ-form nylon 6 prepared by ammonia vapor from phosphoric acid solutions].

In the present work, we prepared nylon 6 crystals via crystallization of nylon from phosphoric acid by using the vapors of ammonium hydroxide as a precipitation regent. Both XRD and FTIR results demonstrate that the obtained nylon 6 sample exhibit characteristic peaks of nylon 6 in gamma form. In addition, treatment of nylon 6 in boiling water for half an hour followed by FTIR and XRD characterization shows that the obtained nylon 6 sample is in gamma form rather than in meta-stable b form. DSC characterization indicates that the nylon 6 sample exhibits two melting peaks (213 and 220 degrees C) when the sample is heated at a heating rate of 10 degrees C x min(-1). The reason for this phenomenon is that the nylon 6 sample has different lamellar thickness. To investigate the thermal behavior of the nylon 6 sample, the sample underwent the following thermal treatment procedure. First, the sample was heated to a pre-set temperature (T(s)) and kept at that temperature for an hour. Subsequently, the sample was cooled down to 100 degrees C at a cooling rate of 1 degrees C x min(-1), and then cooled down to room temperature at a cooling rate of 10 degrees C x min(-1). The treated samples were characterized by FTIR and DSC method. Experimental results show that the treated nylon 6 samples exhibit different crystalline behavior. When T. ranges from 130 to 160 degrees C, no significant changes were observed. When T(s) is 170 degrees C, a small fraction nylon 6 crystals is destroyed and recrystallized into thin lamellae in a form. As a result, a pre-melting peak appears in DSC result. The pre-melting peak moves to higher temperature and its peak area increases significantly upon increasing T(s) from 170 to 198 degrees C. When T(s) amounts to 200 degrees C, the pre-melting peak and the melting peaks 213 degrees C merge into one melting peak and two melting peaks are observed at 212 and 220 degrees C in the DSC results. FTIR spectra indicate that significant amount of crystalline nylon 6 in a form appears but the majority of crystalline phase of the sample is still gamma phase. As T(s) increases from 200 to 209 degrees C, the melting peak at lower temperature moves to higher temperature with increasing its peak area. On the other hand, the melting peak at 220 degrees C decreases in intensity but does not show any peak shift. As T(s) reaches 209 degrees C, the two melting peaks merge into one peak and FTIR results demonstrate that nylon 6 in a form becomes dominate phase in the sample. In the whole heat-treatment process, the gamma phase nylon 6 sample began to transform to a phase at the heat-treatment temperature of 170 degrees C, which is far below the melting point of the original sample (221 degrees C). This is different from the results reported in the literature, which state that gamma phase nylon 6 will not transform to alpha-phase until nylon is melt.